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1. Figure 2 1 9 Easting and Northing profiles data and model response containing the selected point vy EM4Soil Q 3D Inversion Module Figure 2 1 9 shows the Setting menu when the Q3Dm is active after inversion The menu is almost the same for the EM4Soil Map menu with the distance view scroll added This allows the user to vary the distance between the observer and the 3D cube E EM4Soil Map module 0 x Exit Data Grid geometry Raw Data xmin C Plot sites NO sites Tmin Conductivity distance view C Resistivity al m gt Contour type 4 0 Linear Slices C Logarithmic Elev m Proportional xY scaling C Depthim f NO C YES Grid lines NO C YES OK ma n Minimum elev 0 0 Kdaximum elev 28 1 Figure 2 1 9 Settings menu The elevation depth options only will select the horizontal slice of the Q 3D model that will be displayed if the option Display Horizontal slices is used It does not have influence in the 3D cube display vy EM4Soil Q 3D Inversion Module 2 2 Data Processing These options are mainly devoted to prepare data for Q3D inversion However they can be used in any imported data Their use was already explained in the EM4Soil manual and is repeated here W EM45oil Map module Exit Display Data Processing Tools Profile mode Inversion Zoom Save Rotate Undo Rotation Action Plot Editi NotePad Plot R Gridding Filter Data Cor2. EM4Soil Q 3D Inversion Module EM4Soil A program for 1 D laterally constrained inversion of EM data Quas 3D Module Version 0 0 This Software is produced by EM TOMO with the collaboration of John Triantafilis Email emtomog gmail com May 2013 EM4Soil Q 3D Inversion Module DISCLAIMER The programs software included in any version of the EM4Soil packed are provided as are without any express or implicit warranties including their suitability for a particular purpose The authors and EMTOMO LDA will not assume any responsibility for any indirect or consequential damages or any loss caused by the use of these programs Efforts will be made to correct any program bug that appears during the usage of the package vy EM4Soil Q 3D Inversion Module CONTENTS 1 Introduction 2 The menu bar for Q3Dm 2 1 Display 2 2 Data Processing 2 3 Inversion yo EM4Soil Q 3D Inversion Module 1 Introduction The software described in this manual is for inversion of EM data LIN approach using the 1D spatially constrained algorithm This software is a module of the EM4Soil package Moreover the Q 3D module Q3Dm is composed by a set of tools for data processing visualization and inversion that are available through the EM4Soil Map module The data is the measured apparent soil electrical conductivity og as measured by EM instruments and is input through EM4Soil using the Input input data area in t
3. two dimensional models from magnetotelluric data Geophysics 55 1613 1624 Dualem Inc 2008 DUALEM 421S user s manual Dualem Inc Milton ON Canada 16 vy EM4Soil Q 3D Inversion Module Goldstein N E Benson S M and Alumbaugh D 1990 Saline groundwater plume mapping with electromagnetics In Geotechnical and Environmental Geophysics Ed By Ward S H Investigations in Geophysics n 5 SEG Golub and Reinsch 1970 Singular value decomposition and least squares solution Num Math v 14 no 3 403 420 Gomez Trevino E F J Esparza and S M ndez Delgado 2002 New theoretical and practical aspects of electromagnetic soundings at low induction numbers Geophysics 67 1441 1451 Huang H 2005 Depth of investigation for small broadband electromagnetic sensors Geophysics 70 6 G135 G142 Johansen H K 1977 A man computer interpretation system for resistivity soundings over horizontally stratified earth Geophysical Prospecting 25 677 691 Kaufman A A and G V Keller 1983 Frequency and transient soundings Methods in Geochem and Geophys 16 Elsevier New York Keller G V and F C Frischknecht 1996 Electrical Methods in Geophysical Prospecting Pergamon Press Inc 513 p McNeill J D 1980 Electromagnetic terrain conductivity measurement at low induction numbers Geonics Limited Technical Note TN 6 Monteiro Santos F A 2004 1 D laterally constrained inversion of EM34 profiling dat
