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"Structural Index" in Euler Deconvolution (T44)

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1. gt Specify the output point dataset to be created with the results of the process Use Specify Output Point Dataset from the File menu See Specifying input and output files for detailed instructions If the complete set of Euler solutions does not already exist for the current grid specify the Euler Deconvolution parameters and choose Apply Deconvolution See Creating the complete set of Euler solutions Steps for details If you only wish to produce the complete set of Euler solutions without rejecting any go tostep 11 In this case INTREPID produces only the complete set of solutions see Output the complete set of Euler solutions It does not produce the output point dataset that you specified see Output E uler solutions point dataset Specify the criteria for selecting classifying Euler solutions for output See Selecting and classifying Euler solutions Steps for details When you have made specifications and settings according to your requirements choose Apply Sort INTREPID selects the solutions and save the output data as specified If you wish to record the specifications for this process in a job file in order to repeat a similar task later or for some other reason use Save Options from the File menu See Specifying input and output files for detailed instructions If you wish to repeat the process repeat steps 3 11 varying the parameters and data files as required To exit from Euler Deconvolution cho
2. And now an example in the new V5 0 syntax We distribute this file at V5 0 as part of the sample data examples tasks area Example job file Euler deconvolution Euler consists of two stages Stage 1 generates a solutions file from the grid rs Stage 2 accepts rejects solutions according to user specified criteria and writes the accepted solutions to an Intrepid point dataset 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 49 Library Help Top lt 4 Back gt The example job file computes both stages and creates a report file the fault contact importer for Geomodeller is available from V2012 onwards Usage fmanager batch euler task when done combine all the by worm contact orientation and limited fault extents solutions into a coherent fault network for import into Geomodeller IntrepidTask Euler InputGridName datasets mlevel grid ers Band 0 Output datasets euler DIR ReportFile datasets euler rpt SurveyHeight 60 0 ExportTypes Database 3D visual formats of solutions Dump VRML false Dump BREP false Sort main rejection of false solutions criteria LowerGoodnessClip 0 0 UpperGoodnessClip 1 0 LowerStructuralIndexClip 0 5 UpperStructuralIndexClip 4 5 NumberVerticalLayers 1 MinimumDepth 0 0 MaximumDepth 5000 0 if vector from observation point to solution dips less than 20 disca
3. In the Euler Deconvolution area e Check or clear the Convolve Derivatives Anti aliasing check box e Check or clear the Save derivatives and analytic signal check box Derivatives and analytic signal task files Within the Solve Begin End block e Set the ConvolveDerivatives keyword to Yes or No e Set theSaveDerivatives keyword to Yes or No Example SaveDerivatives Yes ConvolveDerivatives Yes 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 31 Library Help Top lt 4 Back gt Apply Deconvolution Parent topic Euler Deconvolution parameters and execution Interactive Task files Library Help Top After you have specified the input grid and parameters for calculating the complete set of Euler solutions choose Apply Deconvolution INTREPID calculates the solutions saves them and also saves intermediate results datasets if you have specified this You can specify how you want INTREPID to use the INTREPID_MEMORY system parameter RAM virtual memory and temporary workfiles in the processing task files only See INTREPID system parameters and install cfg RO7 The options are for INTREPID to e UseRAM according tothe INTREPID MEMORY system parameter value If more memory is required use temporary workfiles AUTO e Usetemporary workfiles for all data FORCE DISK All INTREPID data is written to temporary workfiles as it is processed e Use
4. Vertical Component of Gravity grid nb Units must be mGals Browse 2 In the Euler Deconvolution area select e The Tensor Coordinate Convention of your dataset Estimate Tz from Tensor 3 In the Euler Deconvolution area specify e The Structural Index See Structural Index e The Vertical component of gravity grid Task files Tensor gravity estimator with fixed SI Task files Within the Solve Begin End block e Set the EquationCombo keyword to Tensor Gravity Estimator e Set the required value for the StructuralIndex keyword See Structural Index Example EquationCombo Tensor Gravity Estimator StructuralIndex 1 Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 22 Library Help Top lt 4 Back gt Euler Deconvolution parameters and execution Parent topic Euler Deconvolution T44 In this section e Fast Fourier transform e Structural Index e Determining the maximum depth for solutions window size e Survey observation height e Reduction to the pole e Derivatives and analytic signal e Apply Deconvolution Fast Fourier transform Parent topic Euler Deconvolution parameters and execution Library Help Top The Euler Deconvolution process requires partial derivatives and analytic signal of the input grid For a scalar input grid INTREPID performs a Fast Fourier Transform FFT as the first step in obtaining the deri
5. e FFT grid of original signal 1 e Original signal with Hilbert in X and Y 2 e Analytic signal analytic signal with Hilbert in X and Y 3 e Derivatives of signal in X Y and Z 3 e Derivatives of signal with added Hilbert in X 3 e Derivatives of signal with added Hilbert in Y 3 Here is a complete list of intermediate grids The filenames consist of e Theinput grid name inputgrid_ e A unique numeric code tempcode_ to distinguish between different times that you run the task and e Thetype of intermediate grid e Thetext RESIZED if INTREPID expanded the grid beyond its boundaries to prepare it for FFT This does not normally happen if you use a subsection and specify the border within the grid see Specifying the region for calculating solutions and Expanding the boundary of the input grid INTREPID saves these grids in the folder install _path temp Since this is a routine process INTREPID does not include options for you to manually prepare these grids yourself and submit them to the tool You can specify whether to retain these files after the Euler Deconvolution process See Derivatives and analytic signal for instructions You can examine any of the grids to make sure the FFT work does not contain ringing If there is ringing work on the input grid to reduce noise Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 9 Library Help Top
6. HANNING HAMMING BLACKMAN TRIANGLE NONE gt UseSymmetry lt Yes No gt If Hilbert No If no Hilbert ves FFTPrecision lt datatype gt IEEE8ByteComplex EquationCombo lt Classic Processing option See The standard and Classic Hilbert_Only extended Euler equation options Al13_ Fixed SI A113 For Contact Case No SI Known Depth TensorBouguer TensorEstimateGravity DiskUsageRule lt AUTO See Apply Deconvolution AUTO FORCE MEMORY FORCE DISK gt Required Points See Input input grid band all points in x y depth The presence of this block changes the way dataset the tool ol ust the required points are used instead of the whole grid ConvolveDerivatives lt Yes No gt See Derivatives and analytic signal Yes SaveDerivatives lt Yes No gt No DoReductionToPole lt Yes No gt See Reduction to the pole No Date lt date gt Survey date for calculated GRF model 31 12 1999 Solve End Library Help Top 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Euler Deconvolution T44 45 Library Help Top lt 4 Back gt Statement Description Unit Default Sort Begin Sort block LowerGoodnessClip lt number gt See Goodness 0 UpperGoodnessClip lt number gt 1 LowerStructuraliIndexClip See Selecting Euler solutions for output 0 5 lt number gt UpperStructuralIndexClip 4 5 lt number gt MinimumDepth lt number gt See Selecting so
7. e Selecting solutions by depth e Maximum absolute alpha e Maximum singularity ratio e Restricting solutions to the grid boundary e Goodness Reject solutions with values outside Upper Structural op 450 Lower Structural elpfO50 Min Obs S ource dip Minimum depth 0 0 Maximum depth Percent Depth Error Max Absolute Alpha Max Singularity ratio1000000000 0 Cull Solutions to Grid extent Structural index clips Parent topic The structural index clip determines which of the solutions are to be selected based Shield egal on the characteristic power fall off of the signal The structural index reflects the type Peon of causative body for the anomaly see Structural ndex output Option Purpose Lower Structural clip Should range between 2 and say 2 Upper Structural clip Should range between 0 and say 4 Task files Example LowerStructuralIndexClip 0 5 UpperStructuralIndexClip 4 5 Minimum observed dip Parent topic The dip from the current point of observation of the field to the calculated source body iii youd is a good filter for rejecting poorly conditioned solutions The deconvolution process conrad ail ensures there are dusters of solutions around the causitive bodies and those solution output j estimates that derive from further away for shallow bodies are suspect Option Purpose Minimum The default angle should be lower for gravity as the field is les
8. files Process Begin Task file outer block Tool name and date stamp ee Input and output files specification Parameters Begin Parameters block SurveyHeight Survey height for calculating solutions Sort Begin Selecting and classifying solutions block Sort End Solve Begin Calculating solutions block Solve End Subset Begin Region for calculating solutions block Subset End Parameters End End Process End End Displaying options Parent topic You can view the parameters selected for the Euler Deconvolution process Displayi peli e Inthe controls of the Euler Deconvolution window OR using task e By saving the task specification job file and viewing its contents specification oo files e At V5 0 look at the protobuf language specification file intrepid_tasks proto that is available under the API directory identify the syntax section for Euler and there it all is with lots of comments The beauty and power of this approach is that this is exactly the same file that is being used by INTREPID to build the parsers that decode the task files Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 44 Library Help Top lt 4 Back gt Syntax table Parent topic This table has a complete task specification file outline with all possible statements Displaying and blocks options and using task specific
9. potential fidd data Unpublished M Sc Thesis International Training Centre Delft McDonald A J W Fletcher C J N Carruthers R M Wilson D and Evans R B 1992 Interpretation of the regional gravity and magnetic surveys of Wales using shaded relief and Euler deconvolution techniques Geol Mag v 129 p 523 531 Marson l and Klinglele E E 1993 Advantages of using the vertical gradient of gravity for 3 D interpretation Geophysics v 58 p 1588 1595 M F Mushayandebvu A B Reid J D Fairhead 2000 Grid Euler Deconvolution with constraints for 2D structures Extended Abstract GM XX pxxx SEG Annual Meeting Calgary Mushayandebvu M F van Driel P Reid A B and Fairhead J D 2001 Magnetic source parameters of two dimensional structures using extended Euler deconvolution Geophysics v 66 no 3 p 814 823 Nabighian M N and Hansen R O 2001 Unification of Euler and Werner deconvolution in three dimensions via the generalized Hilbert transform Geophysics v 66 no 6 p 1805 1810 Neil C 1990 A computer program to interpret automatically potential fidd data using Euler s equation of homogenaty Unpublished M Sc thesis University of Leeds 72p 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 52 Library Help Top lt 4 Back gt Neil C Whaler K A and Reid A B 1991 Extensions to Euler s method for three dimensional potential fidd interpretat
