SCEC Award Number 11017 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Characterizing fault roughness evolution using acoustic emission and micro-structural analysis of frictional sliding experiments
Name Organization
Thorsten Wolfgang Becker University of Southern California Danijel Schorlemmer University of Southern California Georg Dresen Deutsches GeoForschungsZentrum Potsdam (Germany)
Other Participants Thomas Goebel (grad student)
SCEC Priorities A10, A4, A11 SCEC Groups FARM, Seismology
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
This project is on the study of laboratory stick-slip experiments in granite samples, performed with the advanced acoustic emission monitoring setup at the GeoForschungsZentrum Potsdam, Germany. Our objectives are to, a), relate micro-seismicity clustering and b value (slope of the frequency magnitude relationship) anomaly maps to structural heterogeneity (from CAT scans, thin sections, and topography analysis of the sample fault surface), b), identify the relationship of spatio-temporal b value anomalies to rupture dynamics, and, c), to determine how fault roughness evolves over repeated slip cycles. Project funding partially supported graduate student Thomas Goebel and his visit to the GFZ lab in the summer of 2011.
Intellectual Merit This project documents strike-slip cycle seismicity in laboratory experiments and so builds crucial connections between micro-physics of frictional and fracture processes, large scale fault zones, and observed seismicity patterns. Such efforts are important to the establishment of a fault constitutive law, to understand if and how structural heterogeneity on fault zones, including asperities, may be linked to seismic heterogeneity and rupture initiation and propagation. Those are core science objectives for SCEC with general implications for fault mechanics and seismic hazard. In particular, this project addresses objective A10, to “Develop statistical descriptions of heterogeneities (e.g., in stress, strain, geometry and material properties)”.
Broader Impacts This project strengthens international collaborations by building ties between USC/SCEC and GFZ Potsdam. Project funding partially supported the training of a graduate student, Thomas Goebel. Renewed efforts of studying potentially earthquake-analog experiments in the lab helps cross-fertilizes the fields of rock mechanics and earthquake source seismology.
Exemplary Figure Figure 1