IRFFM2 v1.2 - Research School of Earth Sciences
Contents
1. However IRFFM v1 2 featured here uses its own version of iterdecon re written in Java Currently available Gaussian filters are a 1 0 2 5 5 0 and 10 0 Therefore a remaining part of the IRFFM2 software that is still dependent on Ammon s original package is respknt Another dependent executable is called dispersion which computes surface wave dispersion based on the program written by Saito 1988 The third executable is called sac2asc it converts sac to ascii files N B The users should make sure that they have respknt dispersion and sac2asc executables compiled and running independently on their Mac before they can execute IRFFM2 The wrapper script used by IRFFM2 is called IRFFM SCRIPT and all executables are called from that script Therefore if executables do not run properly IRFFM2 will not work either All three executables are provided with the package and should be working on your Mac If for some reason they do not their source codes will be made available upon request IRFFM is a work in progress and we welcome and encourage your feedback The enquiries and feedback can be sent to Hrvoje Tkalcic anu edu au REFERENCES Dziewonski A M amp Anderson D L 1981 Preliminary reference Earth model Phys Earth Planet Inter 25 297 356 Kennett B L N 1983 Approximations to the response of the stratification in Seismic Wave Propagation in Stratified Media chapter 9 Cambridge Univ Press New York Kenn2. IRFFM2 helps constructing one dimensional model of the earth that reduces the misfit between the synthetic and observed receiver functions and surface wave dispersion curves RSES ANU Interactive Receiver Function Forward Modeller IRFFMv2 5 Goodness of Fit 86 51 0 4 ww RF Amplitude o ES 10 i 12 1a 1A tS 16 1A 1R 19 20 21 27 Time sec Synthetic RF Observerd RF 15 0 3 85 45 50 55 60 65 70 Time sec Model Management RF Management Current Synthetic Model ak135 mod Filter a 1 0 example_observed Save Current Model Change Starting Model Filter a 2 5 Change Observed RF nikne 0 0 Filter a 5 0 Slowness 0 065 km sec 2 feet s TO Change Slowness SWD Management Frf vs Ratio 0 0 Love Group Change Obs Love Gr Appl Ay Love Phase Change Obs Love Ph rSplit Delete Layer pihy Rayl Group Change Obs Rayl Gr Input splitting point 0 0 Ray Phase Change Obs Ray Ph Split Layer Controls f Delete selected layer Delete layer T Run Mouse Movement Control Print to File O Horizontal t I O verica A Print to Printer IRFFM Manual Any Figure 1 Screen Shot of IRFFM2 The user interface as seen in Figure 1 consists of four main parts 1 The model display section left hand side The receiver function display section upper right section The dispersion curves display sec
3. Interactive Receiver Function Forward Modeller 2 IRFFM2 v1 2 Hrvoje Tkal i 4 3 f with contributions from Debdeep Banerjee Jason Li and Chris Tarlowski Research School of Earth Sciences The Australian National University Canberra Australia October 2015 All rights reserved General Information amp User Manual Research School of Earth Sciences The Australian National University e mail Hrvoje Tkalcic anu edu au tel 061 0 2 6125 3213 www http rses anu edu au hrvoje A note to IRFFM2 users The predecessor to IRFFM2 was IRFFM The abbreviation stands for Interactive Receiver Function Forward Modeller It is a Java program written during 2008 09 for interactive forward modelling of receiver functions RFs and it is featured for the first time in Tkal i et al 2011 in a study of lithospheric structure of southeast China IRFFM2 is an extension of IRFFM it enables a joint modelling of receiver functions RFs and surface wave dispersion SWD It was presented and used in Tkalcic et al 2012 in a study on lithospheric structure of southeast Australia IRFFM2 is a useful complement to the inversion or a stand alone tool An easy to use graphic interface is designed to enable the user to efficiently manipulate lithospheric thicknesses and velocities as well as V V ratios in a 1D Earth model It rapidly displays the theoretical and observed RFs and SWD and provides insights through forward modelling into
4. Observed RF Save Current Model 0 0 O Filter a 5 0 Slowness 0 065 km sec 00 Filter a 10 0 Change Slowness SWD Management frf Vs Ratio 0 0 v Love Group Change Obs Love Gr Love Phase Change Obs Love Ph Split Delete Layer Ray Group Change Obs Rayl Gr Input splitting point Rayl Phase Change Obs Rayl Ph Split Layer Delete selected layer Delete layer Mouse Movement Control Print to File O Horizontal I Vertical Print to Printer IRFFM Manual Any The source file for the observed dispersion graphs can be changed using the Change Obs X Y buttons where X is either Love or Rayleigh and Y 1s either Phase or Group Mouse Movement Control e Horizontal The effect of mouse dragging is limited to the x axis This means that only the velocity of a layer can be changed by dragging the mouse to the left or right This is the default setting e Vertical The effect of mouse dragging is limited to the y axis This means that only the thickness of the layers can be changed by dragging the mouse up or down e Any This option does not limit the effects of mouse dragging and both the thicknesses and the velocities of the selected layers can be changed simultaneously This is often less convenient than it looks Controls e Run When the Run button is pressed a script i
