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PROCMT User's guide - Metronix Geophysics

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1. 1 2 1 Main Window Sonfiguration Gresentation Pajameters Bnalys is Services Filename Equip SiteID Chan Site JMTO3ALL GMS0S jmto 5 Cal Ref N window Blocks sel On 29 ors 2158 Dio 99 02 02 Date Thursday 29 05 1997 Bal Bd2 Bd3 Bd4 Bas Time 09 16 11 Coh F 0 70 0 70 0 70 0 70 0 70 ProcMT V2 0b c 94 96 METRONIX Germany Radius M L L L Figure 1 1 Main window of PROCMT with menu bar The upper part of the screen shows the menu bar The menu will be described in detail later The rest of the screen represents the main window in which the most important information about the measurement data is displayed Additional information about the station and channel configuration can be seen via the Configuration menu In the upper third of the main window the most important information about the time series which has been read in is displayed The user can see the filename of the time series file without extension and the type of measurement system MMSO3e or GMSO5 It follows the name of the recording site the number of the channels connected and finally information about the measured bands The four lines content the local site RTS file with calibration file and the RTS and CAL file of the reference site for remote reference is metronix 16 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program The status information about the band requires some further explanation T
2. EP gid bzw fir j l N 3 48 w max x min x 0 9 1 The iteration stops when Fe lt Fler x 3 49 The searched is then Ee is 3 50 is metronix 81 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 2 0N 1 F e lt F 1 02 Y 0 5 en a e 2E 1 02 0 gt Enu K e F e lt F 0 98 Figure 3 8 Flow chart of the algorithm to determine g according to HAJAGOS 80 An efficient algorithm to determine g is proposed by HAJAGOS 80 Figure 3 9 shows the method in a flow chart 3 2 5 2 Weighted Average of the Transfer Function In contrast to all other methods here the coherencies are not used It is assumed that a distortion will influence the computed transfer function and cause a deviation outlier Therefore at first a weighted average of the transfer functions is computed and after that with the same weights a weighted average of the spectral matrices in metronix 82 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis At first a simple average is computed from all transfer functions Gp Gy 3 51 i l b b 3 52 i l ed ZX i YY YX ik ZY Oi h Tre x x 7 3 53 XX ix YY XY YX ix as ZY XXi T XY ZX i b 3 54 n XXi YY 2 XV YX with XXi XY WY os ZY ZX E
3. 1993 Description of the Format for the Calibration File FCT GMS05 Metronix GmbH Braunschweig 1993 Oppenheim Alan V Schafer Ronald W Zeitdiskrete Signalverarbeitung Oldenbourg Verlag Miinchen Wien 1992 99 100 28 08 02 Rev 2 1 PMT21_E2 doe RITTER 88 SCHMUCKER 85 STEINER 80a STEINER 80b SUTARNO 89 SWIFTI85 VOZOFF 85 is metronix Literature Ritter Oliver Auswertung von Audiomagnetotellurik Registrierungen auf der Insel Milos Diplomarbeit am Institut f r Geophysiklische Wissentschaften FU Berlin 1988 Schmucker U Vorlesungsschrift an der Universitat Gottingen Institut fiir Geophysik Gottingen 1985 Steiner F M Fitting Fitting According to the Most Frequent Value and its Comparison with the Method of Least Squares Acta Geodaet Geophys et Montanist Acad Sci Hung Tomus 15 1 pp 37 44 1980 Steiner F Cserny k L Practical Computation of the Most Frequent Value of Data Systems Acta Geodaet Geophys et Montanist Acad Sci Hung Tomus 15 1 pp 59 73 1980 Sutarno D Vozoff K Robust M estimation of Magnetotellutic Impedance Tensors Exploration Geophysics 1989 20 383 398 Swift Charles M A Magnetotelluric Investgation of Electrical Conductivity Anomaly in the SouthwesternUnited States Society of Exploration Geophysicists Magnetotelluric Methods pp 156 166 1985 Vozoff Keeva The Magnetotelluric Method in the Exploration of S
4. The cursor keys gt and lt will switch to the next resp previous section of the time series The number of the section displayed and the total number of all sections will be shown in the status display in metronix 43 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 4 9 Jump Five Time Series Slices PgUp Pgdn scroll five blocks This option allows to jump to the next or to the previous five section using the PgUp and PgDn keys 1 3 4 10 First Time Series Slice Pos 1 select first block Pressing the HOME key will display the first slice of a time series 1 3 4 11 Last Time Series Slice Ende select last block Pressing the END key will display the last slice of a time series 1 3 5 Special Functions 1 3 5 1 Change of Menu Bar M change menu Pressing the M key will switch from the first to the second from the second to the third or from the third to the first menu bar This is necessary as the high amount of functions implemented in the display mode cannot be explained on only one menu bar 1 3 5 2 Screen Hardcopy Alt H hard copy Copies the contents of the display into a file The precise data format is given in the Metronix manual File Formats The file will be written into the directory which has been defined with the PROCMTDIR environment variable Up to 99 screen hardcopies are possible and they are named with PROCMTTS HOI to PROCMTTS H99 These files can be printed on
5. 4 channel 5 channel 6 channel 7 channel 8 The highest frequencies of the bands are The phase offset for other frequencies than the highest frequency of a band is AQ AQ frequency HFreq band in metronix 97 100 28 08 02 Rev 2 1 PMT21_E2 doc Literature Literature BENDAT 71 BEST 91 BRIGHAM 92 CLARK 85 ELLINGHAUS 93 EGBERT 86 FERENCZY 80 is metronix Bendat Julius S Piersol Allan G Random Data Analysis and measurement procedures Wiley Intersience Los Angeles 1971 Best Roland Digitale Me wertverarbeitung Oldenbourg Verlag M nchen 1991 Brigham Elbert Oran FFT schnelle Fourier Transformation 5 Auflage Oldenbourg Verlag M nchen 1992 J Cark T D Gamble W M Goubau R H Koch and R F Miracky Remote Reference Magnetotelluric Equipment and Procedures Society of Exploration Geophysicists Magnetotelluric Methods pp 556 575 1985 A Ellinghaus Entwurf und Realisierung eines Systems f r die Analyse von Me daten des erdelektrischen und erdmagnetischen Feldes Diplomarbeit Technische Universit t Braunschweig Institut f r Geophysik und Meteorologie Braunschweig 1993 Egbert Gary D Booker John R Robust Estimation of Geomagnetic Transfer Functions Geophys J R astr Soc 1986 87 173 194 Ferenczy L M Fitting in the Processing of Magnetotelluric Data Acta Geodaet Geophys et Montanist Acad Sci Hung Tomus 15 1 pp 45 58 198
6. Due to that reason for each measurement and for all target frequencies different thresholds have to be fixed in order to obtain optimum results Note With the menu Estimate SPM Coh Threshold this method of stacking can be selected Whereby the coherency factors c will be determent by the factors which are displayed at the right lower edge of the main window 3 2 4 3 Selection by Adaptive Coherency Threshold Mathematically this method can be described as a simple coherency threshold method 3 32 3 33 with the following iteration algorithm to determine the threshold c 0 c 1 0 G Gi D 24 cy c 0 01 The iteration stops as soon as in metronix 76 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis yi ps i gt n 3 35 with ie l n c c and f factorofbandb In order to avoid the disadvantages of the coherency threshold method not the coherency threshold itself is set but a number of matrices which shall be selected Here the matrices with the lowest coherencies are excluded from averaging In case a factor f 0 9 is selected and we have 200 matrices in total then 180 matrices will be selected All those with a higher coherency will be selected As the noise differs from band to band normally band 3 has the highest noise and the lowest signal a different factor can be defined for each band Note With the menu Estimate SPM Coherency this method of stacking can be sel
7. a 3 23 XX YY XY YX with XX XY YY ZY ZX eS In order to point out the difference of the two coherency terms coh Z 7 is called local coherency as it only refers to one single matrix The essential difference between the global and the local coherency is the computation of equation parameters a and b resp gand b At the global coherency the parameters are computed from the matrix S which is a result of stacking of all matrices Sj see equations 3 20 to 3 23 At the local coherency the parameters are computed from the matrix S for which also the coherency is calculated equations 3 14 to 3 17 3 2 2 Scaling of the Spectral Matrices The measured electromagnetic fields strongly vary in their amplitude The searched transfer functions are not affected by this As they result as quotients of electromagnetic fields the part of the amplitude is reduced in denominator and numerator However this is not valid for the cross and auto spectra of the spectral matrix In contrary by means of the multiplication of two measurement channels the influence of the amplitude is amplified even These strongly varying amplitudes of the cross and auto spectra would influence the weighted stacking is metronix 731100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis Another motivation to implement a scaling is the following consideration It can be assumed that just some of the strongly distorted matrices have an especia
8. are multiplied by the reciprocal of the transfer function of the measurement system and by this means almost cleaned f rom influences of the instruments Two different possibilities to determine the transfer function exist the theoretical model function or the measured transfer function can be used Only the is metronix 65 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis GMS05 allows the direct measurement of the calibration function Appendix A describes the theoretical model functions in detail 3 1 2 Computation of the Cross and Auto Spectra For each target frequency the cross and auto spectra are computed from the calibrated spectra Each of these values results from the sum of spectra over all frequency lines Fourier coefficients within a window whereby in its middle the target frequency is located In the following the computation for one frequency line is shown This procedure is repeated for all the other target frequency lines correspondingly In the appendix an overview about the predefined frequency lines is given see file PROCMT FRQ 3 1 2 1 Parzen Window 1 0 8 0 6 04 0 2 0 eet Pee s Sa Sr fz Sat fr Figure 3 4 The Parzen window over the target frequency f In order to determine the value of the cross spectra at the target frequency line not only the spectral value at the target frequency line is taken but a window is applyed at this frequency Here the P
9. can be found in figure 3 7 Epsilon 0 5 u Epsilon 2 5 Be Epsilon 5 m Epsilon 10 0 1 001 Ur en m haa oe i 0 007 HHHH HHHH HHHH EEE EEE HEH 1 Figure 3 7 Weighting function G x with x Axis x M Distance from As M is defined recursively its value is computed iteratively The optimum value for the parameter results by the following stipulation F e el few rod max 3 41 oo Figure 3 8 shows the shape of the function f for different example data is metronix 79 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis Figure 3 8 F e with four example data sets For the searched is F Maximum With the following equations the transfer from the continuous to the discrete range is accomplished n G yg Xi y 3 42 n G Ls i 1 1 G i 2 12 e d 1 I 3 43 For i e correspondingly a 2 F e eof s 2 n 1 2 _ 3 44 j 2 j 1 2 me aa Maximum The distances result from in metronix 80 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis d x xD 13 45 It stays to clarify the problem how to fix the start values for iteration 0 For X the simple average or median can be taken Ta x x 3 46 x 2 x 3 46 or x Median x 3 47 In order to determine the maximum of the function F a simple arrangement can be used
10. d a f with q 5 p j Fry s 0 if Notch switched off s 1 if Notch switched on and kis the number of notches The following frequencies exist for n 16 66 50 60 150 oder 180 Hz A 2 6 Switchable Low pass Filter 2 and 4 The following frequencies are adjusted for f depending on the selected band A 2 7 Amplifier 1 The amplifier 1 is always adjusted to F 1 in metronix 94 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 2 8 High pass Filter fup is adjusted depending on the selected band 17273 3 98 Sec 4 5 2048 3 Sec A 2 9 Amplifier 2 The possible settings for the amplifier 2 are or depending on the selected pregain A 2 10 Low pass Filter 3 The low pass filter 3 has the transfer function 1 1 a 0 630 with p j7 and 8192 Hz a 0 991 Fip3 2 1 a p a ps A 2 11 Amplifier 3 The 3rd amplifier F is set dynamically depending on the measurement value possible gains are 1 4 16 or 64 The gain is contained in the 3rd byte of the GMSO5 time series and the user therefore must not care about this in metronix 95 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 2 12 High pass filter for Band 1 Some GPU 05 systems have a 800 Hz high pass filter In case it is implemented and switched on its transfer function is Ps 1 s with 7 k Ps J 300 Hz Ps 8 Furg The high pas
11. drives are selected using the same keys as used with the file selection When pressing ENTER the input path will be set to the corresponding drive is metronix 19 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program Note The file selection window only operates properly when the system variable Lastdrive is set to the last drive installed in the system otherwise also drives will be displayed which are not available at all A second problem may occur in connection with disk drives In case such a floppy drive is selected and no or a disk is damaged the program will hang Therefore it is recommended to use PROCMT with harddrives or network drives only 1 2 3 2 Read Time Series files With the menu item Read Files a submenu is opened allowing to read the time series and calibration files After selection of the filename information about the status and the configuration of the corresponding station will be displayed Further information is available in the Configuration menu see chapter 1 2 4 The menu item Clear all allows to remove the files Please note that the station is removed from the PC s memorynot on the harddisk the file itself is not modified at all If a file is read in deletion of the previous station may be omitted It is sufficient just to read the new file the old file will be overwritten then Note In any case data access to a file is only a reading one The original files always keep unmodifi
