SCEC Award Number 15029 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Development of a Unified Structural Representation for Central California
Name Organization
John Shaw Harvard University Andreas Plesch Harvard University
Other Participants
SCEC Priorities 4a, 4c, 6a SCEC Groups Seismology, USR, CCSP
Report Due Date 03/15/2016 Date Report Submitted 03/13/2016
Project Abstract
This past year, we developed an initial Unified Structural Representation (USR) for Central California in support of the newly established Central California Seismic Project (CCSP). This project was a natural extension of the current SCEC USR in southern California, and is designed to help facilitate more comprehensive assessment of earthquake sources and physics-based waveform modeling to define path effects in the region.
Specifically, we:
1) Enhanced the SCEC Community Fault Model (CFM) to include more detailed representations in the study region, making use of relocated earthquake hypocenter and focal mechanism catalogs;
2) Developed and refined 3D models of basin structures (e.g., Santa Maria, San Joaquin), including top basement surfaces and sediment velocity parameterizations based on tens of thousands of direct measurements from boreholes and seismic reflection/refraction datasets.
3) Presented these results at a workshop with the USGS Menlo Park to facilitate coordinating collaborative fault and wavespeed modeling efforts.
This proposal represents a new effort to develop community-based fault and velocity models in support of the CCSP Project by the lead developers of the SCEC CFM and CVMH models. We used these models to populate computational grids and meshes that will be used for 3D seismic waveform tomography to developed improved velocity models in the region. These, in turn, will be used to assess ground motion hazards through numerical simulation of rupture and wave propagation.
Intellectual Merit This effort has developed a Unified Structural Representation (USR) for central California as part of the CCSP project. This model enhances our understanding of crustal structure in the region. Moreover, it will help facilitate 3D waveform tomography to improve our understanding of crustal wavespeeds in the region, and be used in subsequent numerical simulations of seismic wave propagation for strong ground motion characterization.
Broader Impacts This work directly addresses SCEC’s primary mission to improve seismic hazards assessment in California by defining the 3D geometry and interaction of active fault systems and crustal wavespeed structure. These models will serve as the basis for improved seismic hazards assessments, with the aim of reducing loss of life and damage to property, including PGE facilities, during future large earthquakes.
Exemplary Figure Perspective view of CCSP USR at sea level showing Vp structure.