Document Type : Article
Dept. of Environmental EngineeringrnUniversity of Tehran
International Institute of Earthquake Engineering and Seismology
After the 26 December 2004 mega-tsunami in the Indonesia coastlines, wide efforts were devoted to assess the hazard of tsunami, and to develop tsunami warning systems in the Indian Ocean basin. Based on these efforts, two main tsunamigenic sources that can trigger tsunami-generating earthquakes in the Indian Ocean basin
have been identified as the Indonesian subduction zone in the east and the Makran subduction zone (MSZ) in the north of the Indian Ocean. MSZ is located off the southern coasts of Iran and Pakistan in the north-western Indian Ocean and any possible tsunami from this zone has the potential to affect Iran, Oman, Pakistan, and India. The last major historical earthquake and tsunami in the MSZ occurred on 28 November 1945 killing more
than 4,000 people along the Makran coast. Therefore, considering the hazard of tsunami in southern coasts of Iran bordering the Indian Ocean, in this study the potential for tsunami generation in this region has been investigated using modeling of tsunami generation phase. In this regard, a computer program based on
Mansinha and Smylie (1971) formula has been developed to predict the seafloor deformation due to underwater earthquake occurrence.
The results obtained here show that the risk of tsunami generation from MSZ can be classified into three main categories, as follows: (1) very little risk for tsunami generation in the case of occurrence of an earthquake having magnitude up to 7; (2) little to medium risk (Magnitude ranging 7 to 7.5); and (3) high risk (Magnitude
greater than 7.5). At the end of the paper, considering the results of our tsunami hazard assessment, the necessity for development of a tsunami warning system for southern coasts of Iran is emphasized and the structure, components, and mechanism of such a system is presented.