12. each printer which is compatible to the EPSON ESC sequences During the creation of the file no other command can be entered in metronix 44 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 5 3 Change of Polarity Ctrl P change channel polarisation Allows to change the polarity of a specific channel which has been activated by the This option is very useful in case a faulty field set up of the sensors has been done accidently The option will only be performed for the band selected and therefore must be repeated for all bands when necessary The data to be modified can have a length of up to some MBytes and the polarity change may last a while during which no other interactions are possible A corresponding Note on the upper left corner of the screen is given Please note that this option will modify the file on the harddisk 1 3 5 4 Selection of Time Series Sections space select block Pressing the SPACE bar allows the selection resp rejection of single sections of time series In case a section has been rejected this will be indicated by a cross and this section will not be respected in data analys Pressing the SPACE bar again will delete the cross and the time series section is selected again Special care has to be provided when selecting the time series sections The max possible horizontal scaling should be chosen here The size of the selected sections is defined in the main window By
13. in this manual When performing the data analysis not the whole frequency band is used which has two reasons first of all each target frequency line shall be correlated to a specific frequency band on the other hand the corners of a frequency band cannot be used because a Parzen window is applied to each target frequency that may not exceed the measurement range of the bands Due to this reason only the range given under target frequencies in table 2 1 is used Table 2 2 gives further information about sampling rates measurement times etc Measurement Range Target Frequencies 16384 Hz 32 Hz 8192 Hz 256 Hz BLA AZ ies 1 Hz 256 Hz 8 Hz 2 sec 1024 sec 4 sec 128 sec 64 sec 32768 sec 128 sec 4096 sec Table 2 1 Frequency bands measurement ranges and used frequency ranges i Input data for the program PROCMT is time series recorded with the measurement systems GMSO5 or MMSO3e RTS resp 03E A third data format exists in connection with the calibration of the measurement channels the calibration files FCT which contain the calibration data of the GMS05 A complete discription of the file format is given in the Metronix manual File Formats The calibration of the measured time series is required in order to eliminate the influence of the measurement system filters gains etc For this purpose the data is divided by the calibration function of the instrument in frequency domain Beside the possibility to cal
14. of the transfer function of the KIM 877M The Metronix Magnetometer KIM 877M is an induction coil magnetometer operating with feedback principle The feedback loop is closed for frequencies higher than 4 Hz Figure A 1 1 explains the transfer function of this sensor The following formula gives a mathematical description between the magnetic field H and the sensor output voltage V ef eB V Vy Se or a mit Baars 1 j i 4Hz E is the calibrated sensitivity of the sensor and it is paty yi Bee 1 P 4Hz and keat y hep 1 P 1591 Hz in metronix 86 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 1 2 Transfer Function of the Electric Fields E G d Fe 0 Ve Figure A 1 2 diagram of the transfer function of an electric field sensor The Metronix E field device includes a built in preamplifier for amplification of the very weak sensor signals coming from the electric field probes Figure A 1 2 explains the transfer function of the electric field sensor The electrical field is determined by the voltage difference between the two electrodes which have contact with the soil and are located from each other with the probe distance d VG ar Si Pia ar ei 1 P 1591 Hz Bee 1 P Here E is the measured electrical field and V the output voltage between the sensors G is the amplification and d the probe distance A 1 3 Overview about SCU 884 The SCU 884 Signal Co
15. or down scrolling is performed then 1 4 3 2 Upper Scaling upper scale Using the or key will change the upper scaling of the window The contents of the window is modified correspondingly Only the active window marked by a can be rescaled 1 4 3 3 Lower Scaling PgUp PgDn lower scale Using the PgUp or PgDn key will change the lower scaling of the window The contents of the window is modified correspondingly Only the active window marked by a can be rescaled in metronix 51 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 4 4 Special Functions 1 4 4 1 Screen Hardcopy Alt H hard copy Copies the contents of the display into a file The precise data format is given in Metronix manual File Formats The file will be written into the directory which has been defined with the PROCMTDIR environment variable Up to 99 screen hardcopies are possible and they are named with PROCMTEO HOI to PROCMTEO H99 These files can be printed on each printer which is compatible to the EPSON ESC sequences During the creation of the file no other command can be entered in metronix 52 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments Chapter 2 Introduction to Magnetotellurics and Measurement Instruments In this chapter a short overview about the geophysical background and the equations which define the combination of the
16. provided on the harddisk The required harddisk capacity depends on the amount of data to be analysed The free harddisk capacity should not be smaller than 5 MByte The maximum space required is about 10 Mbyte not included the necessary space to keep the time series files 1 1 2 Harddisk Cache Program When the program is running it will extensively access to data which is stored as temporary files on the harddisk Therefore it is highly recommend to install a so called Cache program Such a program SMARTDRV EXE belongs to the DOS system V5 0 or higher therefore the installation should not be a problem Please refer to the DOS manual Of course another comparable cache program of a third party distributer could fulfill the same requirements Again it should be mentioned that the program accesses several 10 000 times to the harddisk A cache program increases the speed enormously more than four times and reduces the physical harddisk accesses by a multiple in metronix 12 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 1 3 EMS Memory The program runs with a DOS extender in the so called Protected Mode It therefore requires Expanded Memory An installed driver for instance EMM386 EXE which is included in the DOS should be removed or installed with the RAM option It can be a line into your CONFIG SYS file like DEVICE C DOS EMM386 EXE RAM or a similar statement in order to provide some EMS memory P
17. run in the graphics mode and are much more complex in operation than the other menu items The equation input on one hand is used to define those transfer functions which shall be displayed under menu item Presentation Equations and on the other hand to define the equations which shall be used to calculate the multiple coherency which is required for some of the stacking algorithms At first the input of univariate equations is described and than the more complex one of the bivariate equations Please refer to chapter 2 to get more information about the geophysical equations is metronix 271100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 5 1 Univariate Equations Univariate equations have the form Z aX where Z and X are any two channels Later the transfer function a Z X will be presented versus the target frequencies see Chapter 1 4 At the equation input beside the channels Z and X it is also decided whether the complex transfer function will be presented as a plot of real and imaginary part or as a plot of apparent resistivity and phase Selection of univariate equations Channel 1 2 3 4 5 6 7 8 Station fl Ex Ey Hx Hy Hz Station B Ex Ey Hx Hy Hz Statin Station D ee ee Station E 1 Ex Al A Hy Ad 2 ak 3 RUB nm Ex ee Z ES 9 not defined X no channel 6 not defined 7 not defined 8 not defined ALT D de
18. setup size of section and overlap mode also influences the display of the time series especially for the selection of time windows for data analysis The effects for the display and selection of time series windows are explained in section 3 The display of time series Note All possible setups which can be done in the Parameter menu must be done before the display of time series if the default setup is not used After the selection of time windows or after time series analysis these setups may not be changed Otherwise all interim results the window selection resp the temporary spectral matrices will be lost is metronix 31 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 6 1 Selection of the Active Bands All bands which contain data will be activated for the data analysis initially The menu item Toggle Band allows an exclusion of single bands Sometimes it may happen that the program deactivates bands not rendered in the main window in spite of valid data exists This happens especially when switching from the sequentiel to the parallel mode or vize versa Those bands must be reactivated manually again Activating of bands without valid data is not possible anyway 1 2 6 2 Overlapping Windows of Time Series The overlap mode for the time series windows is activated on standard With help of the menu item Overlap this option can be toggled for each band separately It is recommended to activate the o
19. temporary files in some systems especially when the standard directory for temporary files is on a RAM disk is metronix 14 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program Note The program accesses these temporary files very often It is therefore recommended to use a cache program for the directory PMTTMPDIR too 1 1 4 6 PMTCOLOR This environment variable can be used in order to change the preadjusted colours grey blue in text mode and gray cyan in graphic mode suitable for a monochrome black and white display This may be especially necessary when a monochrome or greyscale LC display is used laptop computer as the different colours cannot be distinguished very well on these displays Five possible adjustments exist e COLOR Colour display grey blue resp grey cyan MONO Black letters on bright background e MONOINV White letters on dark background e LCD MONOINV adjustment in text mode and MONO adjustment in graphics mode e GMS05 Special adjustment when PROCMT is used with GMS05 The special LCD adjustment causes that text and graphics being displayed black on a bright background In the standard case Colour display the variable PMTCOLOR should be set to COLOR or it can be omitted completely as the colour display is selected automatically if PMTCOLOR is not found in the environment is metronix 15 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 User Interface
20. the degree of freedom of the computed matrix S results from the following equation v p S v 3 37 As is v v for all i j 1 n it results v pS 3 38 The simple stacking can be considered as a stacking with the coherency threshold 0 0 The equation standing above is valid correspondingly expected value 3 2 5 Stacking with Weights Robust Methods Another possibility to counteract the outlier problem ref chapter 3 2 3 are robust methods A statistical method is called robust when it is not sensitive against outliers It means that some few outliers do not or only little influence the estimation of the expected value of a probability distributaion 3 2 5 1 MF Method fitting according to the most frequent value This method was developed by STEINER 80a 80b It is a robust method with a weighting function which tries to give the highest weight to the most frequent values Less frequent values with bigger deviation from the average get less and less meaning from iteration step to iteration step By this means a better and better adaption of the average to the most frequent values is achieved in metronix 78 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 00 69 f dx M 3 39 So r War 1 ne 3 40 The estimated value is expanded in a way that the probality density f x is multiplied by a weighting function G x The shape of the weighting function for differnt
21. this means it may happen that when marking a time window as bad also the previous or the next window is marked in case the section size is larger than the window size This may happen if the section size is 2048 or 4096 data points as only max 1024 points can be displayed If the overlap mode has been selected the marked sections which overlap in the displayed window will be excluded from the data processing Note The selection of time series sounds more complicated than it really is The simplest way is to follow this scheme at first the max possible horizontal scale is selected by pressing the key several times Then one observes all time series sections and marks those which seem to be disturbed When having reached the end and one thinks that not enough or too many have been deselected one can just jump to the beginning and select or deselect more sections The SPACE bar operates as a toggle switch in metronix 45 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 5 5 Deselect All Blocks Ctrl B deselect all blocks All sections are deselected for the data processing This option allows to proceed differently at the data selection Instead of excluding sections with strong noise you here will include those sections which you want to select for data processing by pressing the SPACE bar 1 3 5 6 Select All Blocks Ctrl N select all blocks By pressing Ctrl N you select all blocks for the data proc
22. to obtain a more detailed overview about station and channel configuration than given in the main window 1 2 4 1 Channel Configuration Channel Parameters Station B 11123409 Channel Labels Pregain Postgain Distance Angle 3 103 3 158 10 30 3 1 1 1 Press lt ESC gt to exit Figure 1 3 Channel configuration window DO O O O O O OGS ssa metronix 23 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program The menu item Channel Config presents the channel configuration of each station read in The window provides the following information for each of the eight channels for a selected station Label The channel name it can be an electrical E or a magnetical H sensor which is aligned in N S x E W y or vertical z direction Therefore the channel names Ex Ey Hx Hy Hz exist e Pregain The preamplification of the measurement instrument can be selected separately for each of the channels At the MMS0O3e it can be 1 3 10 30 100 or 300 At the GMS05 it can be 1 or 16 e Postgain The postamplification factor 1 4 16 or 64 is only to be found in connection with the GMSO5 It is set to 1 when the MMSO3e was used e Distance The probe distance shows the spacing between the two electric field probes of an E dipol Angle The angle represents the deviation of the sensor spread from the predefined main direction North in degree The Ex channels normally point to the North 0
