HighF v14.12
This page collects information about a proposed high frequency verification and validation exercise. Planning started in Dec 2014.
Contents
- 1 Goal
- 2 Approach
- 3 Problem Statement
- 4 Simulation Region
- 5 Station Lists
- 6 Source Description
- 7 1D Velocity Model Definition
- 8 Simulation Box / Velocity Model
- 9 Solver Parameters
- 10 High-F VandV Exercise Planning Documents (2015)
- 11 High-F Project Plan (2012)
- 12 Agreements Needed
- 13 Related Entries
- 14 References Used
Goal
Most regional scale deterministic earthquake simulation verification and validation exercises have been done at frequencies 1Hz or lower [1] [2]. With the introduction of high performance CPU and CPU-GPU wave propagation codes, there has been significant recent progress running simulations up to 4Hz. As we increase the capabilities of our deterministic earthquake simulation codes, we need to re-evaluate the codes performance at these higher frequencies that are now possible. The goal of this activity is to evaluate the performance of multiple wave propagation codes that are capable of simulation regional scale earthquakes at frequencies 4Hz+.
Approach
High frequency simulations introduce several code modifications intended to more accurately model the physics of high frequency earthquake wave propagation simulations. Modification to existing wave propagation codes to support 1Hz+ simulations include:
- Source descriptions with energy above 1Hz
- Small scale heterogeneities in the 3D velocity models
- Frequency dependent attenuation
- Near fault plastic yielding
- Large displacement plastic yielding
To help isolate the impact of each of these changes, we propose to start with simple (possibly unrealistic) high frequency (4Hz) ground motion simulations and compare the simulation results produced by different methods. Then we will introduce these modifications one at a time, as a way if isolating the impact of each change individually.
Problem Statement
We have defined common input parameters for use by both AWP-ODC, and Hercules. The problem statements includes the following parameters:
- Simulation Region
- Station Lists
- Velocity Model
- Source Description
- Simulation Duration
- Simulated Frequency Range
- Sample per Wavelength
Simulation Region
The simulation region four corners are:
- -119.288842 34.120549
- -118.354016 35.061096
- -116.846030 34.025873
- -117.780976 33.096503
Volume size:
- 180,000 m x 135,000 m x 61,875 m = 1.503e15 m3
Station Lists
- En-Jui Station List w/ Simulation Region (KML Format)
- En-Jui Station List (Text Format)
- Hercules La Habra Stations
Source Description
Trimmed, low-pass filtered (fc=5Hz, Butterworth, 2 forward passes, 4 poles), 4300 points, dt=0.001s (and plot of what is should look like).
- Time domain Plot of Select Source
- Data File For 5Hz Plot
- Source Frequency Domain Plot w/ and w/o Filtering
1D Velocity Model Definition
Simulation Box / Velocity Model
| Parameter | Value | Notes |
|---|---|---|
| Dimensions (km) | 180 x 135 x 61.875 (31 km for 1d Model) | |
| Bounding Box (LL) | -119.288842 34.120549, -118.354016 35.061096, -116.846030 34.025873, -117.780976 33.096503 | |
| Rotation Angle | 39.9 | |
| UCVM Version | 14.3.0 | No heterogeneities |
| Velocity Model Versions | CVM-S4v26 | |
| Miniumum Vs | 500 m/s | |
| Samples per wavelength | 6 to 7 - AWP | 10 to 12 - Hercules |
Point Source Parameters
| Parameter | Value | Notes |
|---|---|---|
| Event Name | La Habra | |
| Mw | 5.1 | Ref: http://www.scsn.org/2014lahabra.html |
| Moment | 5.764 E+23 Dyne-cm | Source: En-Jui |
| Origin Time | 2014/03/29 04:09:42.97 | Source: En-Jui |
| Origin Location | -117.930; 33.922; 5.0km | Source: En-Jui |
| Strike/Dip/Rake | 239/70/38 | Source: En-Jui, based on review of aftershock sequence |
| Rise Time | 0.75 s |
Solver Parameters
| Parameter | Value | Notes |
|---|---|---|
| Frequency | 4.0 Hz | |
| Simulation Length (Duration) | 100 s | |
| Delta T | 0.005 | |
| Plane Output Resolution | 250m | |
| I/O Print Rate | every 10 steps | |
| Station List | TBD | |
| Software Version | TBD |
High-F VandV Exercise Planning Documents (2015)
High-F Project Plan (2012)
Agreements Needed
- Simulation Volumes
- Rotation Angle
- Projections used
- Points per wavelength used
- Number and location of sites used for ground motion comparison
- Proposed Station List to save results
- La Habra Point Source parameters
- Currently available code capabilities in GPU codes
- small scale heterogeneities
- FDQ
- Plasticity
- dynamic rupture source
- V and V exercise stages - need to be reviiewed and approved
Related Entries
References Used
- Taborda, R. and J. Bielak (2013). Ground-motion simulation and validation of the 2008 Chino Hills, California, earthquake, Bull. Seismol. Soc. Am. 103, no. 1, 131–156, doi 10.1785/0120110325.
