SCEC Award Number 07133 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title HOT Faults-Feedbacks in the Earthquake Process
Investigator(s)
Name Organization
Ralph Archuleta University of California, Santa Barbara Gregor Hillers University of California, Santa Barbara
Other Participants
SCEC Priorities A4, A9, A10 SCEC Groups Seismology, FARM, EFP
Report Due Date N/A Date Report Submitted N/A
Project Abstract
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Intellectual Merit The application of the integrative HOT approach to geophysical problems in general and the investigation of rare states allowing the largest events to occur in particular, and the aspirated synthesis of feedback mechanisms tractable in numerical models represents a highly innovative and thus risky idea. However, because the geophysical system shares some fundamental
properties with other highly complex, far-from-equilibrium, feedback driven system successfully described by HOT, this idea potentially advances our understanding in earthquake source physics. In particular, the representation of spatial variations of governing variables are at the core of the development of realistic heterogeneity descriptions in fault properties, and they present a tractable way to incorporate heterogeneities in numerical models of different resolution. Furthermore, we aim to separate the contributions of small-scale
processes in the produced seismicity distributions and during single rupture propagations. While numerous examples of HOT have now been successfully explored in the context of biology, technology and ecology, our proposal represents the first effort to extend this concept to earthquakes. This will be done in close collaboration with Prof. J. Carlson (UCSB) and Prof. J. Doyle (CalTech). The conditions on the fault that give rise to large events have to
be understood in a context that allows these rare events to be rare. There are hundreds of thousands of small events that never trigger a large earthquake; but some how the conditions on the fault are such that in rare cases a small event is amplified and cascades into a large event. Understanding how the large events are so different from the median sized events will infuence seismic hazard analyses and estimates of strong motion that arise from the largest events. Perhaps the most significant broader impact is that HOT represents a paradigm shift in how one classifies available observation, and looks at the largest earthquakes. If it plays out as we expect, the HOT fault may serve as the building block for other aspects of tectonics. Because the novel application of the HOT concept to geophysical problems in general and
FARM-related problems in particular may provide new insights, positive results originating from this research project will support future research proposals. This will help to leverage additional resources from other funding agencies more easily.
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