Understanding megathrust behaviour over the earthquake cycle through inversion of geodetic data and dynamic modelling
Date of Issue2016-10-17
Asian School of the Environment
Earth Observatory of Singapore
I here present three studies that depict megathrust behavior over different time periods of the seismic cycle. First, I present a study on how the local morphology of a fault can control the extent of seismic rupture, and how these morphological bounds can modify the rupture dynamics within a seismic cycle. Second, I investigate postseismic deformation following recent large earthquakes of the Sumatra subduction zone to probe the rheology of the mantle wedge flow. Lastly, I examine the spatial and temporal afterslip of the 2005 Mw 8.6 Nias-Simeulue earthquake, using joint inversion of long GPS time series for both afterslip and viscoelastic processes. I assess the spatial distribution of the afterslip relative to an updated coseismic slip distribution for this event. My results are important for understanding seismic and tsunami hazard on megathrusts; they help to understand why fully locked patches sometimes rupture only partially, and the relative contributions of coseismic slip and afterslip in relieving fault stress.