In the event of a major submarine earthquake, not only severe ground shaking but also high tsunami waves are expected posing a significant threat to coastal community and structures. Apart from having a sound warning system, it is necessary to design and construct Earthquake and Tsunami-Resistant (ETR) shelters for the evacuees as a part of civil protection measures during such mega events. In this paper three typical structures are chosen and forces against different types of earthquakes and tsunamis are calculated. From the investigations, a useful guideline is evaluated for determining the depth of inundation where both the forces will be of equal magnitude.
Past history and geological evidences reveal that great earthquakes are considered to occur at tectonic plate boundaries, particularly along the coastal belts that rim the Pacific and Cross Southern Asia. On 26th December, 2004, Indonesian submarine earthquake generated catastrophic tsunamis killing more than two lakh people and created a major economic impact on the countries surrounding the Indian ocean. Such mega events reminded the coastal community alert on the preparedness against initial ground shaking and subsequent effects followed by tsunamis. As most of the tsunamis are earthquake induced tsunamis, it is necessary that coastal structures should be designed against both earthquake and tsunami loads. Seismic and Tsunami resistant analyses are complicated as the motion is transient and the forces are time dependent. Though there are no well established design procedures for tsunami resilient buildings, FEMA CCM provided some guidelines based on the considerations of tsunami forces. A review by Harry Yeh, Ian Robertson and Jane Preuss (2005) suggested that fluid forces exerted on a structure can be evaluated in terms of hydrodynamic and impact forces for a given depth of inundation and the velocity of the approaching tsunami.