4. cube pushing the right mouse button Q3D Model Survey LagodD Layer 5 Altitude 2 3 m 40 0 35 0 Q 30 0 29 0 wgw puo 20 0 15 0 Figure 2 1 5 Displaying horizontal slices EM4Soil Q 3D Inversion Module survey Lago3sD Cut at X 33 3 m 40 0 35 0 4 30 0 gur puo 20 tI 20 0 13 0 Figure 2 1 6 Displaying vertical slices parallel to Y direction Surve E arn inii Cut a 2a0 mMm Figure 2 1 7 Displaying vertical slices parallel to X direction yo EM45Soil Q 3D Inversion Module Clicking in the option profiles with the Q3D cube in the screen the program will display the mesh of measurements used in the inversion Figure 2 1 8 and the mouse pointer will be modified into a cross Move it till the row and column of the mesh you want to see and click sequentially without moving the mouse in the left and right buttons The easting and northing profiles of data and model response will be displayed Figure 2 1 9 W EM4Soil Map module 2 5 x Exit Display Data Processing Tools Profile mode Inversion Zoom Save Print Help About Action Plot Survey Plot Raw Data Quit Figure 2 1 8 Mesh for selection of the profiles Ml EM4Soil Map module i Exit Display Data Processing Tools Profile mode Inversion Zoom Save Print Help About O x Plot Raw Data Quit Bo oF amp t Nerthing wo pos an 17 0 X Easting m Northing m
5. different initial models before to select the final inversion 15 vy EM4Soil Q 3D Inversion Module Examples of initial models for DUALEM 421s DUALEM 642s PROFILER for very high conductivity terrain and EM34 are presented below see formats in the section 9 of the EM4Soil Manual DUALEM 42Is 9 0 3 0 6 1 0 1 5 2 3 3 3 4 5 5 7 30 30 30 30 30 30 30 30 30 DUALEM 642s 8 0 6 1 2 2 2 3 3 4 5 6 0 8 0 10 10 10 10 10 10 10 10 PROFILER 6 0 3 0 7 1 2 2 4 3 7 1600 1600 1600 1600 1600 1600 EM34 8 3 0 6 0 9 0 12 0 16 0 24 0 40 0 100 100 100 100 100 100 100 100 ACKNOWLEDGMENTS Several people have contributed indirectly for this work We are particularly grateful to Richard Taylor Dualem Inc Scott Holladay Geosensors Inc and Michael Gehrig GEHRIG Inc for their comments and suggestions References and useful bibliography Sikiru A Amidu S A and Dunbar J A 2007 Geoelectric Studies of Seasonal Wetting and Drying of a Texas Vertisol Vadose Zone Journal v 6 n 3 511 523 Anderson W L 1979 Numerical integration of related Hankel transforms of order 0 and by adaptative digital filtering Geophysics 44 1287 1305 Callegary J B T P A Ferr and R W Groom 2007 Vertical spatial sensitivity and exploration depth of low induction number electromagnetic induction instruments Vadose Zone J 6 158 167 DeGroot Hedlin C and Constable S C 1990 Occam s inversion to generate smooth
6. immediately after rotation Click OK firstly to get the limits and mean distance corresponding to the rotated survey The inverse distance option uses the GETMAT subroutine in DISLIN The value at the grid point j k is calculated by Where j k are the indices from 1 to Nx lines and 1 to Ny lines respectively d is the distance of the grid point i k from the point Pi w is a weighting number default is 2 0 and N is the number of data points lying in the area controlled by the parameters in the smoothing section around the grid point j k The grid files can be filtered The available filters are linear low pass filters and should be applied to reduce the high frequency noise They calculate weighted averages of the neighbouring input grid nodes In the Moving Average SxT filter the weight are equal to one In the Inverse Distance SxT filter the weights fall off with increased distance The role of the distance is controlled by the Power The higher the power the more rapidly the weights fall off with distance The filter can be applied to all data set or only to specific channels 11 EM4Soil Q 3D Inversion Module in xi Exit Filter options e Moving average E Distance Weighting Filter Height S and idth T i l Power Data to be filtered Flevation All HCP Figure 2 2 3 The Filter parameters menu D 21S If the number of negative values in the data set is less than 30 of all data th
7. a J Appl Geophys 56 123 134 Monteiro Santos FA Triantafilis J Taylor R Holladay S and Bruzgulis K 2010 Inversion of conductivity profiles using full solution and a 1 D laterally constrained algorithm Journal of Envirnmental and Engineering Geophysics 15 3 163 174 Monteiro Santos FA Triantafilis J Bruzgulis K and Roe J A E 2010 Inversion of multiconfiguration electromagnetic DUALEM 421 profiling data using a one dimensional laterally constrained algorithm Vadose Zone Journal 9 1117 125 doi 10 2136 vzj2009 0088 Monteiro Santos FA Triantafilis J Bruzgulis K 2011 A spatially constrained 1D inversion algorithm for quasi 3D conductivity imaging application to DUALEM 421 data collected in a reverine plain Geophysics 76 2 B43 B53 doi 10 1190 1 3537834 Sasaki Y 1989 Two dimensional joint inversion of magnetotelluric and dipole dipole resistivity data Geophysics 54 254 262 Sasaki Y 2001 Full 3 D inversion of electromagnetic data on PC Journal of Applied Geophysics 46 45 54 17 vy EM4Soil Q 3D Inversion Module Triantafilis J Roe J A E Monteiro Santos F A 2011 Detecting a landfill leachate plume using a DUALEM 421 and a laterally constrained inversion model Soil Use and Manamgement in review Triantafilis J Monteiro Santos F A 2010 Resolving the spatial distribution of the true electrical conductivity with depth using EM38 and EM31 signal data and a latera