5. cation as the jar file RFFM2 jar Initially all 4 pairs of graphs are displayed as described in the following figure Velocity 35 40 45 50 55 60 65 70 Time sec RF Management Current Synthetic Model ak135 mod Filter a 1 0 example_observed Save Current Model Change Starting Model Filter a 2 5 Change Observed RF O Filter a 5 0 Slowness 0 065 km sec O Filter a 10 0 Change Slowness SWD Management v Love Group Change Obs Love Gr v Love Phase Change Obs Love Ph split Delete Layer v Rayl Group Change Obs Ray Gr Input splitting point wv Rayl Phase Change Obs Rayli Ph Split Layer Delete selected layer Delete layer Mouse Movement Control Print to File Horizontal O Vertical m Print to Printer IRFFM Manual Any To remove a pair of graph from the dispersion graph display user must uncheck the boxes against the type of graphs The following figure describes the situation where only two graphs are selected for display Velocity 20 0 22 5 25 0 27 5 30 0 32 5 35 0 375 400 425 450 47 5 50 0 52 5 55 0 57 5 60 0 62 5 65 0 67 Time sec A Obs Lv Gr Syn Lv Gr A Obs Lv Ph Syn Ly Ph Model Management RF Management Current Synthetic Model ak135 mod Filter a 1 0 example_observed Change Starting Model Filter a 2 5 Change
6. ett B L N Engdahl B E amp Buland R 1995 Constrains on the velocity structure in the Earth from travel times Geophys J Int 122 108 124 Ligorria J P and C J Ammon 1999 Iterative deconvolution and receiver function estimation Bull Seismol Soc Am 89 1395 1400 Saito M 1988 DISPER80 a subroutine package for the calculation of seismic normal model solutions in Seismological Algorithms pp 294 319 ed Doornbos D J Academic Press New York Tkal i H Pasyanos M Rodgers A G k R Walter W amp Al Amri A 2006 A multi step approach in joint modeling of surface wave dispersion and teleseismic receiver functions Implications for lithospheric structure of the Arabian peninsula J Geophys Res 111 B11311 doi 10 1029 2005JB004130 Tkal i H Y Chen R Liu Z Huang L Sun and W Chan Multi Step modelling of teleseismic receiver functions combined with constraints from seismic tomography Crustal structure beneath southeast China Geophys J Int 187 dot 10 1111 1365 246X 2011 05132 x 303 326 2011 Tkal i H N Rawlinson P Arroucau A Kumar and B L N Kennett Multi Step modeling of receiver based seismic and ambient noise data from WOMBAT array Crustal structure beneath southeast Australia Geophys J Int doi 10 1111 j 1365 246X 2012 05442 x 189 1681 1700 2012 Introduction This document describes the functionalities of the IRFFM2 user interface The
7. gure 2 It 1s important to note that to perform any manipulation of a layer we need to select the layer first when selected the colour of the layer will turn dark blue The velocity of a layer can be increased by dragging the mouse to the right or decreased by dragging the mouse to the left The thicknesses of the layers are associative which means that increasing or decreasing the thickness of a layer effects the thickness of the layer immediately below The following sub sections describe the effects of increasing decreasing the depth of a layer and the effects of splitting and deleting a layer Increasing Thickness of a Layer To increase the thickness of a layer first select the layer and then drag the mouse pointer downwards The thickness of the selected layer will increase by the amount proportional to the movement of the mouse Figure 3 illustrates the process Figure 3 If the depth of the selected layer reached the bottom of the layer below then the selected layer will subsume the layer below In other words the bottom layer will be deleted as described in Figure 4 Figure 4 Decreasing Thickness of a Layer First select the layer and then drag the mouse upwards to decrease the thickness of the selected layer as shown in Figure 5 Figure 5 If the bottom of the selected layer layer 2 reached the bottom of the layer above layer 1 the layer below layer 3 will absorb the selected layer In other words
8. he period s in the first column the velocity m s in the second column and the error m s in the third column The Dispersion Graphs Display This section displays 4 pairs of graphs Love Phase and Group and Rayleigh Phase and Group one for observed and one for synthetic The following table describes the legends used in the display Legend Data Red Filled Up Triangle Observed Love Group Red Continuous Line Synthetic Love Group Red Hollow Up Triangle Observed Love Phase Red Dashed Line Synthetic Love Phase Orange Filled Up Triangle Observed Rayl Group Orange Continuous Line Synthetic Rayl Group Organe Hollow Up Triangle Observed Rayl Phase Orange Dashed Line Synthetic Rayl Phase The Control Panel The control panel provides the buttons and input fields that enable the user to load different model files and observed RF files manipulate a model by deleting or splitting a layer and execute the program that generates the synthetic RF from the model data Further description this functionality will be given at the end Changing the Earth Model The main aim of the IRFFM is to provide a flexible way for modifying Earth model Modifying a model means changing the layer parameters and or simply deleting or splitting layers The parameters of each layer can be changed by selecting a layer and then dragging a mouse in four directions up down left and right as illustrated in Figure 2 Fi
