HighF 2018

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This page documents the High-F activities and decisions for the 2018 verification and validation runs for three groups: Olsen et al. (AWP), Graves (RWG) and Taborda et al. (Hercules).

USGS Earthquake Information

Observational Data

Region Definitions

Mesh generation rules and parameter constraints

Velocities

  • 1. Set Min Vs=500 m/s
  • 2. If Vs was lower than 500 m/s and adjusted, then adjust Vp with original Vp/Vs ratio (so that we don’t have the automatic Vs/Vp of 3). We may want to set a minimum value of Vp (Rob to check)
  • 3. Then set Max Vp/Vs= 3, if lower Vp to maintain the max of 3 ratio

Lame parameters (mu and lambda)

Use mu and Lambda parameters to fix Vp/Vs issues in the CVM where necessary, as part of the mesh generation. Need to make sure that patches are physical and not only to make the codes run.

  • Rob to check if raw model produces lambda of <=zero.
  • Note: lambda of zero corresponds to Vp/Vs= sqrt(2)=1.45
  • Note: typical Vp speeds are 330 m/s in air, 1450 m/s in water and about 5000 m/s in granite

Anelastic attenuation (Q)

Frequency-independent Q definition

  • Qs=100*Vs(km/s)
  • Qp=2*Qs

Upper frequency

  • 5Hz: based on 500 m/s and 20 m spacing
  • Kim and Rob have been low-pass filtering the slip function at 5 Hz
  • Ricardo and Naeem don’t filter the source

Source Models

We discussed various sources, both point source (PS) and finite-fault (FF) in the past for our verifications and validation.

  • Also ran various smoothed variations of the GP15 FF (need to find a reference for that)
  • Rob to follow-up with Wei (last communication was in April 2017).

Proposed models for verification and validation:

  • PS: model from En-Jui (moment tensor). Can we replicate En-Jui's results? Would need to use CVMS4.26 (cms5) - not desirable. We could perform a check with CVS4.26.M01 at 5 sec. Need to use the same record En-Jui used. Proposed to use records from Figure 6 in:
    • Lee E.-J., P. Chen, and T.H. Jordan (2014). Testing Waveform Predictions of 3D Velocity Models against Two Recent Los Angeles Earthquakes. Seismol. Res. Lett., 85 (6): 1275–1284 (Paper here)
  • FF: Summary of agreed-upon FF model (gp.5.3.02)
  • FF refined with velocity model Slides from Graves presented on Feb. 21 2018

Site Selection

Simulation results

Results shared on March 5 2018

Description: results for the small region from November 10 2017:

Description: small region simulations for Hercules, AWP (updated since November 2017) and RWG (medium size model to avoid boundary reflexions):

Results shared on March 12 2018

Description: results for the small region from November 10 2017:

Description: small region simulations for Hercules (updated to use simulations including Q), AWP (updated since November 2017) and RWG (medium size model to avoid boundary reflexions):

2019-12-02 Call, summary of plans for 2020

Goals for 2020

    • Verification paper (2020 Q1+?)
    • Validation paper(s) (2020 Q2+?)

Action items from call

  • Rob to test other finite fault models using near-fault data and perform initial screening of candidate sources
  • Christine to coordinate with Phil and Fabio for Jan. High-F sprint
    • to allow use of BBP GOF post-processors with high-f results and data
    • to revive GOF map plotting tools (last run in 2016)
    • Christine to verify that PSA results are ok (see anomaly on 20181125 results for observations of CE_13066).
    • need to confirm start time as documented in post-processing code. Is it more or less constant with offset at all stations?
  • Christine to re-start verification paper development
  • Group need to document their submissions for point source or rerun them (see section below; finite fault is documented).

Latest 2018 results documentation

Description: results for the small and large regions (model dependent) from November 10 2017, computed 20181125 using the latest ts_processor codes:

Summary documentation of extended source simulations submitted at high-f:

Hercules 20171106 notes:

  • Simulation of Mw 5.14 Lahabra Earthquake.(2014/03/29 04:09:42.97) with damping and using the extended source model provided by Robert Graves (downsampled version of the SRF for La Habra and based on 3D velocity model.The subfault spacing is 100 m). This simulation is part of High-F project. The simulation is done using the CVM-etree extracted from CVM-S4.26.M01 (28*28*14 km) at the “Small Domain." See readme.txt in their folder for more info.

