Characterizing the Spatial Uncertainty of Coseismic Slip for Past and Future Cascadia Subduction Zone Full-Margin Events

Date: 4/24/2019

Time: 04:45 PM

Room: Pike

Although numerous studies have been conducted along the US west coast to estimate the coseismic subsidence of past Cascadia subduction zone (CSZ) events, some estimates that are not based on state-of-the-art microfossil analyses are sometimes regarded as too noisy to use to fit any earthquake source model. This severely limits the amount of data that can be used for model fitting. Additionally, some earthquake source models attempt to characterize the full uncertainty in their predictions by using a handful of prespecified earthquakes rather than building a statistical model yielding an entire distribution of different possible outcomes. We attempt to overcome these obstacles by building a spatial statistical CSZ earthquake source model. Since spatial statistical models use spatial smoothing to produce robust estimates even in the presence of noisy observations, we are able to fit the model using both micro- and macrofossil based paleoseismic subsidence estimates. Additionally, we incorporate a set of locking rate estimates based on three decades of GPS data to provide information on coseismic slip spatial correlation range. We use this model to estimate the coseismic slips of the 1700 event as well as to cautiously make predictions about future full-margin CSZ events.

Presenting Author: John L. Paige

Authors