Northridge 10Hz

Elements of Simulation

• 10Hz Source from SORD
• Convert SORD SRF to format that can be input both both AWP-ODC and Hercules
• Updates to AWP-ODC-GPU to include plastic yielding and Freq Dep. Q.
• Construct a CVM-S (or CVM-H, or CVM-S4.26) mesh at high resolution (20m?) with small scale heterogeneity.
• Definition of lat/lon (sites) where seismograms must be calcualted to match observed NR data
• Discussion of which BBP GOF measures we can apply to deterministic simulation results.
• Define min Vs in simulation

Simulation Inputs

• Site List for BBP Northridge
• SRF for Northridge
• Region definition for Northridge

Simulation Volume Definition

• Station Map

SCEC researchers are planning simulations of the Northridge Earthquake. Planning information about these simulations is posted below:

Source Description

Sam Shi (SDSU) has created a few different sources that looks reasonably good in terms of rupture complexity, PGAs and frequency content (flat up to ~10 Hz, similar to the strike-slip case) of the ground motions. Following are some animations, made for a case with 1D SoCal velocity structure:

• Animation of slip rate on the fault
• Animation of vertical acceleration on the free surface:
• Animation of vertical acceleration at cross-section plane x1 = 16 km:

Note that in the plots/animations involving map view of the free surface, the rectangle box denotes the surface projection of the fault slip plane and the dashed line denotes the intersection of the dipping fault plane with the free surface. The star symbol denotes the epicenter location.

Fig 1 shows results from another case with an extended model but with a half-space velocity structure. (Image Credit: Sam Shi (SDSU))

Velocity Model Definition

18
  0.0020   1.7000   0.4500   2.0000    45.00    22.50
  0.0040   1.8000   0.6500   2.1000    65.00    32.50
  0.0060   1.8000   0.8500   2.1000    85.00    42.50
  0.0080   1.9000   0.9500   2.1000    95.00    47.50
  0.0100   2.0000   1.1500   2.2000   115.00    57.50
  0.0700   2.4000   1.2000   2.2000   120.00    60.00
  0.2000   2.8000   1.4000   2.3000   140.00    70.00
  0.2000   3.1000   1.6000   2.4000   160.00    80.00
  0.2000   3.4000   1.8000   2.4500   180.00    90.00
  0.3000   3.7000   2.1000   2.5000   210.00   105.00
  2.0000   4.4000   2.4000   2.6000   240.00   120.00
  2.0000   5.1000   2.8000   2.7000   280.00   140.00
  1.0000   5.6000   3.1500   2.7500   315.00   157.50
  5.0000   6.1500   3.6000   2.8250   360.00   180.00
  5.0000   6.3200   3.6500   2.8500   365.00   182.50
  5.0000   6.5500   3.7000   2.9000   370.00   185.00
 10.0000   6.8000   3.8000   2.9500   380.00   190.00
999.0000   7.8000   4.5000   3.2000   450.00   225.00

SRC Parameters

#
# Northridge source file for PEER Validation Study
# Currently, DLEN and DWID are temp values until correct are selected
# Also DT and CornerFreq are under review
#
MAGNITUDE = 6.73
FAULT_LENGTH = 20.00
FAULT_WIDTH = 24.90
DEPTH_TO_TOP = 5.00
STRIKE = 122
RAKE = 105.00
DIP = 40
LAT_TOP_CENTER = 34.344
LON_TOP_CENTER = -118.515
HYPO_ALONG_STK = 6.00
HYPO_DOWN_DIP =  19.40
MOMENT = 1.40E+19
#
# Model specific parameters
#
DWID = 0.2
DLEN = 0.2
DT = 0.025
CORNER_FREQ = 0.15
#
# Alternative SEEDS create alternative .srf
#
SEED = 2379646