23. will be opened or closed toggle function Windows for which no data is available cannot be opened 1 3 4 2 Open all Windows O open all windows Opens all windows 1 3 4 3 Select a Window 1 8 select window The active window is marked by a on its left side This is important for two functions which refer to the active window e The virtical scaling using the cursor keys und J see next chapter e Change of channel polarisation Ctrl P see chapter 1 3 2 4 1 3 4 4 Vertical Scaling 7 increase decrease vertical scale Values can be defined manually for the borders of a window which are symmetrical to the zero axis same absolute value different sign The contents of the window and the border values displayed on the left side of the window are adapted accordingly Only the active window which is indicated by a will be modified and only time series can be scaled manually The automatical scaling will be always activated for spectra 1 3 4 5 Automatical Scaling A enable disable autoscale Activates resp deactivates the automatical scaling toggle function The limits of the window are selected as small as possible whereby the curve is displayed in metronix 42 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program completely beside some few outliers in the window All windows are scaled independently from eachother When the contents of a window changes the limits of a window will be re
24. 0 98 100 28 08 02 Rev 2 1 PMT21_E2 doe HAJAGOS 80 HARTUNG 93 Heimsoeth 85 KAUFMANNIS1 MARTINEZ 88 Metronix 86 Metronix 89 Metronix 9 1a Metronix 91b Metronix 93a Metronix 93b OPPENHEIM 92 is metronix Literature Hajagos B Method for the Rapid Calculation of the Most Frequent Value and M Fitting Problems Acta Geodaet Geophys et Montanist Acad Sci Hung Tomus 15 1 pp 75 85 1980 Hartung Joachim Statistik Lehr und Handbuch der ange wanden Statistik 9 Auflage Oldenbourg Verlag M nchen 1993 Turbo Graphix Toolbox Version 1 0 Heimsoeth Software M nchen 1985 Kaufmann Alexander A Keller George V The Magnetotelluric Sounding Method Elsevier Scientific Publishing Company Amsterdam 1981 Martinez Mauricio M Grundlagen neuerer Inversionsmethoden und ihre Anwendung auf die 1 D Inversion in der Magneto tellurik Dissertation am Institut fiir Geophysiklische Wissentschaften FU Berlin 1988 Modular Magnetotelluric Measurement System MMSO03e Volume III 1 Interfacing the MMSO3e Metronix GmbH Braunschweig 1986 Advanced Electromagnetic Exploration Metronix GmbH Braunschweig 1989 GMS05 Broadband Geophysikal Measurement System Metronix GmbH Braunschweig 1991 Specification of the SMX Data Format Preliminary Version Metronix GmbH Braunschweig 1991 GMS05 Transfer Function Analog Channel and Sensors Metronix GmbH Braunschweig
25. 2 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis Note The degree of freedom increases with overlapping sections of the time series whose neighbored sections have been removed by hand selection see chapter 1 3 4 corresponding to equation 3 12 A correction of the degree of freedom is not done in this special case 3 2 Stacking Algorithms and Robust Methods The cross and auto spectra can be written in form of a square matrix The length of the matrices edges corresponds with the number of channels recorded This matrix with the cross and auto spectra is meant when in the further chapters is spoken about the spectral matrix S This chapter describes the methods to determine an optimum matrix for each target frequency It is the task to compute a single matrix from all matrices up to several hundred which is achieved with statistical methods Two basically different methods are used here the selective stacking and the stacking of weights Before stacking the matrices are scaled in order to avoid that extremely differing amplitudes of the natural stimulation influence the result of stacking 3 2 1 Coherency The coherency between two channels is a quantity describing the linear dependence between these channels AB coh A B Rp 3 13 AA BB This coherency term can also be used to compare the measurement result of a channel with a predicted result of the same channel predicted channel In this case it is cal
26. 8Hz j f 4 Hz in Band4 or Band5 ss metronix 89 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 1 5 High pass Filters of the SCU 884 The SCU contains a switchable 1 pole high pass filter with a cut off frequency which depends on the selected band and the position of the HP DC switch see table B 1 If the high pass is switched off it is FH 1 else it is F P mo P jf 4 Sec in Band 2 and 3 Fl P j f 4096 Sec in Band 4 and 5 A 1 6 256 Hz Low pass Filter of the SCU 884 The last stage of the SCU electronics is a five pole 256 Hz Butterworth low pass filter with the following transfer function 1 1 1 x x 1 P 1i axP P 1 2 xP P2 F f with a 1618 a 0 618 P jean A 1 7 Overall Transfer Function of the E and H channel The transfer functions of sensors and SCU electronics can be combined as follows Vz pE G Fy FR Fag G Re Fed F for the electric field channels and F 08 V nT F F F G F Fp Fy for the magnetic field channels in metronix 90 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 1 8 Analog Digital Converter of the SCU The A D converter has a resolution of 16 Bit with a maximum input voltage of V 10V inMax This results in a resolution of Vise 10 Vs 305 2 uV per Bit Due to the influence of the round robin scheme of the ADC the channels are effected by a phase shift This phase offset depends on the freq
27. Bivariate equations have the form Z aX bY where Z X und Y represent any three channels Later the estimate value of the transfer function in metronix 29 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program q Kr YK ZY XX YY XY Yx respectively pa ZY XX XY ZX XX YY XY YX will be displayed over the target frequencies When entering the equation beside the channels X Y and Z it is also determined whether the complex transfer function a or b will be presented the corresponding letter will be displayed in capitals and whether it shall be presented as real imaginary or amplitude phase plot Selection of bivariate equations Channel 1 2 3 4 6 7 Station A Ex Ey Hx Hy Station B Hy Station C Station D Station E ak b 2 Channel Ey A2 K Channel Hx A3 not defined y Channel Hy A4 not defined Presentation not defined Krr Channel Hx B3 not defined Yrr Channel Hy B4 ALT D delete ALT C clear ALT M default ALT P presentation ESC Exit PgUp PgDn next equation A E station 1 8 channel ALT R remote ref Figure 1 8 Input window for bivariate equations Additionally there is a possibility to define equations with a reference station remote reference This requires the input of two more channels X and Y For the transfer functions in this case it is ce ZX YY YX ZY XX YY XY YX respectively TT m
28. CHMUCKER 85 by 5 4 ZZ Aal lt g v 7 7 2 19 v 4 xx 1 r2 resp 3 4 ZZ An 5 2 20 Berl There is g v the value of the Fischer function v with a security of the confidence interval of 68 The error AZ becomes small if the measured field component Z is optimally in line with a X b Y Accordingly the error becomes small with a high coherency of both components and big with a low coherency In the errror calculation this is respected with the residue _ a XZ b YZ g ZZ 2 21 Only in case the field components X und Y are independent from each other the parameters can be determined from the equation set 2 15 with good reliability Due to this reason the error calculation also respects the coherency between the channels X and Y r 2 22 2 2 2 Remote Reference Method A second possibility to minimize especially the noise of the magnetic field components is using so called Remote Reference techniques When using the normal arrangements equations 2 15 to 2 17 the autospectra of all channels are affected by a so called Bias which increases the values artificially This is caused by noise which is correlated in the auto spectra The noise of the two channels however is not correlated in the cross spectra In order to determine the tensor elements the conjugate complex components of the magnetic fields are replaced by the corresponding components of a remote station Remote Reference
29. CLARK 78 The original arrangement 2 15 is not is metronix 57 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments modified only the computation of the parameters 2 16 und 2 17 is modified as follows _ ZX IV YX ZY fee ee a 2 23 I yx and ZY XX XY ZX XX YY XY YX The components X and Y are the channels of the reference station corresponding to the original channels X and Y The confidence intervals for the computed parameters atAa and btAb are determined according to the equations 2 19 to 2 22 by 5 4 Ee ZZ Aal lt gr v 2 25 v 4 gerne and a 4 ZZ Are 2 26 v4 vy 1 72 Hereby is computed according to equation 2 21 with the parameters resulting from equations 2 23 and 2 24 Furtheron it is IK Py mhe TE Son 250 YY 2 _ 2 27 2 2 3 Univariate Equations In case the main elements Z and Z are equal or near to zero the equation arrangements derived above 2 15 bis 2 17 can be simplified to univariate arrangements Z aX AZ 2 28 a i 2 29 XX ssa metronix 58 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments The confidence interval atAa results from a modification of the equations of the bivariate arrangement 2 19 bis 2 22 Pan 2 30 ZZ IA E lt ae ZZ 2 31 ee te Raye The
30. Figure 3 1 shows an overview about the first part of data analysis First of all the calibrated spectra are computed for all channels and succeeding to that the spectral matrix is computed for each target frequency Trend elimination Hanning window FFT Calibration with CAL file or model function Calibrated Spectra Station A Calibrated Spectra Station B Calibrated Spectra Station C Calibrated Spectra Station D Calibrated Spectra Station E Parzen window Computation of cross spectra Spectral Matrix Station A E Trgetfreq 1 Spectral Matrix Station A E Targetfreq n Figure 3 1 Overview about data analysis from the measured time series up to the computation of the spectral matrices in metronix 62 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 3 1 1 Transformation into Frequency Domain This chapter describes the used algorithms and methods for time series analysis First of all it is shown up how the raw data of the electrical and magnetical fields is transformed from time to frequency domain where the calibration of the data is Measurement Sampling Frequencies Resolution time rate 5192 Hz 256 Hz 256 We 6 z Z performed 5 32 He 128 sec z Table 3 1 Measurement times sampling rates and resolution of the spectra in relation to the measurement range frequency band and to the size of the time series se
31. MT21_E2 doe Introduction of segments can be increased as the program also allows a 50 overlap of the segments Normally the measurements are affected by more or less strong distortions which may cause wrong results For this reason the second step of data analysis provides a Statistical estimation of an average spectral matrix Several algorithms are implemented and can be selected according to the requirements and the data quality Furtheron PROCMT includes options to display the configurations and numerous possibilities to display the recorded electromagnetic fields in time and frequency domain with or without calibration The display option allows a selection of suitable segments for the data analysis and gives a first impression of the data quality of the measurements Also the results of the apparent resistivity and phase versus frequency can be displayed This provides a quick impression of the results of the different analysis methods Either bivariate as well as univariate equation sets can be selected with or without reference station The following sections comprise a short summary of the different chapters of this documentation and give an overview about the contents of the documentation Chapter 1 explaines the installation and operation of PROCMT in detail Beside the installation and the optimum configuration of a given PC the different screens and menus are explained Chapter 2 describes the used measurement methods
32. OS commands and programs can be performed here By entering EXIT you will return to PROCMT 1 2 9 Termination of PROCMT The program is terminated with the menu item Exit or the key combination ALT X Before the termination of the program and return to DOS the security query has to be answerded with y in metronix 34 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 Time Series Presentation Figure 1 9 Presentation of the measurement data as time series The presentation of the time series mainly serves two aims First of all the data quality can be checked For this purpose a couple of different display modes beside the standard time series mode are available which allow to display spectra and calibrated data as well as the comparison of the data with a reference station On the other hand single sections of the time series which are obviously affected by noise can be marked as bad and excluded for the further processing 1 3 1 Screen Setup The screen can be split into five sections e the title line first upper text line e the status line second upper text line in metronix 35 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program e the menu display on the right side of the screen e the horizontal axis labels on the lower border of the screen e the window where the time series and spectra are displayed incl vertical axis labels on the left side At first the single comp
33. PROCMT User s guide OFFLINE PROCESSING SOFTWARE FOR MAGNETOTELLURIC TIME SERIES A Ellinghaus 29 5 97 Rev 2 1 Metronix GmbH Neue Knochenhauerstr 5 D 38100 Braunschweig Germany metronix E Mail geo metronix de www metronix de Tel 531 480 840 Fax 531 132 61 Copyright Notice The information in this document is subject of change without notice and does not represent a commitment on the part of METRONIX No part of this manual may be reproduced or transmitted in any form or by any means electronically or mechanically including photocopying and recording for any purpose without the expressed written permission of METRONIX Table of Contents Table of Contents Eopyrieht Notice ea cxauy cusae densevnces ducers senceccsus ceeaetencseasne sas PADIE OF COMES sascshscssseivcadsyceaaesneidecsossshexsssecacecontshoesaneaneasonixbedsisncneccnvisvecsnseeee Used Symbols and Nomenclatura csssccssssscssssecssssecssssecsssseessssessssssessssssees Introduction a Operating the Prosa cicavasssccsssiazssevacaccenvavaxagepecaassornuadegesneyacanesverscevecstseonstorees LA Installation a re 12 LEAS Veter Requirements ar nu Er 12 1 1 2 Harddisk Cache Prosa RER 12 PI EMS ME a dic a le 13 1 1 4 Environment Varables an RER 13 W2 User TIS aCe eds eiad a a deta aaa aa aiaa aaa 16 12 M n Windows sense 16 1 2 2 Menu Syste Mii oe Colcord te ect aaa E aE detach als Aa IE cide 18 BAR PUG WI E 1 1 RTE A A 19 1 2 4 D
34. S ke 1 m m number of equations ie l n n number of matrixes These transfer functions are used as start values for the iteration according to the MF method in order to determine a weighted average of all transfer functions Hereby the entered equations are not computed independently but all together The distance is defined as a 2 2 ve d a a b 5 3 55 k 1 As the distance definition delivers positive values only the start initialisation of is modified correspondingly see chapter 3 2 5 1 It is now max d 3 56 For the iterative computation is e Fiel dF do dF 3 57 ee SR 3 58 2 2 e d is metronix 83 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis T l gt Na 3 59 Ye i l i b 1 ye b 3 60 j i 1 ys i 1 The iteration is stopped when the parameter for the weighting function does not change any more or only changes very little 2Ae mit Ae 0 99 3 61 S gis 3 62 j i 1 ys i 1 The degree of freedom results in v vy gP 3 63 ssa metronix 84 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix B Transfer Functions Appendix A Transfer Functions of GMS05 and MMS03e ss metronix 85 100 Appendix A Transfer Functions A 1 Transfer Function of MMSO3e A 1 1 Magnetometer KIM 877M H O8 eee Fu Fr oym Figure A l 1 diagram
