User Manual
Contents
1. none 11 4 References 12 1 Preliminaries 1 1 The AxiSEM Concept The basic idea behind AxiSEM is to take advantage of axial symmetry with respect to an axis going through the center of the earth and the source In such axisymmetric models the response to a moment tensor or single force point source can be expanded in a series of multipoles mono di and quadrupole The dependence of the 3D wavefield on azimuth can be solved analytically and the remaining 2D problems four of them for a full moment tensor source are solved numerically using a spectral element approach Source Decomposition 2D numerical problems u u s z u u s z f sind cos db u u s z f sin 2 cos 2 1 2 Software and hardware requirements 1 2 1 Essential requirements Operating system The software should run on any UNIX like operating system and has been tested on Linux Debian Ubuntu SuSe RedHat Mageia Cray et al and MacOS X Compilers Fortran 90 compiler tested on ifort gfortran 4 6 portland Cray Libraries MPI NetCDF optional fftw optional Systems Unix based OS on desktop scale tested on Linux and MacOS and HPC scale tested on Cray XT4 XE6 and XK7 HECToR UK National Supercomputing Service SuperMUC Leibniz Rechenzentrum Garching Pacman Arctic Region Supercomputing Center Tools tcshell perl Useful tools ObsPy Needed for the automated tests Follow the instructions for your system2. AxiSEM has been run for 400000s 5 days to compare amplitude spectra with a normal modes summation Nissen Meyer et al 2014 SOLVER inparam_advanced change parameter SAMPLING_RATE By default the sampling rate is set to the time step length of the simulation We strongly recommend to leave it as such to avoid aliasing The resampling can better be done with ObsPy or another tool that supports filtering 3 10 Include lateral heterogeneities 2 5D simulation SOLVER inparam_basic change parameter LAT_HETEROGENEITY to true The actual heterogeneity model is set in SOLVER inparam_hetero This functionality is currently under development and not documented See the example files SOLVER inparam_hetero TEMPLATE for an idea of what to do 11 4 References Directly dealing with this code When using this code please cite one or more of these publications 1 Tarje Nissen Meyer M van Driel S C St hler K Hosseini S Hempel L Auer A Colombi and A Fournier 2014 AxiSEM broadband 3 D seismic wavefields in axisymmetric media Solid Earth 5 425 445 doi 10 5194 se 5 425 2014 2 Tarje Nissen Meyer F A Dahlen A Fournier 2007 Spherical earth Fr chet sensitivity kernels Geophysical Journal In ternational 168 3 1051 1066 doi 10 1111 j 1365 246X 2006 03 123 x 3 Tarje Nissen Meyer A Fournier F A Dahlen 2007 A two dimensional spectral element method for sp
3. and click apply in the properties panel on the left you might get an OpenGL Error on the virtual box which you can ignore To see the mesh change the representation from surface to surface with edges On some host systems the dropdown menu seems to be messed up in that case go to the Display context in the Properties panel on the left If the plot appears all yellow click on play You can open other vtk files to look at other properties of the model and the mesh You might need to rescale the color range by clicking on the left right arrow symbol in the top left Mi ParaVi Properties Information Properties EX File Edit View Sources Filters Tools Macros Writers CoProcessing Prism F apply reset Delete 2 j TA stnae 1 al Display UnstructuredGridRepresentation BoO Poaeg ag jo data zj EOLO Color Cs i gl CubeAxes U visible Representatid 4 Move the mesh to the solver directory and give it a meaningful name movemesh csh PREM_50s 2 3 SOLVER solve the elastic wave equation 1 Go to the SOLVER folder and open the inparam_basic file with your favourite editor cd SOLVER vi inparam_basic Set these parameters SIMULATION_TYPE single SEISMOGRAM_LENGTH 1800 RECFILE_TYPE stations MESHNAME PREM_50s ATTENUATION true SAVE_SNAPSHOTS true WARNING Only save snapshots if the mesh is rather low
