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Predicting quakes 'guesswork'
16/12/2005 13:47 - (SA)
Hyderabad - Earthquake prediction is still much like forecasting life span or investing in the stock market - data is available, but it's largely guesswork, seismologists and experts say.
In September 2004, an earthquake with a magnitude of 6.0 on Richter scale shook the San Andreas fault in California, surprising seismologists despite their close monitoring of activity.
"The fault was wired like a patient in intensive care," Walter Mooney, a geophysicist at the US Geological Survey, said on the sidelines of an UN meeting on tsunami warning systems in Hyderabad.
"Everything was monitored. The earthquake occurred without any signal. We even tried going back and reprocessing all the data. We found nothing. Boom. It just happened."
Mooney said every earthquake happens on a fault with unique characteristics.
"It is like various organs of the human body. I would compare predicting an earthquake to estimating an individual's life span. You could be struck down by a bus on the highway or die of heart attack or natural causes. You may live to be 50, 90 or 104 years of age," Mooney said.
Japan, where 20% of the world's earthquakes take place, has launched an ambitious project to dig deeper under the Earth's surface than ever before to detect earthquakes including Tokyo's dreaded future "Big One".
'There is no forecast'
The project seeks clues from tectonic plates that shake the planet's foundations.
Mooney said projects like this "may have some success" but results could vary as "characteristics such as how often it occurs and how deep it is triggered off varies from nation to nation".
For instance, several nations could have easily been warned an hour before last year's deadly tsunamis - triggered by an earthquake off the Indonesian coast - made landfall, experts say.
EN Bernard, director of US-based Pacific Marine Environmental Laboratory, said unlike the less-than-exact science of studying earthquakes, new emerging technologies could help control tsunami-related damage.
"A buoy embedded in the seabed, a technology which was under development for over a decade, can now give us reliable data in real time.
"There is a chance of warning others when all the nations set up their centres and link-up data," Bernard said.
"But in the scenario of an earthquake there is no forecast. You got to just watch it happen," he said.
However, the seismologists said the October 8 earthquake that hit Kashmir, killing more than 74 000 people in Pakistan and India, could not be predicted.
Earthquakes only "talk to each other" and when a temblor strikes it transfers some of the "stress" to the adjacent faults and raises the chances of a quake in that fault, Mooney said.
"Earthquake prediction is something for the future and it is not something that we can do today. What we can do is to calculate the probability of a quake in a fault zone. These calculations are favoured by insurance companies and planners," Mooney said.
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