SCEC Award Number 12057 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Thermally Driven Shear Localization in Fault Zones
Name Organization
James Rice Harvard University
Other Participants John D. Platt
SCEC Priorities 3c, 3b, 4b SCEC Groups FARM, Seismology, Geology
Report Due Date 03/15/2013 Date Report Submitted N/A
Project Abstract
We have focused on identifying physical mechanisms controlling the thermal weakening and related localization of rapid shear in fault gouge. The particular processes
identified involve weakening through frictional heating and the consequent pressurization of pore fluids. In our earliest studies, those were in-situ pore fluids, i.e., groundwater, but recently published experiments and field observations led us to understand that fluids released by the thermal decomposition of fault gouge components may also be important sources of weakening and localization, and these too are considered in our most recent work.
Intellectual Merit The research advanced understanding of strain localization and dynamic weakening in fault zones, building on our efforts extending over several years on thermal pressurization weakening, and extending that to fault zones in which constituents such as phyllosilicates or carbonates undergo thermal decomposition.
Broader Impacts The project has supported education of doctoral student John D. Platt and of (briefly) visiting postdoctoral researcher Nicolas Brantut.
Exemplary Figure Figure 4 (from 4th page of report): Depletion of reactant causes reaction rate profiles to evolve during slip; deforming zone location is not fixed in a specific location and moves across the gouge layer, leaving laminated strain pattern. (Based on as yet unpublished research of J. D. Platt, N. Brantut and J. R. Rice.)