4. moment tensor depth and location of the source must be set in the file CMTSOLUTION The submit csh script starts four separate runs in parallel the postprocessing script sums the results to get correct seismograms 3 8 Change source time function SOLVER inparam_advanced change parameter SOURCE_FUNCTIONI AxiSEM generally calculates displacement seismograms The source time function selected here is equivalent to the moment function m t Note that to calculate seismograms similar to those of an earthquake i e with a persistent displacement at the source the setting errorf has to be used Note that that is different to the literature that usually defines the source time func tion as the moment rate function rm t However it is consistent with SpecFEM To create seismograms with a flat zero phased source spectrum use the setting dirac_0 Seismograms calculated with this setting can be convolved with other source functions in AxiSEM postprocessing or manually with a program of your choice However note that seismograms or wavefields calculated with a dirac_0 STF will contain numerical noise Therefore visual ization and wavefield plotting should be done using errorf or one of the Gaussian STFs 3 9 Change seismogram length or sampling rate SOLVER inparam_basic change parameter SEISMOGRAM_LENGTH Default value is 1800 s although the exact length is rounded to the next multiple of the simulation time step There is no maximum limit
5. referred to as event 1 in the later tasks Stations are defined in the STATIONS file Go back to the SOLVER directory and change the inparam_basic file such that SIMULATION_TYP moment GI SAVE_SNAPSHOTS false Run the solver giving the run a meaningful name submit csh prem_50s_eventl This command compiles the code if needed and starts four simulations at once each simulating a basic source type two monopoles a dipole and a quadrupole for details see Nissen Meyer et al 2007 You can observe the progress in the outputfiles in each job s subdirectory cd prem_50s_eventl tail f MZZ OUTPUT_MZZ Once all the jobs are done check with htop you can proceed with postprocessing 2 4 POSTPROCESSING rotate and sum seismograms and wavefields Postprocessing is a key feature of AxiSEM the source mechanism and source time function can be modified without redoing the more expensive simulation 1 For the previous simulation the contribution of the elemental sources needs to be summed up to get seismograms for a full moment tensor source In the main rundirectory prem_50s_event1 open the file param_postprocessing It should contain these settings auto generated by the solver REC_COMP _SYS enz CONV_PERIOD 0 CONV_STF gauss_0 The source mechanism depth and location cannot be changed in postprocessing is read from the CMTSOLUTION file in the same directory Start the postprocessing postp
6. s kg m 6800 6800 8190 8186 8183 8179 3900 3900 4611 4607 4602 4598 m 00000 1 00000 e e e E a km km km s g cm These units are often used because the values are between 1 and 10 For an elastic isotropic model 90039 90233 90428 90622 radius depth radius or depth of the layer Allows to define the position of the layers in radius beginning from the center or depth beginning from the surface rho p density vpv a vertical P velocity x vsv vertical S velocity For an anelastic model additionally qka Qx qmu Qu For an anisotropic model additionally vph horizontal P velocity vsh horizontal S velocity eta anisotropic parameter n marks comment lines The header variables UNITS and COLUMNS allow to customize the structure of these lines which should facilitate the import of external models from other programs First order discontinuities are enforced by double layers with the same radius see layers 2 3 and 4 5 in the example and are honoured by the MESHER For an example file select one of the internal models in MESH run the MESHER It will write a valid input file of the selected model into MESH this file according to your needs The overall radius of the body is given by the radius of the outermost layer and can take any reasonable value Read Planets moons and tennis balls can be simulated
