SCEC Award Number 13119 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title US-Japan Collaboration on Strong Ground Motion Prediction Techniques
Investigator(s)
Name Organization
Paul Somerville URS Corporation Andreas Skarlatoudis URS Corporation Jeff Bayless URS Corporation
Other Participants Partial funding of this $30K budget by Norm Abrahamson, PG&E
Collaboration with Japanese team led by Professor Hiroshi Kawase, separately funded
SCEC Priorities 6e, 6, 6 SCEC Groups GMP, GMSV, CME
Report Due Date 03/15/2014 Date Report Submitted N/A
Project Abstract
 This project has the goal of implementating the Irikura Recipe on the SCEC Broadband Strong Motion Simulation Platform. Example implementations of the Irikura Recipe for the Loma Prieta and Northridge Earthquakes were given in Appendix 1 of our 2012-2013 report, listing input parameters and showing goodness of fit figures. The goodness of fit showed large biases that we were unable to resolve. A key uncertainty was in the specification of the stress of the source model use in the generation of the stochastic Green’s functions. In order to avoid that uncertainty, we decided to implement another version of the Irikura recipe, developed by Dr Arben Pitarka, which does not require the specification of the stress parameter.
Intellectual Merit The objective of this project is to implement the Irikura Recipe on the SCEC Broadband Strong Motion Simulation Platform. This helps us to compare strong motion simulation methods in California and Japan. This is important because SCEC’s experience has been that differences in source characterization are the main causes of differences in ground motion simulations performed using different simulation methods (SDSU, UCSB, and URS) on the SCEC Broadband Ground Motion Simulation Platform.
Broader Impacts The SCEC Broadband Platform’s SRF file contains a full description of the spatial and temporal evolution of rupture on the fault, which is partly stochastic. In contrast, the Irikura Recipe, which is used in Japan, is based on a deterministic model of asperities embedded within a background zone. This project has expanded the scope of the SCEC Broadband Strong Motion Simulation Platform to include the Irikura Recipe, and increased the understanding of differences in approaches to strong ground motion simulation between California and Japan.
Exemplary Figure Figure 1. Slip model generated with the Pitarka version of the Irikura recipe for a M6.72 strike slip earthquake. Contour lines indicate the location of rupture front at different times. The rupture front location was calculated using a layered 1D velocity model.