2004 Tsunami Was Biggest In 600 Years

(AP)  The tsunami that killed 230,000 people in 2004 was the biggest in the Indian Ocean in some 600 years, two new geological studies suggest.

That long gap might explain how enough geological stress built up to power the huge undersea earthquake that launched the killer waves four years ago, researchers said.

The work appears in Thursday's issue of the journal Nature. Two research teams report that by digging pits and taking core samples in Thailand and northern Sumatra, they found evidence that the last comparably large tsunami struck between the years 1300 and 1400.

The researchers found deposits of sand that were apparently left by the waves, and estimated their age with carbon dating of associated plant debris.

The December 2004 disaster killed people in 14 countries. Waves more than 100 feet high struck northern Sumatra and deposited sand more than a mile inland, researchers said. In Thailand, the waves also ran more than a mile inland, leaving deposits of sand some 2 to 8 inches thick.

[lloydbest1]

Posted by cockamammy at 06:03 PM : Oct 30, 2008

Half a mile!? Yeah, that could make one a touch nervous....
So, I hunted around a bit and came up with a paper written by Drs. Simon Day and Steven Ward and which can be found here:

http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf

They postualte a catastrophic lateral collapse of La Palma''s main volcano, Cumbre Vieja, during an eruption that could generate a slide block land slip (where the whole she-bang goes at once rather than failure in bits and pieces) of anywhere between 150 and 500 cubic kilometers (36 to 125 cubic miles).
The tsunami generated by such an event, even at the minimum volume would radiate out from the source and inundate Atlantic Basin countries from Iceland to Brazil. Waves would be in the order of 30 feet in height when they made landfall. At the maximum theorized volume, coastal cities from Reykjavic to Halifax to New york, Charleston, Miami, San Juan, all the way to Forteleza and Recife could face an onslaught of 80 foot waves hitting at 60 to 90 mph.
I won''t specualte on death tolls but even with the nine hour lead time some of these places would get, the number of casualties would be astronomical.

[cockamammy]

I once watched an interesting article on massive landslides and their ability to launch a huge tidal wave. This happened before somewhere in Alaska and the result of this tidal wave is still visible. I''m sure the earthquake of 2004 also caused a massive underwater landslide and added to the severity of the tidal wave that caused so much damage to the afflicted areas. Another thing that should be considered is the fact that the island of La Palma in the Canary Islands could possibly cause the largest landslide in the history of mankind and if this were to happen, scientists are predicting a tidal wave could reach 1/2 mile high and completely wipe out the entire eastern coast from Maine to Miami. Some scary stuff to think about.

[emilymhanson]

People like srz25: please read the article in question before posting your political rants. This story has nothing to do with Florida. Go get a free blog or live journal to post your rants on, that''s what they are for.

[lloydbest1]

The quake that spawned those killer waves is a taste of what will happen to the U.S. and Canadian west coasts in the near future. Our Cascadia Subduction Zone is a twin of the same plate boundary that sits off Sumatra and the Malay peninsula.
Through a set of fortuitous circumstances geologists have been able to date precisely the last time the Cascadia Fault cut loose: January 26, 1700; at about 9 PM local time.
http://www.geophys.washington.edu/SEIS/PNSN/HAZARDS/CASCADIA/simple_tree_rings.html outlines tree ring and sediment deposition data to get a rough guestimate of when...and...
http://earthquake.usgs.gov/regional/states/events/1700_01_26.php provides links to the methods used to hone in on January 26, 1700 as the exact date and time as well as the estimated magnitude.
There were no seismgraphs then but it appears this one was AT LEAST as powerful as that awful Sumatran quake and, also since, the Cascadia Fault ruptures on an average frequency of once every 300 years; the clock is now running. The next big one could strike at any time - in a hundred years, or tomorrow.

[nojoy01]

I''''ll never forget that day. For me it was worse than 9/11. A quarter of a million people killed in one hour. Never on earth have that many humans died in a single day. It makes me feel so sorry.

Posted by hennighg at 06:17 PM : Oct 29, 2008

In One Hour? I didn''t realize that tsunamis were supersonic.

[ubrew12]

CountSlapula said: "And I''m supposed to believe in the God who did this, and insist he loves me? Pffft. No thank you! "

God can off me anytime.

[countslapula]

And I''m supposed to believe in the God who did this, and insist he loves me?

Pffft. No thank you!

[downsteamjim]

They could have asked Ted Kennedy.

[hennighg]

I''ll never forget that day. For me it was worse than 9/11. A quarter of a million people killed in one hour. Never on earth have that many humans died in a single day. It makes me feel so sorry.