7. 600 8 Click on the stations or source to see more 2 5 Computational aspects Running in a 2D computational domain the code is obviously significantly faster than comparable 3D methods 30min seismogram Total CPU cost 10 m 2 20 7 v E 10 e 10 5 5 5 D 3 5 2 10 E 1 0 5 fi fi fi l 0 5 1 0 2 0 4 0 1 2 5 10 20 50 seismic period s seismic period s On the left you may deduct the mesher s RAM occupation as a function of frequency Going towards very high resolution around and above 1Hz you will need a rather fat node gt 16GB RAM for the shared memory meshing On the right we depict the computational cost associated with the solver to compute seismograms of 30 min length The relation between seismic period and CPU hours is an approximate proxy to estimate how many cores and wall clock time is optimal for your infrastructure Scaling of CPU hours is approximately to the third power of the maximum frequency strong scaling ert weak scaling o 1 optimal optimal S 1 2 e e axisem S e e axisem 5 5 5 2 1 4 2 O e un un 2 1 8 5 1 16 g 0 1 32 5 256 512 1024 2048 4096 8192 8 32 128 512 2048 8192 cores cores Scalability plots from test runs on a Cray machine at CSCS Switzerland The left shows strong scaling fixed global problem size the right plot weak scaling fixed problem size pe
8. COMPUTATIONAL INFRASTRUCTURE FOR GEODYNAMICS CIG Ax SEM User Manual Version 1 1 www axisem info en Tarje Nissen Meyer Martin van Driel Simon St hler Kasra Hosseini Stefanie Hempel Alexandre Fournier www geodynamics org AXISEMV1 1 MANUAL Tarje Nissen Meyer Martin van Driel Simon St hler Kasra Hosseini Stefanie Hempel Alexandre Fournier Oxford University UK ETH Zurich Switzerland LMU M nchen Germany Universit t M nster Germany 5 IPG Paris France www axisem info aug Oxford UK July 7 2014 AxiSEM is a parallel spectral element method to solve 3D wave propagation in a sphere with axisymmetric or spherically symmetric visco elastic acoustic anisotropic structures Such media allow the computational domain to be collapsed to a 2D disk where the third azimuthal dimension is solved analytically on the fly posteriori This leads to extreme speedup by many orders of magnitude with respect to methods that discretize the 3D domain and enables a full coverage of the seismic body and surface wave frequency spectrum between 0 001 1Hz The time domain code delivers full spatio temporal wavefields that can be stored on disk and transformed to frequency domain Due to the dimensional reduction global wave propagation at typical seismic of periods down to 5 seconds can be tackled on laptops and at 1Hz on moderate clusters The Fortran 90 code is divided into a Mesher a Solve
9. al dipole source 100 km source depth Start from within the AXISEM directory 1 10 11 12 13 14 15 16 copytemplates csh creates various input files from templates Check file make_axisem macros whether the compiler settings fit your system cd MESHER Check file inparam_mesh for background model period of simulation and number of CPUs Default is PREM 50 s and 2 CPUs to be running within a few minutes on a modern PC submit csh gt Check file OUTPUT Wait for DONE WITH MESHER to appear in OUTPUT move mesh files to SOLVER MESHES directory and give it a name movemesh csh PREM_50s cd SOLVER In inparam_basic set the value for MESHNAME to the meshname from above here PREM_50s submit csh PREM_mrr_50s_gauss_1800s compiles and runs the code cd PREM_mrr_50s_gauss_1800s go to the run directory Wait for PROGRAM axisem FINISHED to appear in OUTPUT_PREM_mrr_50s_gauss_1800s use tail f OUTPUT_PREM_mrr_50s_gauss_1800s post_processing csh cd Data_Postprocessing googleearth open googleearth_src_rec_processed kml click earthquake info receivers seismograms matlab run plot_record_section m plotting all components of displacement seismograms If the Solver is re run with different parameters but the same mesh you may start at step 9 To change model frequen
