SCEC Award Number 07072 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Continued analysis of small-scale strain patterns associated with southern California earthquakes
Name Organization
Thorsten Becker University of Southern California
Other Participants Bailey, Iain (grad student)
SCEC Priorities A10, A4, A7 SCEC Groups Seismology, FARM, CDM
Report Due Date N/A Date Report Submitted N/A
Project Abstract
Funding is requested to continue statistical and mechanical analysis of Kostrov (1974) summations and co-seismic strain patterns based on focal mechanisms of small to moderate-size earthquakes. Our work addresses
the degree of complexity of small-scale strain release in relation to geometrical features of mapped faults and previous large earthquake ruptures. With the alternative analysis methods which we were able to develop through SCEC funding, we found that the heterogeneity of strain orientations in several, well sampled locales follows a Gaussian-type distribution. This is consistent with generic noise, but not fractal complexity. Moreover, stable small-scale patterns exist across different magnitude ranges. These patterns look similar to boundary element predictions of strain patterns around faults with geometrical complexities. Our preliminary results imply that small events carry information, that strain and stress may be more
homogeneous than previously thought, and that more study is warranted. We propose to further refine our analysis method, try to detect variations in the strain distributions associated with faults at different evolutionary stages, and eventually understand how large scale, regional patterns emerge from smaller scale features. These questions pertain to SCEC3 FRP issues A4, A7, and A10. The immediate targets of the proposed research are to: 1) Improve the statistical analysis of regional tensor sums, 2), establish robust cross-magnitude strain patterns using a new multi-resolution imaging method, and, 3), compare imaged strain patterns with predictions from mechanical fault interaction models.