Tsunami Inundation from Great Earthquakes on the Cascadia Subduction Zone along the Northern California Coast

We model tsunami runup and inundation along the Northern California Coast caused by hypothetical earthquakes on the Cascadia Subduction Zone (CSZ). The CSZ forms the boundary between the Pacific and North American tectonic plates and extends from Northern California to Southern British Columbia and is believed capable of producing great earthquakes with moment magnitudes (M_w) 9.0 or greater. A suite of CSZ rupture scenarios based on the geological characteristics of the southern part of the CSZ were simulated with the tsunami propagation and inundation model MOST. CSZ inundation projections were compared and related to historical accounts and modeled data for two teletsunamis at Crescent City: the tsunami of 1 April 1964 that caused 12 deaths and more than 17 million in damages to Northern California, and the 15 November 2006 Kuril Islands tsunami that caused nearly 10 million in damages to the Crescent City harbor. Our modeling suggests that near field tsunamis from the CSZ present a hazard greater than the 1964 event for the northernmost part of the State. However, south of Shelter Cove tsunamis generated by great earthquakes along the Alaska — Aleutians subduction zone are potentially more damaging.