IGPP Seminar Series 2022: Ryo Okuwaki

IGPP is pleased to invite you to join its Fall 2022 Seminar Series presentation featuring University of Tsukuba's Ryo Okuwaki. Dr. Okuwakis talk, "Accounting Epistemic Uncertainty in Finite-fault Inversion; Illuminating Complex Earthquake Rupture Processes" will be available via Zoom on November 15, 2022, starting at 12:00pm. Zoom: https://ucsd.zoom.us/j/99722112406pwd=aWliSnk2Qlk5RzNXelNETDBFRHRLZz09 Password: igpp

Time: 12:00 pm, Pacific Time
Location: Revelle 4000 (on-site with a zoom link)

Abstract: Imaging earthquake-rupture kinematics is fundamental to understand earthquake-source physics. Finite-fault inversion of the seismic data is a primary means to resolve the spatiotemporal evolution of earthquake rupture. In the last decade, efforts have been made to associate with the uncertainty of the finite-fault solution and to mitigate the modelling errors. Introducing uncertainty of Green's function into the data covariance matrix has made it possible to stabilise the solution without forcing the non-negative slip, which opens a window into flexible source modelling requiring fewer prior constraints, such as fault geometry: another major source of modelling errors that may distort the solution.

One such major advance is the development of the finite-fault potency-density tensor inversion. Instead of fixing the fault-normal and slip directions on a fault a priori as adopted in conventional inversion schema, it solves distributed potential sources on the model fault that may have any types of faulting mechanism required by the data, without requiring detailed assumptions about fault geometry. We present this new framework of earthquake-source inversion that is capable of accounting for the uncertainty of fault geometry and enables us to flexibly model complex earthquake rupture geometry. We then present some recent case studies of complex earthquake source processes in various tectonic environments. We have gained new insights into the causative relationship of the rupture process with the geometric complexity of the fault system and the stress/strength state in the source region, which are critical inputs into physics-based and geodynamic modeling.

Nov 15 2022 - 12:00pm