10. am_basic parameter RECFILE_TYPE SOLVER STATIONS Similar to SPECFEM3D Globe an ASCII file with six columns which are station name network name latitude longitude elevation depth n b AxiSEM puts all receivers to the surface the last two rows are ignored RAYN GD 23 52 45 50 PALK GD 7 27 80 70 MAJO GD 36 54 138 21 ERM GD 42 02 143 16 oo O QO O O O O o gt 19 gt OS The station names are used by post_processing to assign names to the seismogram files SOLVER receivers dat Plain ASCII file with number of receivers in the first line and then nrec lines with colatitude and longitude 3 3 Change background model MESHER inparam_mesh parameter BACKGROUND_MODEL afterwards the steps from 5 have to be rerun Supported models are prem_iso Isotropic continental PREM model prem_iso_solid like prem_iso replace fluid outer core with vs vp sqrt 3 prem_iso_onecrust like prem_iso but extend lower crust to surface prem_iso_light like prem_iso but with mantle material extended to surface prem_iso_solid_light like prem_light but in fluid outer core vs vp sqrt 3 prem_ani Anisotropic continental PREM model actual PREM prem_ani_onecrust like prem_ani but extend lower crust to surface prem_ani_light like prem_ani but with mantle material extended to surface ak135 AK135 Isotropic PREM attenuat
11. cy or number of CPUs repeat steps 3 to 7 and select the new mesh in SOLVER inparam_basic The solver input can be changed in inparam_basic between 8 and 9 changing post processing input between 11 and 12 Using a new mesh requires recompilation of the solver done automatically in step 9 If post processing parameters are changed also change the post processing directory or delete the old one 2 2 MESHER generate a Mesh 1 Open a terminal go to the MESHER folder and open the inparam_mesh file with your favourite editor cd MESHER vi inparam_mesh The parameters should be readily set but you might want to double check and verify BACKGROUND_MODEL prem_iso DOMINANT_PERIOD 50 0 NTHETA_SLICES 2 NRADIAL_SLICES al WRITE_VTK true COARSENING_LAYERS 3 The file should be self explanatory NB Models without crust light allow for a larger time step and hence run a lot faster WARNING Only write vtk files if the dominant period is rather large i e above 10 or 20s as these files become exceed ingly large 2 Run the mesher and watch the progress submit csh tail f OUTPUT The meshing should be really fast i e on the order of seconds for the chosen parameters Wait for DONE WITH MESHE to appear 3 Take a look at the mesh with paraview paraview Open one of the vtk files in the subfolder Diags e g mesh_vp vtk
12. herical earth seismograms I Moment tensor source Geophysical Journal International 168 3 1067 1092 doi 10 1111 j 1365 246X 2006 03121 x 4 Tarje Nissen Meyer A Fournier F A Dahlen 2008 A two dimensional spectral element method for spherical earth seis mograms II Waves in solid fluid media Geophysical Journal International 174 3 873 888 doi 10 1111 j 1365 246X 2008 03813 x 5 Tarje Nissen Meyer 2007 Full wave seismic sensitivity in a spherical Earth Ph D thesis Princeton University This in cludes refs 2 4 and more details Other references 6 Deville M O Fischer P F Mund E H 2002 High Order Methods for Incompressible Fluid Flow Vol 2 Cambridge monographs on Sppl amp Comp Math Cambridge University Press 7 Tufo H M Fischer P F 2001 Fast Parallel Direct Solvers For Coarse Grid Problems 61 151 177 J Par and Dist Comput 8 Bernardi C Dauge M Maday Y 1999 Spectral Methods for Axisymmetric Domains Vol 3 Series in Appl Math Gauthier Villars Paris 9 Chaljub E 2000 Mod lisation num rique de la propagation d ondes sismiques en g om trie sph rique Application a la sismologie globale Ph D thesis Universit de Paris 7 10 Komatitsch D Tromp J 2002 Spectral element simulations of global seismic wave propagation I Validation 149 390 412 Geophys J Int 12