10. 1 Standard Euler see The standard and extended Euler equation options the correct setting is No For Method 1 Standard Euler the correct setting is Yes If you use interactive mode for the tool to run it or create a task file INTREPID automatically selects the correct setting FFT grid precision You can specify the precision of the spectral domain grid See Data Types in INTREPID datasets in INTREPID database file and data structures RO5 for the available numeric data types You can choose between 4 byte and 8 byte precision Saving the derivative and analytic signal grids See Output F FT and derivative products for information and instructions Fast Fourier transform interactive 1 Choose main menu option Spatial gt Rectangle 2 Ensurethat you have specified any subset rectangle that you require see Specifying the region for calculating solutions 3 Enter the border width in metres in the FFT Border text box and then choose OK In the Euler Deconvolution area check or clear the Use real 4 precision for Fourier work check box See also Output F FT and derivative products 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 24 Library Help Top q Back gt Task files Fast Fourier transform task files 1 Within the Subset Begin End block e Set the FFTborder keyword to the width in distance units you require 2 WithintheSolve Begin End block set the
11. Euler Deconvolution 2 If editing Load the task specification job file File menu Load Options 3 Set parameters as required 4 Savethe task specification j0b file File menu Save Options gt gt To usea task specification file in an interactive Euler Deconvolution session Load the task specification job file File menu Load Options modify any settings as required then choose Apply Deconvolution or Apply Sort or both as required gt gt To usea task specification file for a batch mode Euler Deconvolution task Type the command euler exe with the switch batch followed by the name and path if necessary of the task specification file For example if you had a task specification file called surv329 job in the current directory you would use the command euler exe batch surv329 job Task specification file example Here is an example of a Euler Deconvolution task specification file Process Begin Name Euler Comments Intrepid Audit Stamp v4 0 Build 69 22 4 2006 Input C Intrepid cookbook eulerplay tmi_ns ers Output C Intrepid cookbook eulerplay eulersols DIR ReportFile euler rpt Cluster C Intrepid cookbook eulerplay eulercluster DIR Parameters Begin SurveyHeight 0 0 Sort Begin ExportTypes Database LowerGoodnessClip 0 0 UpperGoodnessClip 1 0 LowerStructuralIndexClip 0 5 UpperStructuralIndexClip 4 5 NumberVerticalLayers 1 MinimumDepth 0 0 MaximumDepth 5000 0 MinimumObservationDip
12. Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 8 Library Help Top lt 4 Back gt Task files Example VerticalComponent C Intrepid cookbook grav_ z ers Input solutions for re sorting Parent topic Interactive only If you already have a set of solutions rs file see Output E uler ee solutions point dataset and you want to classify and select from it to create an output Input an g Ge files points dataset use this option to spoecify the solutions file Interactive Choose main menu option File gt Open solutions for resorting Task files In batch mode you must calculate the solutions in the same task You cannot load an existing set of solutions for sorting There is no keyword in the task file language for this input file Input options Parent topic If you wish to usean existing task specification file to specify the Euler Deconvolution Specifying process choose File gt Load Options to specify the task specification file required ae INTREPID will load the file and use its contents to set all of the parameters for the Euler Deconvolution process See Displaying options and using task specification files for more information Output FFT and derivative products Parent topic For extended Euler deconvolution we need to prepare up to 15 grid products for usein SRRA the process INTREPID prepares and these automatically input an output files The products include
13. We use this to continuously validate that for known models this technique is functioning as well as we can manage and that the answers are correct to within less than 1 error for the perfect cases with no noise Of course this scenario then also opens up the perfect opportunity to devise ways to find the outlier solutions and why they occur in the first place See the task specification section for more details INTREPID has a range of available formats for the output dataset The Euler Decomposition tool uses components of the analytic signal of the data to calculate the model See Analytic signal filter reference in INTREPID spectral domain operations reference R14 Stages in the extended Euler deconvolution process Parent topic Euler Deconvolution T44 Library Help Top The extended Euler deconvolution process has two stages 1 Generating extended Euler solutions for the grid The left side of the Euler Deconvolution window has controls for the input of your grid It enables you to e Select the Euler Werner or Hilbert variation that you require e Immediately reject solutions with unrealistic depth e Perform reduction to pole for magnetic data e Save intermediate derivative and analytic signal grids for inspection At the end of this stage you create an intermediate solutions file a large ASCII text file 2 Selecting the solutions for output Using the selecting and sorting features you can generate
14. Y Z SI B a B With some options you need to specify parameters or provide input data SI depth or vertical component Z a and B are body property indicators calculated in some options Background represents background magnetic field or gravity without local anomalies Method 1 Standard Euler Parent topic The standard and extended Euler equation options Interactive Task files Library Help Top This method uses only the Classic equation This suffers from scatter and noise if the gradient grids are not very good It assumes fixed structural index SI which you specify as a parameter see Structural Index It solves for X Y Z and B Background Background represents background magnetic field or gravity without local anomalies Standard Euler interactive In the Euler Deconvolution area 1 Select Standard Euler 2 Specify the Structural Index see Structural Index Standard Euler task files Within the Solve Begin End block e Set the EquationCombo keyword to Classic e Set the required value for the StructuralIndex keyword Example EquationCombo Classic 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 17 Library Help Top lt 4 Back gt StructuralIndex 1 Method 2 Euler Werner Parent topic This extended Euler method uses all three equations The standard and extended It assumes fixed structural index SI which
15. Y andSI from Method 3 E uler Werner 2 Equation SI solver e The best Z results from the two methods This is the deepest of the two depths with a small scaling adjustment derived from the Bishop study Interactive Hybrid 2 pass Euler solver interactive In the Euler Deconvolution area 1 Select Hybrid 2 pass Euler solver Task files Hybrid 2 pass Euler solver task files Within the Solve Begin End block e Set the EquationCombo keyword toHilbert then_no SI Example EquationCombo Hilbert then no SI Method 6 Euler Werner Full Solver Parent topic This extended Euler method uses all three equations The standard and extended It solves for X Y Z SI Q B Euler equation options This method solves for all unknowns Interactive Euler Werner Full Solver interactive In the Euler Deconvolution area 1 Select Euler Werner full solver Task files Euler Werner Full Solver task files Within the Solve Begin End block Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 19 Library Help Top lt 4 Back gt e Set the EquationCombo keyword toAl13 For Contact Case Example EquationCombo All13 For Contact Case Method 7 Euler Werner property solver Parent topic Not recommenede for the novice user This extended Euler method uses all three The standard equati ons and extended Euler equation It solves for SI B options It assumes k
16. collection of solutions which is well distributed Classifying geographically In order to achieve this Euler Deconvolution has a system of Euler solutions geographic bins subregions of the output dataset area You define the size of the bins and INTREPID applies the Goodness selection see Goodness to each bin separately This means that although solutions are selected from each region of the dataset solutions from sparsely populated geographic bins may have a lower average reliability than those from more densely populated bins Use Bin Size East Bin Size North to specify the dimensions in dataset distance units of a geographic bin If you have specified a geographic region for selecting output See Restricting solutions to the grid boundary a geographic bin will be a subregion of this If you have not selected a geographic region a geographic bin will be a subregion of the whole input dataset If you specify a bin size larger than the whole output dataset INTREPID will not use this selection method Option Purpose Do Binning Analysis Check this box to perform vertical and horizontal binning classification See also Binning analysis dassifying Euler solutions by depth To disable horizontal binning specify bin size larger than the dataset or subsection see Specifying the region for calculating solutions Bin size East Use this parameter to specify the easting dimension in dataset distance unit
17. errors and covariance 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 16 Library Help Top lt 4 Back gt For a particular model such as a dipping contact you can calculate other properties including dip strike and physical property contrast density or susceptibility The Euler Deconvolution tool currently offers eight extended Euler equation options You can select the options in the user interface or using keywords in the task files Eulerf ermer Deconvolution Tensor Grid Euler Deconvolution Full Gravity Gradiometry Supported Tensor Coordinate Convention ENU NED END C Euler Wemer assumes fixed SI XYZ B Structural Index C Eulerf erner 2 Eq SI solver lt YZ SLb Eulerf erner Basement solver XYZ a_b Estimate Tz from Tensor assumes fixed SI lt YZ Tx y z Structural Index 1 00 C Hybrid 2 pass Euler solver XYZ_ SI a b C Euler erner Full solver lt YZ SLa_b C Euler from Gravity Tensor and Tz XYZ SLTx Ty Vertical Component of Gravity grid nb Units must be mGals Browse C Eulerf erner property solver Sl_a_b Depth to basement grid nb depth in grid are ve Browse The extended E uler calculations use combinations of three equations e Classic Euler equation Classic e Hilbert transformation in North and East directions Hilbert Depending on the options you can solve for X
18. following keywords see the explanation of each parameter in this section and Syntax table for the available options e DetrendDegree e FillType e RolloffType e WindowType e UseSymmetry e iImproveEstimate e FFTPrecision Example Subset Begin FFTborder 5000 0 Subset End DetrendDegree 1 FillType ARTHUR RolloffType COSINE WindowType NONE UseSymmetry Yes FFTPrecision IEEE4ByteComplex ImproveEstimate No See also Output F FT and derivative products Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 25 Library Help Top lt 4 Back gt Structural Index Parent topic Euler Deconvolution parameters and execution Library Help Top The extended Euler deconvolution processes calculates the Structural Index SI If you are using standard Euler or Euler Werner you need to specify the SI If you are using the other extended Euler options you no longer need to specify SI See The standard and extended Euler equation options for details The following table contains a summary showing the relevance of the SI to each calculation option Structural Index Option Parameter that you specify Method 1 Standard Euler Method 2 Euler Werner Method 9 Tensor gravity estimator with fixed SI Calculated output field Method 3 Euler Werner 2 Equation SI solver Method 5 Hybrid 2 pass Euler solver Method 6 E uler We
19. for data points whose northern coordinate is less than or equal to the northern boundary value Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 14 Library Help Top lt 4 Back gt Task files Example Subset Begin XLower 520129 158 XUpper 595129 158 YLower 7236236 0 YUpper 7311236 0 Subset End Creating the complete set of Euler solutions Steps Parent topic In the first stage of the Euler Deconvolution process INTREPID generates a complete Euler set of Euler solutions Deconvolution T44 It saves these solutions to a file from which you can select solutions for the output dataset See Output the complete set of Euler solutions for details gt gt To create the complete set of Euler solutions 1 Ensurethat you have specified the input grid dataset See Specifying input and output files for instructions 2 Specify e Theextended Euler equation option see The standard and extended Euler equation options e Standard Euler and Euler Werner only The required structural index see Method 1 Standard Euler Method 2 E uler Werner and Structural Index e Euler Werne property solver only The depth to basement grid see Method 7 Euler Werner property solver and Input depth to basement grid e TheFFT parameters see Fast Fourier transform e Thesurvey height See Survey observation height e Thesize of the Euler windo
