Tsunamis Induced by Submarine Slumpings off the Coast of Israel

In the course of history several extreme changes in the sea level along the coast of the Levant have occurred. As these events have always been associated with earthquakes they were often described as tsunami or seismic sea waves. Reviewing the historical descriptions of such events at Israel’s coast, one finds more often a recession of the sea than a flooding of the shore. Such events may have been caused by slumpings on the continental slope. Based on data of actual submarine scars, a quantitative evaluation of this hypothesis was made. It was found that the slumping of a mass 6 km long, 2 km wide and about 50 m deep would cause the formation of a shock-induced solitary wave of about 10 m in height at the edge of the continental slope. The accompanying draw-down of the sea level at the coast would last aboul hours, and lay the sea floor bare for a distance of about ½-1½ km, in agreement with some historical descriptions. Though possibly occurring only once or twice in a millennium, earthquake-induced slumpings may constitute a danger to nuclear power plants, and not just to maritime vessels and installations