13 - Tsunami Hazard in Vietnam

Abstract

The tsunami hazard along the coast of Vietnam was evaluated based on field survey of past tsunami events, reviewing present research results on the tectonic plate structures and seismic activity in the East Sea. It was found that there is no reliable information to confirm a strong tsunami on the Vietnamese coast in the past, and if tsunamis ever attacked the Vietnamese coast in the past, they were weak events with minor damage. From reviewing the published literature, it was found that the only sources for significant tsunamis that could affect the Vietnamese coast are the earthquakes in the Manila Trench. Calculated results using numerical models for the generation of a tsunami by a submarine earthquake, the propagation of tsunamis from the source to the coast of Vietnam and the flooding of coastal land by tsunamis, and with earthquake parameters derived from literature, show that if an earthquake with magnitude of Mw=8.0 at the Manila Trench, a part of the coast of central Vietnam would experience tsunami heights of more than 1m. With larger earthquakes, the part of the coast of Vietnam with a tsunami height of more than 1m would expand to entire central Vietnamese coast and might cause significant damage to life and property among coastal residents. However, the possibility of an earthquake with magnitude of Mw>8.0 happening at the Manila Trench is very small. Thus, the tsunami hazard and risk at the Vietnamese coast and its islands is insignificant.