20. implementation of Euler deconvolution first appeared in 1993 It is based on earlier implementations by De Beers and Stockdale Since then after work by Nabighian and Hansen 2001 we have extended the Euler method to include equations from Hilbert transformations Using this you can obtain superior depth solutions and data about geological structure that is you can use the process to calculate structural index See Fitzgerald et al 2004 for details of this method Also full tensor gravity and magnetic gradient grids derived directly from observed survay data are also supported in this tool FTG data as it is known gives a better performance at estimating depths to structures and alsoin more sharply defining boundaries as there is more constraints in the signal and also more information about the causitive bodies comarped to the integrated response of a vertical gravity or TMI survey Often it is quite hard to get a good Euler solution from ground gravity data whilst gravity tensor data behaves much better The following illustrations show a basement depth model and a corresponding population of calculated structural index of the Bishop dataset Fitzgerald et al 2006 We used this test data to validate the hybrid Euler solver for basin studies pe A y Ff i i Sy oye The Euler Deconvolution tool creates a solution set from your grid dataset containing proposed sources which explain the grid s anomalies We r
21. itself allows you to create a simple rectangular subset Choose Euler Deconvolution from the Interpretation menu in the Project Manager or use the command euler exe INTREPID displays the Euler Deconvolution window The left part of the window is different depending on whether you are processing a scalar grid or a tensor grid E epa tee o a File Spatial Help Euler Wemer Deconvolution Euler Werner Deconvolution Solution Sorting amp Reporting Tensor Grid Euler Deconvolution C Standard Euler assumes fixed SI lt YZ B Reject solutions with values outside Full Gravity Gradiometry Supported C Euler Werner assumes fixed SI XY Z B Upper Structural clip 4 50 Tensor Coordinate Convention ENU NED END Structural Index Lower Structural clip 9 50 EulerfWerner 2 Eq SI solver XYZ SLb Min Obs Source dip 20 0 ae 5 p Eaa C Euler Werner Basement solver XYZ a b ae A 00 Swecturl ladex Hybrid 2 pass Euler solver 72 SL ab Meo T I Euler from Gravity Tansor and Tz XYZ SI Tx TY C_EuterWerner Full solver XYZ SL a b r e eee SLO Vertical Component of Gravity grid C Euler Werner property solver SLa b nb Units must be mGals Depth to basement grid nb depth in grid are ve a Browse V Cull Solutions to Grid extent _ 3D Spatial Binning options Use Real 4 precison for Fourier Work J Do Binning Ana
22. you specify as a parameter see Euler equation Structural ndex options It solves for X Y Zand B Background If you already know the SI perhaps because you have sythetic data from models you can compare the standard and extended Euler methods and assess which one gives the more acceptable error distribution In all cases this method should yield the lowest error range as we are solving for the least number of unknowns with the most equations Interactive Euler Werner interactive In the Euler Deconvolution area 1 Select Euler Werner 2 Specify the Structural Index Task files Euler Werner task files Within the Solve Begin End block e Set the EquationCombo keyword toAl13 Fixed SI e Set the required value for the StructuralIndex keyword Example EquationCombo Al13 Fixed SI StructuralIndex 1 Method 3 Euler Werner 2 Equation SI solver Parent topic This extended Euler method uses only the two Hilbert equations This is the default The standard and our preference for the new user and extended Euler equation It assumes fixed background options It solves for X Y Z SI B We have found that this has a good focusing ability with a tight error envelope around discrete bodies It is using phase inherent in the local stationary signal to best advantage In practice it does the best on deep basement contacts We suggest that in the selecting and sorting stage you apply an upper and lower clip to calculated v
23. 20 0 Maximum Percentage Depth Error 900 MaximumAbsAlpha 100 0 XYBinEast 10000000 0 XYBinNorth 10000000 0 Mask Solutions Yes Dump VRML No Dump BREP No Cluster Analysis Yes 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 47 Library Help Top Library Help Top lt 4 Back gt Binning Analysis No Maximum Point separation 900 0 Sort End Solve Begin StructuralIndex 1 0 LateralSize 7 RolloffType COSINE WindowType NONE FillType ARTHUR Band 0 DetrendDegree 1 FFTPrecision IEEE4ByteComplex UseSymmetry Yes EquationCombo Classic DiskUsageRule AUTO SaveDerivatives Yes ConvolveDerivatives Yes DoReductionToPole Yes Date 31 12 1999 Solve End Subset Begin XLower 520129 158 XUpper 595129 158 YLower 7236236 0 YUpper 7311236 0 FFTborder 5000 0 Subset End Parameters End Process End Now for a model study example where we already know the correct answer and we wish to verify that Euler can get the right answer The job repeats for each Euler equation type and then checks the answer at known HOT SPOT locations for each of the formulations This model data and the results are available for anyone wishing to try this and devise something similar for themselves This is taken from our internal test system type Classic Hilbert Only A113 Fixed SI All3 For Contact Case No SI Repeat Begin Process Begin Name Euler Input models ModelCo
24. D uses this file when you select and classify solutions for output These are ASCII and contain all of the information necessary to preserve sort cull your solutions INTREPID does not overwrite any existing rs file when you recalculate the extended Euler solutions using different parameters It adds 1 2 3 tothe name of theinput grid name as necessary Thus if you wish to resort to a previous output you just need to choose the appropriate intermediate solutions file 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 10 Library Help Top lt 4 Back gt Output Euler solutions point dataset Parent topic When you select and classify the extended Euler solutions INTREPID saves this Specifying data to a point dataset input and output files Task files Example Output C Intrepid cookbook eulerplay eulersols DIR Dataset fields The output point dataset for selected Euler solutions has the following fields Field Description CellSize Group by Input grid cell size group by field previously CELLSIZE Window Group by Size of Euler window group by field previously WINDOW Structural Indx Structural Index for solutions group by field previously STRUCTURE BIN Geographic bin number LAYERDEPTH Depth of mid point of layer m This acts as the layer number field x East West geographic location Y North South geo
25. Euler solutions using binning see Binning analysis classifying Euler solutions by depth and Binning analysis specifying geographic bins INTREPID performs separate goodness clipping within each layer or geographical bin If you do not use binning INTREPID performs goodness clipping for the whole set of Euler solutions Option Purpose Lower goodness Lower goodness clip value should be greater than or equal clip to zero It determines the percentile at which you want INTREPID to start selecting the poorer solutions Specify a value between 0 and 1 representing 0 100 For example if you set a a value of 0 1 INTREPID omits the bottom 10 of results Upper goodness U pper goodness clip value should be less than or equal to 1 clip It determines the percentile at which you want INTREPID to reject the higher reliability solutions Specify a value between 0 and 1 representing 0 100 For example if you set a value of 0 9 INTREPID omits the top 10 of results Example LowerGoodnessClip 0 0 UpperGoodnessClip 1 0 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 37 Library Help Top q Back gt Classifying Euler solutions Parent topic You can classify Euler solutions by binning analysis or cluster analysis Binning Euler f analysis is the older of the two methods Deconvolution T44 In this section e Binning analysis classifying Euler solutions
26. INTREPID User Manual Euler Deconvolution T44 1 Library Help Top lt 4 Back gt Euler Deconvolution T44 Top In this chapter Library Help Top Introduction to the extended Euler process Stages in the extended Euler deconvolution process Using the Euler Deconvolution tool Steps Specifying input and output files Specifying the region for calculating solutions Creating the complete set of Euler solutions Steps The standard and extended Euler equation options e Method 1 Standard Euler e Method 2 Euler Werner e Method 3 Euler Werner 2 Equation SI solver e Method 4 Euler Werner basement solver e Method 5 Hybrid 2 pass Euler solver e Method 6 Euler Werner Full Solver e Method 7 Euler Werner property solver Notes about tensor deconvolution e Method 8 Tensor Bouguer solver e Method 9 Tensor gravity estimator with fixed SI Euler Deconvolution parameters and execution Selecting and classifying Euler solutions Steps Selecting Euler solutions for output Classifying Euler solutions Displaying options and using task specification files Bibliography 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 2 Library Help Top lt 4 Back gt Introduction to the extended Euler process Parent topic Euler Deconvolution T44 Library Help Top This tool enables you to conveniently obtain Euler depth estimates using best practice This
27. RAM and operating system virtual memory as required for data being processed FORCE MEMORY If you Select this setting INTREPID ignores its INTREPID_MEMORY system parameter value Apply deconvolution interactive To execute the extended deconvolution process and produce the full solution set in the Euler Deconvolution area e Choose Apply Deconvolution Apply deconvolution task files Within the Solve Begin End block e Set the DiskUsageRule keyword to AUTO or FORCE MEMORY Or FORCE DISK Example DiskUsageRule AUTO 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 32 Library Help Top lt 4 Back gt Selecting and classifying Euler solutions Steps Parent topic Euler Deconvolution T44 Library Help Top After you have obtained the complete set of Euler solutions you can produce Euler solutions point datasets containing selected and classified solutions See Output E uler solutions point dataset for details about the output dataset In the following sections Selecting Euler solutions for output e Structural index clips e Minimum observed dip e Selecting solutions by depth e Maximum absolute alpha e Maximum singularity ratio e Restricting solutions to the grid boundary e Goodness Classifying Euler solutions e Binning analysis classifying Euler solutions by depth e Binning analysis specifying geographic bins e Cluster analysis g
28. adjusting the sorting binning quality and fractions of the solutions as requried depending upon the underlying geophysical responses to the geology of the area For instance 1 in areas of deep sand cover magnetic response can be quite muted compared to outcroping basement rocks 2 your objective might be to find magnetic sources that are of a more 2D or 3D character so you sort looking for higher Structural Index bodies By way of example the Australian TMI high resolution grid is 8 Gigabytes with a cell size of 80m Euler requires typically 8 or 9 gradient grids if the 2 Equation Euler 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 40 Library Help Top lt 4 Back gt Werner solver case is chosen in order to not just get depths but also estimates of the Structural Index On a desk top computer the elapsed time to do the preconditional work of gradient computation can amout to more than a week of time No one wants to have to carry this overhead nor to be restricted to a limited number of runs The features of the new workflow are e You must create all the necessary gradient grids however you like and have them sitting in a designated directory that can then be referenced by each invocation of the Euler tool e This also applies to the primary spatial grid dataset In this case the prior work involves a simple conversion to the spectral form of the same dat
