Project title regionalization of earthquake source and ground motion models of subduction interface earthquakes period of performance 1 1 2023 through 12 31 2023AWARD purpose in skarlatoudis ET AL…

Project title regionalization of earthquake source and ground motion models of subduction interface earthquakes period of performance 1 1 2023 through 12 31 2023AWARD purpose in skarlatoudis ET AL (2016 SEA16), recipient developed a set of global scaling relations, with seismic moment(M0), of physical source properties such as earthquake rupture area (S), total asperity area (SA), slip (D),and fault width (W), for large subduction interface events. The resulting set of relations significantly reduced the aleatory variability in the prediction of these source parameters. Since the publication of this work, researchers and institutes worldwide have been using these scaling relations to predict ground motions and tsunamis from great subduction earthquakes for various applications (e.g. US national seismic hazard maps nshm). In the time since the development of the database used in SEA16, 79 additional subduction interface events with published finite fault solutions have been catalogued in the USGS finite fault database, the online database of finite fault rupture models (MAI and thingbaijam, 2014), and the next generation attenuation subduction (NGA sub) database, nearly trebling the available data. In the recipients search for subduction interface events, they use the SLAB2.0 (hayes, 2018) subduction zone geometries. Moreover, as part of the NGA sub, strong regional differences in the ground motions expected from various subductionzones have been quantified. The observed regionalization of ground motions is likely the result of differences in the geological, geometrical, and mechanical properties of the plate interface and the kinematic and dynamic processes of megathrust rupture generation in each region (e.g. campbell, 2020 heuret ET AL., 2011 schafer and wenzel, 2019 and schellart and rawlinson, 2013). Activities to be performed augment the existing database of subduction interface events with the additional models that became available in recent years and update set of global scaling relations doing so will improve the predictions of the various source properties and further minimize the associated uncertainties. Moreover, for the subduction zones with adequate number of earthquakes in the database, develop regionalized scaling relations and seek physical explanations for the observed regional differences insubduction interface ground motions by searching for correlations with the many parameters that were considered by schellart and rawlinson (2013), heuret ET AL. (2011) and schafer and wenzel (2019).deliverables and expected outcomes this project will address an important need by improving models for subduction earthquake groundmotions that embody regional variation in earthquake source characteristics. The products that this project will generate are (1) global and regionalized source scaling relations of subduction earthquakes (2) evidence providing a physical basis for the observed variations in regionalized NGA sub groundmotion models for interface earthquakes and (3) publication of subduction source scaling relations and correlations between physical sourceproperties and regional ground motion models in a peer reviewed journal.intended beneficiaries these products will be beneficial to many hazard analysts and engineers, including those at the USGS, and will improve our characterization of subduction ground motions and tsunami genesis.subrecipient activities none