35. a complex number Imaginary part ofa complex number complex conj values Average value with or without weight indirect computed channels 2 xe predicted channels i Iteration Indices ass metronix 6 100 28 08 02 Rev 2 1 PMT21_E2 doc Symbols and Nomenclature Conventions in Text All names foreign language expressions and references to figures tables and other text parts are printed in talics Beside names of persons also names of programs files modules procedures and variables are marked correspondingly All words which shall be pointed out especially are printed in bold This is also used for all key descriptions menu entries and screen outputs The wild cards and are used in the same manner as in the DOS operating system The stands for any string and the for any character This abbriviation is used especially in connection with file names and sometimes with the names of modules procedures and variables Dereferencing of menu entries or procedures is done with the File Read RTS Station B references to the menu item Station B which is to be found under menu item Read RTS which finally is to be found under the menu file is metronix 71100 28 08 02 Rev 2 1 PMT21_E2 doc Introduction Introduction The program PROCMT is a program system for off line processing of time series recorded with the Metronix MT systems MMSO3e or GMSO5 The following main features are implemented e Display of ra
36. alized when a new window is drawn 1 4 1 2 Status Line The status line shows the kind of equation bivariate or univariate which is presently presented and the name of the data file without path name 1 4 1 3 Menu The menu shows all available functions with the keystrokes to invoce them Functions which are not available in actual display mode will not be indicated For instance the display mode Display of two equations in one window is only available with a horizontal window configuration Correspondingly the key ALT T with the short description of its function only appears in the menu bar when horizontal window mode has been selected in metronix 48 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 4 1 4 Scaling and Labels of the Axis The lowest line of the screen shows the horizontal window axis labeling The window is scaled logarithmically with a range from 1 0E 4 Hz to 1 0E 4 Hz The powers of ten are indicated by vertical lines and the grid which can be deactivated resp activated with the B key toggle function The vertical scaling is also logarithmically in case real and imaginary part or the amplitude is displayed If the phase is displayed the vertical scale will be a linear one The gridding has a distance of 10 then The vertical scale of the active window can be changed by the and the PgUp PgDn keys The axis labels on the left side of the window will be adapted 1 4 2 Window an
37. and systems as well as the geophysical equations which define the combination of the measured electromagnetic fields Especially the splitting of the frequency spectra into the different bands is explained In spite of the program allows the definition of any equation combining the different measurement channels there exist some of special interest which are also explained here Additionally the remote reference mode is demonstrated beside the normal uni or bivariate single site mode The intention of this chapter cannot be the complete derivation of the theory moreeven the background knowledge to understand the further chapters esp chapter 3 shall be given Chapter 3 gives a mathematical description of all algorithms and computing methods used in this program The first part shows the computation of the spectral matrices which are calculated from the different selected time segments The analysis of the time segments is performed independently for each segment By this means for each time segment a different spectral matrix is computed It is the task is metronix 9 100 28 08 02 Rev 2 1 PMT21_E2 doe Introduction of the algorithms described in the second part to compute an optimum average spectral matrix for each target frequency from the many single raw spectral matrices it can be up to several hundreds using statistical analysis methods Different methods are shown here which attempt to reach this aim Appendix A gives a detail
38. and the Ey channels to the East 90 1 2 4 2 Notch and High pass Configuration The menu item Notch High pass indicates the configuration of the notch filters and of the high pass in a separate window see below The high pass can be switched on or off If the notch filters are switched on the corresponding notch frequency will be displayed if they are switched off a dash is shown in metronix 24 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program Notch and Highpass Configuration Station Notch 1 Notch 2 Notch 3 Highpass A 10123409 50 00 Hz 150 0 Hz 16 66 Hz on B 11123409 50 00 Hz 150 0 Hz 16 66 Hz on Press lt ESC gt to exit Figure 1 4 Window to display the notch and high pass configuration Note It has to be considered that the notch frequencies of the MMS03e cannot be read from time series files Due to that reason the frequency 50 Hz is always assumed for notch 1 150 Hz for notch 2 and 16 667 Hz for notch 3 These frequencies are also assumed when calculating the model function 1 2 4 3 Target Frequencies The menu item Frequencies opens a window in which the selected target frequencies can be displayed Not all 60 possible frequencies must be used necessarily a part of them can be shown as not used After the index number follows the frequency in Hertz or seconds than the number of the target line the radius as a number of target lines Fourier frequencies and finally the num
39. arzen window is used u n f f Fr 3 3 1 if f sl 0 parzen f 4 sin w u if O lt f f lt fe 3 4 0 ie re is metronix 66 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis with f target frequency and f radial frequency Herby the target frequency is the center frequency of the window and the radial frequency determines the width of the window The radial frequencies are fixed depending on the target frequency fr fz 3 5 whereby for the factor c a small c 0 125 medium c 0 25 wide c 0 5 or very wide c 0 75 radius can be selected MAAA 0 0 Figure 3 5 The target lines of a band with the Parzen windows belonging to From top to bottom small medium wide extra wide radia Figure 3 5 gives an overview about the logarithmic equidistant target frequency lines of a band with the different adjustments for the width of the Parzen window The default in PROCMT is wide radius An exception is band 2 where a small radius is default in order to minimize the influence of the electromagnetic noise caused by the powerlines 16 Hz 50 Hz and harmonics is metronix 67 100 28 08 02 Rev 2 1 PMT21_E2 doe Chapter 3 Methods of Data Analysis 3 1 2 2 Crossing and Summing At the cross multiplication at first two frequencies are multiplied with eachother under respect of the Parzen window and then the sum over all frequencies is built XY parzen
40. ber of the band belonging to the frequency Nr Frequency TLine Radius Band 23 11 00 Hz Q A 24 8 00 Hz 008 04 2 ao G5 MNN 25 6 00 Hz 192 26 4 00 Hz 128 64 27 3 096 48 28 2 00 Hz O6 32 3 29 1 50 Hz 048 2 3 30 1 00 Sec 032 16 3 31 1 33 Sec 024 12 3 Figure 1 5 Window to display and edit the adjusted target frequencies aes metronix 25 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program With the cursor keys different frequencies can be chosen in the window When pressing the key E the selected frequency can be edited and replaced by any other Input format is here the common nomenclature for floating point numbers l nnn nn E l nn S Normally the input is regarded as a frequency in Hertz However it is also possible to enter values for periods in sec just be adding an S as the last character after the float number Pressing of RETURN will delete the old frequency and sort the new frequency into the list Pressing ESC will abort the input mode without modifying the list In case the entered frequency is greater than 8192 Hz or smaller than 1 4096 sec this frequency will be sorted at the beginning or the end of the list and set to not used By this means frequencies can be removed from the list If a new frequency shall be added to the list without deletion of a used frequency it is sufficient to select a not used frequency if available The maximum number of fre
41. ctions H H The time series analysis is based on the sections of the measured time series These sections can consist of 512 1024 2048 or 4096 data points user selectable Depending on the sampling rate in the specific band and the adjusted section length different resolutions and frequency ranges are achieved Table 3 1 gives an overview about the corresponding values which stand in a closed relationship with the measurement systems see also the transfer function of the instruments in Appendix A The frequency range does not correspond with the range obtained sa metronix 63 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis with the FFT Fast Fourier Transform moreeven it means the range which is used to fix the target frequencies 3 1 1 1 Trend Elimination ans Naoto Vy Yor we yy Figure 3 2 Example for trend elimination Before applying the Fourier transformation the raw data is processed with a trend elimination and a so called window function The trend elimination removes a possible systematic deviation from the x axis The mean value bias is set to zero and a straight line in the data trend which differs from the x axis is removed Hereby it is 1 1 t 2 zt de Y dr u al y del 2 a 3 1 n t l ln 2 t 1 1 2 t 1 Bias Trend te 1 2 ne e 512 1024 2048 4096 z time series raw data z time series without trend Figure 3 2 illustrates th
42. d Screen Configuration 1 4 2 1 Change Number of Windows Alt 1 Alt 8 number of windows Definition of the number of window pairs which are displayed on the screen real and imaginary part resp amplitude and phase side by side This definition is only valid for horizontal window setup 1 4 2 2 Change Window Configuration Alt W window configuration At the vertical window setup only two windows will be displayed which are located among one another The upper one displays the amplitude or the real part the lower one the imaginary part or the phase of an equation At the horizontal configuration both windows are displayed side by side and up to 8 equations can be displayed simultaneously The key combination ALT W toggles between the two possible window configurations in metronix 49 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 4 2 3 Presentation of two equations Alt T two equations In the vertical configuration you can select the display of one equation or two equations per window Always two succeeding equations will be displayed then This mode may be of special interest if you want to present both polarisations of the apparent resistivity and phase curve in one display The result of the first equation appears in white colour with the boxes filled out The result of the second equation is presented in yellow open boxes If more than two equations are selected you may use the T and J keys to s
43. e trend elimination The upper figure shows an example curve superimposed by a straight line the lower figure shows the same data set after the trend elimination is metronix 64 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 3 1 1 2 Window Function windowing 0 Figure 3 3 The Hanning window which is multiplied with the time series before the FFT is performed After the trend elimination it follows the multiplication of the time series with a window function windowing This is necessary in order to suppress side effects discontinuities are generated at the edges at the FFT and to obtain an optimum sharp mapping of the frequency spectra In the program a so called Hanning window with the function 1 1 Ut lt cos gt les 3 2 Hanning t 2 2 T 0 tl gt 7 has been realized 3 1 1 3 Fast Fourier Transformation FFT After the time series has been treated with the trend elimination and the windowing the fast Fourier transformation FFT is applied to the data In the program a so called mixed Radix 8 algorithm has been realized The given time series now has been transformed into the frequency domain All the further steps of computation are done with spectral data 3 1 1 4 Calibration of Spectra The measured time series data is affected by the transfer function of the instru ments MMSO3e or GMS05 In order to eliminate this influence the data must be calibrated The spectra
44. ected Whereby the coherency factors f will be determent by the factors which are displayed at the right lower edge of the main window 3 2 4 4 Adaptive Selection Method Respecting a Mean Coherency This method is another conjugation of the coherency threshold method and is oriented to the selection method mentioned above The difference is that the number of the matrices to be selected is not determined by the user the program computes this factor for each target line In order to determine the number of matrices to be selected first of all the mean coherency of all matrices is computed Then the part of the matrices to be selected is determined according to the formula 1 f pe 3 36 The idea is here that the number of the strongly distorted matrices is the bigger the smaller the mean coherency becomes It has to be respected that the computed factor corresponds with the average coherency However the factor f is no coherency threshold but represents the number of the matrices to be respected in averaging This means when the mean coherency threshold is 0 6 60 of all matrices will be included in averaging is metronix 771100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis Mainly this algorithm corresponds to the algorithm with selection by adaptive coherency threshold where the factor fp in equation 3 35 is replaced by f 3 2 4 5 Degree of Freedom for the Selective Methods For all shown selective methods
45. ed An accidently deletion of a file is impossible by this means 1 2 3 3 Reading of Calibration Files Reading and removing of CAL files into resp from memory is principially done in the same manner as reading of RTS files However a time series file has to be read before Only then it is possible to check whether the CAL file fits with the read time series file In case a time series file is deleted or overwritten the corresponding CAL file will also be removed from memory In case the calibration file is not compatible with the station file i e the configuration data of both files do not fit to eachother an error message is displayed A message will also be shown in case it is tried to use a Cal file in connection with MMSO3E data in metronix 20 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program Note It is possible that calibration data is only available for a part of the bands contained in the RTS file Only those bands will be labelled with a C in the main window for which calibration data is available The other bands will be calibrated with the model function labelled with M It is possible that the calibration file is compatible to the time series file but does not contain information about the recorded data This might happen for example if the calibration file is gained with notches switched on the time series in contrast have been recorded with notches switched off 1 2 3 4 Combination of Time Serie