29. ag data not necessary DoReductionToPole false IGRF Date 31 12 1999 it is possible to specify a smaller internal area within a grid Subset size of expanded grid as a percentage of original grid size FFT BorderPercentExpansion 120 0 i Bibliography Parent topic Allsop J M Evans C J and McDonald A J W 1991 Visualizing and interpreting 3 Euler Deconvolution T44 Library Help Top D Euler solutions using enhanced computer graphics Surveys in Geophysics v 12 p 553 564 Barbosa V C F Silva J B C and Medeiros W E 1999 Stability analysis and improvement of structural index estimation in Euler deconvolution Geophysics v 64 No 1 p 48 60 Barongo J O 1984 Euler s differential equation and the identification of the magnetic point pole and point dipole sources Short Note Geophysics v 49 p 1549 1553 Beasley C W and Golden H C 1993 Application of Euler Deconvolution to Magnetics Data from the Ashanti Belt Southern Ghana Extended Abstract GM 1 6 p417 420 SEG Annual Meeting Washington DC Corner B and Wilsher W A 1989 Structure of the Witwatersrand Basin derived 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 51 Library Help Top Library Help Top lt 4 Back gt from interpretation of the aeromagnetic and gravity data in Garland G D ed Proceedings of Exploration 87 Third decennial inte
30. alues of the SI See Structural index clips Interactive Euler Werner 2 Equation SI solver interactive In the Euler Deconvolution area 1 Select Euler Werner 2 Equation SI solver Task files Euler Werner 2 Equation SI solver task files Within the Solve Begin End block e Set the EquationCombo keyword toHilbert Only Example EquationCombo Hilbert Only Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 18 Library Help Top lt 4 Back gt Method 4 Euler Werner basement solver Parent topic This extended Euler method uses all three equations Not recommenede for the The standard novice user and extended Euler equation It solves for X Y Z B options We designed this option to solve for depth Z when you do not require the SI It eliminates the SI producing a superior result for X Y Z Interactive Euler Werner basement solver interactive In the Euler Deconvolution area 1 Select Euler Werner basement solver Task files Example EquationCombo No SI Method 5 Hybrid 2 pass Euler solver Parent topic Not recommeneded for the novice user This extended Euler method is a combination The standard of and extended Euler equation e Method 3 Euler Werner 2 Equation SI solver and options e Method 4 Euler Werner basement solver It solves for X Y Z Sl B It produces all solutions using both of the methods It then selects e X
31. arge scale b high resolution c subsection tiling involving precomputed grids that can be treated as READ ONLY this example uses FFT grid as input previously computed this example also uses precomputed gradient grids for the ILBERT 2 equation case the precompputed grids are refeneced via a new keyword SaveDerivativeDirectoryName reuse derivative grids Euler consists of two stages Stage 1 generates a solutions file from the grid rs Stage 2 accepts rejects solutions according to user specified riteria and writes the accepted solutions to an Intrepid point dataset H AO HH HHH HO HH HH HOH HOH H 2012 Intrepid Geophysics q Back gt Library Help Top INTREPID User Manual Euler Deconvolution T44 41 Library Help Top lt 4 Back gt The example job file computes both stages and creates a report file Usage fmanager batch euler task IntrepidTask Euler InputGridName D test data FullTests euler test real data grids mag t ers start with an FFT grid as input InputGridName D test data FullTests euler test real data fftGridName ers Band 0 Output D test data FullTests euler test real data output mag t DIR ReportFile euler rpt SurveyHeight 100 0 ExportTypes Database 3D visual formats of solutions Dump VRML false Dump BREP false Sort main rejection of false solutions criteria LowerGoodnessClip 0 0 UpperGoodnessClip 1 0 LowerS
32. aset Fourier transfornmed grid and then making sure the correct back refernce tothe original spatial form of the grid is carried in the metadata refeneced Intrepid isi file This is a block structred ASCII file so easily examined and edited The gfilt tool will do this job for you e The existing subsectioning capability within the tool has a modified behaviour when the above conditions are presented to the tool nstead of cookie cutting a small part of the spatial grid into a new smaller grid as is normally done it instead just references back to the large scale gradient and original signal grids picking out the required readings by row and column e Asthesolver section of the tool is likely to be exercised by geology sheet boundaries provision for storing the intermediate raw solutions in seperate directories is also made e This then just leaves the task of sorting clustering sifting the solutions to reject the many that fall outside your requirements This aspect has not received any attention so far with the new workflow e This is only available through the batch interface at present and not all the Euler Werner equations are tested or available Choose the 2 equation Hilbert for now An example of using the tool in this manner via a batch task file follows This task is distributed with V5 0 and forms part of the internal testing suite v5 0 Euler deconvolution Example job file A workflow for a very l
33. ation files Statement Description Unit Default Process Begin Name Euler Specifies Euler Deconvolution as the application for this task Input lt path gt See Input input grid band oblig Depth lt path gt See Input depth to basement grid oblig VerticalComponent lt path gt See I nput vertical component oblig Output lt path gt See Output E uler solutions point dataset oblig ReportFile lt path gt See Output report euler rpt Cluster lt path gt See Output cluster dataset oblig Parameters Begin Parameters block Subset Begin XLower lt number gt Extents of subsection mor extent of XUpper lt number gt See Specifying the region for calculating mor dataset solutions s YLower lt number gt m or YUpper lt number gt mor FFTborder lt number gt Width of FFT border See F ast F ourier m or 5000 transform Subset End SurveyHeight lt number gt See Survey observation height m 0 Solve Begin Solve block Band lt ord gt Band of input grid to process 0 See Input input grid band StructuralIndex lt number gt Structural Index setting when required 1 or calc See Structural Index LateralSize lt ord gt Euler window size See Determining the 7 maximum depth for solutions window size DetrendDegree lt 0 1 2 gt PreFFT and FFT settings 1 Filltype lt ARTHUR MEM gt See Fast Fourier transform ARTHUR RolloffType NONE lt COSINE LINEAR NONE gt WindowType lt COSINE_BELL COSINE
34. by depth e Binning analysis specifying geographic bins e Cluster analysis Binning analysis classifying Euler solutions by depth Parent topic You can divide the range of solution depths into layers The layers are numbered Classifying from 1 the shallowest INTREPID will classify each solution according to the depth Euler solutions aver to which it belongs INTREPID computes statistics separately for the individual layers Layers have equal thickness divided equally between minimum and maximum depths If you have set minimum and maximum depths see Selecting solutions by depth INTREPID divides up the distance between them for the layers If you have not specified depths INTREPID uses the actual depth range of the full set of solutions The default number of layers is 1 Option Purpose Do Binning Analysis Check this box to perform vertical and horizontal binning classification See also Binning analysis specifying geographic bins To disable vertical binning layers specify 1 vertical layer Number of Vertical Use this text box to specify the number of depth layers for layers the Euler solutions Task files Example Binning Analysis Yes NumberVerticalLayers 1 Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 38 Library Help Top lt 4 Back gt Binning analysis specifying geographic bins Parent topic You may wish to obtain a
35. d for more details Box Dimensions for Clipping E uler S olution Search Make use of real grid data for FFT expansion and filling if at all possible otherwise expand and fill as normal Lower Left Corner L Easting 740000 0000 L Northing 8408080 0000 Upper Right Corner R Easting 752000 0000 R Northing 84200000000 Minimum expansion border meters FT Border 5000 0000 OK Cancel Option Purpose LL Easting Minimum value for eastern direction This value allows the interpreter to specify a minimum eastern value which forces statistical calculations to be performed only for data points whose eastern coordinate is greater than or equal to the eastern boundary value UR Easting Maximum value for eastern direction This value allows the interpreter to specify a maximum eastern value which forces statistical calculations to be performed only for data points whose eastern coordinate is less than or equal to the eastern boundary value LL Northing Minimum value for northern direction This value allows the interpreter to specify a minimum northern value which forces statistical calculations to be performed only for data points whose northern coordinate is greater than or equal to the northern boundary value UR Northing Maximum value for northern direction This value allows the interpreter to specify a maximum northern value which forces statistical calculations to be performed only
36. e of a relatively small grid cell size and a large convolution kernel for a 2D body This appears in the xy_err term The weighted least squares single value solver directly determines these The log file reports a full account of all solutions attempted and their reject or accept status based on depth XY SI or Numeric issues Also the Norm Covariancexy field is a report of the estimated normalised covariance for each solution window for all the XY terms in the observations Typically over 80 of observations have strong covariance Output cluster dataset If you choose to classify your extended Euler solutions using clustering see Cluster analysis INTREPID saves the cluster data to a point dataset Parent topic Specifying input and output files Library Help Top Cluster C Intrepid cookbook eulerplay eulercluster DIR Dataset fields Kurt iS Kurtosis a population statistic Skew is a measure of skew in the distribution of a cluster Error is SD of the data in the cluster The output cluster dataset has the following fields Field Description X Y X Error Y Error Elevation Elevation Error Elevation Kurt Depth estimates for solutions Structural_Indx SI_Error SI Skew SI Kurt See Structural Index Alpha Alpha Error Alpha Skew Alpha Kurt See Maximum absolute alpha for information Beta Beta Error Beta Skew Beta Kurt See Maximum absolute alpha for info
37. e population of and B are well worth examining for patterns such as trends and bi modal peaks Option Purpose Maximum absolute alpha Task files Example MaximumAbsAlpha 100 0 Maximum singularity ratio Parent topic The solution for a least squares best fit involves a Singular Value Decomposition SelectingEuler where each term being solved for has a singular weight The ratio of the maximum of Seana Ta these weights to the minimum is known as the singularity ratio and reflects partly output j the likelihood of the causitive body being 2 dimensional It also has an element of ill conditioning and signal strength Tests indicate that solutions with high singularity ratio greater than 2000 are likely to be less plausible solutions The behaviour of this factor varies markedly for gravity and magnetics with much higher values reporting for gravity Option Purpose Max singularity ratio Task files Example MaximumSRatio 20000 Restricting solutions to the grid boundary Parent topic See also Specifying the region for calculating solutions Selecting Euler solutions for Option Purpose output Cull solutions to Grid Extent Task files Example Mask Solutions Yes Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 36 Library Help Top Goodness Parent topic Selecting Euler solutions for outpu
38. ed dyke in a grid is 300 m wide and the grid cell size is 100 m square a window size of 5 x 5 is adequate 25 Eigen vectors INTREPID would process this 4 times faster than the default of 10 x 10 100 Eigen vectors A simple rule of thumb A rule of thumb for Euler Deconvolution is that maximum reliable depths are about twice the window size For example 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 28 Library Help Top lt 4 Back gt Max reliable depth 2 x Grid Cell Size x Window Size Survey Height This simple rule should help you tune the parameter settings for a predicted range of depth estimates Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Interactive Task files Euler Deconvolution T44 29 q Back gt Width of window interactive In the Euler Deconvolution area enter the number of data points in the Width of window points text box Width of window task files Within the Solve Begin End block usethe LateralSize keyword to specify the number of data points in the window Example LateralSize 7 Survey observation height Parent topic Euler Deconvolution parameters and execution Interactive Task files The height above the ground that the observations were taken in the same units as the grid cell size The Euler depths are offset by this amount to convert them to d
