SCEC Award Number 11041 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title The Depth Dependence of Slip: Applying 3D Elastodynamic Models to Seismic Hazard Questions
Name Organization
Bruce Shaw Columbia University
Other Participants
SCEC Priorities A10, C SCEC Groups FARM, EFP, CDM
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
The depth dependence of slip in large earthquakes has important implications for our understanding of earthquake physics, and for seismic hazard estimates. Here we explore observational constraints, including magnitude-area scaling and surface slip-length scaling observations and ways to reconcile the two. Results from sequences of spontaneous events in 3D elastodynamic models are examine for further insights. A number of interesting behaviors are seen in the models, including an exponential falloff in slip in the strengthening layer below the seismogenic layer with a scale length that depends linearly on the amplitude of the logarithmic strengthening in that layer; the potential for substantial fractions of subseismogenic moment for lab-based v alues of strengthening parameters; mainly long period motion in the strengthening layers compared with long and sho rt period motion in the seismogenic layer; and potentially observable impacts on interseismic creep behavior for regions with significant deep coseismic slip, with, in particular, an expected average interseismic locking depth greater than the seismogenic depth. Implications of these various behaviors for seismic hazard analysis are discusse d, including impacts on moment and slip rate balancing, and functional forms use ful for synthetic source modeling such as cybershake.
Intellectual Merit How slip depends on depth has important implications for
our understanding of earthquake ruptures and for our
estimates of seismic hazard. This work contributes
to improving our understanding of the science and its
Broader Impacts Results from this work is being incorporated into the
new seismic hazard methodologies being developed in
the UCERF3 project.
Exemplary Figure 2