46. edimentary Basins 100 100 28 08 02 Rev 2 1 PMT21_E2 doc
47. elect the next Show Equations ProcNT V1 6 lt c 94 96 Metronix Germany 13 15 49 26 07 1996 Tipper Files JNTGW3 SPN 1 00 MENU AltH i Window 0 50 mode AltT i R one e equations 3 9 00 lower scale UprpgDwni 0 50 Pinan scale i upzdown 1 00 honesend eftzrighti 1 00 select equation ay li aseline mee on z off I Bi Bivar u i ne i Tipper a 0 00 i Skew g I Induc D Bost Noi Magn 0 50 C Coh 1 00 Ea AltX i 1E 4 Hz 1E 2 Hz 1E 0 Hz Figure 1 13 Presentation of tipper function 1 4 2 4 Show Bivariate Equations Alt B bivariate equations Pressing the ALT B key displays the bivariate equations in metronix 50 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 4 2 5 Display of Univarite Equations Alt U univariate equations Pressing the ALT U key displays the univariate equations 1 4 2 6 Enable Disable Grid B grid on off The B key toggles the gridding on or off 1 4 3 Window Selection and Scaling 1 4 3 1 Window Selection T 4 e gt window selection Selection of the displayed equations and marking the active window With the left and right cursor key the left or right window can be selected in the horizontal display mode With the cursor up and cursor down keys the window of a specific equation can be activated for scaling purposes The active window is indicated by a If more equations are selected than windows displayed an up
48. en window is preselected to a large radius L large for bands 3 4 5 medium for band 1 and small radius S small for band 2 The size of the radius in band 1 and band 2 have been selected smaller in order to reduce the effects of the electromagnetic noise caused by the powerlines to the target frequencies The menu item Radius allows to select the width of the Parzen window as shown below e S small small radius e M medium medium radius e L large large radius e XL extra large extra large radius Note Only a relative and not an absolute radius is fixed This means that the exact size of the parzen window results from the target frequency and the selected relative radius The ratio of radial frequency and target frequency of a band is constant 1 2 7 Data Analysis Via the menu entry Analysis Analysis RTS the analysis of the time series will be performed according to the algorithms presented in chapter 3 1 trend elimination Hanning window Parzen window etc The adjustments which have been done in the Parameters menu will be respected here The progress of the data analysis is indicated in the middle part of the main window under Blocks Comp Hereby the number of analysed time series sections is displayed Sections which have been rejected during the presentation of the time series will be counted also but they are not analysed When having finished the time series analysis the number of the analysed sections will be displa
49. es 57 2 2 3 Univariate EGQUANONS 2303152502033 2a seien 58 2 2 4 Presentation of the Parameters 222404400eeessssnnnnnnnnnnnnnennen 59 2 3 Measurement Systems GMSOS and MMSOS3e uuceeesnnnneessnnnneersennnnnenen 59 Chapter 3 Methods of Data AnallySis sssccccccccssssssssssscsscccsssssssssssssseees 3 1 Analysisof Time Serena ae uke A eons 62 3 1 1 Transformation into Frequency Domain ssssnenennennen 63 3 1 2 Computation of the Cross and Auto Spectra ueeeeennnneessnnnneesenenn 66 3 2 Stacking Algorithms and Robust Methods 2uu0222244n0e seen 71 32 T Coheren Y irs cecssscste a a a woaeueeace as 71 3 2 2 Scaling of the Spectral M trices a uu u a 13 3 2 3 Short Introduction into the Robust methods Outlier Problem 74 3 2 4 Selective Methods ns 75 3 2 5 Stacking with Weights Robust Methods uurr ss nnner een 78 Appendix A Transfer Functions of GMS05 and MMS03e sscsssssssesees A 1 Transfer Function of MMS03e 2222ssssesessssennnnnnnnnnnsnenennnnnnnnnn 86 A 2 Transfer Function of GM SOS unser svaasuancazessastervenntcoeass 92 CALAN e NEA A TETT nsa metronix 5 100 28 08 02 Rev 2 1 PMT21_E2 doc Symbols and Nomenclature Used Symbols and Nomenclatura Mathematical Symbols Symbol Nomenclature other Variables italics capital or lower 8 v XY case lower case normal max coh RL Real part of
50. essing This option will delete all deselections which have been done previously 1 3 5 7 Quit Display Mode Alt X Esc exit Quits the time series display The graphic mode will be left and the text mode main screen will appear in metronix 46 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 4 Presentation of Transfer Function a a Figure 1 12 Presentation of the transfer function The display of the transfer function allows a quick check of the results of the data analysis The transfer functions will be calculated for the entered uni resp bivariate equations see section 1 2 6 and the apparent resistivity and phase will be presented as amplitude and phase resp real and imaginary part versus frequency Please refer to chapter 2 2 to the calculation of error bars in metronix 47 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 4 1 Screen Setup The screen can be split into 5 sections e the title line first upper text line e the status line second upper text line e the menu display on the right side of the screen e the horizontal axis description on the lower edge of the screen e the windows in which the transfer functions are displayed with their vertical axis labels The following sections describe the single components in more detail 1 4 1 1 Title Line Beside the version number the title line shows the actual date and time Date and time are actu
51. etronix 30 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program _ ZY XX XY ZX XX YY XY YX i The meaning of the input window corresponds almost with that of the univariate equations see previous section In the following description only the differences between the univariate and bivariate input window will be mentioned Instead of two channels you have to enter three resp five channels The actual equation is displayed on the left side if all channels have been entered correctly As an additional function you have the possibility to define an equation with a reference station Alt R remote reference Switches from normal bivariate mode to the remote reference mode This requires two more channels normally H channels of a second station Equations according to the remote reference method are marked on their right side by an rr The transfer function will be displayed always as an amplitude phase plot Note Any possible bivariate equations can be entered with any possible channel combination No check is done whether the equations are meaningful or not However the result will be calculated according to the above standing formulas and also be presented 1 2 6 Parameters of Data Analysis The menu Parameter comprises all possible setups to control data analysis The setups met here will influence the first part of data analysis and the stacking algorithms are influenced indirectly A part of the
52. f RTSDIR is not defined in the environment the program will start searching for time series files in the directory where you started PROCMT 1 1 4 3 SPMDIR Defines the directory in which the files containing the cross and auto spectra SPM or EDI format files shall be written In case this variable is not defined the start directory of PROCMT will be selected to store the files 1 1 4 4 SPMTMPDIR In this directory the spectra which have been computed from the time series are stored These files exist only temporarily during program runtime In case this variable is not found the program will look for the MSDOS standard variable for temporary files TEMP resp TMP In case this variable is also not defined the start directory of PROCMT will be selected to store these files Note The program will access these temporary files up to several 10 000 times during the program run Due to this reason a harddisk cache program f i SMARTDRV should be installed or the directory SPMTMPDIR is set to a RAM disk 1 1 4 5 PMTTMPDIR PROCMT uses this directory to write other interim results of the cross and auto spectra Also these files exist only temporarily If PMTTMPDIR is not found in the environment the program will not search for the standard directory for temporary files but use the start directory of PROCMT This is necessary as the temporary files with the cross spectra can become very big up to 20 MByte which may exceed the space for
53. f X f YY 3 6 f X and Y are the two channels XY fy is the cross product belonging to the frequency f X f resp Y f are complex spectral values and parzen f is the the function of the Parzen window described above In order to achieve an independence of the amplitudes of the cross and auto spectra from the width of the Parzen window equation 3 6 is expanded by a scaling factor which results from the weights of the Parzen window parzen f X f YUY xy fz Deven a In the following an indexing of the cross spectra is ommited However it has to be considered that all the further steps of computation are performed for each target frequency independently from other target frequencies 3 1 2 3 Degree of Freedom The degree of freedom for the cross and auto spectra results from the number of independent values which form the single spectra Hereby the weighting which is caused by the Parzen window has to be drawn into consideration v parzen f 3 8 f By this means the degree of freedom results basically by the Parzen window which determines the number of spectral values mentioning the summing and fixing the corresponding weighting is metronix 68 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 3 1 2 4 Overlapping Sections of Time Series Normally the time series is split into sections succeeding to oneanother and then the data analysis is performed It means that a part of info
54. factor 4 in equation 2 19 is replaced by a factor 2 as the equation arrangement 2 28 only contains two unknown values real and imaginary part of a in contrast to four unknown values real and imaginary part of a and b 2 15 2 2 4 Presentation of the Parameters Generally the apparent resistivity p and phase curve are presented versus frequency which results from the equations po ao 2 32 and E S a o l a rt al 2 33 respectively from the above equations where a is replaced by b in order to obtain the other polarization It also exists the possibility to present the real and imaginary part versus frequency 2 3 Measurement Systems GMS05 and MMSO3e The field components necessary to compute the cross spectra are recorded by the Metronix instrumets GMS05 and MMSO3e The magnetic field sensors are aligned in North South Hy East West Hy and in vertical Hz direction Each of the electrical fields are measured between 2 poles which are aligned from North to South Ey and East to West Ey in metronix 59 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments The frequency range which can be recorded by the instruments is split into five GMSO5 resp four MMSO3e frequency bands Hereby band 1 can only be recorded with the GMS05 All the other frequency bands correspond to eachother Please note that band 1 in the MMSO3e manual corresponds with band 2
55. gram 1 3 1 3 Menu All available functions are listed on the right side of the screen As the amount of available functions cannot be listed in one column the menu is subdivided into three columns which can be switched with the key M The menu only serves as a list ofthe available commands with a short description of their function here yh Ba Figure 1 10 Display of the measurement data as calibrated spectra The display always shows the function being presently active It may change depending on the activated presentation mode For example a scaling is not possible if the spectra is displayed and by this means the automatical scaling or manual scaling option is not availabe in the menu 1 3 1 4 Scaling and Axis Labels The vertical axis labels show the upper and lower window border for each window The lowest row in the display will show the start and stop time of the presented in metronix 37 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program recording display window in case the time series mode has been selected In the middle of this row you will find the corresponding date If inside of a display section the time oversteps 0 00h the displayed date will belong to the start time The horizontal resolution i e number of data points is not indicated Note When changing the number of data points in a window the number of data points of all windows will change In order to avoid confusions between the sl
56. he same configuration is metronix 21 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program L e all files must have identical channel configurations and also the notch filter and high pass adjustments must be identical Of course it is impossible to link files which have been recorded with different measurement systems MMS03e and GMS05 All data which shall be linked must be recorded with the same type of instrument If the configuration check has been finalized successfully and no error message has been displayed you will be asked to enter a name for the new file The program will append the extension RTS automatically and write the file into the directory from which the last file has been read Also when files are linked together the original files will not be modified In case these files are not used any longer they have to be deleted in the DOS command shell 1 2 3 5 Reading of Spectral Files SPM The menu item Read SPM allows to read of spectral files SPM format The station and channel configurations will be read from the file as far as possible for instance no recording times are contained in the file and displayed in the main window as well as under the Presentation menu It is only possible to read one spectral file at the time which however may contain data of up to 5 bands A deletion of spectral files is not provided When reading a new spectral file or a time series file the old one will be re
57. here is no data in this band available e M Data available calibration with theoretical transfer function of the measurement system model function e C Data available calibration with a calibration function which has been gained with the measurement system calibration files only exist with the GMS05 Furtheron it can be seen which bands have been activated for the time series analysis Those bands are rendered white Bands with black status signs are available but not disabled for data processing NOTE Normally in the documentation of the MMSO3e the bands are numbered 1 4 In order to keep the numbering consistent same numbers for the MMSO3e and the GMS05 here band 2 corresponds to the original band 1 band 2 corresponds to band 3 of the MMSO3e and so on The MMSOs3e is not capable to record band 1 data frequency range 256 Hz 8192 Hz this can only be done with the GMS05 In the second part of the main window the recording times for all bands are displayed The times displayed here show the beginning and the end of the period of time during which data has been recorded If a reference station is loaded these times must not necessarily fit with the original recording times The true times can be seen under the menu item Configuration Measurement times The measurement period is set to a multiple of the measurement time of one section of the time series If for example a time window of 49 6 sec was found out and the sect
