Ductile Rheology of the Southern California Lithosphere: Constraints from Deformation Modeling, Rock Mechanics, and Field Observations

Wayne R. Thatcher, Elizabeth H. Hearn, & Greg H. Hirth

Published August 2013, SCEC Contribution #1824

A workshop was held May 1-2, 2013 in Menlo Park, California to investigate properties and processes of ductile lithosphere deformation. This workshop provided overviews of the newest results from lab, field and geodetic modeling disciplines relevant to better understanding earthquake processes in southern California. A principal goal of the workshop was to bring together niche experts in tectonic geodesy, laboratory rock mechanics, and field observations of ductile rocks to gain better interdisciplinary understanding of the stress transfer process between brittle-elastic upper crust and ductile lithosphere in southern California. Principal outcomes of the meeting were (1) a greatly improved understanding of the relation between the lab- derived transient and steady state flow laws, their relation to field examples of crustal flow, and their application to modeling surface crustal deformation; (2) near unanimous agreement that relatively narrow ductile shear zones exist beneath active faults in the seismogenic crust; and (3) a goal of mapping of the southern California ductile lithosphere using results of seismic imaging and anisotropy to constrain rock type and flow, combined with laboratory inferences of appropriate ductile flow laws at relevant pressure, temperature and state conditions

Citation
Thatcher, W. R., Hearn, E. H., & Hirth, G. H. (2013). Ductile Rheology of the Southern California Lithosphere: Constraints from Deformation Modeling, Rock Mechanics, and Field Observations. Eos, Transactions, American Geophysical Union, 94(32), 280. doi: 10.1002/20.