Influence of Elevation Data Resolution on Tsunami Loss Estimation and Insurance Rate-Making

Jie Song,Katsuichiro Goda

doi:10.3389/feart.2019.00246

Jie Song, Katsuichiro Goda

Open Access

https://doi.org/10.3389/feart.2019.00246

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Abstract

Tsunamis triggered by large offshore earthquakes are devastating, and buildings located near the coast experience damage and loss due to such extreme events. In evaluating regional tsunami impact via numerical tsunami simulations, it is important to pay close attention to local geographical features represented by a digital elevation model (DEM), because tsunami loss estimation is sensitive to its quality and resolution. This study investigates the influence of elevation data resolution on tsunami loss estimation at different scales by comparing tsunami risk results using DEMs of four resolutions (i.e. 10-m, 50-m, 150-m, and 450-m). Using stochastic tsunami modelling, a case study is carried out by focusing on the Tohoku region in Japan to investigate the influence of DEM resolution on tsunami loss estimation considering the effect of location attributes (i.e. coastal topography, distance from the coast, and land elevation) for two building portfolios on plain coast and ria coast. The results indicate the significance of DEM resolution for local tsunami loss estimations at different locations. The local tsunami risk is closely related to the building location, and the increase of distance from the coast and/or land elevation dramatically reduces the local tsunami risk. The investigations extend discussions regarding the calculations of pure insurance premium rate for tsunami loss coverage depending upon structural attributes and location attributes.

Highlights

A tsunami is a series of traveling waves of long wave-length and period, which is initiated by a sudden deformation of sea-floor (Kanamori, 1972; Okada, 1985; Tanioka and Satake, 1996; Synolakis et al, 1997; Titov et al, 2005; Fujii and Satake, 2007)
Similar to flood modeling which is sensitive to spatial resolution (Fewtrell et al, 2008; Sangati and Borga, 2009), resolutions of digital elevation model (DEM) represent the ability of reflecting the local geographical features and make a significant difference to local tsunami intensity (Griffin et al, 2015; Schäfer and Wenzel, 2017; Muhammad and Goda, 2018)
Based on the stochastic tsunami modeling method, the uncertainty in tsunami risk caused by different DEM resolutions was investigated

Summary

Introduction

A tsunami is a series of traveling waves of long wave-length and period, which is initiated by a sudden deformation of sea-floor (Kanamori, 1972; Okada, 1985; Tanioka and Satake, 1996; Synolakis et al, 1997; Titov et al, 2005; Fujii and Satake, 2007). The comparisons of the tsunami loss distributions and the corresponding risk metrics for different grid resolution cases highlight the importance of the elevation data resolution to the accurate estimation of the potential financial impact due to catastrophic tsunamis.

Results

Conclusion