13. ion ak135f AK135 Isotropic own attenuation iasp91 Isotropic IASP91 model with PREM density and attenuation external Layered external model give file name in EXT_MODEL the inner core needs to be big enough check VTK output 3 4 Use external 1D velocity model MESHER inparam_mesh change parameter BACKGROUND_MODEL to external and EXT_MODEL to the filename of your model The model should be stored in a file of the following form ANELASTIC T ANISOTROPIC T UNITS m COLUMNS radius rho vpv vsv qka qmu vph vsh eta 6371000 2600 5800 3200 57827 600 5800 3200 1 00000 6356000 2600 5800 3200 57827 600 5800 3200 1 00000 Discontinuity 6356000 2900 6346600 2900 Discontinuity 6346600 3380 6341600 3380 6336600 3379 6331600 3379 1 depth 6800 6800 2 depth 8190 8186 8183 8179 3900 3900 4396 4397 4398 4399 15 00 km 57827 57827 24 40 km 57827 57827 57827 57827 600 600 600 600 600 600 In the header four keywords are mandatory to describe the following model ANELASTIC Is the model anelastic viscoelastic or not e ANISOTROPIC Is the model anisotropic or not e UNITS Are the units in this file given in S units Allowed values e COLUMNS Describe the column order in the file Necessary values This header is followed by an arbritrary number of lines with velocity layers where m S units m m
14. mpiler has to be the same as the one you are using for AxiSEM The script should be run from a scratch directory like tmp cd tmp AXISEM_DIRECTORY SOLVER UTILS make_netcd sh Especially the HDF5 compilation can half an hour and will produce tons of warnings They can be ignored as long as the tests pass If one of the tests should fail the reason is most likely a wrong compiler configuration We can offer only very limited support for the compilation of the libraries Windows While we never tested it installation of NetCDF on Windows should be possible http www unidata ucar edu software netcdf docs faq html windows_netcdf4_2 1 3 Preparation of a Debian Ubuntu Linux system To prepare a fresh Debian based Linux system the absolutely necessary packages can be installed with sudo apt get install gfortran build essential tcsh openmpi bin libopenmpi dev The processing and visualization tools can be installed with sudo apt get install paraview gnuplot 2 Running the code 2 1 Quick start This is the step by step blackbox procedure i e running a workflow from raw source code to analyzing seismograms and wave field movies upon pre set parameters It assumes your system fulfils all requirements mentioned above The default simulation parameters are PREM velocity model isotropic anelastic continental crust 50 s dominant period of the mesh 2 CPUs used for the SOLVER 1800s seismogram length Vertic
15. on http www obspy org Paraview Can be used to check meshes and watch wavefield movies Google Earth Can be used for a quick overview on seismograms at the locations of the receivers gnuplot Used to make quick overview plots matlab Used for plotting record section script included 1 2 2 NetCDF AxiSEM allows to output larger datasets especially wavefields in the NetCDF format The current version also has full support for binary dumps but the development will move towards NetCDF containers Unfortunately the installation of the NetCDF libraries may still be cumbersome below we list some limited support for installing NetCDF HPC systems The libraries should be provided by the system Use the recommended settings Ubuntu 12 10 and newer Debian Wheezy and newer The code is working with the NetCDF libraries delivered with the system for gfortran They can be installed by sudo apt get install libnetcdff5 Ubuntu 12 04 and older MacOS The libraries delivered with Ubuntu 12 04 and earlier do not seem to work reliably We therefore generally recommend to compile the NetCDF libraries from source This can be done with the script make_netcdf sh in the SOLVER UTILS directory It downloads current versions of the zlib hdf5 and netcdf4 libraries from http www unidata ucar edu compiles them and runs the included tests By default the new libraries are installed in HOME local In the first lines of the script specify your co
