Caribbean tsunamis : An initial history

Report of 50 tsunamis of varying certainty are listed for the Caribbean beginning with an event off the coast of Venzuela in 1530. Fifteen of these have reports of damage associated with them and six have reported fatalities. As a throughly researched history for the region has not been done, these numbers are approximate and probably low. The author has just learned of but not yet seen, a paper an Caribbean tsunamis by Myrtle Thorm and Compton Deane at the Civil Engineering Department, University of the West Indies, St. Augustine, Trinidad written in the late 1970's. Also, given the increase in coastal development, a repeat of these events today would cause much higher damage and fatalities. Although the history of the Caribbean area is the longest in the Western Hemisphere, the tsunami history has not benn studied in detail. The varied colonial past and the number of political divisions make such a study difficult and needing local involvement. Tsunamis has affected the whole arc of the Antilles. It is subject to tsunamic of tectonic origin associated with the trech and with structures cutting the arc. Notable is the 1867 tsunami originating in the Anegada trough between St. Thomas and St. Croix, Virgin Islands, which caused 14 to 16 fatalities and was observed throughout the Caribbean. The 1918 tsunami off the northwestern corner of Puerto Rico caused about 40 fatalities and extensive damage. The Caribbean area is also subject to rare but destructive teletsunamis from Atlantic sources. The 1755 tsunamis which affected Lisbon, North Africa and England put waves as high as 7 meters at Saba, and 3.7 metres at Antigua and Dominica. Waves reached the second story of buildings in Martinique. The Caribbean may also be subject to tsunamis generated by volcanic activity as seen bt the 1690 landslide on Nevis peak and as explosion od a mud volcano near trinidad in 1911. Kitck-em Jenny, a submarine volcano discovered in 1939, may havegenerated small, local tsunamis in the 1939 or 1990 eruptions (Sigurdsson, 1996) and may in the future produce a larger wave. Landslides are another source of tsunamis. Each type of source produces tsunamis with different characteristics. The risk should be thoroughly evaluated by a multi-national effort to improve the history and predict effects by using models. (AU)

Alaskan tsunamis revisited

The study of Alaskan tsunamis presents a number of problems. The first European visitorsand settlers were Russian fur traders first arriving in 1741, and the written record for more than the first century is mainly in old style Russian scrip. A sparce population, particularly in the highly activeAleutian islands, continues to the present day. There are tecttonically - generated tsunamis predominantly from the Aleutian Arc and Alaskan Peninzula, at least one volcanic tsunami from a landslide from an erupting volcano, and, most important locally, subaerial and submarine landslide tsunamis from the Prince William Sound and southeastern Alaska. The latter are related to the glacial topography and have caused most of the fatalities and damage. They are usually associated with a single bay and occur almost immediately after the triggering earthquake, posing severe problems for warnings and evasive actions. Teletsunamis have historically not been a significant problem (AU)