Heterogeneous slip and rupture models of the San Andreas fault zone based upon three-dimensional earthquake tomography
Abstract
Crystal fault zones exhibit spatially heterogeneous slip behavior at all scales, slip being partitioned between stable frictional sliding, or fault creep, and unstable earthquake rupture. An understanding the mechanisms underlying slip segmentation is fundamental to research into fault dynamics and the physics of earthquake generation. This thesis investigates the influence that large-scale along-strike heterogeneity in fault zone lithology has on slip segmentation. Large-scale transitions from the stable block sliding of the Central 4D Creeping Section of the San Andreas fault to the locked 1906 and 1857 earthquake segments takes place along the Loma Prieta and Parkfield sections of the fault, respectively, the transitions being accomplished in part by the generation of earthquakes in the magnitude range 6 (Parkfield) to 7 (Loma Prieta). Information on sub-surface lithology interpreted from the Loma Prieta and Parkfield three-dimensional crustal velocity models computed by Michelini (1991) is integrated with information on slip behavior provided by the distributions of earthquakes located using the three-dimensional models and by surface creep data to study the relationships between large-scale lithological heterogeneity and slip segmentation along these two sections of the fault zone.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- November 1992
- Bibcode:
- 1992PhDT........15F
- Keywords:
-
- Creep Properties;
- Earthquakes;
- Friction Factor;
- Geodynamics;
- San Andreas Fault;
- Sliding;
- Elastic Properties;
- Lithology;
- Seismology;
- Three Dimensional Models;
- Tomography;
- Geophysics