RWG 20180425 notes:

  • 20180425 - RWG simulation results for full-size model region (135 km x 180 km x 60 km). Velocity mesh was created on BlueWaters using UCVM interface that Scott C. created. Model is CVM-S4.26.M01 (at least I believe so, I selected 'cvmsi' as input to single_exe.py). Vp/Vs capped at 3.0, Vsmin=500 ms, Qs=100*Vs(m/s), Qp=2*Qs. Time step is dt=0.001 sec. Waveforms are ground velocity and have been low-pass filtered using zero-phase 4th order butterworth with corner at 5 Hz.

AWP 20181203 notes:

  • The latest anelastic simulation using cap of vp/vs=3, minimum Vs at 500 m/s with simulation length to 120 seconds in the large domain (180 km * 135 km * 60 km, grid spacing = 20 m). Number of stations: 351.

2020 updates from weekly calls: path forward on VERIFICATION paper

Verification of 5 Hz time series (4Hz PSA, multiple bands verification)

Misc definitions

Domains

  • Small domain: defined here.
  • Large domain: defined here.
  • Proposed medium domain:
The four corners of medium La Habra Simulation domain are:
 c1= -118.387131  33.887287
 c2= -117.970993  34.301479
 c3= -117.472496  33.955025
 c4= -117.889359  33.542511
And the model dimensions are:
 xlen=    60.0000 km
 ylen=    60.0000 km
 zlen=    25.0000 km

Note that this is not a UTM projection. It is transverse Mercator with spherical reference and corresponds very closely to the proj4 projection: 
+proj=tmerc +lat_0=%f +lon_0=%f +ellps=sphere +a=6378139.0 +b=6378139.0 +units=m +no_defs

where lat_0, lon_0 are the domain center coordinates, which in this case are: lon= -117.930000 lat=  33.922000

The regional seismic velocity model used by all modelers is: CVMS4.26.M01 (called cvmsi in UCVM, as per Table 1 in this UCVM paper), do NOT apply a GTL to the model, but apply the rules described here.

Vs30 at recording stations

  • For interpretation of recorded data, use in order of preference
    • values listed as "Vs30 (m/s) selected for analysis" in the NGA-West2 database flatfile
    • if stations are not included in the NGA-West2 database, we will use the values from Will et al. 2015 as retrieved from UCVM (with interpolation)
  • For interpretation of simulation data
    • We retrieved the Vs30 values using UCVM v19.4 for CVM-S4.26.M01 (cvmsi), for CVM-S4.26 (to show impact of adding .M01 GTL), for CVM-S4 (to check if Vs30 matches .M01 exactly), and from the Wills 2015 Vs30 model embedded in UCVM.
  • For the Vs30_query against the models uses a slowness algorithm, and a 1 meter spacing.
  • The Wills 2015 Vs30 values are based a processing sequence that includes converting a GIS shape file into a rasterized Vs30 grid of values produced by Kevin Milner. Kevin provided a file raster_0.00025.flt, which is rasterized with 0.00025 degree spacing (~25 meters). This file is then used to generate an etree which is used to stored the rasterized data. When query points are given between grid points, then ucvm implements interplolation of Vs30 values between associated grid points. More
  • More details on the Willis Map integration here: Wills Map.
  • Descriptions of UCVM Vs30 Slowness algorithm here: UCVM_Vs30.
  • Description of CyberShake Vs30 Slowness algorithm here: CyberShake_Code_Base#Stochastic codes


