Unified Structural Representation (USR)

The primary mission of the USR Focus Area has been the development of a unified, object-oriented 3-D representation of activefaults and earth structure (velocity, density, etc.) for use in fault-system analysis, ground-motion prediction, and hazard assessment.

The USR consists of integrated• Community Fault Models

(CFM, CFM-R)• Community Velocity Models

(CVM, CVM-H)

Plesch et al., (2007)

Basement structure(CVM-H)

SCEC Community Velocity Model (CVM-H)

SCEC3 highlights • Version 5.7 available• Updates include:

- major basin and fault structures from CFM (Salton, Ventura, Santa Maria, …)- basins embedded in updated tomographic and teleseismic shear wave models- independent Vp and Vs parameterizations- geotechnical layer

• Used in strong ground motion & seismic hazards studies in SCEC.

Chen, Zhao, & Jordan (2008): F3DT, scattering integral method

Tape et al., (2009): Adjoint, spectral element methods

CVM 3.0 (Vs)

USR has pioneered efforts to develop and implement methods of 3D waveform tomography for improving our resolution of structure, and thus improving strong ground motion simulations

LAF3D model Perturbations LAF3D to CVM

CVM-H 3.0 (Vs) Vs model (m16) Perturbations m16 to CVM-H

9km

CVM-H 6.0: integrating 3D waveform inversion resultsCVM-H 6.0CVM-H 5.8

5 km depth

Moho surface

0 km depth

The latest version of the SCEC Community Velocity Model (CVM-H 6.0) includes basin structures embedded in the 3D waveform inversion model of Tape et al. (2009), and an explicit representation of the Moho (after Yan and Clayton, 2007; Chulick and Mooney, 2002).

Validation of Shakeout Ground Motions with PBRs

Source Description• CFM, ERF• Mw, Dimension,

Geometry• …

Kinematic Rupture Generator

1. Beroza2. Archuleta3. Graves4. …

Standard Rupture Format

• GF Libraries• Site Lists• Velocity Models• …

High Frequency Simulation (> 1 Hz)

1. 1D / Ray GF2. Scattering3. Site Effects4. …

Low Frequency Simulation (< 1 Hz)

1. 1D / 3D GF2. 3D AWM3. Site Effects4. …

Combine Low & High Frequency

1. Filters2. Time Shift3. …

Broadband Time Histories

(0 – 10 Hz)

Broadband Ground Motion Simulation Platform