Inundation maps for the State of California

Abstract

More than 20 tsunamis of different heights have impacted the State of California in the past two centuries. While some earlier 19th century reports are subject to interpretation, there is little question that offshore seismic sources exist and could trigger tsunamis directly or through coseismically generated submarine landslides or slumps. Given the intense coastal land use and recreational activities along the coast, even a small hazard may pose high risk. California presents nontrivial challenges for assessing tsunami hazards, including a short historic record and the possibility of nearshore events with less than 20 min propagation times to the target coastlines. Here we present a brief history of earlier efforts to assess tsunami hazards in the state, and our methodology for developing the first generation inundation maps. Our results are based on worst case scenario events and suggest inundation heights up to 13 m. These maps are only to be used for emergency preparedness and evacuation planning.