16. r CPU 3 Typical use cases 3 1 Change source type SOLVER inparam_source SOLVER CMTSOLUTION and SOLVER inparam_basic AxiSEM has two principal modes which are selected by the value SIMULATION_TYPE in SOLVER inparam_basic l SIMULATION_TYPE s ingle The Solver simulates one basic source which can be one of the following monopoles Myr explosion Moo Mee Pr dipoles Mo Mor Po Ps quadrupoles Mos Moo Moe where Mi are moment tensor sources with the mentioned components of M set to one and the others to zero P is the same for single forces Choose the source type and set the source depth and amplitude in SOLVER inparam_source 2 SIMULATION_TYPE moment The submit csh script starts four separate simulations for the basic types M r Mog Mog Mor Mog You have to run the postprocessing script after the simulation to sum them up correctly Before the simulation set the source depth and the moment tensor in SOLVER CMTSOLUTION Run postprocessing csh in the simulation directory afterwards You can run postprocessing for different moment tensors on the same simulation but not for different depths since the forward simulation depends on the depth The CMTSOLUTION file is a standard format and can be downloaded from many sites in the web including http www globalcmt org CMTsearch html 3 2 Change station locations SOLVER STATIONS or SOLVER receivers dat dependingon SOLVER inpar
17. r utilizing the message passing interface MPI for communication between separate domains and comprehensive post processing for ease of visualization The essential raison d tre of this method is the efficient calculation of seismograms wavefield movies and those wavefields that underly sensitivity kernels to allow for tomographic inversions of any portion of a seismogram at any relevant frequency Portal for this code www axisem info Contact info axisem info Principal authors Tarje Nissen Meyer Alexandre Fournier Martin van Driel Simon St hler Kasra Hosseini Stefanie Hempel Contributions J P Ampuero E Chaljub A Colombi F A Dahlen D Komatitsch G Nolet J Tromp Research funding Princeton University NSF HP2C Petaquake QUEST ITN Marie Curie ETH Zurich Oxford University Copyright 2013 Tarje Nissen Meyer Alexandre Fournier Martin van Driel Simon St hler Kasra Hosseini Stefanie Hempel AxiSEM is free software you may redistribute it and or modify it under the terms of the GNU General Public License as published by the Free Software Foundation either version 3 of the License or any later version AxiSEM is distributed in the hope that it will be useful but WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE Commercial use must be discussed with the authors prior to usage See the GNU General Public License for more details LICENSE_GPL
18. resolution e g above 20s as these files become exceedingly large You may alternatively opt to only plot a fraction of the 2D domain which can be set in inparam_advanced 2 First we are taking a look at a basic sourcetype a vertical dipole which has a monopole radiation pattern This is set by SIMULATION_TYPE single and defined in the inparam_source file Run the solver giving the run a meaningful name submit csh PREM _mrr_50s_gauss_1800s This command compiles the code if needed and starts the simulation You can observe the progress in the outputfile cd PREM_mrr_50s_gauss_1800s tail f OUTPUT_PREM_mrr_50s_gauss_1800s Once the run is finished take a look at the wavefield with paraview open the PREM_mrr_50s_gauss_1800s Data xdmf_xm1_0000 xdmf file and click apply Go to the last snapshot and rescale the color range then click on play to see the wave propagate You can also choose different components of the wavefield or the absolute value For paraview experienced users choose absolute value and a logarithmic colorscale to see all wave types at once e g black body radiation looks nice iu ParaView 3 98 0 enhanced 32 bit File Edit View Sources Filters Tools Macros Writers CoProcessing Prism Help i Be Cia gt aD Time BERSAERAAs S 20 3 Now simulate seismograms for a full moment tensor source the source is defined in the CMTSOLUTION file and the one
