HighF 2018

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).

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.

• Various models were run in 2016:
  • 2016 runs with 2FF and 1 PS

• 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

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):

• AWP-Hercules-RWG Comparison
• AWP-Hercules-RWG Comparison With Observations

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):

• AWP-Hercules-RWG Comparison
• AWP-Hercules-RWG Timeseries Comparison

Latest 2018 results

Description: results for the large region from November 10 2017, computed 20181125 using the latest ts_processor codes:

Description: small region simulations for Hercules (updated to use simulations including Q, submitted 20171106?), AWP (updated since November 2017, submitted 20181203?) and RWG (large model to avoid boundary reflexions, submitted 20180425):

• AWP-Hercules-RWG-OBS Comparison

Related Pages

• High-F Main page

• Past verification (HighF_v14.12_Data)

• La Habra simulations on Titan

• La Habra Simulation region
• La Habra Observational data