The sizes of deposits are enormously variable although Holcomb & Searle (1991) report that many single landslides affecting oceanic volcanoes may have been sufficiently large as to involve the transport of up to 20% of the edifice volume. Some of the Hawaiian landslides have volumes greater than 5000km3 and lengths in excess of 200km making them the largest such structures recorded on Earth (Moore et al., 1992)...
The Hawaiian Ridge, extending from near Midway Island to Hawaii, provides by far the most impressive evidence for volcano instability and collapse in the marine environment. Following a cooperative submarine survey by the United States Geological Survey and the UK Institute of Oceanographic Sciences, using the GLORIA side-scan sonar system, sixty- eight landslides with lengths in excess of 20km have been identified.
Most recently, the Discovery Channel has replayed a program alleging potential destruction of coastal areas of the Atlantic by tsunami waves which might be generated in the near future by a volcanic collapse in the Canary Islands. Other reports have involved a smaller but similar catastrophe from Kilauea volcano on the island of Hawai`i. They like to call these occurences "mega tsunamis". We would like to halt the scaremongering from these unfounded reports. We wish to provide the media with factual information so that the public can be properly informed about actual hazards of tsunamis and their mitigation.
Here are a set of facts, agreed on by committee members, about the claims in these reports:
- While the active volcano of Cumbre Vieja on Las Palma is expected to erupt again, it will not send a large part of the island into the ocean, though small landslides may occur. The Discovery program does not bring out in the interviews that such volcanic collapses are extremely rare events, separated in geologic time by thousands or even millions of years.
- No such event - a mega tsunami - has occurred in either the Atlantic or Pacific oceans in recorded history. NONE.
- The colossal collapses of Krakatau or Santorin (the two most similar known happenings) generated catastrophic waves in the immediate area but hazardous waves did not propagate to distant shores. Carefully performed numerical and experimental model experiments on such events and of the postulated Las Palma event verify that the relatively short waves from these small, though intense, occurrences do not travel as do tsunami waves from a major earthquake.
See www.sthjournal.org... for the full story
See the following link (it is a .pdf) for the April 2003 International Tsunami Information Center Newsletter that contains info on this subject www.prh.noaa.gov...
Wrong show... that would be result of "dino-killer" hit to ocean. (but in that case tsunamis would be smallest of your worries)
Originally posted by orionthehunter
The entire East Coast of the US and other countries in the Atlantic and possibly around the world will be hit hard, very hard I believe. I heard tidal waves on the US east coast could be higher than virtually any common skyscraper and reach 100 miles inland.