The flat top of the coral marks lowest tide levels before the giant earthquake. Credit: J. Galetzka
Posted on 11/02/2006 12:03:54 AM PST by SunkenCiv
The Sumatra-Andaman earthquake of Dec. 26, 2004, was one of the worst natural disasters in history, largely because of the devastating tsunami that followed. Now, scientists have discovered that regions of the earth previously thought to be immune to such events may actually be at high risk of experiencing them... "This earthquake didn't just break all the records, it also broke some of the rules," says scientist Kerry Sieh of Caltech, an author of the report... [T]he researchers found that the surface rupture spanned a distance of up to 93 miles, and that along this huge contact area, the surfaces of the two plates slid against each other by up to 60 feet. Extrapolating to the deeper fault, they also found that the 2004 earthquake was caused by rupture of a 1,000-mile stretch of the megathrust--by far the longest of any recorded earthquake. Indeed, the researchers say, the 2004 disaster was so much larger than any previously known rupture of this type that scientists may need to reassess many subduction zones that were previously thought to be at low risk. For example, "the Ryukyu Islands between Taiwan and Japan are in an area where a large rupture would probably cause a tsunami that would kill a lot of people along the Chinese coast," says Sieh. "And in the Caribbean, it could well be an error to assume that the entire subduction zone from Trinidad to Barbados and Puerto Rico is not seismic."
(Excerpt) Read more at nsf.gov ...
The flat top of the coral marks lowest tide levels before the giant earthquake. Credit: J. Galetzka
Analysis of the Sumatra-Andaman Earthquake Reveals Longest Fault Rupture EverThe great Sumatra-Andaman earthquake was an event of stunning proportions, both in its human dimensions--nearly 300,000 lives lost--and as a geological phenomenon. The sudden rupture of a huge fault beneath the Indian Ocean unleashed a devastating tsunami. It was the largest earthquake in the past 40 years and was followed by the second largest just three months later on March 28, 2005.
National Science Foundation
May 19, 2005
The new analysis gives the Sumatra-Andaman earthquake a seismic magnitude of at least 9.1, and possibly as high as 9.3. Earlier estimates had put it at magnitude 9.0. By comparison, the 1960 earthquake in Chile was magnitude 9.5, and the 1964 Alaska earthquake was magnitude 9.2.
1958, 1700+ foot megatsunami, Lituya Bay:
http://www.freerepublic.com/focus/f-bloggers/1607979/posts?page=145#145
Aleutian finding topples [TSUNAMI] theory
Anchorage Daily News | December 25, 2004) | DOUG O'HARRA
Posted on 12/27/2004 1:56:24 AM EST by BenLurkin
http://www.freerepublic.com/focus/f-news/1308869/posts
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