Landslide-generated Tsunami Warning in the United States: a Pilot

Abstract:

The U.S. National Tsunami Warning Center has embarked on a pilot project to provide tsunami warning for a large, deforming landslide recently identified in Prince William Sound, Alaska. The landslide mass, perched high on a coastal mountainside in Barry Arm, poses a very short-fused, high tsunami hazard to mariners and local communities in Prince William Sound if it releases suddenly and coherently. While modern tsunami warning systems are specialized for providing warnings about tectonic tsunamis, generated by displacement of the ocean floor during a large earthquake, landslide tsunami warning remains much more challenging. Steep coastal slopes abound in the glacially carved terrain of Alaska, British Columbia, and other areas of the Pacific Northwest. This creates widespread hazard, with immense practical limitations on instrumentation and monitoring of all potentially hazardous areas. Here, we detail the process of standing up the first modern, local landslide tsunami warning system in the United States. This effort will help protect lives and property in Prince William Sound, while also providing guidance on the feasibility of implementing targeted tsunami warning for other areas at high risk for landslide tsunami impacts in the future.