EVALUATING THE POTENTIAL FOR TSUNAMI GENERATION IN SOUTHERN IRAN

Makran Subduction Zone (MSZ) offshore of Iran and Pakistan is one of the most tsunamigenic sources in the Indian Ocean. Historically, the MSZ has generated some tsunamigenic earthquakes like that of28 November 1945 with the death tool of more than 4000 people along the coasts of Iran, Pakistan, India, and Oman. In this study, the tsunami hazard associated with the MSZ is investigated. At first, a review of historical tsunamis in the Indian Ocean basin was performed which reveals the Makran region has experienced all east 4 tsunamis including events of 326 BC, 1897, 1008, and 1945. Consequently, since the pattern and extent of vertical ground deformation from an earthquake determines whether or not a tsunami is formed, a computer program is developed to predict the seafloor deformation due to the earthquake occurrence in the MSZ. The model was verified through run of it on some actual tsunamis so far occurred. Then, using the data of the 1945 Makran tsunami, the seismic parameters of the MSZ were calibrated. Finally, we used the developed computer program to calculate seafloor deformation at the location of Makran subduction zone for several earthquake scenarios with moment magnitudes ranging between 6.5 and 8.5. The results of this research 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 the occurrence of an earthquake having magnitude up to 7; (2) little to medium risk for moment magnitudes ranging between 7and 7.5; and (3) high risk for moment magnitude greater than 7.5. At the end of the paper, modeling of tsunami propagation is performed for an earthquake scenario with magnitude of 8 offshore Chabahar, in order to give preliminary information about tsunami behavior in this region.