39. efer to these sources as Euler solutions Euler Deconvolution calculates location depth below sensor and reliability for each solution as well as error estimates in the form of standard deviations The primary signal that is measured in potential field data derives from the edges or contacts of geological units So this fact should reflect in what the solver is reporting In the standard Euler deconvolution process each model contains solutions of a particular structural type defined by the structural index parameter In the extended Euler process the solution calculates structural type as the structural index output field The extended Euler method assumes that within a window all gradients are caused 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 3 Library Help Top lt 4 Back gt by just one causative body This body has simple shape with an integer power dropoff for structural index These assumptions may not hold truein many real geological situations After INTREPID calculates the full set of solutions you can output a dataset containing classified and selected solutions e Selected according to reliability goodness depth and depth error structural index location and other calculated values e Classified according to depth geographic location or cluster There is also the batch option for restricting the Euler Deconvolution process toa select set of XY pairs
40. ept in Euler deconvolution of isolated gravity anomalies Geophys Prosp v 48 No 3 p 559 575 Sahil A and Ebinger C 1999 Interpretation of gravity data in the Murzugq Basin SW Libya Petroleum Research J ournal Petroleum Research Centre Tripoli v 11 1429 1999 p 13 17 Silva J B C Barbosa V C F and Medeiros W E 2001 Scattering symmetry and bias analysis of source position estimates in Euler deconvolution and its practical implications Geophysics v 66 no 4 p 1149 1156 Slack H A Lynch V M and Langan L 1967 The geomagnetic gradiometer Geophysics v 32 p 877 892 Stavrev P 1994 Euler Deconvolution and similar transformations of gravity or magnetic anomalies Extended Abstract P004 EAEG Annual Meeting Vienna Steenland N C 1968 Discussion on The geomagnetic gradiometer by H A Slack V M Lynch and L Langan Geophysics October 1967 p 877 892 Geophysics v 323 p681 684 Thompson D T 1982 EULDPH a new technique for making computer assisted depth estimates from magnetic data geophysics v 47 p 31 37 Wilsher W A 1987 A structural interpretation of the Witwatersrand Basin through the application of automated depth algorithms to both gravity and aeromagnaiic data Unpublished M Sc dissertation University of the Witwatersrand J ohannesburg 70 p Yaghoobian A Boustead G A and Dobush T M 1992 Object delineation using Euler s Homogeneity Equation Location and Depth Det
41. epths below the ground surface This also significantly reduces the number of spurious near surface solutions by accepting only admissible depth solutions Survey observation height interactive In the Euler Deconvolution area enter the required height in metres in the Survey observation height text box Survey observation height task files Within the Parameters Begin End block usethe SurveyHeight keyword to specify the survey observation height in metres assign a numeric value Example SurveyHeight 100 0 Reduction to the pole Parent topic Euler Deconvolution parameters and execution Interactive Task files Library Help Top For magnetic grids optionally reduce the dataset to the pole RTP Enter the survey date so that INTREPID can calculate the correct IGRF As Euler is sensitive to the instantaneous phase of the field the RTP dataset is new and independent of the original TMI grid We have found that RTP is not necessary in Euler deconvolution and recommend that you do not use it This withdrawn from the User interface at V4 5 Reduction to the pole interactive In the Euler Deconvolution area e Check or clear the Compute a reduction to the pole check box e Enter the date of the survey in the Survey date text box Reduction to the pole task files Within the Solve Begin End block e Set the DoReductionToPole keyword to Yes or No e Set the Date keyword to the date of the survey
42. er only Within the Solve Begin End block e Ensurethat the value of EquationCombo iS Classic Of A113 Fixed SI see The standard and extended Euler equation options e Usethe StructuralIndex keyword to specify the fixed structural index Example StructuralIndex 1 0 EquationCombo Classic 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 27 Library Help Top lt 4 Back gt Determining the maximum depth for solutions window size Parent topic Euler Deconvolution parameters and execution Library Help Top If you have come to this point in the manual you maybe having problems Do not worry aS a new user there area few things it takes time to grasp Firstly the grid extent dictates how deep you can see buried body edges You cannot expect to see deeper than 1 5 the horizontal extent of your grid If your grid is 2km square you will be lucky to get many solutions deeper than 200 m Also you can influence the maximum depth for Euler solutions found using the size of the Euler window The Euler window size is the number of cells INTREPID uses for calculating derivatives and the analytic signal The size of the Euler window is directly related to the maximum depth of solutions Where D Maximum solution depth W Euler window size C Grid cell size k a constant D kWC In the second stage of the Euler process INTREPID stores the E uler window size as t
43. ermination of Buried Ferro Metallic Bodies Proceedings of SAGEEP 92 San Diego California Zhang C Mushayandebvu M F Reid A B Fairhead J D amp Odegard M E 1999 Euler deconvolution of gravity tensor gradient data Geophysics v 65 no 2 p 512 520 March April 2000 2012 Intrepid Geophysics 4 Back gt
44. es Library Help Top Euler Deconvolution T44 26 lt 4 Back gt The following table shows typical structural index values for different structures and potential fields FTG full tensor gradient data Geological Geophysical Gravity Magnetic FTG FTG Gravity Magnetic basalt plug point dipole 2 3 4 kimberlite point pole 1 2 3 fault dyke line of dipoles 0 1 2 step 0 5 0 5 1 5 contact edge dipping contact 1 0 0 1 The negative values correspond generally to an inadmissable non homogeneous situation There is no Euler solution in these cases Recent studies show that SI for gravity is on average not negative as shown above The contact case appears to be non homogeneous for gravity and therefore further moving away from the fundamental requirements of Euler s assumptions Typical values of 0 2 for contact and 0 5 for a step are shown for model studies You can specify other non integer values such as 0 5 depending on the type of source Structural index interactive Standard Eule and Euler werner only To set a fixed structural index value in the Euler Deconvolution area 1 Ensurethat you have selected the Standard Euler Euler Werner or Tensor gravity estimator with fixed SI equation option see The standard and extended Euler equation options 2 Enter the value required in the Structural Index text box Structural index task files Standard Eule and Euler wern
45. graphic location Elevation Depth estimate for solution m previously DEPTH Reliability Reliability 0 1 of solution previously RELIABILITY Background Average field value in the region Goodness See Goodness for an explanation Strike The strike is the artan of the ratio of the two horizontal gradients y x Obs Dip The vertical angle from observed grid point to the computed body location If these are low we reject them See Minimum observed dip Grad Amp Gradient amplitude of the analytic signal Trace Sum of leading diagonal terms in the matrix solver Grid loc Ordinal position of the cell in the grid numbered columnwise then rowwise Alpha See Maximum absolute alpha for information Beta Sratio See Maximum singularity ratio for explanation MaxDeterminant Group by A constant output value for the whole dataset INTREPID looks through every solution takes determinant of each solution matrix and then places the maximum value in this field Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 11 Library Help Top q Back gt Field Description X Error The quantities xy err YZ err ZSI_err represent the cross correlation Y_Error of individual terms with each other Elevation Error Background Error SI_ Error XY Error YZ Error ZX Error ZSI Error values Surprisingly the cross correlations are extremely small except for the cas
46. he value of the group by field Window in the output Euler solutions point dataset See Output E uler solutions point dataset for more details Deciding the Euler window size Size of the window is used for determining the number of observations to pass to the solver SVD for the current point of interest in the grid Choice of window sizeis mainly determined by the resolution of the data and the spatial extent of the anomalies Thelarger the window size the larger the matrices for the singular value decomposition and thus the more CPU consumption is required n n equations are formed for standard Euler While ensuring that you obtain solutions of sufficient depth we recommend that you minimise the size of the Euler window The size of the Euler window also greatly affects processing speed Time for Euler Deconvolution process increases as the cube of window size The default window size is 7 x 7 grid cells We recommend window sizes in the range 5 x 5 to 15 x 15 We suggest that you match window size with the grid and the resolution of its features ensure that it adequately spans the features being modelled With extended Euler the number of equations passed to the solver is at least twice that for standard Euler and so the window size does not need to be as large Thisis said from the perspective of an overdetermined set of input equations The issue of independence of observations in a window is separate For example if an observ
47. in the format dd mm yyyy Example DoReductionToPole Yes Date 31 12 1999 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 30 Library Help Top lt 4 Back gt Derivatives and analytic signal Parent topic Euler Deconvolution parameters and execution Interactive Task files Library Help Top You can specify e Whether to convolve the derivatives e Whether to save the derivatives Convolve derivatives The quality of Euler solutions critically depends on the coherence of your derivative grids Derivatives amplify noise so will naturally strengthen any incoherence in your data Of particular concern is aliasing where there is more coherence in one direction than the other By nature aerial survey data is aliased and poor gridding can fail to eliminate it The derivative covolution is a low pass filter using local 3 x 3 Gaussian kernel Our ongoing testing shows that this filter distorts the perfect model tests and forces the depths to be worse estimates than when we don t apply this filter This is withdrawn from the User interface at V4 5 Save derivatives You can save the derivatives used in the Euler deconvolution process It may be useful to display the Euler solutions point dataset with a derivatives grid as a backdrop See Output F FT and derivative products for information about the output files Derivatives and analytic signal interactive
48. ion Abstract Presented at EAEG Florence Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 53 Library Help Top Library Help Top lt 4 Back gt Paterson N R Kwan K C H and Reford S W 1991 Use of Euler Deconvolution in Recognizing Magnetic Anomalies of Pipelike Bodies Extended Abstract G M 2 6 p 642 645 SEG Annual Meeting Houston Ravat D 1994 Use of fractal dimension to determine the applicability of Euler s homogeneity equation for finding source locations of gravity and magnetic anomalies in Proceedings of the Symposium on theApplication of Geophysics to Engineering and Environmental problems Boston March 1994 Environmental and Engineering Geophysical Society Englewood CO p 41 53 Reid A B Allsop J M Granser H Millett A J and Somerton I W 1990 Magnetic interpretation in three dimensions using Euler deconvolution Geophysics v 55 p 80 91 Reid A B 1998 Prospect scale interpretation Euler depth estimates Can Soc Expl Geophys J our v 34 nos 1 amp 2 p23 29 Ruddock K A Slack H A and Breiner S 1966 Method for determining depth and falloff rate of subterranean magndic disturbances utilising a plurality of magnetometers US Patent 3 263 161 filed Mar 26 1963 awarded J uly 26 1966 assigned to Varian Associates and Pure Oil Company Roy L Agarwal B N P amp Shaw R K 2000 A new conc
