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Earthquakes, tidal waves, rock Asia
The chain reaction that sent enormous, deadly tidal waves crashing into the coasts of Asia and Africa on Sunday started more than six miles beneath the ocean floor off the tip of the Indonesian island of Sumatra.
Geologic plates pressing against each other slipped violently, creating a bulge on the sea bottom that could be as high as 10 yards and hundreds of miles long, one scientist said.
“It’s just like moving an enormous paddle at the bottom of the sea,” said David Booth, a seismologist at the British Geological Survey. “A big column of water has moved, we’re talking about billions of tons. This is an enormous disturbance.”
Moving at about 500 mph, the waves took more than two hours to reach Sri Lanka, where the human toll has been horrific, and longer to spread to India and the east coast of Africa.
And because such tidal waves rarely occur in the Indian Ocean, there is no system in place to warn coastal communities they are about to be hit, such as exists in the Pacific, Booth said.
“With 20-20 vision of hindsight, that’ll be reconsidered,” he said.
The underwater quake, which the US Geological Survey put at magnitude 9.0, was the biggest since 1964, when a 9.2-magnitude temblor struck Alaska, also touching off tsunami waves. There were at least a half-dozen powerful aftershocks, one of magnitude 7.3.
The earthquake occurred at a spot where the Indian Ocean plate is gradually being forced underneath Sumatra, which is part of the Eurasian plate, at about the speed at which a human fingernail grows.
Indonesia is well-known as a major quake center, sitting along a series of fault lines dubbed the “Ring of Fire.” But scientists are unable to predict where and when quakes will strike with any precision.
The force of Dec 26 earthquake shook unusually far afield, causing buildings to sway hundreds of miles from the epicenter, from Singapore to the city of Chiang Mai in northern Thailand, and in Bangladesh.
The quake probably occurred about 6.2 miles beneath the ocean floor, causing the huge, step-like protrusion on the sea bed and the resulting tidal waves.
More than a dozen large sperm whales may have died in a beaching incident on Australia’s southern island state of Tasmania, local wildlife rangers said.
A pod of 19 sperm whales became stranded in rough weather on Tasmania’s west coast and poor conditions hampered rescue efforts, said district ranger Chris Arthur. “We know that the majority of the whales are dead and that they are in the surf zone,” Arthur said.
He said the whales ranged in size from seven to 14 metres in length and weighed up to 45 tonnes. “These are not small animals, these are quite large animals,” he added.
Authorities learned of the stranded whales on Dec 27 but severe weather had hampered efforts to fly to the area to see if any of the animals could be saved. “The weather is incredibly difficult,” he said.
In November, 117 pilot whales and dolphins died after a mass stranding on Tasmania’s east coast.
Scientists have long been puzzled about why the ocean mammals become beached in groups.
Theories range from diseases that upset internal navigation systems to herd behavior in which large numbers of whales blindly follow a leader into trouble.
Others believe they may follow stocks of food such as crayfish too close to the shore.
Dr Jonathan Drummond-Webb, a heart surgeon whose work was the focus of a four-part television series and who successfully implanted a life-saving miniature heart pump in a child, was found dead Sunday of a suicide. He was 45.
Drummond-Webb took an overdose of medication and left a note for his wife, who discovered the body, according to Arkansas Children’s Hospital. The hospital said friends believe the surgeon suffered a sudden bout of depression.
Dr Jonathan Bates, chief executive officer of Arkansas Children’s Hospital, said Drummond-Webb worked tirelessly to save his patients.
Drummond-Webb, chief of pediatric and congenital cardiac surgery at the hospital, earned a national reputation. In 2002, his work was the subject of a four-part ABC news documentary mini-series. The network had said it was attracted by Drummond-Webb’s record at the time: 830 surgeries in 18 months with a 2 per cent mortality rate.
In September, Drummond-Webb performed the first successful implant of a miniature heart pump in a 14-year-old boy with a heart defect, keeping him alive until a heart transplant was possible. He said the only reason he allowed cameras to follow him was to get the message out about organ donation— Sci-tech World Report
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