Modeling of large destructive waves

Personal staff

	Background and motivation During the last century, many small and three big accidents due to slide generated waves have occurred in Norway, taking a toll of 170 deaths in addition to huge material damage. At present, 11 areas in Norway are under survillance of NGI due to the significant probability of large, slide-induced, destructive waves. There is geological evidence of several giant under-water slides at Storegga (5000 B.C.) on the Norwegian continental margin. The associated wave may have caused a water elevation of up to 10 meters at the Norwegian coast. Signatures of several similar slide incidents are recently discovered in other parts of the world. Such slides are also of great interest for geologists, due to the massive redistribution of sediments in ocean basins. An actual question is if marginally stable sediments at the continental slopes may be released through off-shore activity in the Norwegian Sea. The consequences, both for oil installations and coastal regions, might be disastrous. In a European perspective, destructive ocean waves have received increasing attention in recent years, e.g., through EU projects. The Mechanics Division has participated in two such projects. There have been several serious European catastrophes throughout history. The most severe incident in the present century took place in Vaiont in Italy, 1963, and caused 2600 casualties. A historic survey of important slide-generated tsnumais is found in Voight (1979). while the Norwegian incidents are compiled by Jørstad (1968). Counting among the seismic events, tsunamis are the no. 5 killer among natural hazards worldwide. In Japan, alone, more than 150 serious accidents have been registered in this century.		Destructive wave at a ship.