8. e user can try to correct or delete them It must be noted that correcting data can originate false anomalies The user must pay attention to this relevant issue Grid Data HeF 1 Htr a HtF A a T AGU T 490 0 a g 3 re Fo rm a u 4000 a 480 0 a a T m m m a H b 4700 4700 460 0 456 0 205 910 5 PxD D 8060 0 810 0 Bet BOO HG ee Distance X fm Distance X fm Distance X fra FEF 1 FRF 3A PRF 4 a H 490 0 J 490 0 H H H g g 450 0 g 4500 A faj 4 4 a A 470 0 a 470 0 466 460 6 PAGA Bio TAUA 00 0 BL0 0 Reno BOO a10 0 r rt Distance X m Distance m Distance X fm 10 0 PLO H A 40 0 m m Figure 2 2 4 Example of a gridded data set 12 vy EM4Soil Q 3D Inversion Module The survey can be rotated according to an angle measured from North The program can calculate the rotation angle selecting the option Automatic However the user should confirm the survey is properly rotated New rotations are added to previous ones E Survey Rotation O x lees Rotation C Automatic Angle Clockwise rotation in Degrees angle OK Figure 2 2 5 Options for rotation The rotated survey will be displayed in a new window The rotation is made relatively to a point located approximately in the geometric centre of the survey which is the origin of the local coordinates used for the rotated survey When a rotated survey is inverted the original coordinates are recovered at the end of t
9. he menu bar please see the EM4Soil manual This version of Q3Dm only can deals with data collected with DUALEM and GEONICS instruments The inversion procedure used in Q3Dm is a 1 Dimensional Spatially Constrained technique 1 D SCI It is also known as a Quasi 3D inversion Monteiro Santos et al 2011 The forward modelling is based upon the cumulative function McNeil 1980 The called full solution of EM fields is not implemented in this version The inversion algorithm is based upon the Occam regularization method e g DeGroot and Constable 1990 Sasaki 1989 vy EM4Soil Q 3D Inversion Module 2 The menu bar for Q3Dm Figure 2 1 shows the screen shot of the EM4Soil Map module containing the Q3Dm functions EM4Soil Map module Exit Display Data Processing Profile mode Inversion Zoom Save Print Help About Plot Raw Data Quit Figure 2 1 Screen shot of the EM4Soil Map module with Q3D functions At follow a short description of those Q3Dm functions is presented 2 1 Display Click in the Display Q3D Model entrance to display the results of an inversion The results can be displayed as horizontal or vertical slices or in a 3D cube Note that options or display Thickness and Bottom Elevation should be used with results calculated with algorithm S3 The Misfit entrance will display maps of misfit for each sensor In Settings you can make choices about how to display your results Me EM4Soil Map modu
10. he inversion 2 3 Inversion The inversion entrance allows the user to define the parameters of the inversion the initial model as well as to run the inversion Figure 2 3 1 to 2 3 3 Inversion zoom Save Print Help About Input initial model Inversion Q30 Inversion Calculation CF Trace Inversion Appraisal inversion Q30 Figure 2 3 1 The inversion menu 13 EM4Soil Q 3D Inversion Module E Inversion Parameters Ioj x Exit Damping factor 0 30 Number of iterations Data error Misfit target 0 20 C Algorithm 1 Algorithm S2 C Algorithm 3 OK a o o Figure 2 3 2 Selecting parameters for inversion The algorithms used in the Q 3D inversions are basically the same of those used in the Q 2D inversion with one exception the S3 algorithm The S3 algorithm is designed to invert data collected with instruments containing only one sensor like DUALEM Is 2s 4s or with EM38 and EM31 In this case the initial model should be defined manually usually a two layer model or read in a file Regarding algorithms S1 and S2 the reader is referred to the EM4Soil manual The same is valid for the different formats of initial model La Inversion Parameters Manually 1 D Automatic from data Open File 1 D Uniform medium Figure 2 3 3 Selecting the initial model In this version of Q3Dm the inversion only can be done on gridded data Therefore the user must produce a grid fi