58. ibrate the measurement data with a measured calibration function GMS05 only there exists the possibility to apply a theoretical model function to the raw data This model function is also integrated into the program PROCMT A complete description of the theoretical model function of the GMS05 and MMS03e is given in Appendix A in metronix 60 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis Chapter 3 Methods of Data Analysis The analysis of the time series can be divided into two main sections First the time series are split into sections of a fixed preselectable size For each of these sections the first part of data analysis is applied independently For each section a matrix containing all cross and auto spectra is computed for a number of determined target frequencies This procedure is repeated for all measured frequency bands During the second main section of data analysis the optimum matrix is computed from all the present matrices This procedure is repeated for all target frequency lines In the following the first part of data analysis is called Analysis of Time Series while the second part is named Computation of the Spectral Matrix in metronix 61 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 3 1 Analysis of Time Series In this chapter an explanation is given how a single spectral matrix is computed from a specific time series section for all target frequency lines
59. ice of time series displayed in the window and the slice of time series used for the analysis we will distinguish in futere between time series slice if the display in a window is meant and time series section if the data for the analysis is meant Note As mentioned before in time slice mode of the GMSO5 only single time slices of 1024 points and no continous time series are recorded For that reason the displayed times for band 1 and band 2 may not be correct 1 3 2 Presentation Modes 1 3 2 1 Presentation of Time Series Ctrl T raw time series This mode shows the data as they have been recorded RTS bzw 03E 1 3 2 2 Presentation of Calibrated Time Series Ctrl A calibrated time series In order to calibrate the data the time series first will be released from a possible mean deviation from the x axis trend elimination Then it will be transformed into frequency domain divided by the theoretical or measured calibration function and transformed back to time domain In frequency domain some more data manipulations are done So for instance only the first half of the frequency band is taken when the data is transformed back to time domain in metronix 38 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program The multiplication with a Hanning window prior to the Fourier transformation is not performed in order to avoid a distortion of the time series at the window s edges This may produce noise in
60. ion size has been set to 2048 points the time window will be set to a multiple of 2 sec this is the duration of a recording of 2048 points in band 3 ref table 2 1 and results in a total of 48 sec Note If two stations are read which have no time series recorded at the same time then no measurement times are displayed on the main window Behind the measurement times the number of sections of time series which fit into this time window are displayed Succeeding to that you will find the number of the selected time sections and the number of the sections analysed It follows the selected section length and finally the label ov in case overlapping time sections have been selected or ts if data is recorded in time slice mode The meaning of the overlap and the different informations to the sections is explained later is metronix 17 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program Note The GMSO5 normally records band 1 256 Hz to 8192 Hz and band 2 8Hz to 256 Hz data in a time slice mode see GMSO5 manual In this case the lines with the measurement times are marked with ts at the end The displayed end times for time slice recording may not be correct It is also not allowed to increase the time series length see chapter 1 2 4 3 beyond 1024 points and it is not possible to use overlapping time series see chapter 1 2 4 2 On the lower right corner of the main window the adjusted factors for the selective stacki
61. isplay of Station and Channel Configuration 23 1 2 5 Presentation men 1 3352 caceshacacads ececudsalchcadada ebasunddluncdeadaesroabeauhesendaiae 27 1 2 6 Parameters of Data AnalySis ccccccceeeseseesneeceeeeeeeseeennneeeeeeees 31 12 7 Data Analysis ansehen lese 33 1 2 8 The DOS Shells ne ae euer 34 1 2 9 Termination of PROCMT aan aan 34 13 T meseries Presentallon a 2 a sauce se e a a a 35 L Sul SCreen sep rss OS Ae E R 35 1 3 2 Presentation Modes as sdlesasd 38 1 3 3 Window and Screen Configuration ccssseeccceeeeeeeeeetneeeeeeees 41 1 3 4 Window Selection and Scaling eee eeeesnceececeeeeeeeeeennneeeeeeees 42 mss metronix 4 100 28 08 02 Rev 2 1 PMT21_E2 doc Table of Contents 1 3 52 Special Funeti ns 2 2 2 eee ee 44 1 4 Presentation of Transfer Function 47 LAT Sereen SEWED es ersehen 48 1 4 2 Window and Screen Configuration usssseseeeesssseennnnnnnnenennnen 49 1 4 3 Window Selection and Scaling eee eeesenceeeceeeeeeeeennneeeeeeeees 51 LAs Special Funetions a2 Ai 52 Introduction to Magnetotellurics and Measurement Instruments 2 1 Introduction into Magnetotellurics eceecccccceeeeeeeeeenteeeeeeeeeeeeeeenaneees 54 2 2 Equations for PROCM TD i csi cists 02 56 2 2 1 Bivariate Equ tions u 2 0n unidoaeiekekne ia 56 2 2 2 Remote Reference Method sisi dsassseisedadsciuvaastaasscatens toaaseaavedadearevaa
62. lease refer to your DOS manual for further information 1 1 4 Environment Variables The program flow especially the access to the files is mainly controlled by a number of environment variables Environment These variables are set with the SET command of the MSDOS operating system The best way is to set these variables during the system initialization in the AUTOEXEC BAT file or in a special batch file which also starts the PROCMT program The following chapters give an explanation of all these environment variables 1 1 4 1 PROCMTDIR The program searches in this directory for initializing files especially for the file PROCMT FRO In case this variable is not found in the environment the program searches in the actual directory from where PROCMT is called Note It is important to set this variable in case PROCMT shall be started from another directory Otherwise the file with the target frequencies PROCMT FRO will not be found by the program and the execution is interrupted with an error message in metronix 13 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 1 4 2 RTSDIR Defines the directory where PROCMT searches for files containing time series after having started the program If another directory is selected in order to read a time series file this directory will be used by the program in the future automatically as long as the program is not terminated or another search path has been selected I
63. least square method LSQ where the error AE is minimized B ZAZA AE 2 6 E Z H Z H AE 2 7 sa metronix 54 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments The equations 2 6 resp 2 7 contain two complex unknown quantities Z and Z resp Z and Z this requires at least two complex Fourier coefficients of the spectra H H and E resp E in order to determine the unknown Z elements However more Fourier coefficients are comprehended in order to minimize noise This is achieved using a Parzen Window p i parzen i see chapter 3 1 2 1 As result for the elements of the impedance tensor one obtains from equation 2 6 PH He pWE H pli HE POE H i l i l i l i l Zi T an n n n 2 8 PA H pA H Pi HH POA H i l i l i l i l pOH Hy pPWE A pOH H LL POEL A Z i l i l i l i l 2 9 xy PH H Y POH H Y pli H H gt pli H H i 1 i 1 i 1 i 1 and from equation 2 7 POH H Ys pWE H Y p H H pWE HH i 1 i 1 i j Lig on n n 2 10 PH H Y pH H Y pH HH pOH A i 1 i l i l i l L PAH pWE H pH H pW E H Z i 1 i 1 i 1 i 1 2 11 xy pi H H pH He 9 pli H pli He i l i l i l i l The Index i stands in the equations 2 8 to 2 11 for the i th Fourier coefficient of the transformed time series Instead of the impedence tensor Z the admit
64. led mathematical description of the transfer functions of the MMSO3E and the GMS05 system The data formats are explained in the Metronix manual File Formats of the GMS05 is metronix 10 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program Chapter 1 Operating the Program metronix 11 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 1 Installation The installation of the program is very simple it is sufficient to copy the files PROCMT EXE and PROCMT FRO into any directory of your choice When you are in the directory where these two files are installed you can start the program by typing PROCMT However there are some requirements to the system which shall be described now Furtheron the user can adapt the program by using some environment variables DOS Environment according to his requirements 1 1 1 System Requirements The program PROCMT has been developed and compiled using the JPI Modula Compiler Topspeed 3 1 under MSDOS 5 0 or higher The program runs on all AT compatible computers with 386 processor or higher with minimum 1 MByte of RAM Due to the very high amount of numerical calculations a 387 coprocessor or better a 486DX or a Pentium processor is required A bigger memory with 4 Mbyte or more is highly recommended The programm runs with a so called DOS extender and profits from the gain of memory Enough space for the temporary files and the result files has to be
65. led multiple coherency It is F ZI coh Z Z z 3 14 zz 22 sa metronix 71 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis with Z aX bY TDS aXZ bYZ 3 15 IT ax bY For a and b it is oa ZX YY YX ZY XX Y XY YX 3 16 _ ZY XX XY ZX 7 yy z z 3 17 XX YY XY YX with XX XY YY ZY ZX es The coherency between one channel and the predicted result delivers a value for the quality of the measurement and by this means for the spectral matrix S computed from the time series As several equations can be defined with the matrix for the standard MT method these are for instance FE a H b H and E a H b H the term of the coherency of a spectral matrix is defined as follows coh min coh Z Z 3 18 with ke 1 m m number of defined equations and the equations itself Zr Z 4 X POY 3 19 When in the following chapters the coherency is mentioned then mostly the coherency of a spectral matrix is meant Especially for the Q and W algorithm Junge 90 an additional coherency term has to be defined the so called global coherency A a7 coh Z Z 3 20 many is metronix 72 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis with aX bY TH oe eb 3 21 ZZ NZ 4 bYZ Hereby it is and b i EE 2 _ 13 22 XX YY XY YX and 2u SB
66. lete ALT C clear ALT M default ALT P presentation ESC Exit PgUp PgDn next equation A E station 1 8 channel Figure 1 7 Input window for univariate equations The window in which the univariate equations will be entered Fig 1 8 consists of four main sections The upper part of the window is a matrix showing the actual channel setup of all the 8 channels of all 5 stations A means that no channel has been connected All channels which have a valid channel label can be used for the equation input The middle left part of the window serves to display all entered equations and allows a selection of the equation which should be entered next The selection is done with help of the PgUp and the PgDn keys The actual equation will be rendered resp displayed inversely Up to 32 equations can be defined The display will always show a section of 8 equations An equation labelled with a will be presented as amplitude and phase curve an equation not labelled will be shown as a plot of real and imaginary part The default is amplitude phase presentation is metronix 28 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program The middle right part of the window serves to enter the actual equation which has been emphasized in the equation list The first input section is used to enter the channel on the left side of the equation the second input section below is used to enter the right part of the equation The correspondi
67. ll connected SCU channels simultaneously The next sections describe the transfer functions of these filters in detail in metronix 88 100 28 08 02 Rev 2 1 PMT21_E2 doe Appendix A Transfer Functions A 1 4 Notch Filters of the SCU 884 The following equation describes the notch filter transfer function F I gt Mit MOSS e ee 1 4 1 Sa N Q 2 EB Q defines the quality of the notch filter fy is the center frequency of the selected notch and S is a factor depending on the notch v being switched on or off If Notch v is not switched on than S 1 else 0 Up to four of the flowing frequencies can be realized 16 66 Hz 50 Hz 60 Hz 100 Hz 120 Hz 150 Hz 180 Hz 200 Hz 240 Hz 250 Hz and 300 Hz Note As the files of the time series recording do not contain the notch frequencies but the status of the notches only PROCMT assumes that the order of the notches is as follows notch 1 50 Hz notch 2 150 Hz notch 3 16 667 Hz Otherwise PROCMT will not operate properly with MMSO3E data This mainly refers to band 2 The error can be neglected for all other frequency bands The Low pass filters are switched according to the selected band The corresponding frequencies can be seen in table B 1 The filters are implemented as 5 pole Butterworth low pass filters and have the following transfer function 1 1 1 a 1 618 F x zX 2 mit 1 P 1 4xP PF 1 a xP P a 0 618 with P 0 in Band2 Bse pe inbad
68. lly strong stimulation i e the distortion amplitude This would have the effect that just the distorted matrices would have a high influence to the result of the stacking Due to the above reasons the matrices are scaled and released from the influence of distortions 1 Eee spur S S 3 24 As all cross and auto spectra are divided by the same value the result of the transfer function is not changed as they are computed by the quotient of the fields Ss S 53 spur S 3 25 i By this means the spectral matrix contains cross and auto spectra whose amplitude corresponds to the mean measured amplitude 3 2 3 Short Introduction into the Robust methods Outlier Problem When determining the optimum matrix it is assumed that all spectral matrices Sj are combined by the searched optimum error free matrix Sg and an unknown error matrix AS S S AS 3 26 In case that the error matrices have a symmetrical distribution an approximation to the desired optimum matrix can be achieved just by simple stacking of many matrices Y S 8 YAs 3 27 sa metronix 74 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis S 8 3 28 For sufficient high n it is 1 S S AS So 3 29 Often the measurement results are affected by strong noise which does not obey the hypothesis of a symmetrical distribution lim Das 0 3 30 no n Another problem of these strongly disto