9. how a 1D model has to be altered to reduce a misfit between the observations and theoretical predictions Input RFs are in a two column ascii format while input SWD are in a three column ascii format containing errors in the third column and the package comes with an example The input velocity models are in ascii format and the models provided with the package are ak135 Kennett et al 1995 and PREM Dziewonski et al 1981 The users can use one of these two as a starting model construct their own model from other geophysical constraints or simply guess an initial earth structure Apart from global velocity models we typically start with a resulting model from a grid search as described in Tkal ic et al 2006 2011 with 3 or 4 layers in the crust and layer in the mantle It is possible to save the current model at any time during the forward modelling for the future use or upload a new observed RF or SWD at any time The method used in IRFFM2 for the calculation of the theoretical RFs consists of the synthetic seismogram algorithm by G Randall respknt based on the method developed by Kennett 1983 IRFFM2 vl l used a time domain iterative deconvolution procedure iterdecon described by Ligorria and Ammon 1999 to produce synthetic RFs in the same manner it is done for the observed RFs Therefore the program was closely tied to the package available from the web site of Charles J Ammon http eqseis geosc psu edu cammon
10. s called and the output is written in the file outmodel slowness param filter value eqr asc For example if the slowness is 0 065 s km and the Gaussian parameter is 1 0 then the generated file name will be outmodel 0 065 1 0 eqr asc This file will be read and displayed in the display section e Reset Resets everything to the starting points with their default values e Print to File Prints a jpg image file containing the Model and RF display e Print to Printer Prints Model and RF display via selected printer User should choose Landscape mode of printing to get desired print Quit Quits the application e About Information about the IRFFM2 program
11. the selected layer will be deleted as described in Figure 6 Figure 6 Splitting Layers There are two ways to divide a layer 1 splitting a layer by half and 2 dividing a layer at a desired point 1 Select a layer and press Split Layer button from the control panel This will split the current selected layer into two equal depth layers and the upper half will be selected This is illustrated in Figure 7 Figure 7 2 Specify a position in km from where the selected layer will be split in the field Splitting Point and then press the Split Layer button in the control panel The result of this operation is illustrated in Figure 8 Figure 8 Deleting Layers To delete a layer select the layer to delete and then press the Delete Layer button in the control panel This is illustrated in Figure 9 Delete Layer 2 Figure 9 The Control Panel The functions that can be performed from the control panel are described below Model Management The current model file name is displayed in red To change the starting synthetic model press the Change Starting Model button and select a new model file The corresponding synthetic receiver function will be recalculated To save the current model press Save Current Model button To change the parameters of a selected layer input the new thickness Vs speed and V V ratio into the corresponding input fields and press the Apply but
12. tion middle section The control panel bottom right section a The Model Display The earth model 1s displayed on the left hand side of the main window The model display consists of two columns the left one representing the shear wave speed V5 and the right one representing the ratio of compressional and shear wave speeds V V The y axis of each of these columns shows the depth in kilometres Each column is divided into layers of varying thicknesses so that the parameters of the model are layer thickness Vs speed and the V V ratio The procedure for changing these parameters is described in the sections that follow Only the layers within the first 220 kilometres are displayed The default starting model is the ak135 model the file called ak135 mod which can be modified or replaced later The IRFFM2 Display The observed and the synthetic RFs and SWD curves are displayed at the right hand corner of the main window The thick grey line represents the observed RF and the thin yellow line represents the synthetic RF calculated from the current model displayed on the left hand side of the screen The default observed RF is read from a file called example _observed sac asc The default observed SWD curves are in the following files provided with the distribution of IRFFM2 data disp love group data disp love phase data disp rayl group and data disp rayl phase These are 3 column ascii files that contain t
13. ton To split the selected layer put the depth point form where you want to split the layer and then press Split Layer button To delete the selected layer press the Delete Layer button Receiver Function RF Management The current receiver function file name and the slowness in s km are displayed in red To change the observed receiver function click on the Change Observed RF button and select a new observed receiver function file After selection the display will be updated Four different values of the Gaussian parameter can be selected 1 0 2 5 5 and 10 To change the Gaussian parameter select one of the parameters and press the Run button in Controls At the start 1 0 is default value of the Gaussian parameter Match the value of the Gaussian parameter with the value you used to calculate the observed receiver function To change the slowness press the Change Slowness button and select a value Then press the Run button in Controls At the start the default value is 0 065 s km Match the value of the slowness with your best estimate for the slowness of the observed receiver function Surface wave dispersion SWD Management This part of the control panel allows users to selectively display the dispersion graphs Note that the default observed values are be read from the files data disp X Y where X can be love and rayl and Y can be group and phase These 4 files must be placed in the same lo
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