Posted on 03/19/2008 2:45:31 PM PDT by blam
Forecasting Tsunami Threats Through Layers of Sand and Time
Map Of The Bay Of Bengal
The catastrophic Indian Ocean event in December 2004 that killed 230,000 people in a dozen countries – including 15,000 in India – was hardly a one freak occurrence. It could happen again.
Newswise — Azhii peralai: from the deep … large waves.
This is the expression for ‘tsunami’ in Tamil, the oldest language in southern India.
For an ancient dialect to have its own phrase for destructive waves triggered by earthquakes, the people of Tamil Nadu likely experienced tsunamis periodically through the centuries, says Halifax scientist Alan Ruffman.
In other words, the catastrophic Indian Ocean event in December 2004 that killed 230,000 people in a dozen countries – including 15,000 in India – was hardly a one freak occurrence, he says, and people could have been much better prepared for it.
The proof lies in the layers below the Earth’s surface, says Mr. Ruffman, honorary research associate in Dalhousie’s Department of Earth Sciences. What better way to predict the threat of future tsunamis than studying patterns from the past? Coastal sediments provide a potent geological record of recent and ancient tsunamis, he says, adding that the size of the sand particles can provide clues about the actual height of the water column.
He points to a compelling photo of a research colleague at a dig in Thailand, showing four distinct bands of sand. The surface layer was deposited by the 2004 tsunami, and Mr. Ruffman figures the next layer was left by an event dating back 400 to 600 years. “The tsunami that laid that one down was probably about the same size as the one in 2004,” he says.
This kind of research is relatively new. Much more study is required to develop statistics and timelines that can serve as a guide to help people in Southeast Asia better prepare for the next monster wave. And Halifax will be part of that important effort, Mr. Ruffman learned last week. The Shastri Indo-Canadian Institute has awarded a seed grant to help Dalhousie develop a tsunami research partnership with the University of Madras in Chennai, India.
In his funding proposal, Mr. Ruffman envisioned a long-term alliance to generate potentially life-saving new knowledge from research by faculty and students in the two coastal cities, starting with in-depth study of the history of tsunamis in the Bay of Bengal. This will range from detailed geological sediment studies to analysis of southern India’s early writings and folklore, to find human accounts of early tsunamis.
“There are more than 1,500 unanalyzed early documents in the Tamil language that stretch back one to two thousand years,” says Mr. Ruffman.
And if the Tamil Nadu sediments tell a similar story to the layers shown in the striking photo from Thailand, “then our scientific team should be able to put a solid estimate on the return period of such devastating events. This would allow communities and governments to put in place the necessary tsunami warning systems and evacuation procedures for future events,” Mr. Ruffman says.
It could go much further than that, with such proactive steps as restoring mangrove vegetation, to help prevent tsunami erosion along coastlines, and even moving whole villages to safer locations.
“If the understanding of the very real and present tsunami hazard leads to better location of coastal villages, housing and infrastructure, then the financial and human losses during future tsunamis will be greatly reduced. But planners and governments will have to believe that the 2004 tsunami was not a unique event ... and there’s nothing like finding a signature of a historic event to convince the local policy-makers it has occurred before.”
The Shastri funding proposal suggests Dalhousie would host a week-long series of workshops, seminars and social functions, attended by tsunami researchers from Madras, as well as local scholars and members of Halifax’s Indo-Canadian community. The Earth scientists would also use the time to hammer out a plan for their cooperative research program, and explore opportunities for graduate student exchanges between the two universities.
The core research team would include four Madras scholars, six Dalhousie faculty members in Earth Sciences and Oceanography, and the Bedford Institute of Oceanography.
Mr. Ruffman has been researching tsunamis for more than two decades. His main focus thus far has involved historic events in the Atlantic, such as the 1755 Lisbon Tsunami, and the 1929 Grand Banks event that killed 28 people in Newfoundland.
“In 1929 the tsunami surged up to a kilometre and a half inland,” he noted. “Houses were floating out to sea with oil lamps still seen burning in the windows. These events, though rare, do occur in the Atlantic.”
In a recent presentation to the Atlantic Geoscience Society, he also discussed possible connections between climate change and tsunamis—coastal areas with rapid deglaciation can become vulnerable to shifts in the Earth’s crust, triggering seismic activity that could launch tsunamis.
“It’s not a hazard that will happen tomorrow, or often,” says Dr. Ruffman. But once tsunami researchers get a handle on the Bay of Bengal, there’s plenty more work to be done in Greenland, Iceland and Labrador, he says.
GGG & Catastrophism Ping.
You better put me on your ping list. Thanks.
A basic understanding of the tectonics of this region would seem to have been enough as well...but it wasn’t.
Something that happens every 500-1000 years is routine in terms of the Earth, but unthinkable to the average person.
I’m sure the Apocalpytikook/”God’s Punishment!” Brigade will ignore this story in their desperate attempts to portray every new natural disaster as something unique and special.
Complicated tectonics. The Indo-Australian plate (upon which the Indian Subcontinent and Australia rest) meets with Asia along the Himalayas (the tectonic collision which led to its rise) and through the islands of South-East Asia.
The dynamics between the meeting-points were responsible for the famous tsunami.
There’s some evidence there’s a tsunami threat along the boundary to the north running all the way to the Burma/Bangladesh coast, paper on that in the last year.