69. magnetic and electric field components is given In the following the two measurement systems MMSO3e and GMS05 are described and their correlation with the program is shown up The file format of the time series the calibration and the splitting of the frequency spectra into the different frequency bands is shown ass metronix 53 100 28 08 02 Rev 2 1 PMT21_E2 doe Chapter 2 Introduction into Magnetotellurics and Measurement Instruments 2 1 Introduction into Magnetotellurics The basis of the magnetotelluric equations are electromagnetic fields which can be described by the Maxwell equations The Maxwell equations for homogenous relations in the quasi static approximation i e without displacement currents are E 2 1 Ot VxH u 0E 2 2 V E 0 2 3 V H 0 2 4 V E is the electrical field in 4 m H is the magnetical field in 7 l S o is the electrical admittance in A m V L is the magnetic permeability u 47107 m is the radian frequency 27f in Hz From these relations a linear equation system for the relationship between electrical and magnetical fields can be derived in the frequency domain in form of E Z H Z H x XX x E Z H Z H 2 5 These linear relationships are valid if a quasi homogenous wave geometry and a mainly 2 dimensional field is assumed H 0 i e H lt lt Hy und H lt lt Hy The equation system 2 5 is solved using the
70. moved from memory automatically 1 2 3 6 Reading of Spectral Files EDI The menu item Read EDI allows to read of spectral files EDI format The function of this menu item is the same like Read SPM Note After data processing PROCMT stores the resulting cross and auto power spectra in two different file formats The EDI and SPM files contain the same spectral data Because the EDI files are in ASCII text format and the SPM files are in binary format reading of SPM files is much faster then reading EDI files Therefor it is recommended to rather read the SPM format files in metronix 22 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 3 7 Save PROCMT configuration With the menu item Save Config the parameter settings and selection of time series windows can be stored The configuration file will have the same name like the first time series file with the file extension CFG This option should be used after selection of time series Because the selection of time series windows take some time a reprocessing can be done much faster when the selection is stored in a CFG file 1 2 3 8 Read configuration file CFG With the menu item Read Config a complete configuration time series file with parameter settings and time series selection which was stored before with Save Config menu camn be read 1 2 4 Display of Station and Channel Configuration The Configuration menu offers a couple of possibilities
71. nditioning Unit from Metronix is used for amplification and filtering of up to 8 analog channels in a frequency range from DC to 256 Hz The hardware is the same for each of the channels Due to the high dynamic range of the input signals and for data reduction at lower frequencies this wide frequency range is split into 4 bands with three different sample frequencies In the lowest frequency band a digital filter for data reduction during recording is implemented Vin O _ Fn Fl Fh G Fl mo Vout Figure A 1 3 Block diagram of the transfer function of the SCU 884 channels in metronix 87 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions The table A 1 1 shows the filter settings of the bands and the sampling rates Table A 1 2 shows an overview about the frequency ranges of the bands NOTE Normally the bands are numbered with 1 to 4 in the MMSO3E documentation In order to keep the numbering consistently same band numbers for MMSO3e and GMSO5 the enumeration starts with band 2 here Sampling rate dig filtered 1 Hz Table A 1 2 Cut off frequencies and frequency bands The gain of each channel can be adjusted separately Possible gain settings are x1 x3 x10 x30 x100 x300 Further on there are up to 4 notch filters for suppression of cultural noise caused by power lines The setting of a notch filter as well as the band and high pass settings always influence a
72. nfiguration 1 3 3 1 Changing the Displayed Band Alt 1 5 select band Allows to change the displayed band Only bands can be selected for which data is available 1 3 3 2 Station Mode S station mode All channels of one station are displayed The key combinations ALT A to ALT E select the station which shall be displayed 1 3 3 3 Channel Mode C channel mode Only one channel of all stations is displayed The key combinations ALT Fl to ALT FS8 select the channel that shall be displayed 1 3 3 4 Selection of a Station Alt A Alt E select station Allows to change the displayed station in station mode The keys have no meaning in channel mode Only those stations can be selected which have been selected with the menu item File Read RTS in the main program 1 3 3 5 Selection of a Channel Alt F1 Alt F8 select channel Allows to change the displayed channels in the channel mode The keys have no meaning in the station mode Only channels with valid data can be presented 1 3 3 6 Zeroline B baseline on off Switches zeroline dashed line in the window on or off in metronix 41 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 4 Window Selection and Scaling 1 3 4 1 Open resp Close a Window F1 F8 open close window Hereby the window with the corresponding channel index 1 8 will be opened or closed in station mode In the channel mode the window with the corresponding station
73. ng see 2 2 4 3 selection with adaptive coherency threshold and the relative width of the Parzen window are displayed The length of the sections is chosen in the menu Parameters and the factors in the menu Analysis Further explanation is given in the corresponding sections of these chapters On the lower left corner of the main window the actual time and date is displayed This display is not refreshed all the time Only when an output is done in this window or a menu item is selected time and date will be refreshed 1 2 2 Menu System The menu control is achieved by selection of a menu item using the cursor keys 1 gt and pressing the ENTER key or just by typing the bold letters These hot keys are only valid for the menu item being actually active frame with double line Initially the main menu is activated When typing for instance F the file menu will be opened and is now activated In the following sections the single menus and submenus will be described in their function and mode of operation Two menu items of the Presentation menu are an exception here i e the presentation of time series Time Series and the presentation of the transfer functions which have been selected by entering the equations Equation Both menu items switch to the graphics mode and have a user interface of their own Therefore they are not described in subchapters but have own chapters see 7 3 The Presentation of the Time Series and 1 4 The Presenta
74. ng input section is selected with the cursor keys TL The channel input is done with the keyboard by entering the name of the station first keys A B C D or E and then the number of the channel keys 1 8 If the channel is occupied beside the entered station and channel number for instance A4 also the channel label will be displayed Ex Ey Hx Hy or Hz In case the selected channel was not occupied a double question mark will be displayed as an error message If both channels have been entered correctly the equation will be shown on the left side In the lower part of the window you will find a Help section indicating all other possible key combinations In detail those are Alt D delete Deletes the actual emphasized equation Alt C clear Deletes all equations Alt M default Deletes all equations and defines the standard MT equations automatically Ex aHy und Ey aHx for all stations Alt P presentation Toggles the display mode for the actual equation between real imaginary and amplitude phase display ESC oder RETURN Terminates the equation input Both keys have the same function Note The input window for univariate equations allows the definition of all possible combinations of two different channels as an equation It is not checked whether the equations make sense or not In any case the result will be presented under the menu entry Presentation Equation 1 2 5 2 Bivariate Equations
75. onents are described in more detail It follows an overview about the function and control of the display 1 3 1 1 Title Row The title row shows beside the version No the actual date and time as well as the kind of display mode Date and time will be always refreshed when a part of the screen or the window contents is drawn The following display modes exist raw time series calibrated time series raw spectra calibrated spectra transfer function 1 3 1 2 Status Line The status line shows some information related to the displayed data First it is displayed whether the station or the channel mode is activated In the station mode the station index A E and the file name will be displayed additionally Furtheron the selected band the number of the actual display section as well as the number of all display sections is indicated The number of sections and the total number of sections for data analysis follow in brackets In brackets the number of sections which have been selected for data analysis are shown A further explanation about the difference between display sections and sections for the data analysis is given in chapter 1 3 2 4 The Selection of Time Series Sections In case the automatic scaling or the trend elimination is activated this will be indicated by a special indicator at the end of the status line auto trend is metronix 36 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Pro
76. quencies in this list is 60 Note It is only possible to enter the frequencies all the other displayed parameters are computed automatically It is recommended rather to use a standard DOS editor to changed the frequencies in the file PROCMT FRQ The file format is described in the seperate Metronix manual File Formats of GMSO05 Any changes of the frequency list done in PROCMT will change also the frequency file PROCMT FRQ is metronix 26 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 4 4 Recording Times Mesurement Times Band 4 Station Begin End A 10123409 20 05 91 22 00 00 000 21 05 91 18 03 12 000 f 11123409 20 05 91 22 00 00 000 21 05 91 18 48 00 000 D E 20 03 91 22 00 00 000 21 05 91 17 20 32 000 Press lt ESC gt to exit Figure 1 6 Window to display the recording times for all stations Via the menu item Measurement times the user obtains information about the recording times of all bands In contrast to the main window here the real recording times are displayed The item all the start and stop time of the time window is displayed Hereby the same conditions concerning the section length are valid as already discussed at the display in the main window ref Chapter 1 2 1 1 2 5 Presentation menu The two most important functions of the Presentation menu Time series and Equations will be explained in separate chapters 3 and 4 because they
77. r function of this sensor H 0 8 Fu Fips Vu Figure A 2 2 Blockdiagram of the transfer function of the MFSO5 in metronix 92 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions The following formula gives a mathematical description between the magnetic field H and the sensor output voltage V F E V qad gaar Sie ips f nT Hz ae 4Hz E is the calibrated sensitivity of the sensor and it is io Re with pases 1 P 4Hz and pinnt a Bee o 1 P 8192 Hz A 2 3 Analog Channels of GPU 05 The GPU 05 contains a lot of filters and amplifiers for signal conditioning of the weak sensor signals The settings of the notches or low passes and high passes always refer to all analog channels simultaneously The transfer function F of the analog channels of the GPU 05 is Fona Fu Fires Far Fup Fao Frps Fipa Faz Fure It follows a detailed description of the single transfer functions A 2 4 Low pass Filter 1 1 Fp with j m g P Po 5J 8192 Hz The low pass is switchable by a jumper on the analog board This filter is implemented off standard sa metronix 93 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 2 5 Notch Filter The GPU 05 can have up to 3 notch filters which may have center frequencies as listed below The transfer function of the notch filters is 1 Fr i aera Pi S
78. rmation of the time series gets lost see Fig 3 4 upper plot In order to minimize this loss of data the program offers the possibility to use overlapping time segments Fig 3 4 lower plot Also here the data analysis is performed independently to the single sections It has to be considered nevertheless that the sections of time series are no longer independent from eachother as they partially overlap This results in a decrease of the degree of freedom which can be determined from the size of the overlapping range 0 De NT serien DS Figure 3 6 Time series with Hanning window without upper and with lower overlapping sections The correction factor for the degree of freedom of a section results from the overall area of the hanning window is metronix 69 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis cj costs 3 9 1 2 Flot 4 cos x dx 3 10 h2 2 n 2 The corrected degree of freedom v results from the full part of the non overlapping area and the half part of the overlapping area whereby the areas are scaled with the overall area Go Go Gs a 14 a 3 11 tt v 0818 This degree of freedom is not valid for the first and the last section of time series Here the area of the overlap is only half For these two sections the degree of freedom is a a v v G TAG 2 245 3 12 74 On v 0 909 is metronix 70 100 28 08 0
79. rted matrices is that they mostly have too big deviations from the searched value This leads to the phenomena that even a few strongly distorted matrices are sufficient to effect a considerable deviation from the true result the optimum matrix 3 2 4 Selective Methods The selective methods try to minimize the outlier problem by excluding a number of matrices from taking the average The problem on one hand is to select a maximum number of matrices and on the other hand to exclude almost all outliers from averaging 3 2 4 1 Simple Stacking un S S t i 1 3 31 2 mit ie 1 7 3 31 This method is only mentioned for completeness It is no robust method is metronix 75 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 3 Methods of Data Analysis 3 2 4 2 Selection with Coherency Threshold This method uses the coherency see chapter 3 2 1 to separate the outliers from the rest of matrices Hereby only those matrices are taken for averaging whose coherency exceeds a certain threshold 1 wenn coh gt c p S 3 32 0 wenn lcoh S lt C with c coherency threshold For the stacked matrix it is S Yps s 3 33 ps N l I It is important to fix the threshold c properly If it is too small some strongly distorted matrices are included When it is too big only a few and perhaps even no matices at all are selected Additionally the coherency distribution varies from target frequency to target frequency considerably