Station List

#BBP Station List for EQID=120 (Northridge)
#SLong    SLat     RSN   Rrup(km)  Vs30(m/s) LoPass_Freq(Hz) HiPass_Freq(Hz)  Obs_File
-118.481 34.312  2001-SCE   5.2   371 0.3067  17.6001    NORTHR/2001-SCE_N.acc
-118.444 34.326  2002-SYL   5.3   441 0.1600  15.3846    NORTHR/2002-SYL_N.acc
-118.496 34.312  2003-JEN   5.4   373 0.1333  16.0000    NORTHR/2003-JEN_N.acc
-118.498 34.313  2004-JGB   5.4   526 0.1333  20.0000    NORTHR/2004-JGB_N.acc
-118.483 34.294  2005-LDM   5.9   629 0.1961  11.1111    NORTHR/2005-LDM_N.acc
-118.396 34.334  2006-PAC   7.0  2016 0.2133  11.1111    NORTHR/2006-PAC_N.acc
-118.396 34.334  2007-PUL   7.0  2016 0.2133  10.5263    NORTHR/2007-PUL_N.acc
-118.375 34.296  2008-PKC   7.3   508 0.1867  18.3999    NORTHR/2008-PKC_N.acc
-118.478 34.249  2010-SPV   8.4   380 0.1733  23.9998    NORTHR/2010-SPV_N.acc
-118.421 34.221  2019-RO3  10.1   309 0.1333  23.9998    NORTHR/2019-RO3_N.acc
-118.426 34.419  2013-LOS  12.4   309 0.1961  21.2766    NORTHR/2013-LOS_N.acc
-118.303 34.269  2011-GLE  13.3   446 0.1333  23.9998    NORTHR/2011-GLE_N.acc
-118.666 34.264  2018-KAT  13.4   557 0.5000  16.3934    NORTHR/2018-KAT_N.acc
-118.710 34.232  2017-SSU  16.7   715 0.1333  23.9998    NORTHR/2017-SSU_N.acc
-118.405 34.127  2014-MU2  18.4   546 0.2439  23.9998    NORTHR/2014-MU2_N.acc
-118.254 34.238  2020-NYA  18.5   446 0.4000  23.9998    NORTHR/2020-NYA_N.acc
-118.225 34.286  2015-TUJ  19.7   446 0.4400  23.9998    NORTHR/2015-TUJ_N.acc
-118.380 34.114  2012-WON  20.3  1223 0.4000  23.9998    NORTHR/2012-WON_N.acc
-118.560 34.571  2016-H12  21.4   602 0.1600  36.7999    NORTHR/2016-H12_N.acc
-118.600 34.084  2024-TPF  22.3   390 0.1961  23.9998    NORTHR/2024-TPF_N.acc
-118.339 34.090  2025-PEL  24.0   316 0.2667  9.5238    NORTHR/2025-PEL_N.acc
-118.244 34.115  2021-FLE  27.3   446 0.1733  23.9998    NORTHR/2021-FLE_N.acc
-118.189 34.111  2028-FIG  31.2   405 0.4000  23.9998    NORTHR/2028-FIG_N.acc
-118.271 34.043  2022-PIC  31.3   353 0.2667  36.7999    NORTHR/2022-PIC_N.acc
-118.230 34.004  2030-VER  36.8   309 0.4000  23.9998    NORTHR/2030-VER_N.acc
-118.243 34.596  2026-LV3  37.3   387 0.2667  10.0000    NORTHR/2026-LV3_N.acc
-118.199 34.580  2023-ANA  38.0   446 0.2667  36.7999    NORTHR/2023-ANA_N.acc
-118.361 34.758  2027-ATB  46.9   822 0.1600  18.3999    NORTHR/2027-ATB_N.acc
-118.196 33.899  2029-CAS  47.0   309 0.2439  23.9998    NORTHR/2029-CAS_N.acc
-118.194 33.840  2032-LBR  51.9   405 0.2133  14.2857    NORTHR/2032-LBR_N.acc
-118.214 34.739  2039-LAN  52.1   306 0.4000  18.3999    NORTHR/2039-LAN_N.acc
-117.883 34.137  2031-OAK  53.9   446 0.4400  23.9998    NORTHR/2031-OAK_N.acc
-118.196 33.768  2034-LBC  57.7   381 0.4000  11.1111    NORTHR/2034-LBC_N.acc
-118.084 33.757  2037-SEA  64.8   387 0.2133  36.7999    NORTHR/2037-SEA_N.acc
-118.206 34.870  2038-RMA  64.8   353 0.4000  18.3999    NORTHR/2038-RMA_N.acc
-119.362 34.016  2033-ACI  68.9   822 0.4000  18.3999    NORTHR/2033-ACI_N.acc
-117.709 33.869  2036-FEA  82.3   309 0.4000  18.3999    NORTHR/2036-FEA_N.acc
-118.175 35.070  2035-MJH  85.4   309 0.4000  18.3999    NORTHR/2035-MJH_N.acc
-119.851 34.422  2040-SBG 109.1   353 0.2667  18.3999    NORTHR/2040-SBG_N.acc

Proposed GOF Measure

• BIAS GOF Plot

Small-scale Heterogeneity Mediums

Mediums containing small-scale heterogeneities have been generated with the following parameters:

d1 = 20 (corresponding to 20m grid spacing)
hurst = 0.1
l1 = 1000
st23 = 5
seed = 5

There are four mediums in total that have been generated (from largest to smallest):

284km x 204km x 40km
n1 (vertical) = 2048
n2 (EW) = 14200
n3 (NS) = 10200

200km x 140km x 40km
n1 = 2048
n2 = 10000
n3 = 7000

60km x 60km x 40km
n1 = 2048
n2 = 3000
n3 = 3000

40km x 40km x 40km
n1 = 2000
n2 = 2000
n3 = 2000

These are currently on USC HPC but will be transferred to Titan shortly.