Multiscale Quantification of Tsunami Hazard Exposure in a Pacific Small Island Developing State: The Case of Samoa

GeoHazards

Josephina Chan Ting¹  Finn Scheele²  Kieron Wall³  Ryan Paulik³  Shaun Williams³  Cyprien Bosserelle³  Titimanu Simi⁴  Rebecca Weaving⁵ 

[1] Disaster Management Office, Ministry of Natural Resources and Environment, Apia WS1339, Western Samoa;GNS Science, Lower Hutt 5011, New Zealand;National Institute of Water and Atmospheric Research (NIWA), Christchurch 8011, New Zealand;Project Unit, Samoa Green Climate Fund Project, Ministry of Finance, Apia WS1339, Western Samoa;School of Geography, Environment and Geosciences, University of Portsmouth, Portsmouth, Hampshire PO1 2UP, UK;

关键词: tsunami inundation;    BG-Flood;    RiskScape;    samoa;    2009 South Pacific tsunami;    risk management;   

DOI  :  10.3390/geohazards2020004

来源: DOAJ

【 摘 要 】

This study presents a scenario-based approach for identifying and comparing tsunami exposure across different sociopolitical scales. In Samoa, a country with a high threat to local tsunamis, we apply scenarios for the 2009 South Pacific tsunami inundation at different grid resolutions (50 and 10 m) to quantify building and road exposure at the national, district and village levels. We show that while the coarser 50 m model is adequate for use in the rapid identification of exposure at the national and district levels, it can overestimate exposure by up to three times more at the village level. Overestimation typically occurs in areas characterized by flat, low-lying, gentle-rising terrain. Overall, a 35% increase in buildings exposed to the 50 m model is observed compared with the 10 m scenario on southeast Upolu island. Similarly, a 31% increase in road exposure is observed for the 50 m scenario. These observations are discussed within the context of tsunami evacuation planning and logistics. Notwithstanding the variability in exposure, a precautionary approach leads us to conclude that while higher-resolution models are recommended where available data and/or financial resources permit, the absence of such datasets should not preclude the use of coarser hazard datasets in risk assessments. Finer-resolution models provide more credence in detailed local-level exposure evaluation. While the results of this study are specific to the Samoan context, the results can be applied to the multiscale assessment of tsunami risk exposure in similar hazard contexts.

【 授权许可】

Unknown