SCEC Award Number 10025 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Possible tectonic and thermal controls on apparent stress
Investigator(s)
Name Organization
Peter Bird University of California, Los Angeles
Other Participants Carpenter, Ivy (graduate student)
SCEC Priorities A4, A8, B2 SCEC Groups Seismology, FARM, GMP
Report Due Date 02/28/2011 Date Report Submitted N/A
Project Abstract
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Intellectual Merit We find dependences of median stress drop on temperature, depth, and long-term tectonic strain rate that suggest two regimes in which stress drop is controlled by different physics: a low-temperature regime controlled by rate-and-state friction, and a high-temperature regime controlled by dislocation creep. This supports and extends existing models of the physics of crustal earthquakes. Our inference that small earthquakes frequently occur in regions whose stress level may be regulated by dislocation creep is surprising, but can be understood if the crust is heterogeneous on small spatial scales as well as large.
Broader Impacts In the area of "broader impacts" our primary goal was benefit to society through an enhanced ability to forecast the likely stress drops (and thus intensity of shaking) through study of objective predictive factors. Unfortunately, we are only able to explain a small fraction of the variance in stress drops.
Exemplary Figure N/A