SCEC Award Number 11139 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Application of a Physics-based Earthquake Simulator to Southern California
Name Organization
Keith Richards-Dinger University of California, Riverside James Dieterich University of California, Riverside
Other Participants Collela, Harmony
SCEC Priorities A3, A10, A6 SCEC Groups FARM, EFP, SHRA
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
A central objective of SCEC3 is to develop the means for physics-based
assessments of earthquake probabilities. To this end, SCEC3 research priorities
seek to improve our understanding of stress interactions and earthquake
triggering; develop models of fault slip, earthquake occurrence and deformation
in fault systems; and apply fault system models to questions of earthquake
occurrence and predictability. This project contributes to those efforts through
the development a 3D physics-based earthquake simulator (RSQSim) for a)
investigation of earthquake processes in geometrically complex fault systems,
and b) use in evaluations of earthquake probabilities. To meet these goals
RSQSim is 1) sufficiently flexible to incorporate alternative models of
earthquake source processes and input parameters; 2) capable of modeling
earthquake occurrence over a large range of length and time scales to
permit comparisons with earthquake catalogs and paleoseismology data; 3)
fully three-dimensional to properly represent fault interactions and to permit
comparisons with deformation observations; 4) able to model time-dependent
fault interactions, as well as foreshocks and aftershocks, by incorporating
time-dependent earthquake nucleation inherent to rate- and state-dependent
friction; and 5) suitable for implementation with complex fault system
geometry, including the SCEC community fault model at a resolution
appropriate to items 1) through 4).
Intellectual Merit Project goals are to develop a large-scale, computationally efficient, 3D physics-based earthquake simulator for a) investigation of earthquake processes in geometrically complex fault systems, and b) use with the SCEC community fault model to simulate of earthquake occurrence and deformation in southern California, and to evaluate earthquake probabilities. For this effort we are continuing development of the fault system earthquake simulator RSQSim. A long-term objective is to implement simulations using the SCEC community fault model at a 1km2 resolution with simulations of at least 106 events. At this scale, direct comparisons with the southern California instrumental catalog data at a minimum earthquake magnitude threshold of about M3.5 will be possible.
Broader Impacts The RSQSim project did not involve undergraduate interns this year, but we have involved such interns in past years (and plan to again the future) very successfully in validating RSQSim against fully dynamic 3D rupture codes. RSQSim (and other earthquake simulators) have contributed in minor ways to the UCERF3 process and are slated to make larger contributions to future UCERFs.
Exemplary Figure Figure 2. Snapshot during an M2.2 event of the rupture propagating across one of the repeating earthquake sources in a detailed Parkfield model. Each fault element is colored on a logarithmic scale according to its slip speed, with full blue representing slip speeds below 10-12 m/s and full red-brown representing 1 m/s. This rupture nucleated in the lower-right quarter of the N10 repeater. The event is able to expand slightly beyond its unstable region into the surrounding creeping area on the right side.