19. rocessing csh The resulting seismograms and plots can be found in the directory Data_Postprocessing Seismograms can be viewed with your favorite image viewer e g eog cd Data_Postprocessing GRAPHICS eog lt filename gif gt For a nice overview you can use google earth might not run on all computers and depends on internet connection Open the googleearth_src_rec_seis kml file in the Data_Postprocessing directory double check the exact path google earth might have something older from history which is quite confusing You should now see the earthquake and the receivers in the places menu on the left vw Places EEEE BLOWSsUW d 16 colat lon 50 8892 249 4762 epicist 112 82376218371142 amp My Places 22 J SEISMOGRAMS SAU_UU disp post Mil_conv0l00 Ndat amp ME Sightseeing Tour Make sure 3D age gt Buildings MS Temporary Places 5 VI eartnquake i gt earthquake s at des FE 409 200 0 200 A00 600 800 1600 1200 1400 1600 Event details f Tip D colat lon 50 8892 249 4762 eplaist 112 82376218371142 i colat lon deg a j f j 4 P Be 14 eMOGRAMS SRU_UU_disd_post mij_conv01d0 Zutat H 60 14 M 109C TA d 1 al station ki N pn 20 14 109C_TA_disp_po er o H F bissel i 26 14 ME AAK II di 2 Gk ager a station i Ber i AAK_Il_disp_post_ i I g AAK KN di 3 gt Dv me 1899 200 o 200 400 600 800 1000 1200 1400 1
20. single electrons probably not 3 5 Change number of CPUs ESH Hs ER inparam_mesh parameter NTH he number of CPUs used is the product of the two parameters ETA_S ETA_SLIC ES and NRADIAL_SLICES ER inparam_mesh enable the option WRITE_1DMODEL and ER Diags 1dmodel_axisem bm Modify ICES needs to be 1 2 4 or a multiple of 4 To get a suggestion for optimal decomposition run the Mesher with NTHE A_S _SUGGEST_NTHETA true and check the OUTPUT file NRADIAL_SLICES should be on the order of 8 larger numbers work for very high frequencies It can be left at 1 for ICES lt 64 CPUs but should be increased then to reduce MPI communication To ensure scaling each proces sor should have at least about 500 elements N B This value is for ONE simulation To calculate the wavefield of a full moment tensor 4 parallel simulations have to be run and the number of necessary CPUs is NTH ETA_SLIC 10 ES NRADIAL_SLICES 4 3 6 Change the maximum frequency of the simulation MESHER inparam_mesh parameter DOMINANT_PERIOD As arule of thumb Simulations with DOMINANT_PERIOD gt 10s can be run with 2 or 4 CPUs on a modern workstation and cost around 1 CPUh 3 7 Calculate the response to a full moment tensor solution SOLVER inparam_basic change parameter SIMULATION_TYPE to moment The
21. txt Contents 1 Preliminaries 2 L1 TREAZBEM CONCEP e co ee ers Sd ee BAe nee aa ee PR oe hed oe amp 2 1 2 Software and hardware requirements 23 sk nenne eee eee he 3 1 2 1 Essential requirements se 24 eee HR Msn une ern eier 3 122 ANGE 2 ite a at ch Se eee Be ra Sed ie ine Be ek dir ae 3 1 3 Preparation of a Debian Ubuntu Linux system 2 2 2 m nm ee ee ee 3 2 Running the code 4 21 Quickst ft cocoi eh ren 4 22 MESHER generate a Mesh ca 4 8 an BH EAL ea ROO Gs ER Ge Y 5 2 3 SOLVER solye the elastic waveequation ex e wa Seh an a Ber Er ae we 6 2 4 POSTPROCESSING rotate and sum seismograms and wavefields o o aa 7 23 Conmiputitionallaspecis oan ca a ae ee ee 8 3 Typical use cases 8 3 1 Chanae SOUICE AVS ee ee GE ae SG eS oe ee a a ae a 8 3 2 Change smuontocavons ae ge ee ec SPA 9 33 Change backsround model ar u aa a 24 e SERS ESE READE ENG ER Ede ee EGS 9 oe Useextemal 1D veloci model enra ek A ae ar oe Re eee a eee Den et e 9 3 3 Change numberof CPUS 4 2 624 baw BASS CEES EMS GEE we EA Oe EOS ORR DED we a 10 3 6 Change the maximum frequency of the simulation 2 2 oea 11 3 7 Calculate the response to a full moment tensor solution 2 2 00 nn 11 58 Chanie sourcedime NCHOD lt osi s aor a ee Oe ER SR SORE ee hw we a 11 3 9 Change seismogram length or sampling rate s sse casaca taa nek ee 11 3 10 Include lateral heterogeneities 2 5D simulation
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