Nearly a third of the large historical earthquakes along the Dead Sea Transform (DST) fault system have produced submarine landslides and consequently tsunamis which devastated the eastern Mediterranean coast – highlights the research project “Tsunami Hazard evaluation of the eastern Mediterranean:Historical Analysis and Selected Modeling” carried out by the Earth and Planetary Sciences Department of the Santa Cruz University in California. Therefore it is important to assess the likelihood of a future earthquake from that source.
Examination of the seismic history of the DST and estimates of the strength accumulated in the DST indicate “3-5 m of potential slip which is most likely to be released in a large earthquake (M>7). Thus there should be great concern in Syria, Lebanon and in Israel, not only for the possible occurrence of a near-future large earthquake, but also for the significant likelihood that the earthquake will be accompanied by a tsunami produced by an offshore slump within minutes of the mainshock”.
The eastern Mediterranean – including the coasts of Egypt along the Nile Delta and Sinai, Israel, Lebanon, Syria and the Bay of Iskendrun (Alexandretta) in southern Turkey - stands out for its rather long and detailed earthquake and tsunami historiography. Researchers prepared a detailed compilation of historical reports of tsunamis and earthquakes for this area, tried to correlate tsunamis with earthquakes and to identify possible future tsunami triggering events.
Researchers concluded that, of the 20 reliably reported tsunamis that struck the Levant coast, 10 were triggered by earthquakes that originated along the Dead Sea Transform (DST) fault system - an on-shore seismic zone. Of the other ten tsunamis, eight were associated with sources in the Cypriot and the Hellenic Arcs, and Italy, and two have unknown origin.
Observations allowed researchers to recognize and model two principal mechanisms for the generation of tsunamis that will likely affect this region in the future: submarine landslides produced by on-land earthquake (DST system), and earthquakes originating beneath the sea on nearby seismic zones (Hellenic Arc, Cypriot Arc). Two earthquakes (Cypriot Arc and Beirut Thrust) and one “on land earthquake – submarine landslide’ scenarios were simulated and allowed to conclude that the landslide related tsunamis would produce average waves of 4-6 m, whereas tsunamis directly produced by earthquakes would be much smaller, 1-3 m.
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