11. le Exit Display Data Processing Tools Profile mode Inversion Zoom Sas Ac Survey layout Fam Data d Survey Goa0 Model Horizonotal Slices Layer T Grid Filtered Data O2D Model Slices O30 Model Horizontal slices Conductivity Vertical slices Thickness Settings 3D visualization Misfit Eotkom Elevation Window size Figure 2 1 1 Displaying the results of a Q 3D inversion vy EM4Soil Q 3D Inversion Module Line Lago3D Q 3D Model Vertical Slices nection at Y 26 2 m Azimuth 90 0 Deg 17 P g yi v 44 eo lt or oo at 0 0 2 8 3 7 8 5 11 3 14 2 17 0 198 fey RoS fb Sle J40 Easting 20 0 25 0 30 0 35 0 40 0 Cond m m Figure 2 1 2 Displaying a vertical slice of the Q 3D model Me EM45oil Map module Exit Display Data Processing Tools Profile mode Inversion Zac Ac Survey layout Raw Data b an Bourvey nameLine ee a n Sensor Grid Filtered Data 02D Model Slices O30 Model Horizontal slices Vertical slices Settings 3D visualization Misfit cuts X Profiles Window size Figure 2 1 3 The different options for displaying results of a Q 3D inversion Figure 2 1 3 shows the different options to display the results in a 3D cube vy EM4Soil Q 3D Inversion Module survey Lago3D Cut at X 58 0 m Figure 2 1 4 Displaying the model in a 3D cube The user can move through the 3D
12. le see how to do that in 2 2 Such files should have the EMGR mask or other that have been chosen by the user 14 EM4Soil Q 3D Inversion Module Data Selection Please input the file with the data for inversion You can input grided data EMGR or filtered grided data DAT Figure 2 3 4 Inputting a grid file for inversion According to the dimensions of the grid the program will divide the area in sections performing the inversion of each section separately However contiguous sections will have common areas in the border zones in order to avoid inconsistencies in the final model Nevertheless the process can originate undesirable effects in special occasions We recommend a careful analysis of the final models Exit Figure 2 3 5 Tracing the inversion The initial and final misfit for each section will be displayed in a table Figure 2 3 5 The user can repeat the inversion of any section changing the NO in the last column into YES or Y and repeating the inversion After the inversion has finished the results can be displayed using the options mentioned in 2 1 2 4 Initial models The initial model used in the inversion is one of the most important aspects to take into account Such initial model depends on the data set to be inverted Different sensors have different depth of investigation that is also function of the geoelectrical profile of the earth Therefore it is advisable to invert the data with
13. lly constrained inversion model Australian Journal of Soil Research 48 434 446 Triantafilis J Monteiro Santos F A 2009 2 dimensional soil and vadose zone representation using an EM38 and EM34 and a laterally constrained inversion model Australian Journal of Soil Research 47 809 820 Wait J R 1962 A note on the electromagnetic response of a stratified earth Geophysics 27 382 385 18 EMTOMO 1s a registered mark 2011 EM4Soil Q 3D Inversion Module 19
14. rection negative values Filter Elewation Delete negative values Figure 2 2 1 The Data Processing menu Grid files are necessary for the Q3 D inversion Data files contain in general randomly spaced measuring sites and should be converted into a regular grid before inversion To create a grid file the user must specify the parameters limits of the area to grid number of points in the X and Y directions as well as the output file The output file has the mask EMGr it is assumed by default The output file menu will appear after click OK E Grid Geometry Exit Gridding Method Grid geometry Inverse Distance Mean distance 13 93 Input Data min 0 0000 Raw data C Potated xmax 865 9062 OK lines ymin 0 0000 Ymax 1073 0000 rlines smoothing xlines rlines Weight Figure 2 2 2 The Data Gridding widget 10 vy EM4Soil Q 3D Inversion Module The mean distance between measuring sites 1 25 average distance is used to suggest values for the number of points in X and Y directions The number of points in X directions is approximately calculated by Xmax Xmin mean distance A similar calculation is applied to the Y direction If those values are gt 100 the program write the value 100 recalculating also the mean distance value Changing the Xmax Xmin Ymax and Ymin allows to grid only a part of the area covered by the survey Rotated files can also be rotated The gridding must be done
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