NATO ADVANCED RESEARCH WORKSHOP ON
"UNDERWATER GROUND FAILURES ON TSUNAMI GENERATION, MODELING, RISK AND MITIGATION"
May, 23-25, 2001, Grand Hotel Tarabya,
Istanbul, Turkey
(Field Trip on May 26, 2001)














Overview

Understanding of  tsunami generation mechanisms can contribute to solving the problems of the defence of populations, coastal structures and environment from tsunamis.  The sources (sea bottom deformation, landslides, slumps, subsidence, volcanic eruptions, calderra collapse, meteor strikes) which can generate tsunamis are dangerous and common concerns.  This problem is one the most difficult to study and to simulate by means of numerical models.  It is therefore an important challenge for the research community and an important issue for the civil society at large.  Tsunami investigations need many scientists from different areas ranging from basic and applied sciences to management.  Marine surveys on tsunamigenic ocean areas, underwater faults, landslide and slump geology, sediment stability, underwater mass failures, seismic considerations, theoretical and computational approaches, hydromechanics, new modeling techniques, historical events, database, instrumentation, risk, warning, preparedness, mitigation are the subjects to be discussed at an advanced level. The expert scientists who are working on these subjects do not meet regularly for a specific topic of this kind. This workshop is a step in that direction.

There is a long record of tsunami occurrences and damaging tsunamis have been observed repeatedly in the oceans and seas.  The sources of tsunamis are still active and tsunamis are expected to occur  in the future. Future tsunamis could be even more catastrophic than past events, due to steadily growing occupation of the coasts for the economic development of the coastal countries in the last fifty years. Protection from natural disasters and mitigation of their effects on environment and societies are becoming more important issues all over the world.

Existing analyses of recent tsunami events [the 1979 Nice France, 1992 Nicaragua, 1992 Flores, 1994 Skagway(Alaska), 1998 Papua New Guinea, August 1999 Izmit(Turkey), October 1999 Fatu Hiva(Fiji), December 1999 Vanuatu(Tahiti)] have shown the importance of  geophysical, geological, seismological and geotechnical parameters and their effects on the  ground failures.  The tsunamis generated by mass failures may cause higher tsunami runups along shorter length of coastlines and always cause very strong, near-shore currents.  The  predictions will help to understand this danger better and help the preparedness studies for coastal communities for this kind of marine hazards.

Currently the scientists do not have sufficient comparisons of the methods on tsunami generation. There isn't sufficient information on underwater ground failures and the risks because of the difficulties of marine surveys on this subject.   It is very important to predict their occurrences related to nearby moderate to serious earthquakes and/or underwater triggering mechanisms.

After August 17, 1999 Izmit Earthquake in Turkey,  the investigations showed that the western propagation of North Anatolian Fault in the last century is also warning a considerable probability of a large magnitude earthquake in the sea of Marmara where there also were historical tsunamis documented. The source mechanisms of those tsunamis and the historical tsunamis in the Mediterranean and Aegean Sea have not been identified yet.

The steep slopes at the trenches in the oceans and seas have a potential of submarine landslides. A few number of  them could be found by the analysis of some different purposed surveys.  If the latest tsunamis (Papua New Guinea, Flores, Nicaragua, Izmit, Fatu Hiva) which were thought to be generated by slumps are considered, the sources of some of the historical tsunamis in this region might also be the slumps at these trenches. The similar questions may also be asked for the historical tsunamis in the other regions.

This workshop will compile the existing theoretical and experimental studies and provide the new idea and techniques to investigate and model the source mechanisms of tsunamis. The workshop will also provide the environment to develop and compare the existing numerical models for tsunami propagation. The new approaches and wide discussion opportunity will help the tsunami scientists to determine, predict and simulate the occurrences of these types of future tsunamis.  Necessary information for the tsunami risks and mitigation studies will  also be provided by this Advanced Research Workshop