New generation of tsunami hazard assessment for southern Iran

فاقد چكيده فارسي

We reassess the tsunami hazards associated with the Makran subduction zone (MSZ) offshore southern coasts of Iran and Pakistan based on the lessons learned from the large Japan earthquake and tsunami on March 11, 2011. The large M9+ earthquake offshore northwestern Japan surprised many seismologists and caused extreme destruction and death toll because no one was prepared for such an extreme earthquake and tsunami. This event showed that earthquakes larger than what we expected normally from subduction zones can occur in world’s subduction zones, and hence we may take into account worst-case scenarios for tsunami hazard assessment. In this study, based on historical earthquakes in the MSZ, we defined a worst-case scenario earthquake for the region and then calculated the distribution of tsunami heights along the southern coast of Iran bordering the Indian Ocean. Our scenario earthquake is an Mw 9 earthquake which is capable of rupturing the full length of the plate boundary along the MSZ. The resulting tsunami can produce wave heights up to 15 m along the coastlines of the region which is more than twice larger than the values calculated in the framework on the first generation of tsunami hazard assessment for the region. The results may help to understand the effects of an extreme tsunami and earthquake in the region. The 2011 Japan tsunami taught us that we have to be prepared for worst-case scenarios.