A PETASCALE CYBERFACILITY FOR PHYSICS-BASED SEISMIC HAZARD ANALYSIS

Current applications of probabilistic seismic hazard analysis (PSHA) employ empirical attenuation relationships to model the propagation and attenuation of seismic waves between the source and receiver, but these relationships cannot easily account for 3D structural variations (e.g., basin effects) and source complexities (e.g., directivity effects). A goal of the Southern California Earthquake Center (SCEC) is to use earthquake simulations to improve PSHA. For this purpose, SCEC is deploying as part of its Community Modeling Environment (CME) a new cyberfacility (PetaSHA) that can execute PSHA computational pathways and manage data volumes using the nations high-performance computing resources. The objectives are to extend deterministic simulations of strong ground motions above 1 Hz for investigating the upper frequency limit of deterministic ground-motion prediction; improve the resolution of dynamic rupture simulations by an order of magnitude for investigating the effects of realistic friction laws, geologic heterogeneity, and near-fault stress states on seismic radiation; and compute physics-based PSHA maps and validate them using seismic and paleoseismic data. The cyberfacility comprises several computational platforms that vertically integrate hardware, software, and wetware (technical expertise). One of these platforms, CyberShake, employs advanced workflow management tools to compute and store the large suites of ground motion simulations needed for physics-based PSHA mapping. We are also developing a science gateway for the broader community to access the CME simulation capabilities and data products.