EVIDENCE FOR THE 27th NOVEMBER 1945 MAKRAN TSUNAMI ALONG THE SHORELINE OF OMAN

Recent tsunami events like the Indian Ocean tsunami on 25th December 2004 and the Tôhoku earthquake and tsunami on 11th March 2011 resulted in large number of casualties and immense damage to infrastructure. These events underline the need for tsunami hazard assessment for any potentially vulnerable region. In most cases this can only be done by studying past tsunami records. The coastlines of the Sultanate of Oman are prone to various natural hazards such as tropical cyclones, landslides and tsunamis. The devastating effects of the cyclone Gonu, caused by flash floods and landslides in June 2007 illustrated the need to investigate the recurrence intervals of such events in order to assess the vulnerability and to mitigate damages. So far no scientific research concerning recurrence intervals of natural hazards has been carried out. However, different studies reveal past tsunami events in the Indian Ocean with possible effects for the coastline of Oman. As the population of Oman and the neighboring countries is concentrated along the coastline and large infrastructure projects are planned or completed a holistic scientific approach to decipher the geological record of past extreme events is overdue. On the 27th November 1945 an earthquake occurred in the Makran Subduction Zone offshore Pakistan and triggered a tsunami. Up to 4 000 people were reported dead along the coastlines of NW India and Pakistan. There are almost no historical documents available for Oman for this period as the country was isolated with no international contacts until the 1970s, living conditions were poor and no modern technology was in use. We report geological and historical evidence for the tsunami along Oman's coastline. These evidence are: (a) fine grained lagoon sediments which show distinct layers with allochtonous, offshore species (mollusks and foraminifera); (b) boulder deposits encountered along cliff-coastlines and (c) eyewitness-reports of old people we interviewed.