Rapid tsunami loss estimation using regional inundation hazard metrics derived from stochastic tsunami simulation

This study explores the development of rapid tsunami loss estimation approaches that are based on regional inundation hazard metrics, such as representative inundation height and inundation area. In post-tsunami situations, these inundation hazard metrics can be inferred from remotely-sensed images. Using a probabilistic tsunami loss model for the Tohoku region of Japan, rapid tsunami loss estimation models are developed by regressing predicted tsunami losses against regional inundation hazard parameters, which are derived for coastal cities and towns in Miyagi Prefecture from 4000 stochastic tsunami simulations. Using numerous earthquake sources of moment magnitudes between 7.5 and 9.1 facilitates the robust development of a quick tsunami loss estimation tool. Special considerations are given in investigating the effects of coastal topography (plain versus ria) and the potential bias due to errors in estimating inundation heights and areas on tsunami loss. Performances of the new approaches are compared with conventional methods that are based on earthquake magnitude, source-to-site distance, and offshore tsunami wave profiles. The loss models based on regional inundation area outperform other approaches and thus are recommended for regional tsunami loss estimation.