49. lt 4 Back gt The 3 dimensional analytic signal computes the non directional derivative as the square root of the square of the 2 horizontal and 1 vertical derivatives The analytical signal is used as input to a Single Value decomposition INTREPID deletes these unless you want to save them see Derivatives and analytic signal Transform products inputgrid tempcode FFT inputgrid tempcode HILBERT 0 real inputgrid tempcode HILBERT 90 real inputgrid tempcode Analytic inputgrid tempcode Analytic Hilbert 0 inputgrid tempcode Analytic Hilbert 90 Derivatives inputgrid tempcode XD real inputgrid tempcode YD real inputgrid tempcode ZD real inputgrid tempcode XD HILBERT 0 real inputgrid tempcode YD HILBERT 0 real inputgrid tempcode ZD HILBERT 0 real inputgrid tempcode XD HILBERT 90 real inputgrid tempcode YD HILBERT 90 real inputgrid tempcode ZD HILBERT 90 real Output the complete set of Euler solutions Parent topic Specifying input and output files Library Help Top INTREPID stores the complete set of extended Euler solutions in an ASCII text file The name of this file is derived from the input grid s file name The solutions file name consists of the input grid name with _rs appended For example the Euler solutions file for grid mag 342 will bemag 342 rs INTREPID also produces a history file with the rsh appended The report file and this header file show what each column in the ASCII file represents INTREPI
50. lutions by depth m 0 MaximumDepth lt number gt 5000 MinimumObservationDip lt number gt See Minimum observed dip gi 20 Maximum Percentage_Depth Error m 900 lt number gt MaximumAbsAlpha lt number gt See Maximum absolute alpha 100 Mask_Solutions lt Yes No gt See Restricting solutions to the grid boundary Yes Binning_Analysis lt Yes No gt See Binning analysis classifying Euler No NumberVerticalLayers lt ord gt sol utions by depth and Binning analysis I XYBinEast lt number gt specifying geographic bins mor 10 000 000 XYBinNorth lt number gt mor 10 000 000 Cluster Analysis lt Yes No gt See Cluster analysis No Maximum Point separation See Cluster analysis mor 900 lt number gt ExportTypes lt Database XYZ GDB gt See Output vector dataset formats Database Dump_VRML lt Yes No gt See Output visualisation formats No Dump BREP lt Yes No gt No Sort End Parameters End Process End Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 46 Library Help Top lt 4 Back gt Using task specification files Parent topic Displaying options and using task specification files Library Help Top You can store sets of file specifications and parameter settings for Euler Deconvolution in task specification job files gt gt Tocreateor edit a task specification file with the Euler Deconvolution tool 1 Start
51. lver e Method 9 Tensor gravity estimator with fixed SI Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 20 Library Help Top lt 4 Back gt Method 8 Tensor Bouguer solver Parent topic This extended Euler method calculates the solutions from a tensor grid It requires The standard all three equations and obtains the gradients from the tensor data in the input grid pappen see nput vertical component options It solves for X Y Z SI B Tx and Ty where Tx and Ty are horizontal gravity components This method is similar to Method 6 Euler Werner Full Solver but uses the tensor data to obtain the gradients For important information see Notes about tensor deconvolution Interactive Tensor Bouguer solver nteractive 1 Specify a tensor grid for input INTREPID recognises and validates the tensor grid automatically displaying a different Euler Deconvolution panel in the application window Eulerf ermer Deconvolution Tensor Grid Euler Deconvolution Full Gravity Gradiometry Supported Tensor Coordinate Convention ENU NED END Estimate Tz from Tensor assumes fixed SI XYZ Txy z Structural Index 1 00 C Euler from Gravity Tensor and Tz XYZ SLTx Ty Vertical Component of Gravity grid nb Units must be mGals Browse 2 In the Euler Deconvolution area select e The Tensor Coordinate Convention of your dataset e Euler from G
52. lysts Save Derivatives Analytic Signal Upper goodness clip 1 00 dth of Window Points 7 Lower goodness clip 9 00 Survey Observation height 0 00 3D Spatial Cluster options Do Cluster Analysis Export Type Database XYZ 3D View Type I VRML Status Input File Output File Cluster File Apply Deconvolution Apply Sort E S If you have previously prepared file specifications and parameter settings for Euler Deconvolution load the corresponding task specification file using Load Options from the File menu See Specifying input and output files for detailed instructions If all of the specifications are correct in this file goto step 5 calculating complete set of Euler solutions or step 8 refining the Euler solutions and creating an output dataset If you wish to modify any settings carry out the following steps as required Specify the grid dataset to be processed Use Open Input Grid from the File menu See Specifying input and output files for detailed instructions INTREPID displays the dataset in the Euler Deconvolution window If required specify a rectangular subset of the grid for processing See Specifying the region for calculating solutions for detailed instructions 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 5 Library Help Top Library Help Top 6 10 11 12 13 lt 4 Back
53. many different views of the solutions You can also create 3D views in a two supported formats Continental Studies In response to the availability of large scale contiental datasets Australia Namibia etc that have a high fideleity high frequency content a new workflow is also being released at V5 0 designed to make it practical to handle very large observational geophysical grid datasets in a repetative and sensible manner Typically the base grid can be as large as 5 to 10 Gigabytes and so beyond the capacity of most desktop computers The remaining optimization needed for a practical workflow here is to allow users to divided a continent or province into a series of sheets and then progressively work through each sheet A new section is added to this manual to explain all the thinking and the details 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Euler Deconvolution T44 4 Library Help Top lt 4 Back gt Using the Euler Deconvolution tool Steps Parent topic gt gt To use Euler Deconvolution with the INTREPID graphic user interface e adi Euler Deconvolution is memory and computer intensive If you are using this tool you T44 require a relatively large amount of RAM and virtual memory 1 Before using Euler Deconvolution you could use Subsection See Subsections of 3 Library Help Top datasets T21 to limit your grid to a manageable size if required Alternatively the tool
54. mbo ModelCombo MagAtPole 160mCell ers if you just want to do the sort in batch Input models ModelCombo ModelCombo MagAtPole 160mCell rs Output combo type Parameters Begin will reject initial solutions if depth less than SurveyHeight SurveyHeight 0 0 Sort Begin ExportTypes XYZ 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 48 Library Help Top Library Help Top lt 4 Back gt LowerGoodnessClip 0 0 UpperGoodnessClip 1 0 NumberVerticalLayers 5 MinimumDepth 0 0 MaximumDepth 4000 0 MinimumEast 10000000 0 MaximumEast 10000000 0 MinimumNorth 10000000 0 MaximumNorth 10000000 0 XYBinEast 3000 0 XYBinNorth 3000 0 Dump_VRML Yes Maximum Percentage_Depth Error 10000 Sort End Solve Begin StructuralIndex 2 0 LateralSize 5 SaveDerivatives No RolloffType COSINE FillType ARTHUR FftGridName models ModelCombo ModelCombo MagAtPole 160mCell fft Band 0 DetrendDegree 1 OutputPrecision IEEE4ByteReal FFTPrecision IEEE4ByteComplex UseSymmetry Yes EquationCombo A113 For Contact Case EquationCombo A113 Fixed SI EquationCombo type EquationCombo Hilbert Only EquationCombo No SI EquationCombo Classic DiskUsageRule AUTO Date 25 8 2000 DoReductionToPole Yes DoReductionToPole No Required Points 540200 6466500 500 546500 6458400 400 554000 6452500 250 Solve End Parameters End Process End Repeat End
55. nown depth Z which you specify as a grid dataset possibly sourced from other geophysical techniques such as seismic Note that the values in the depth grid must be negative Use this option to produce property SI values where you know the depth Interactive Euler Werner property solver interactive In the Euler Deconvolution area 1 Select Euler Werner property solver 2 Specify the Depth to basement grid see nput depth to basement grid Task files Euler Werner property solver task files Within the Solve Begin End block e Set the EquationCombo keyword to Known Depth Within the Process Begin End block e Set the Depth keyword tothe path of the depth to basement grid dataset Example Depth C Intrepid cookbook tmi ns depth ers EquationCombo Known Depth Notes about tensor deconvolution Parent topic Notes The standard Le edere e Ifyou are processing tensor data ensure that you know its coordinate system Euler equation See Vector and tensor field data coordinate conventions in INTREPID database options file and data structures R05 Before processing your data select the correct coordinate convention ENU NED END Eulerf ermer Deconvolution Tensor Grid Euler Deconvolution Full Gravity Gradiometry Supported Tensor Coordinate Convention ENU NED END e For information about test work on perfect model data contact our technical support service Tensor methods e Method 8 Tensor Bouguer so
56. oint separation For INTREPID to group points they must be less than this distance from each other Example Cluster Analysis Yes Maximum Point separation 900 0 Continental Studies Workflows Library Help Top At V5 0 a new wokflow is now available Australia Findland Namibia etc have high fideleity high frequency content very large potential field observational geophysical grid datasets The challenge is to be able to work in a repetative and sensible manner while still using this data at its full resolution The typical simple constraint for lower cost and quicker exploitation mining is that mineralised deposits should be no deeper than 500m and perhaps more shallower than that You cannot afford to compromise the geophysical data if you wish to apply this constraint This requires a workflow that removes and or minimizes the need to repeat computation of the required gradient grids using FFT methods Typically the base grid can be as large as 5 to 10 Gigabytes and so beyond the capacity of most desktop computers The use of penta scale LINUX based super computers or the CLOUD allows one to do the gradient operations once store them then with the new workflows just create a refernec to the existing gradient grids The remaining optimizations needed for a practical workflow are to allow users to divided a continent or province into a series of sheets and then progressively work through each sheet
57. ose Quit from the File menu You can execute Euler Deconvolution as a batch task using a task specification job file that you have previously prepared See Displaying options and using task specification files for details 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 6 Library Help Top 4 Back gt Specifying input and output files Parent topic To use Euler Deconvolution you will need to specify at least the grid dataset to be Euler iti examined and the point dataset for saving the results of the process Choose the Deconvolution Options as required from the File menu or from the main Euler Deconvolution ee window You can preload the grid via the command line arguments or via the Intrepid Project manager If you are browsing for a file in each case INTREPID displays an Open or Save As dialog box Use the directory and file selector to locate the file you require See Specifying input and output files in Introduction to INTREPID R02 for information about specifying files In this section e Input e nput input grid band e Input depth to basement grid e Input vertical component e Input solutions for re sorting e nput options e Output e Output FFT and derivative products e Output the complete set of Euler solutions e Output Euler solutions point dataset e Output cluster dataset e Output vector dataset formats e Output visualisation formats e Out
