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Dawah_
September 6, 2007, 10:22 AM
BBC: http://news.bbc.co.uk/2/hi/science/nature/6980422.stm


The northern end of the Bay of Bengal could be at risk of giant earthquakes and tsunamis in the coming decades, an Australian study concludes.

Such events have been thought unlikely there, in contrast to the area further south where the 2004 tsunami began.

But the new work, published in the journal Nature, has found "compelling evidence" for tsunami-triggering earthquake activity to the north.

Geologists have said this warning should be taken "very seriously".

The area is densely populated, and more than a million of people could potentially be at risk.

Releasing pressure

The magnitude 9.2 earthquake that struck off the Sumatran coast on 26 December 2004 and the tsunami it generated killed thousands of people and left millions homeless.

It stemmed from a geological area known as a "subduction zone".

Map showing fault lines

Here, part of the Indian/Australian tectonic plate was slowly burrowing beneath a component of the Eurasian plate.

This created stresses in the upper plate, which were violently released in the form of a "locked-thrust fault" earthquake as it sprung back up, which in turn triggered the tsunami.

Since then, another stress point has been identified to the east of the 2004 epicentre, but the subduction zone further north along the Myanmar coast was thought to be of little concern.

But Phil Cummins, lead author on the Nature paper and a geologist at Geoscience Australia, believes this is not the case.

He said: "I reviewed the geological literature and found the evidence for a lack of tectonic activity along the Myanmar coast was not compelling."

Historical evidence

Recent GPS data, he said, suggested that the plate boundary was at sea in this area, hidden below thick layers of sediment.

Dr Cummins said: "Although these GPS measurements are sparse, these show that there is active deformation near the Myanmar coast that is consistent with a locked thrust-fault offshore, which is the type needed to generate tsunami."

Computer simulation of tsunami
A computer simulation shows the havoc a tsunami could wreak
The geologist also looked at accounts of an earthquake that occurred in the area in 1762, which wrenched up parts of the coast by between 3-7m.

His computer simulation of the quake, which he believes would have measured magnitude 8.8, showed that a similar event today would have significant impacts.

"Such an earthquake would generate a large tsunami that could have a pronounced impact on the Chittagong coast and the Ganges delta," he said.

"The latter region is home to 60 million people living within just 10m of sea level."

Meanwhile the quake itself could cause major damage to the region's largest cities, Calcutta and Dhaka. Overall, the simulation suggested that more than a million lives could be at risk.

'Alarming message'

Professor Richard Arculus, from Australian National University (ANU) in Canberra, said: "Phil Cummins' warnings should be taken very seriously.

"A few months before the devastating earthquake and accompanying tsunami triggered off northern Sumatra in late 2004, Phil Cummins published a perceptive analysis of historic events of this nature in the region.


Disaster planners might need more information than is given in the paper
Kevin McCue

"He warned that countries bordering the Indian Ocean, including the northern coast of Australia, were at significant risk, and the lack of a tsunami warning system analogous to that deployed in the Pacific was a serious issue.

"So his credibility with respect to tsunamigenic earthquakes is established. "

Kevin McCue, a professor at Central Queensland University (CQU), added: "The message is alarming, perhaps justifiably, given the unexpected disaster that followed the great Sumatran earthquake and tsunami of 2004, a disaster of local, regional and global reach."

But he added: "Disaster planners might need more information than is given in the paper, particularly some quantitative measure of uncertainties in the science."

Phil Cummins agrees that more work is needed to confirm his analysis, and suggests this should take place before any drastic mitigation measures are considered.

Tigers_eye
September 6, 2007, 11:15 AM
The simulations are good to measure the point of impact. But effects beyond is too far fetched. Like they are saying might damage Dhaka. Which is very unlikely. Govt. should pay close attention to these type of natural disasters where one may have little time to evacuate or run for higher grounds.

I wonder does anyone have any idea at BD on how to even slow down the Tsunami in the event of it occurence. A warning system needs to be placed in the Bay of Bengal where people may have 30 minutes at least.

Bengaliprince176
September 6, 2007, 11:20 AM
this sounds sort of similar to the cyclone that hit Bengal beofre 71 independence? is it similar- the effects of a cyclone and a tsnumai?? im sure the authorities will take notice in Bangladesh and Indian states like West Bengal and Orissa

Tigers_eye
September 6, 2007, 11:28 AM
this sounds sort of similar to the cyclone that hit Bengal beofre 71 independence? is it similar- the effects of a cyclone and a tsnumai?? im sure the authorities will take notice in Bangladesh and Indian states like West Bengal and Orissa
No Cyclones are regular occurence for BD. The damage is not that much if compared. Tsunami is water surge caused by earth quakes and fault deplacements in the deep ocean. usually the water surge is about 7/8 meters and is a silent assasin. Comes without a notice and hard to detect because the waves only generate very close to the shore. This can happen in broad day light when everything seems to be normal at the calm sea. the height is not the as much as a concern. The Volumn of water that gets in-land is the hardest to survive from. Would clean up everything the shore has to offer. Devastating to say the least.

Animals like Elephants, Monkeys can detect these better. They usually run in-land way before the Tsunami hits the shores. We have noticed this in SL in 2004. may be that is a good natural warning system BD can have.

Bengaliprince176
September 6, 2007, 11:36 AM
ok cool thanks tigers eye bro!! btw cud u explain to me what a cyclone is exactly then? thanks

Tigers_eye
September 6, 2007, 11:41 AM
ok cool thanks tigers eye bro!! btw cud u explain to me what a cyclone is exactly then? thanks
Cyclone is Harricane. (katrina) involves wind and air pressure. Also usually rain is associated with it.

al Furqaan
September 6, 2007, 11:42 AM
ok cool thanks tigers eye bro!! btw cud u explain to me what a cyclone is exactly then? thanks

i think a cyclone is just an eastern word for what we americans call hurricanes.

Bengaliprince176
September 6, 2007, 11:47 AM
ok thanks al furquaan and tigers eye. i thought hurricanes and cyclones were similar in their effects.

Hatebreed
September 6, 2007, 03:42 PM
Animals like Elephants, Monkeys can detect these better. They usually run in-land way before the Tsunami hits the shores. We have noticed this in SL in 2004. may be that is a good natural warning system BD can have.

If this is true, may be we should have lots of elephants and monkeys with tracking devices in the vicinity of the sea. I'm not kidding.

Rabz
September 6, 2007, 07:50 PM
If this is true, may be we should have lots of elephants and monkeys with tracking devices in the vicinity of the sea. I'm not kidding.

ha ha...
but by the time they would start running, it would be too late for the millions of people to relocate...

cricket_pagol
September 7, 2007, 02:05 AM
I really hope that the government takes this seriously... With the current government I have some hope!

Tigers_eye
September 7, 2007, 09:57 AM
ha ha...
but by the time they would start running, it would be too late for the millions of people to relocate...
If there is a will there is a way. 30-40 feet higher than sea - level is may be 2/3 miles in-land. which takes max 30-45 mins if walking normally. If some steps are taken we can easily save lives. May not be able to save the infrastructures and those who live in the Islands. But warning can at least get some people in the shelters.