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JAKARTA - Rescue teams and troops headed on Thursday for Indonesia's Sumatra coast as aftershocks continued to pound a region where a powerful earthquake the night before killed six people and perhaps many more.
Japan's Meteorological Agency issued a tsunami warning for Indian Ocean countries after the latest aftershock, a shallow quake which the US Geological Survey (USGS) said measured 7.5.
"The city is in complete chaos. Everyone is heading to higher ground, I saw one house collapsed to the ground. I'm trying to save my family," said a Reuters witness in Padang, the capital of West Sumatra, soon after the first quake.
Indonesia's Health Ministry crisis centre in Jakarta said the latest casualty figures showed that six people had been killed and 40 injured after the initial 8.4 magnitude quake, which was also felt in neighbouring Singapore, Thailand and Malaysia.
But David Oppenheimer, a scientist with the USGS in California, said the death toll could well rise as authorities take stock of the impact in the light of day.
A quake with an eight magnitude typically leads to partial collapse of buildings, houses moved off their foundations, and other damage, he said.
"That's the kind of stuff that causes death, especially in the Third World. I think there is an information blackout at this point."
Japan's Meteorological Agency warned of a tsunami risk for Australia's Coco Islands and, further afield, the coasts of India's Andaman and Nicobar Islands and Sri Lanka within 3 hours.
A huge earthquake measuring more than 9 struck the same area of Indonesia on December 26, 2004, causing a massive tsunami and over 230,000 deaths in countries across the region.
Indonesia suffers frequent quakes, as it lies on an active seismic belt on part of the so-called Pacific "Ring of Fire".
Many people chose to sleep out in the open on Wednesday night rather than return indoors, a Red Cross official in Bengkulu, close to the epicentre of the quake, told Reuters.
"The emergency rescue system has mobilised and the president has ordered the military to help the rescue effort," President Susilo Bambang Yudhoyono's spokesman said.
Rustam Pakaya, head of the health ministry crisis centre, said the government would send one tonne of medicine, three tonnes of food supplements, and one tonne of noodles on Thursday for displaced people in the area.
SUMATRA QUAKE TOPS MAGNITUDE 8.4 - WHAT DOES THIS MEAN?
A magnitude 8.4 earthquake that hit South Sumatra on Wednesday is the largest of four of magnitude 8 or above that have hit worldwide in 2007, and the most powerful to hit Indonesia since the magnitude 8.6 "Nias" earthquake in March 2005, according to the US Geological Survey (USGS).
WHERE HAVE THIS YEAR'S MAGNITUDE 8+ QUAKES BEEN?
* Jan. 13: East of the Kuril Islands, which stretch between Japan and Russia, magnitude 8.1
* April 1: Solomon Islands, east of Melanesia, magnitude 8.1
* Aug. 15: Near the coast of central Peru, magnitude 8.0
* Sept. 12: South Sumatra, Indonesia, magnitude 8.4
All four locations are on the Pacific "Ring of Fire" a horse-shoe shaped 40,000 kilometre-long arc of volcanoes and fault lines that generates about 90 per cent of the world's earthquakes.
WHAT TRIGGERED THE SOUTH SUMATRAN QUAKE?
The quake hit 130km southwest of Bengkulu, on Sumatra island, as a result of thrust faulting at the boundary of two tectonic plates &
45; the Australian plate and the Sunda plate. At this location, the Australian plate moves northeast from the Sunda plate at a velocity of about 69 mm/year, according to the USGS.
HOW MANY MAGNITUDE 8 EARTHQUAKES ARE THERE PER YEAR?
On average, about one. And there are about 15 to 20 magnitude 7 earthquakes per year, the US Geological Survey says.
HOW MANY PEOPLE HAVE BEEN KILLED BY MAGNITUDE 8+ QUAKES?
The 17 magnitude 8+ quakes since 1990 have killed about 285,491 people.
WHICH WAS THE MOST DEADLY?
The biggest quake - Dec. 2004's 9.1 magnitude quake off the west coast of north Sumatra, Indonesia - was by far the most deadly: accounting for 283,106 deaths from the total.
Indonesia's March 2005 northern Sumatra quake was the second-most deadly in this period - killing about 1,313 people.
Sources: US Geological Survey
- REUTERS