58. patial domain usually determined by Fourier methods d M M M Inputs are dy dy 3z and the structural index The calculated output is a vector distance to the source with estimates of x y z and background and their errors For the extended Euler method after Nabighian and Hansen 2001 and F itzgerald and Reid 2000 we use the Hilbert transform to formulate 2 or 3 equations By4 applying the Hilbert transform we have achieved a circular rotation of the coordinate axes This is an invariant for potential fields that allows us to create the new differential equations The extended Euler options are a unification of the Euler and Werner deconvolution in 3D using the generalized Hilbert transform The 2 Hilbert equations take the following parameters Equation 1 a 2 a 2 a and H M Equation 2 Me n 2 n 2 and H M These extra equations use the Hilbert transform on standrad Euler equations We have shown that if the field satisfies both Euler and LaPlace rce then the Hilbert transform of the fields also satisfies the Euler equation Resulting independent equations can solve for more unknowns and therefore we could achieve an improved resulting set of estimates You can test this by comparing the results of the M ethod 1 Standard Euler option with those of the Method 2 E uler Werner option The calculated output is a vector distance to the source with estimates of X Y Z structural index and corresponding
59. pth If you select Method 7 E uler Werner property solver as your calculation method use the third value of the triplet for the known depth If you select any other calculation method put 0 as the value of the third number in every triplet Example Input C Intrepid cookbook eulerplay tmi_ns ers Band 0 Required Points X Y Depth Input depth to basement grid Parent topic If you select Method 7 Euler Werner property solver as your calculation method Specifying INTREPID requires a depth to basement grid input and output files Interactive You can enter its path or browse for it Task files Example Depth C Intrepid cookbook depth ns ers Input vertical component Parent topic If you use the Method 8 Tensor Bouguer solver method INTREPID requires a Specifying vertical component grid input and output files This could typically be a ground gravity dataset that must share the same grid properties as the full tensor grid the same number of rows and columns and the same origin and cell size Interactive Eulerf ermer Deconvolution Tensor Grid Euler Deconvolution Full Gravity Gradiometry Supported Tensor Coordinate Convention ENU NED END Estimate Tz from Tensor assumes fixed SI XYZ Txy z Structural Index 1 00 C Euler from Gravity Tensor and Tz lt YZ SLTx Ty Vertical Component of Gravity grid nb Units must be mGals Browse Library Help Top 2012 Intrepid
60. put report e Output options e Output Convention for displaying Euler solutions Task files Example of input and output file specifications in a task specification job file Input C Intrepid cookbook eulerplay tmi_ ns ers Depth Cc Intrepid cookbook eulerplay dtm ns ers Output C Intrepid cookbook eulerplay eulersols DIR ReportFile euler rpt Cluster C Intrepid cookbook eulerplay eulercluster DIR At V5 0 the GOOGLE protobuf syntax is also supported The above translates easily by quoting the strings and changing the equals to a colon Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 7 Library Help Top i s sSsSSS Back Input input grid band Parent topic Specify the grid dataset for which you want to calculate solutions aati INTREPID automatically detects tensor grids and processes them accordingly output files Note f you are processing tensor data ensure that you know its coordinate system See Vector and tensor field data coordinate conventions in INTREPID database file and data structures R05 Interactive To specify the input grid choose main menu option File gt Open Input Image Task files Task files only Y ou can also specify a list of individual data points in the grid If you do this INTREPID only calculates solutions for the points specified INTREPID requires x y Z triplets where z is the known de
61. ravity Tensor and Tz 3 In the Euler Deconvolution area specify the Vertical component of gravity grid Task files Tensor Bouguer solver Task files Within the Solve Begin End block e Set the EquationCombo keyword to Tensor Tz Within the Process Begin End block e Set the VerticalComponent keyword to the path of the vertical component grid dataset Example VerticalComponent C Intrepid cookbook grav ns z ers EquationCombo Tensor Tz Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 21 Library Help Top q Back gt Method 9 Tensor gravity estimator with fixed SI Parent topic This extended Euler method calculates the solutions from a tensor grid The standard and extended It assumes fixed structural index SI which you specify as a parameter See Euler equation Structural Index options For important information see Notes about tensor deconvolution Interactive Tensor gravity estimator with fixed Sl nteractive 1 Specify a tensor grid for input INTREPID recognises and validates the tensor grid automatically displaying a different Euler Deconvolution area Eulerf ermer Deconvolution Tensor Grid Euler Deconvolution Full Gravity Gradiometry Supported Tensor Coordinate Convention ENU NED END Estimate Tz from Tensor assumes fixed SI XYZ Tx y z Structural Index 1 00 C Euler from Gravity Tensor and Tz XYZ SLTx Ty
62. rd MinimumObservationDip 20 0 ratio of estimated Depth error to depth value Maximum Percentage Depth Error 900 extended Euler can calculate a property of teh source alpha Maximum Absolute Alpha 100 0 MaximumSingularityRatio 1000000000 0 Binning Analysis false actual bin size XYBinEast 10000000 0 XYBinNorth 10000000 0 Mask Solutions true do not keep solutions outside original spatial grid Cluster Analysis false no cluster if values separated by more than this distance Maximum Point separation 900 0 Solver method specifying which formulation you want Classic Hilbert Only A113 Fixed SI A113 For Contact Case No SI Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 50 Library Help Top lt 4 Back gt EquationCombo Hilbert_Only default SI if one is needed Most Solvers estimate this quantity StructuralIndex 1 0 window size for equations as you pass over the grid LateralSize 7 some conditioning for FFT work RolloffType Cosine_Rolloff WindowType NO Window FillType ARTHUR MEM or maxiumum Entropy FillStopAtEdge false DetrendDegree 1 OutputPrecision IEEE4ByteReal FFTPrecision IEEE8ByteComplex Can exploit FFT symmetry for most operations Hilbert not always UseSymmetry false DiskUsageRule AUTO you can save computation time for repeated runs by saving the outputs SaveDerivatives false do an RTP on m
63. rees in this reference topic Filling the gaps in the expanded grid After expanding the grid INTREPID assigns values to the new cells in the grid using an extrapolation process You can choose one of two available methods Arthur fill algorithm and maximum entropy See Estimating values for data gap cells in INTREPID spectral domain operations reference R14 for details INTREPID notes the extrapolated and interpolated regions of the grid and does not calculate solutions for them 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 23 Library Help Top Interactive Library Help Top 4 Back gt Grid edge rolloff For best results from the FFT the edges of the grid must be set to zero but without sudden changes from the data within the grid The grid data needs to roll off to zero at the edge INTREPID has two sets of available edge roll off methods See Damping of dataset edges before spectral transform in INTREPID spectral domain operations reference R14 for details of this process Symmetry With traditional FFT you can assume that the transformed dataset is symmetrical and therefore we only process one half When you include the Hilbert transfom the FFT grid is no longer symmetrical and you need to process all of it This parameter controls whether INTREPID processes all of the dataset or only half For the options that include Hilbert all except Method
64. rmation Radius Number Radius of cluster area Number of points in the cluster 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 12 Library Help Top q Back gt Output vector dataset formats Parent topic INTREPID can output the selected and classified extended Euler solution data in the AAE following formats See INTREPID direct access import and export formats R11 input an output files Option Purpose Database Any supported binary database XYZ Geosoft XY Z format GDB Geosoft GDB format Task files Example ExportTypes Database Output visualisation formats Parent topic Two formats for 3D representation of your Euler Solutions are available Specifying input and Option Purpose output files VRML Virtual Reality Markup Language VRML is a common file format for internet browsers The file produced here can be looked at in 3D using a plug in such as Blaxlan BREP OpenCascade 3D object representation viewer A free viewer for BREP data is available from the OpenCascade WWW site Task files Example Dump VRML No Dump BREP No Output report Parent topic Euler Deconvolution produces a report file describing its actions The default file oe name of the report is euler rpt in the current folder In task files you can specify a input an output files different name and path Task file
65. rnational conference on geophysical and geochemical exploration for minerals and groundwater Ontario Geological Survey Special Volume 3 960p Durrheim R J 1983 Regional residual separation and automatic interpretation of aeromagnetic data Unpublished M Sc thesis University of Pretoria 117 p Fairhead J D Bennett K J Gordon D R H and Huang D 1994 Euler beyond the Black Box Extended Abstract GM1 1 p 422 424 SEG Annual Meeting Los Angeles Fitzgerald D Reid A Milligan P Reed G 2006 Hybrid Euler magnetic basement depth esti mation Integration into 3D Geological M odds Australian Earth Sciences Convention 2006 Melbourne FitzGerald D Reid A Mclnerney P 2004 New discrimination techniques for Euler deconvolution Computers amp Geosciences 30 461 469 Hansen R O and Suciu L 2002 Multiple Source Euler Deconvolution Geophysics v 67 p 525 535 Hearst R B and Morris W A 1993 Interpretation of the Sudbury Structure through Euler Deconvolution Extended Abstract GM1 7 p 421 424 SEG Annual Meeting Washington DC Hood P J 1963 Gradient measurements in aeromagnetic surveying Geophysics v 30 p 891 902 Huang D Gubbins D Clark R A and Whaler K A 1995 Combined study of Euler s homogenaty equation for gravity and magnetic fiad Abstract Poster presented at EAEG Glasgow Kuttikul P 1995 Optimization of 3D Euler deconvolution for the interpretation of
66. rner Full Solver Method 7 Euler Werner property solver Method 8 T ensor Bouguer solver Eliminated in the calculation Method 4 Euler Werner basement solver About structural index This parameter indicates the shape of the inferred geological bodies that make up the Euler solutions Mathematically the structural index is a power law operator that we use to define the decay response of the source The Structural Index must be non negative The following table shows some values of the Structural Index for four types of data gravity magnetic full tensor gradient gravity and magnetic and the corresponding shapes of inferred geological structures Structural Index Structural Inferred geological structure Grav Mag FTG Mag meer Re snape FTG Grav 0 5 5 1 5 Step Fault 0 1 2 Line of poles Dyke 1 2 3 Point pole Vertical pipe e g Kimberlite 2 3 4 Point dipole Point source nominally spherical Key Grav Gravity Mag Magnetic FTG Full Tensor Gradient Whilst this is correct for homogenous bodies for a basement step over which you have a high quality gravity survey the 2 equation Euler solver returns an SI gt 0 0 Thisis comforting from a basic physics viewpoint but it also indicates that the Euler theory has scope for further development 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Interactive Task fil
67. s observed or varying and weaker say 30 and higher for magnetics say 45 source dip Task files Example MinimumObservationDip 20 0 Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 34 Library Help Top q Back gt Selecting solutions by depth Parent topic You can specify a range of depth values for selecting output solutions If a solution SelectingEuler has depth outside this range INTREPID will not select it for output solutions for output Before final output depth is measured in metres below the survey sensor If it selects a solution INTREPID will store its depth adjusted for Survey observation height in the DEPTH field of the output dataset You will already have limited the depth range when you calculated the complete set of Euler solutions specifying the Size of the Euler Window parameter Specifying the depth range while selecting for output is a further refinement of the set of solutions You can use this selection criterion to eliminate solutions above ground level Set the Minimum Depth equal or greater than the nominal sensor clearance Option Purpose Minimum Minimum value for depth above which INTREPID omits Depth solutions from statistical analysis The default value is 0 units INTREPID rejects solutions above the depth represented by this parameter Maximum Maximum value for depth below which INTREPID omits Depth solutions from s