UCVM Vs30 Values
Station Id Lat Lon Vs30 - NGA Vs30 - Wills 2015 (UCVM v19.4) Vs30 - Slowness Method (1m res) CVM-S4.26.M01 (cvmsi) (UCVM v19.4)
CE_13066 -117.9568 33.8401 275.12 293.500 284.461
CE_13849 -117.8180 33.8535 359.47 351.900 329.762
CE_13878 -117.8870 33.8891 377.00 313.585 344.043
CE_13879 -117.9591 33.8663 283.30 228.200 287.845
CE_13880 -117.9311 33.9086 306.60 386.600 349.812
CE_13881 -117.9557 33.9315 331.70 386.600 349.317
CE_13882 -117.8034 33.9274 378.20 385.100 367.423
CE_13883 -117.8578 33.8534 283.50 228.200 329.762
CE_14026 -118.0469 33.8892 268.70 228.200 287.845
CE_14027 -118.0576 33.9283 338.00 386.600 354.637
CE_23938 -117.8657 34.0209 383.40 418.980 370.670
CI_BRE -117.9812 33.8078 265.59 228.200 285.871
CI_FUL -117.9225 33.8717 351.22 293.500 362.574
CI_OLI -117.9237 33.9454 414.77 385.433 331.459
CI_WLT -117.9508 34.0095 342.64 293.500 309.646

BBP Station List

The BBP station list was updated to include station latitude and longitude coordinates up to 4 decimal places. It includes the Vs30 from the NGA flat file. Please see below the BBP station list for the 15 stations listed above: 

-117.9568 33.8401  CE_13066  275.12  0.1250  4.0000
-117.8180 33.8535  CE_13849  359.47  0.1250  4.0000
-117.8870 33.8891  CE_13878  377.00  0.1250  4.0000
-117.9591 33.8663  CE_13879  283.30  0.1250  4.0000
-117.9311 33.9086  CE_13880  306.60  0.1250  4.0000
-117.9557 33.9315  CE_13881  331.70  0.1250  4.0000
-117.8034 33.9274  CE_13882  378.20  0.1250  4.0000
-117.8578 33.8534  CE_13883  283.50  0.1250  4.0000
-118.0469 33.8892  CE_14026  268.70  0.1250  4.0000
-118.0576 33.9283  CE_14027  338.00  0.1250  4.0000
-117.8657 34.0209  CE_23938  383.40  0.1250  4.0000
-117.9812 33.8078  CI_BRE  265.59  0.1250  4.0000
-117.9225 33.8717  CI_FUL  351.22  0.1250  4.0000
-117.9237 33.9454  CI_OLI  414.77  0.1250  4.0000
-117.9508 34.0095  CI_WLT  342.64  0.1250  4.0000

Step 1: selection and verification of source model using the small domain

  • Use small domain, with Vs floor of 500 m/s (CVMS4.26-M01 (cmvsi)) and constraints, as described here
  • We agreed that all the modelers will use a version of the small domain that is rotated by 39.9 degrees, so as to remove a source of difference we can control. We observed different results due to rotation of the domain in CyberShake simulations a few months ago, for which we could not account for by considering the model edges and boundary effects. There seems to be some anisotropy in the model that may be due to the staggered grid.
  • Focused on 15 near-by stations selected by Rob (need to link to text file here, file to include Vs30 values listed above: from NGA-West2 or Wills et al. 2015 and from the cvm)
  • Use RWG best source:
    • Rob ran a series of tests to select a finite source to use with the Vmod floored at 500 m/s (powerpoint here)
    • The suite of 40 SRF rupture models for the 2.5 km X 2.5 km fault are contained in this tarfile (364 MB). There are 2 resolutions: 100 m subfaults and 20m subfaults. The recommendation is to use 20m subfaults if possible.
  • Verify that best RWG source is good at 15 stations for all models. This is a first-order test for the purpose of the verification paper only, modelers can chose another source for the validation paper later, if, for example, they use another velocity model or different constraints.

Step 2: verification with the selected source, using the large domain

  • Then all modelers rerun large region
    • need to confer on rotations before that step
    • need to review the station list
  • Perform verification using results and plots from
    • tsprocess time series/FAS/PSA combo plots
    • tsprocess Anderson GOF scores and maps (GMT capability needs to be restored due to updates)
    • BBP (GOF with T, distance, mapped, etc.; consider adding Vs30-based plots on BBP)
  • Compare with 1D BBP sims (with Vs30=500 for all stations, with site response)?

Step 3: write paper, publish

Related Pages

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