ONE of the Earth's tectonic plates has cracked in two, broken by the stress of pushing up the Himalayas and the Tibetan Plateau. American and French geophysicists have produced the first direct evidence showing that the Indo-Australian plate has broken just south of the Equator in the middle of the Indian Ocean (see Map).
The two halves of the Plate are now going their separate ways, says Jeffrey Weissel of the Lamont-Doherty Earth Observatory of Columbia University, New York. "If you hold India still in your left hand, and you spin Australia anticlockwise, you get the sense of the motion at that plate boundary," he explains.
A decade ago, geophysicists at North western University in Evanston, Illinois, theorised that the Indo-Australian plate - long thought to be a single unit - was actually two plates, with the Australian portion circling anticlockwise around the Indian one at a rate of about one degree every 3 million years. From mathematical models and indirect measurements, they calculated that the pivot lay about a thousand kilometres south of India.
Weissel and his colleagues have now confirmed this theory by calculating the amount of compression east of the pivot, where the seafloor has buckled. They predicted that the relative motion of the two plates - and thus the amount of compression - should be small close to the pivot and increase with distance.
To test this prediction, the researchers put James Van Orman, an undergraduate student, to work analysing sonar images of the Indian Ocean floor collected in 1986 and 1991. At each point where the ocean floor has buckled, Van Orman calculated how much longer the region would have been if it lay flat. He then summed these values along each of two 800-kilometre transects, one just east of the supposed pivot, the other 300 kilometres farther east.
Van Orman found 11.2 kilometres of compression for the transect nearer the pivot and 27.4 kilometres for the eastern transect (Earth and Planetary Science Letters, vol 133, p 35). This shows that the two portions of the Indo-Australian plate are moving independently, says Weissel.
One problem, however, is that the sonar images could not detect any vertical buckling of less than 10 metres. "It's a fairly blurry look at the crust," says Weissel. "We think we haven't missed too much, but not everybody agrees."
Weissel believes that the Indo-Australian plate began to break up about 8 million years ago. By then, India's collision with Asia had pushed up the Himalayas and the Tibetan Plateau, and the mass of these highlands had become so great that tectonic forces could not lift them any further. "Something had to give, and those stresses were released farther back in the IndoAustralian plate," says Weissel.
Ignorant leadership.
Weissel believes that the Indo-Australian plate began to break up about 8 million years ago.Thanks CarrotAndStick.
7.5 Magnitude Earthquake Hits Sumatra, Indonesia: Tsunami Warning Issued
USGS | 20 Feb 2008 | US GS
Posted on 02/20/2008 3:39:26 AM EST by Alter Kaker
http://www.freerepublic.com/focus/f-news/1973202/posts
Indonesia issues tsunami warning after powerful quake
AP | Feb 25, 2008 10:55
Posted on 02/25/2008 4:31:21 AM EST by maquiladora
http://www.freerepublic.com/focus/f-news/1975803/posts
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Thanks Blam. This kind of research is the wave of the fu-, uh, forget it. |
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Do you want to hear a real earthquake story? Here you go.....
Source: NOAA.gov
Published: ?
Posted on 03/01/2001 20:08:41 PST by Trailer Trash
http://www.freerepublic.com/forum/a3a9f1cc964a4.htm
Arctic Ocean Ice Crashes on Alaska Shores (20’high x100’wide ice tsunami)
ap | Jan 27, 2006 | ap
Posted on 01/27/2006 9:22:19 PM EST by RedBloodedAmerican
http://www.freerepublic.com/focus/f-news/1566611/posts
Research Team Discovers Village (Ancient Bering Sea Island)
Gazette Times | 1-30-2007 | OSU News Service
Posted on 01/30/2007 7:04:22 PM EST by blam
http://freerepublic.com/focus/f-news/1776395/posts
Both Coasts of Americas Seen Vulnerable to Tsunamis
(We’re ALL Gonna DIE !!! Alert)
Reuters | Tue, Feb 08, 2005 | Maggie Fox
Posted on 02/08/2005 11:26:56 PM EST by presidio9
http://www.freerepublic.com/focus/f-news/1339144/posts
Tsunami that devastated the ancient world could return
AFP on Yahoo | 3/9/08 | AFP
Posted on 03/09/2008 10:17:08 PM EDT by NormsRevenge
http://www.freerepublic.com/focus/f-news/1983072/posts
SHIP-SINKING MONSTER WAVES REVEALED BY ESA SATELLITES
European Space Agency | 21 July 2004
Posted on 07/25/2004 3:36:29 AM EDT by Yosemitest
http://www.freerepublic.com/focus/f-news/1178061/posts
Was Bristol Hit By A Tsunami? (1607)
Science Daily | 4-30-2007 | University Of Chicago
Posted on 04/30/2007 7:14:31 PM EDT by blam
http://www.freerepublic.com/focus/f-news/1826205/posts
Indonesia - Tsunami ground zero image.
Wowzo. I probably should have posted links to the topics about those Madagascar formations.
Please do...I’ve lost the images of the ‘chevrons’.
Wow, amazing!
Do you have a link with more information on that photograph?
Sunkenciv, what are the Madagascar formations you’ve mentioned earlier?
sorry, no...I saved the image not the article.
Oh, never mind. I found that the image you posted is a screenshot from a Discovery channel documentary:
http://www.discoverychannel.co.uk/earth/ground_zero/performer/index.shtml
http://www.discoverychannel.co.uk/earth/ground_zero/introduction/index.shtml
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