Fault output

Introduction

Two types of outputs are available for imaging the rupture. The rupture characteristics can be assessed at a set of locations, using ASCII receiver files, or overall the whole fault using files that can be opened in ParaView. Threads or nodes can be dedicated to write this latter output (see Asynchronous Output), but it is usually not necessary. The type of output generated depends on the value of the variable OutputPointType of the DynamicRupture namelist:

&DynamicRupture
OutputPointType = 4
/
0 : no output
3 : ASCII fault receivers
4 : paraview file
5 : both

Paraview output

This output is parametrized by the Elementwise namelist, example:

&Elementwise
printIntervalCriterion = 2 ! 1=iteration, 2=time
printtimeinterval_sec = 1.0
OutputMask = 1 1 1 1 1 1 1 1 1 1 1 1 !described herafter
refinement_strategy = 1 ! or 2
refinement = 1
/

printIntervalCriterion

If printIntervalCriterion = 1, the output is generated every N time steps, where N is set by printInterval. This option only works with Global time stepping. If printIntervalCriterion = 2, output is generated every printtimeinterval_sec.

refinement

If refinement = 0, one triangle is outputted for each mesh cell. The unknowns are evaluated at the center of each cell. refinement = 1 subdivides each triangle, into 3 or 4 subtriangles depending on the refinement_strategy. if refinement_strategy=1 splits each triangle into 3 triangles, sharing the triangle barycenter as a node. if refinement_strategy=2, triangles are split into 4 triangles. Higher refinement would further subdivide each subtriangle.

OutputMask

OutputMask allows visualizing only part of the unknown. The unknown can be switched off or on by changing the corresponding bit in the OutputMask array.

  1. SRs and SRd: slip rates in strike and dip direction
  2. T_s, T_d: transient shear stress in strike and dip direction, P_n: transient normal stress
  3. u_n: normal velocity (note that there is no fault opening in SeisSol)
  4. Mud: current friction, StV: state variable in case of RS friction
  5. Ts0,Td0,Pn0: total stress, including initial stress
  6. Sls and Sld: slip in strike and dip direction
  7. Vr: rupture velocity, computed from the spatial derivatives of the rupture time
  8. ASl: absolute slip
  9. PSR: peak slip rate
  10. RT: rupture time
  11. DS: only with LSW, time at which ASl>D_c
  12. P_f and Tmp: pore pressure and temperature

Ascii fault receivers

The output is parametrized by the Pickpoint namelist, example:

&Pickpoint
printtimeinterval = 1
OutputMask = 1 1 1 1 1 1 1 1 1 1 1 1 !described herafter
nOutpoints = 24
PPFileName = 'fault_receivers.dat'
/

printtimeinterval

The output is generated every printtimeinterval (local) time step. Using this output with local time-stepping may result in differently sampled receiver files.

iOutputMask

same as for ParaView output.

seissolxdmf

SeisSol paraview files (XDMF/Hdf5 or XDMF/binary files, describing the fault outputs and the free-surface/volume wavefield) can also be read using our python module seissolxdmf.

Additional Ascii output

Final seismic moment and energy rate (moment rate and frictional energy rate) outputs can be enabled in the DynamicRupture namelist. The rupture front can also be outputted at every gauss points by enabling RF_output_on.

&DynamicRupture
magnitude_output_on = 1
energy_rate_output_on =1
RF_output_on = 0
/

Because each MPI rank writes its own ASCII file, output files need to be merged in a postprocessing step. The energy rate outputs are combined using this script (use -h for all available options).

Because of the high sampling rate of the energy rate output (outputted for each simulated time step), these ASCII files can easily become large. Writing these files may impact scalability. Postprocessing these files may also be time-consuming. Therefore, we recommend deriving the moment rate function from the Paraview fault output if this output is sufficiently sampled. Similarly, the Paraview fault output can be used for the rupture time instead of the ASCII output.