80. s Files The function Link RTS allows to link different time series files Up to 5 files can be entered which will be combined to one single file by this option For each band one file can be read from the Link RTS window Just selct one band and press RETURN The standard file selection window will open and a RTS file can be selected It is not necessary to enter a file for all stations In case a station is missing the corresponding band will be set to not measured However care has to be taken that the entered files contain valid data in the frequency band corresponding to the station latter otherwise an error message will be displayed Select RTS Files for linking Filename ip SiteID Channels NWOI00111 RTS noiooi 5 NOIOO121 RTS noiooi 5 NOIOO131 RTS noiooi 5 Link Esc Exit A file can be attached to several bands For example the data of the bands 1 2 3 of file X and the data of the bands 4 and 5 of file Y shall be combined in file Z This is achieved by reading file X into the band s 1 2 3 and the file Y into the station 4 and 5 After pressing L Key linking of the files will start A message which asks the user to enter a name for the new data file will appear automatically Just enter a normal 8 letter file name without extension and finish the entry by pressing ENTER As each time series file contains only one section containing the station and channel configuration data it is necessary that all entered files have t
81. s filter F pp is switched off for the bands 2 5 and may only switched on when band 1 is selected In case it is switched off its transfer function is Farsi 1 A 2 13 Overall Transfer Function of Electric Field Channels The following formula describes the overall transfer function of the electric filed channel of the GMSOS V BB Ged Fe Fu Fipa Far Fap Fa Frps Firs Fas Farm A 2 14 Overall Transfer Function of Magnetic Field Channels The following formula describes the overall transfer function of the magnetic filed channel of the GMS03 V V HTE 08 Fu Fios Fu Fipz Ea Fae Faa Fipa Fipa Fas Faem A 2 15 A D Converter sa metronix 96 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions When using the GMS05 the data is stored in 4 Byte words The maximum input voltage is V inMax 10V The 4th byte is always zero The resoltion of the GMSO5 is 22 Bits This is achieved by a 16 Bit ADC and a 6 Bit auto gain range amplifier which is controlled by the ADC By this means the smallest voltage step referred to the input is 1 LSB 4 768 vV tL Due to the influence of the round robin scheme of the ADC the channels are effected by a phase shift This phase offset depends on the frequency band and the channel number The phase offset for the highest frequency HFreq of a channel in respect to the calibration channel in the band are Band channel channel 2 channel 3 channel
82. scaled automatically If the automatic scaling is activated the cursor keys T have no function In the spectra display the automatic scaling is always activated 1 3 4 6 Trend Elimination T enable disable trend Elimination Activates resp deactivates the trend elimination The average of the displayed window is set to zero This option may used be more frequently when band 4 or band 5 data is displayed the time series here often have a greater deviation from the zero axis The automatical and the manual scaling as well only allow a symmetrical scaling same distance between upper and lower limit from the x axis By this means such time series cannot be displayed in high resolution without trend elimination 1 3 4 7 Horizontal Resolution inc dec horizontal scale Modifies the horizontal resolution Using the key will decrease the number of displayed data points zoom in the key will increase it zoom out The max resolution corresponds to the size of the adjusted length of a time series section but will not increase 1024 data points In case overlapping mode has been adjusted the max resolution will be half of the length of a time series section selected in the main screen A horizontal scaling can only be done if time series are displayed the spectra will be always presented in a resolution of 512 frequency lines per interval 1 3 4 8 Next previous Time Series Slice lt gt scroll one block
83. tance tensor W can be calculated also H W E W E AH 2 12 H W E W E AH Impedance and admittance tensor result in is metronix 55 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments Z x Z xy Wo Wy Z Z 2 and W W W 2 13 yx yy Assumed that the field components do not contain any noise AE 0 bzw AH 0 the following relationship between impedance and admittance tensor is valid Z W 2 14 2 2 Equations for PROCMT 2 2 1 Bivariate Equations In the program ProcMT and also in the further documentation the arrangements to determine the impedance and admittance tensor are standardized and written down in the compressed notation Z aX bY AZ 2 15 na Ze Ber 2 16 XX YY XY YX _ ZY ae A 2 17 XX YY XY YX The crossings of two spectra RS DOR 2 18 are named cross spectra In case a field component is crossed with itself i e X Y it is called auto spectra Z X and Y are three given components of the electric or magnetic field a and b are called equation parameters in the following In case of the equations 2 6 2 7 resp 2 12 these are the elements of the impedance resp admittance tensor in metronix 56 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 2 Introduction into Magnetotellurics and Measurement Instruments The confidence intervals for the computed parameters a a and b Ab are determined according to S
84. the higher frequency range after retransformation into time domain caused by discontinuities on the edge of the time window The calibrated time series is released from these distortions as the high frequency lines are not used for the backtransformation Another manipulation is done with the band 2 spectra The amplitudes of the electromagnetic noise caused by powerlines normally exceed those of the natural signal significantly By this means it is often not possible to observe the natural signal activity in the time series of this band Therefore the frequency lines of the 16 Hz 50 Hz 100 Hz and 150 Hz incl their direct neighbor lines are set to zero Again it should be mentioned that this is only done for the data display and not for the data processing 1 3 2 3 Display of Spectra Ctrl W raw spectra First the time series are released from a systematic deviation from the x axis trend elimination and then multiplied with a Hanning window It follows the transformation into frequency domain FFT The transformation is always done for sections with 1024 points independently from the horizontal resolution of the displayed time series and also independently from the section size set in the menu Parameters 1 3 2 4 Display of calibrated Spectra Ctrl S calibrated spectra This mode does not differ much from that of the non calibrated spectra The spectra are divided by the theoretical or measured calibration function In this displa
85. tion of the Transfer Functions is metronix 18 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 3 File Menu The menu item File comprehends all functions to read and write files All inputs of filenames are done by a selection of files in the input window As the file input window is used for most of the functions of the File menu it follows a description of this window at first After that all entries in the File menu are described 1 2 3 1 File selection Window The title of the window displays which kind of files shall be read in Below that you can see the actual path name and the files which shall be displayed If the entry behind Name is for instance SPM only files with the corresponding extension will be displayed If there is a as in the picture printed below all files will be displayed Using the cursor keys and the keys Home End PgUp PgDn a file can be selected which will be read by pressing the ENTER key When typing ESC you can leave the window without reading a file The input path can be changed by selection of the two dots stands for the previous directory or by selection of a path name name is enclosed in brackets Choose your RTS File Path E GHS 5 RTS L 10123409 03E 11123409 03E 21123404 03E Figure 1 2 File selection window file selector With the TAB key the user can switch from the file selection to the drive selection table The
86. uency band and the channel number The phase offset for the highest frequency HFreq of a channel in respect to the first channel are The highest frequencies of the bands are The phase offset for other frequencies than the highest frequency of a band is AQ AQ frequency HFreq band in metronix 91 100 28 08 02 Rev 2 1 PMT21_E2 doc Appendix A Transfer Functions A 2 Transfer Function of GMS05 A 2 1 Electric Field Sensor with Preamplifier EPRO5 E O Ge d Fi 0 Ve Figure A 2 1 blockdiagram of transfer function of an electric field sensor The Metronix E field device includes a built in preamplifier for amplification of the very weak sensor signals coming from the electric field probes Figure A 2 1 explains the transfer function of the electric field sensor The electrical field is determined by the voltage difference between the two electrodes which have contact with the soil and are located from each other with the probe distance d Von an B 1 P 8174 Hz and G 28 64 1 Fp 1 28 64 5 Here E is the measured electrical field and V the output voltage between the sensors G is the amplification and d the probe distance A 2 2 Magnetic Field Sensor MFS05 The Metronix Magnetometer MFS05 is an induction coil magnetometer operating with the feedback principle The feedback loop is closed for frequencies higher than 4 Hz Figure A 2 2 explaines the transfe
87. verlap at least if only a few data for a specific band is available i g band 5 The activated option overlapping windows is indicated in the main window behind the number of blocks with the shortform ov The number of time windows changes depending on this option double or half and is actualized in the main window correspondingly Note Overlap can not be activated for band 1 and band 2 when they are recorded with the GMSO5 in time slice mode The time slice is indicated by the shortform st behind the numbert of blocks 1 2 6 3 Length of the Time Series Sections The section size is preselected to 1024 data points for the bands 1 4 and to 512 data points for band 5 Bigger sections normally lead to somewhat better results as the FFT resolution is improved In any case the data processing is faster Especially the amount of time required for stacking is reduced As normally only a few data is available for band 5 the preselected window length is only 512 data points With help of the menu item Block size different window sizes can be selected 128 256 512 1024 2048 or 4096 Note The length of time series sections is limited to a maximum of 1024 if time series are recorded in time slice mode with GMS05 The time slice mode is indicated by the shortform st behind the numbert of blocks in metronix 32 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 2 6 4 Width of the Parzen Window The width of the Parz
88. w time series of up to 8 channels e Display of calibrated time series e Marking of time segments as bad time series selection e Display of spectra e Definitaion of any equations uni or bivariate e Remote Reference e Computation of cross and auto spectra and impedance tensor e robust estimation of cross and auto spectra e Display of apparent resistivity and phase e Program can read calibration files for fine calibration e Variable FFT length up to 4096 data points e Fully menu operated e File handler included e Trend elimination optional The program can handle a frequency range between 4096 sec and 8192 Hz Due to the large bandwidth a splitting into different frequency bands is necessary which are measured independently at the measurement sites These frequency bands are computed by the program separately and the results for the different target frequency lines are calculated Finally the results for the different bands are combined This results in one file containing the cross and auto spectra of all measured channels E and H and of all target frequencies The time series of the electric and magnetic field components are split into fixed time segments whose length can be determined by the user Data analysis is done for each time segment resulting in many matrices for each target frequency up to several hundred containing the cross and auto spectra of all channels The number in metronix 8 100 28 08 02 Rev 2 1 P
89. y mode it is OdB ee for electric field channels km Hz OdB 1nT for magnetic field channels in metronix 39 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 2 5 Display of the Transfer Function Ctrl F transfer function ProcHT transfer function Y 1 0 c 1993 MTX Metronix 17 46 52 05 12 1993 Station As 27123404 Band 2 Block 1 of 116 7 auto scale 0 dB MENU1 Ci Ex channel mode Agath an station ALANS i select E band Yy home 4 end Boe chon 60 dB scroll 60 dB Fl horizontal scale Hx BE baselin on z of 100 dB MG 60 dB Menu 2 Hy 100 dB 60 dB Hz Es AltX i 100 dB Exit 1 Hz 256 Hz 512 Hz Figure 1 11 Display of the transfer function of the measurement channels Here not the transfer function itself but its reciprocal is displayed The transfer function is identical for all time sections of a band 1 3 2 6 Adding a Reference Station Ctrl R reference station The first station station A is considered as the reference station In each window beside the time series or spectra of the selected station white line the data of the reference station are presented yellow line Note Only colour screens allow a proper distinction of the two curves LCD or monochrome displays provide the same colour for remote station and reference station TT metronix 40 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program 1 3 3 Window and Screen Co
90. yed under Block Comp The interim results spectral matrices for all analysed time series sections and all target frequencies are stored in temporary files This data is used by the stacking algorithms in order to compute a stacked matrix for each target frequency ssa metronix 33 100 28 08 02 Rev 2 1 PMT21_E2 doc Chapter 1 Operating the Program according to the algorithms presented in chapter 3 2 The different methods to compute the spectral matrices are collected under the menu entry Analysis Estimate SPM Before starting the computation it is necessary to have defined the bivariate equations see chapter 1 2 6 2 This is required as most of the stacking algorithms use the multiple coherency see chapter 3 2 1 The last menu entry Coh Factor allows to modify the factors for the stacking algorithms with adaptive coherency threshold The factor determines the number of sections which will be respected during the stacking the sections with the highest coherency will be selected The preadjusted coherency threshold of 0 70 is a good compromise between a high degree of freedom and the rejection of outliers for most of the measurements For time series which have a high amount of noise a smaller facter up to 0 1 can improve the result significantly 1 2 8 The DOS Shell When selecting the menu item Services DOS Shell the program will switch back to the operating system command line without terminating the PROCMT program All usual D

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