Earthquake Modeling
The Cascadia Subduction Zone (CSZ) megathrust (or ‘Big One’) is known to be accumulating tectonic strain that is likely to be released in future M8 to M9 megaquakes, triggering catastrophic tsunamis and cascading hazards – coastal and submarine landslides, ground liquefaction, and mobilization of seafloor sediments creating destructive sediment gravity flows. Hub researchers are studying the CSZ fault to gain a better understanding of earthquake risk to the Pacific Northwest.
Our Research:
The CSZ remains a poorly understood complex of faults, including offshore splay faults that can play a major role in local variability in tsunami hazard. Northern and southern Cascadia have distinct event histories and fault geometry, with differing implications for future hazards. It is unknown how slip will be distributed offshore in the next Cascadia earthquake. Models largely treat the CSZ as a single fault, but great subduction earthquakes have shown that spatial variability and fault complexity strongly affect the resulting hazard. Understanding of plausible and probable patterns of fault slip and seafloor displacement are crucial for assessing tsunami inundation scenarios.
To address this gap, we will investigate offshore faults and assess their potential for slip and displacement, synthesizing new imaging data (lidar, hi-res bathymetry, seismic reflection imaging, geodesy) to illuminate fault interactions, slip history, and geologic structure, focused particularly on the collaboratories. We will merge those results with known faults to build a 3D fault framework needed to (a) guide the transformative realistic earthquake-tsunami-landslide modeling and (b) guide investigation of how spatial variability of earthquake rupture scenarios interacts with geology and topography to control landslide and sediment mobilization hazards.
Uncovering Faults at the
Cascadia Subduction Zone
Journal Articles
Carbotte, S., Boston, B., Han, S., Shuck, B., Beeson, J., Canales, J., Tobin, H., Miller, N., Nedimovic, M.,Tréhu, A., Lee, M., Lucas, M., Jian, H., Jiang, D., Moser, L., Anderson, C., Judd, D., Fernandez, J.,Campbell, C., Goswami, A., and Gahlawat, R. (2024). Subducting plate structure and megathrust morphology from deep seismic imaging linked to earthquake rupture segmentation at Cascadia. ScienceAdvances. 10(23). DOI: 10.1126/sciadv.adl3198
Ledeczi, A.M., Lucas, M.C., Tobin, H.J., Watt, J.T., Miller, N.C. (2024). Late Quaternary Surface Displacements on Accretionary Wedge Splay Faults in the Cascadia Subduction Zone: Implications for Megathrust Rupture. Seismica 2(4). DOI: 10.26443/seismica.v2i4.1158
Stanton, K. M., Crider, J. G., Kelsey, H. M., & Feathers, J. K. (2024). The signature of accumulated permanent uplift, northern Cascadia subduction zone. Quaternary Research, 117, 98-118. doi.org/10.1017/qua.2023.59