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Dynamic Stress Changes during the 2015 Gorkha, Nepal Earthquake

Lingling Ye, Jean-Philippe Avouac, & Nadia Lapusta

Published December 15, 2016, SCEC Contribution #7256

The rupture process during an earthquake is controlled by the pre-stress distribution and the frictional properties of the fault surface. Various friction laws have been developed based on laboratory experiments and widely used in earthquake dynamic simulations. However, direct determination of dynamic friction during large earthquakes is a challenge because of the generally limited resolution of earthquake source models. Near-source less attenuated observations are needed for such studies but rarely available. Here we focus on the 2015 Mw 7.8 Gorkha earthquake for which near source accelerometric, high-rate GPS, and InSAR data, in addition to teleseismic observations, provide particularly extensive constraints on kinematic rupture models. We determine the spatial-temporal variation of dynamic stress change on the fault plane induced by earthquake rupture based on the kinematic slip models by calculating seismic wavefield with the discrete wavenumber method (Bouchon, 1997). We investigate the difference in the stress changes in several slip models with different parameterization on slip-rate functions. To understand the relation between the stress changes in the kinematic slip models, friction-slip relationship, energy partitioning between radiation and dissipation, pre-stress and other properties, we use dynamic earthquake rupture models, in which all source parameters are known. We first construct the slip models similar in spatial and temporal resolution to the kinematic source models. We will report on our current investigation of the relation between the corresponding stress changes and the original synthetic sources. The conclusions from that investigation will be applied to interpret the inferred dynamic stress changes in the Gorkha earthquake.

Ye, L., Avouac, J., & Lapusta, N. (2016, 12). Dynamic Stress Changes during the 2015 Gorkha, Nepal Earthquake. Oral Presentation at AGU Annual Meeting.