Linking sediment strength and earthquake shaking to understand the Cascadia Subduction Zone paleoseismic record

Kiki A. Paroissien-Arce, Tara Nye, & Valerie J. Sahakian

Published August 16, 2021, SCEC Contribution #11628, 2021 SCEC Annual Meeting Poster #241

Records of turbidites offshore Cascadia are an integral part of detangling the Cascadia Subduction Zone paleoseismic record, and support estimates of seismic hazard. In this study, we aim to extend this work, and re-examine some current assumptions about turbidite event history in the Cascadia subduction zone. In particular, these turbidites currently help researchers constrain past rupture locations, lengths and subsequently, magnitudes using empirical “triggering thresholds”. We aim to discover how much shaking actually generates a turbidity current offshore, in order to gain more accurate constraints about past rupture locations and magnitudes. We will use synthetic seismograms, and measurements of sediment shear strength taken on 2020 cruise OC2006A. In an upcoming expedition, we hope to further understand the likelihood that sediment sources offshore the margin would have failed in the past. We will use these forward models to understand likely rupture characteristics that have produced the existing turbidite record. We will present our suites of rupture models, shear strength measurements, and methodology, as well as any preliminary results of rupture constraints.

Citation
Paroissien-Arce, K. A., Nye, T., & Sahakian, V. J. (2021, 08). Linking sediment strength and earthquake shaking to understand the Cascadia Subduction Zone paleoseismic record. Poster Presentation at 2021 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology