Cascadia Simulations

Daniel Roten, Kim Olsen have used AWP-ODC-GPU software to run simulations of large magnitude earthquakes in the Cascadia region.

Cascadia M9.2

• Daniel Roten recently ran a simulation of a M9.2 Cascadia earthquake on Summit, to compare ground motions against the previous Titan simulations, using 375 V100 GPUs for 3:30 hrs.

• These data are on the Alpine file system in

 /gpfs/alpine/proj-shared/geo112/rotend/Cascadia.alpine/scen_13_a_S_66m_dm_summit_flt

Simulation Configuration File

The AWP-ODC-GPU IN3D configuration file used on Summit to run the M9.2:

(base) [pmaech@login5.summit scen_13_a_S_66m_dm_summit_flt]$ more IN3D.out
      448.001 TMAX          = propagation time
      66.6666667 DH            = spatial step for x, y, z (meters)
      0.004 DT            = time step (seconds)
        0 NPC           = PML or Cerjan ABC (1=PML, 0=Cerjan)
       10 ND	  	= ABC thickness (grid-points) PML <= 20, Cerjan >= 20 
     0.95 ARBC          = coefficient for PML (3-4), or Cerjan (0.90-0.96)
      0.0 PHT	        = M-PML coefficient
     25600 NSRC          = number of source nodes on fault
     2400 NST           = number of time steps in rupture functions 
     9720 NX            = x model dimension in nodes
    16065 NY            = y model dimension in nodes
       80 NZ            = z model dimension in nodes
        2 NPX           = number of procs in the x direction
        2 NPY           = number of procs in the Y direction
        1 NPZ           = number of procs in the Z direction
        2 IFAULT        =  mode selection and fault or initial stress setting
        0 CHECKPOINT    =  checkpoint at step
        1 ISFCVLM       =  output options, surface and volume output
        0 IMD5          =  MD5 output option
        1 IVELOCITY     =  output accumulation option
        1 MEDIARESTART  =  initial media restart option
        8 NVAR          =  number of variables in a grid point
        1 IOST          =  max amount of reader (RANKSIZE/IOST)
        1 PARTDEG       =  further XY plane partitioning when mediarestart=2
        1 IO_OPT        =  output data on/off option
        1 PERF_MEAS     =  performance timing measurement on/off
        1 IDYNA         =  mode selection of dynamic rupture model
        1 SOCALQ        =  (or NEG_LAMBDA) Southern California Vp-Vs Q relationship enabling flag
        1 NVE           = visco or elastic scheme (1=visco, 0=elastic)
       0.0 MU_SS       = cohesion
      0.12 MU_DD       = dynamic friction coefficient (not used)
    0.005 FL		= Q bandwidth low frequency
   1200.0 FH		= Q bandwidth high frequency
      1.0 FP		= Q bandwidth central frequency
 10 READ_STEP
100 WRITE_STEP 
 10 WRITE_STEP2
        1 NBGX         = first x node to contain receivers
     9720 NEDX         = last x node to contain receivers
        1 NSKPX        = skip of nodes containing x receivers
        1 NBGY         = first y node to contain receivers
    16065 NEDY         = last y node to contain receivers
        1 NSKPY        = skip of nodes containing y receivers
        1 NBGZ         = first z node to contain receivers
        1 NEDZ         = last z node to contain receivers
        1 NSKPZ        = skip of nodes containing z receivers
       10 NTISKP       = time skip of seismograms (every nth step)
        1 NBGX2          = first x node to contain receivers
      192 NEDX2          = last x node to contain receivers
        1 NSKPX2         = skip of nodes containing x receivers
        1 NBGY2          = first y node to contain receivers
      192 NEDY2          = last y node to contain receivers
        1 NSKPY2         = skip of nodes containing y receivers
        1 NBGZ2          = first z node to contain receivers
      192 NEDZ2          = last z node to contain receivers
        1 NSKPZ2         = skip of nodes containing z receivers
        2 NTISKP2        = time skip of seismograms (every nth step)
'output_ckp/chkp' CHKP  = input and derived parameters for QC
'output_ckp/chkj' CHKJ  = single location output for QC
'sliprate.dat' INSRC  = mt based fault file
'SAF_dyn_50m_test+idx' INVEL  = velocity structure file
'output_sfc/SX_0_' SXRGO  = x regular-grid volume/time output
'output_sfc/SY_0_' SYRGO  = y regular-grid volume/time output
'output_sfc/SZ_0_' SZRGO  = z regular-grid volume/time output
'output_vlm/VX' SXRGO2  =  regular-grid slip/time output 
'output_vlm/VY' SYRGO2  =  regular-grid sliprate/time output
'output_vlm/VZ' SZRGO2  =  regular-grid rupture output
'output_dyn/SGSN' SGSN       =  file to host 19 more variables for SGSN mode
	0	OFASTT       = output format: on(1)/off(0) fast

Metadata

Daniel Roten put together a list of metadata for NVIDIA to work with the Cascadia simulation output. This is for the Cascadia M9.0, but the M9.2 will be similar.

Points in X: 9,720
Points in Y: 16,065
Resolution along X and Y: 66.666 m
The projection is UTM for zone 10.  There is no rotation, with the X
axis pointing from west to east and the Y axis from south to north.
The UTM coordinates for the X and Y axis are given in the two attached
ASCII files.
The sampling interval in the output is 40 ms (250 samples per second).
The total simulation duration is 450 seconds.

The time step used in the finite difference simulation was 4 ms, and
102,000 time steps were computed.

The output files are binary, and contain ground velocities (m/s) as
32-bit floating point numbers.   There is no file header.
Each component is saved in separate files, and the data are aggregated
in files containing 100 time steps.   The naming convention is
S%c_0_%07d, where the character stands for the component (X, Y or Z),
the 7-digit number for the last time step in the file (e.g., 1000 for
the first file, and 102,000 for the last one).
Inside each binary file, X increases fastest, followed by Y, and time t increasing slowest.

Animations:

Daniel Roten created a sample visualization done from a similar simulation (same resolution, but different scenario), which you might want to share along with the data:

• Google Drive Movie

Cascadia M9.0

A previous version of data for a magnitude 9.0 was posted on Rhea/Titan in the directory:

 /lustre/atlas/proj-shared/geo112/rotend/Cascadia/scen_8_a_N_66m_dm/output_sfc

Related Entries

• AWP-ODC
• CME Project