68. s of a geographic bin If you specify a bin size larger than the output dataset INTREPID will not use this selection method Bin size North Use this parameter to specify the northing dimension in dataset distance units of a geographic bin If you specify a bin size larger than the output dataset INTREPID will not use this selection method Task files Example Binning Analysis Yes XYBinEast 10000000 0 XYBinNorth 10000000 0 Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 39 Library Help Top lt 4 Back gt Cluster analysis Parent topic Classifying Euler solutions Task files You can classify Euler solutions by grouping points that are close to each other into clusters INTREPID creates a fusion of dusters based on the centers of gravity of each cluster It stores the resulting data in a cluster dataset The algorithm puts in the same cluster all the clusters whose horizontal center of gravity distances are less than 2 max_horizontal_radius_confidence You can perform iterations around the clusters is possible with a re split and rejoin INTREPID eliminates any cluster with less than 5 points to improve the significance of the statistical analysis of the clusters Since this process creates a good local populaion of similar solutions INTREPID computes skew and kurtosis for further comparison work Option Purpose Maximum p
69. s Example ReportFile euler rpt Output options Parent topic If you wish to save the current Euler Deconvolution file specifications and parameter aeia settings as an task specification file choose File gt Save Options to specify the input an filename and save the file See Displaying options and using task specification files output files f for more information Output Convention for displaying Euler solutions Parent topic It is common practice to display Euler solutions point datasets using Specifyi eal e Symbol colour to represent Depth output files e Symbol size to represent Reliability e Symbol strike to represent Angle Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 13 Library Help Top q Back gt Specifying the region for calculating solutions Parent topic You can specify a rectangular subsection of the input grid INTREPID only outputs Euler solutions located within the subsection Specify the subset in distance units of the Deconvolution T44 grid dataset usually metres If you specify extents of a region that completely contains the input grid INTREPID does use the subset feature INTREPID uses any actual grid data that is available outside the subset for FFT filling and conditioning You can specify the width of the grid expansion border for FFT in relation tothis subset See Expanding the boundary of the input gri
70. t Task files Library Help Top lt 4 Back gt The Euler method generates many solutions and estimates of the errors associated with each solution There has been a lot of work reviewing and comparing the available error estimate techniques The depth error and depth percentage method see Selecting solutions by depth has been popular but our research indicates a belief that it is less trustworthy than the Reliability method Reliability is really just a normalisation of the signal strength for each solution It is a fractional number ranging between 0 and 1 A value of 1 signifies perfect reliability This strength of signal from our experience is one of the better measures that indicate which Euler solutions to accept The reliability field output as part of a solution set is a scaled value of the local solution condition over the maximum condition The maximum condition can be orders of magnitude bigger than those of perfectly good solutions so reliability as a discriminator may not have as much spread as one would wish Goodness is the reliability percentile of a solution Since Goodness only veires between 0 and 1 it is easier to use for selecting solutions You can specify a reliability distribution percentile Goodness range for selecting output solutions The Lower goodness clip and Upper goodness clip parameters specify the percentiles of high and low reliability solutions to reject If you classify the
71. t gt To classify select and output a collection of Euler solutions 1 Ensure that the complete set of Euler solutions is available for you to process You can do this e Immediately before starting the selecting and classifying process without exiting from Euler Deconvolution so that INTREPID has just produced the complete set of Euler solutions See Creating the complete set of Euler solutions Steps for details e By loading a previously created complete set of Euler solutions From the main menu choose File gt Open solutions for resorting See Output the complete set of Euler solutions Specify the criteria for selecting the solutions for output See Selecting Euler solutions for output for details If required Specify the method of classifying the Euler solutions binning or clustering See Selecting and classifying Euler solutions Steps for details Select the format for the output points datasets See Output vector dataset formats If required Specify output to 3D visualisation formats See Output visualisation formats Choose Apply Sort INTREPID selects classifies and outputs the solutions according to your specifications 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 33 Library Help Top lt 4 Back gt Selecting Euler solutions for output Parent topic In this section Euler Deconvoluti n e Structural index clips T44 e Minimum observed dip
72. tatistical analysis The default value is 1000 units INTREPID rejects solutions below the depth represented by this parameter Percent Percentage depth error is the estimated error normalised deptherror INTREPID converts the estimated depth error divided by actual depth toa percentage You can set a maximum percentage and reject high error data Task files Example MinimumDepth 0 0 MaximumDepth 5000 0 Maximum Percentage Depth Error 900 Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Euler Deconvolution T44 35 Library Help Top lt 4 Back gt Maximum absolute alpha Parent topic The Extended Euler equations also solve for a amp B Selecting Euler i R solutions for a is associated with the Classic equation and is solved for instead of the output BACKGROUND term It is meant to reflect dip and material properties for the case of large scale geological structures such as a contact where say theoretically the SI is 0 0 for magnetics The generalized formulations in this tool allow for the calculation of and B without going into what this might mean for specifically solved for bodies A solution discrimination technique is based upon a requirment for this term to be zero or disappear for bodies with an SI gt 0 As it can bea primary output from the solver it is a better error indicator than values such as covariance and standard error estimates Th
73. tions Hilbert not always UseSymmetry false DiskUsageRule AUTO you can save computation time for repeated runs by saving the outputs SaveDerivatives true SaveDerivativeDirectoryName reuse derivative grids do an RTP on mag data not necessary DoReductionToPole false IGRF Date 31 12 1999 it is possible to specify a smaller internal area in this special case of starting from an FFT grid 1 do not write out a subsection grid as the new source file 2 catch the subsection start row col end row col 3 get the euler SVD solver to just use these limits Subset XLower 474550 0 XUpper 485250 0 YLower 5986850 0 YUpper 6000600 0 size of expanded grid as a percentage of original grid size FFT BorderPercentExpansion 120 0 e OH Displaying options and using task specification files Parent topic In this section Euler Deconvolution T44 e Displaying options e Main block structure of a Euler Deconvolution task file e Syntax table e Using task specification files Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 43 Library Help Top lt 4 Back gt Main block structure of a Euler Deconvolution task file Parent topic The following table shows the main block structure of a Euler Deconvolution task file Displaying See Syntax table for more details options and ing task as Block definition Contents
74. tructuralIndexClip 0 5 UpperStructuralIndexClip 4 5 NumberVerticalLayers 1 MinimumDepth 0 0 MaximumDepth 5000 0 if vector from observation point to solution dips less than 20 discard MinimumObservationDip 20 0 ratio of estimated Depth error to depth value Maximum Percentage Depth Error 900 extended Euler can calculate a property of teh source alpha Maximum Absolute Alpha 100 0 MaximumSingularityRatio 1000000000 0 Binning Analysis false actual bin size XYBinEast 10000000 0 XYBinNorth 10000000 0 Mask Solutions true do not keep solutions outside original spatial grid Cluster Analysis false no cluster if values separated by more than this distance Maximum Point separation 900 0 Solver method specifying which formulation you want Classic Hilbert Only A113 Fixed SI A113 For Contact Case No SI Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 42 Library Help Top q Back gt EquationCombo Hilbert Only default SI if one is needed Most Solvers estimate this quantity StructuralIndex 1 0 window size for equations as you pass over the grid LateralSize 7 some conditioning for FFT work RolloffType Cosine RollOff WindowType NO Window FillType ARTHUR MEM or maxiumum Entropy FillStopAtEdge false DetrendDegree 1 OutputPrecision IEEE4ByteReal FFTPrecision IEEE4ByteComplex Can exploit FFT symmetry for most opera
75. vatives For a tensor input grid INTREPID obtains the derivatives directly from the tensor data and does not need to perform FFT INTREPID always saves and retains some products of this process in a temporary folder You can specify that INTREPID retains all products for you to examine In this tool INTREPID always calculates the FFT except for tensor input grid and derivatives Since this is a routine process we do not currently provide an option for you to supply your own FFT or derivatives grids See Output FFT and derivative products Expanding the boundary of the input grid To prepare for the FFT INTREPID extends the boundary of the input grid extrapolates values for this extended region and also interpolates any internal gaps in the grid If you defined a subsection of the input grid dataset INTREPID may use a margin outside the subsection as the grid edge expansion the FFTBorder text box or FFTBorder keyword See Specifying the region for calculating solutions for details If you did not define the subsection in this way INTREPID expands the grid by 10 If INTREPID expands the grid it appends a notation to the temporary grid dataset names that it produces from it See Output FFT and derivative products Detrending the grid INTREPID always detrends the grid See Detrending data values in INTREPID spectral domain operations reference R14 for information The value you assign to the keyword corresponds to the deg
76. w determining the maximum depth of solutions see Determining the maximum depth for solutions window size e Whether to convolve the derivatives before use see Derivatives and analytic signal e Whether to save the derivatives and the analytic signal as grid datasets during the process see Derivatives and analytic signal 3 Choose Apply Euler INTREPID will calculate and save the solutions and intermediate results datasets if specified See the following sections for details about this process Library Help Top 2012 Intrepid Geophysics q Back gt INTREPID User Manual Euler Deconvolution T44 15 Library Help Top lt 4 Back gt The standard and extended Euler equation options Parent topic Euler Deconvolution T44 Library Help Top In this section e Method 1 Standard Euler e Method 2 Euler Werner e Method 3 Euler Werner 2 Equation SI solver e Method 4 Euler Werner basement sol ver e Method 5 Hybrid 2 pass Euler solver e Method 6 Euler Werner Full Solver e Method 7 Euler Werner property solver e Notes about tensor deconvolution e Method 8 Tensor Bouguer solver e Method 9 Tensor gravity estimator with fixed SI The Euler equation is solved using a singular value decomposition to determine the unknowns of a system of linear equations The Traditional or Standard Euler technique uses the components of the analytic signal three orthogonal derivatives all in the s

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