Strong quake shakes Alaska’s Aleutian Islands: USGS:
WASHINGTON – A strong, magnitude 6.3 earthquake shook Alaska’s remote Aleutian Islands early Friday, the U.S. Geological Survey reported.
The quake struck just southeast of Adak Island at 2:16 am local time (11:16 GMT) at a depth of 31 miles (50 kilometers), the USGS said in a bulletin.
The Pacific Tsunami Warning Center reported that there was no threat of a destructive tsunami.
The Aleutians are a long string of islands that are part of the U.S. state of Alasaka and separate the Bering Sea from the North Pacific Ocean.
Canterbury quake: Facts and figures:
The mid-Canterbury quake struck at 4.36am.
It was initially measured at magnitude 7.4 and later downgraded to 7.1.
The epicentre was 40 km west of Christchurch city, close to Darfield.
The depth of the quake was at 10 km.
Most structural damage above ground was in Christchurch CBD and to the north of the city along the coast.
Many areas were left without power, water, sewerage services and gas.
Minor damage was reported from Omihi in North Canterbury through to Timaru in South Canterbury.
In the first 15 hours, there were 28 aftershocks over magnitude 4, ranging up to 5.4.
Christchurch last had 7.1 quakes in March 1929 (Arthur’s Pass), and September 1888 (North Canterbury).
This looks to be a very up to date city with good, up to date, codes. And even then, the damage is massive. I can’t imagine what would have happened in less modern city’s or even NY.
Picking up the pieces in shaken isle:
September 5, 2010
The most damaging earthquake to hit New Zealand in almost eight decades flattened buildings, opened giant chasms in roads, buckled roads and railway lines and left hundreds homeless in the South Island.
The terrifying quake, which measured 7.1 on the Richter scale, caused damages that “could run into billions of dollars”, said New Zealand Prime Minister John Key, who flew over Christchurch to survey the damage.
Victims of the earthquake, which struck the Canterbury region at 4.35am yesterday local time (2.35am Sydney time), are today coping without essential amenities: water has been cut off, petrol stations are closed and farms are without power.
Inspector Mike Coleman said police have cordoned off central Christchurch because it’s dangerous, but also because looters have already been active.
“There’s considerable damage there, and we’ve already had reports of looting,” he said.
“Shop windows are broken and obviously it’s easy pickings for displays and things.”
Miraculously, because of the early hour, there were no deaths but two people were seriously hurt: one man was hit by a falling chimney and a second was cut by flying glass.
Forecast high winds and heavy rain are expected to hamper clean-up operations today.
The quake, whose epicentre was about 40 kilometres west of Christchurch, was the country’s most damaging since 1931. Seismic experts last night said the extent of the damage was lower than expected given its size but there were graphic images of damage.
Heloise Reece, editor of the Hills News newspaper in Castle Hill, Sydney, was in bed with her 16-month-old son Harrison in Spencerville, on the east coast of Canterbury, when the earthquake hit.
Ms Reece, who was visiting for a family member’s 60th birthday party, said: “Harrison had woken up so I had him in bed with me and had just got him settled. All of a sudden, the bed shook about one metre across the room. It was probably the scariest moment of my life.”
She said her cousin and two girls who were also staying in the house came running to them and enormous cracks through the walls appeared immediately.
“We got under the doorway. It started as a bit of a shake and got harder and harder. It all lasted for about one-and-a-half minutes. We are right near the beach and we thought there was going to be a tsunami.
“We grabbed what we could in the dark: I was in my pyjamas so I grabbed my baby and some nappies and [drove] to the house where my parents were staying.”
Prime Minister Julia Gillard said: “I have been in contact with the office of New Zealand Prime Minister John Key to extend Australia’s sympathies and have offered any Australian assistance that might be needed.”
Opposition Leader Tony Abbott said: “Our thoughts are with the people of Christchurch as they come to terms with this disaster . . . Australia would stand ready to assist if required.”
Hundreds of travellers were stranded at Sydney Airport or forced on to alternative flights after four flights to Christchurch and Queenstown were cancelled yesterday.
Some travellers were put up at hotels near the airport overnight and were expected to fly to New Zealand today.
The Department of Foreign Affairs and Trade said Australians concerned about the welfare of family and friends in New Zealand should try to contact them directly. If they could not be reached, the department’s 24-hour consular emergency centre is available on 1300 555 135 (option 6).
Geoscience Australia senior seismologist Clive Collins said a post-disaster reconnaissance team was expected to leave for New Zealand soon. He compared the earthquake with that which struck Newcastle in 1989, killing 13 people, and said the devastation would have been much worse if the tectonic plates had been thrust into each other rather than slipping horizontally past each other.
“There are lessons to be learnt about how buildings behave in an earthquake, which will benefit us as well as New Zealand,” he said.
Mark Edwards, of Geoscience’s Risk and Impact Analysis Group, said there would have been more casualties if the quake had not occurred with almost no one up and about on the streets.
Bigger earthquake predicted to come:
By SUSAN PEPPERELL – Sunday Star Times
Scientists fear a bigger earthquake could be in the wings.
They admit they were caught out by the location of yesterday’s earthquake, expecting a serious jolt to occur further west.
Now they are warning the 4:36am 7.1 on the Richter Scale quake – centred 40km west of Christchurch and with its epicentre 10km south-east of Darfiel – was not the big one they had been predicting.
GNS scientist John Ristau said while quakes of such magnitude were expected every so often in the South Island, the area of yesterday’s quake was not known to be particularly seismically active.
The earthquake triggered a release of pressure caused by the collision and locking together of the Pacific and Australian plates, which are constantly moving in different directions.
”Stress builds up and then everything snaps,” Ristau said.
Canterbury University geologist Mark Quigley said there was a network of blind faults under the Canterbury Plains that could not be detected on the earth’s surface, but the location of yesterday’s quake was unexpected and didn’t match any known faults.
His students had located the scarp or stretch of displaced ground at the centre of the earthquake at Kirwee, 9km from Darfield. It was a long crack in the ground and about half a metre deep.
Other scientists said it was astonishing that for such a large, shallow quake so close to a main city, the damage in Christchurch was relatively light.
The quake was 10km deep, not surprisingly shallow, according to Quigley, who said aftershocks could continue for weeks but would gradually diminish in size and frequency.
But South Islanders can expect to be hit by a much bigger quake which would cause far more extensive damage, depending on where it was centred.
In an article in the Sunday Star-Times in February, Otago University geology professor Richard Norris said a huge earthquake, measuring about 8 on the Richter Scale, would hit the South Island within the next 50 years. He predicted it would be big enough to crush homes and cut electricity, water and sewerage.
Yesterday Norris said that would still happen, most probably along the Alpine Fault, a 400km stretch running from Milford Sound to the Lewis Pass.
”Yesterday’s had nothing to do with the Alpine Fault and was not the big one,” he said.
A magnitude 7.5 or 8 earthquake is expected to occur on the Alpine Fault about once every 300 years and it has been about 300 years since the last one.
The good news, according to Norris, was that the faults around Canterbury had a low rate of recurrence, producing earthquakes about once every 1000 years.
”But because theres’a lot of them it’s a lot more random and a lot more difficult to say which one will break.”
Norris said the Alpine Fault only released 70 percent of the seismic strain in the South Island. ”We’ve still got 30 percent displacement along myriad other faults. But why this one broke who knows.”
However, scientists are planning to set up about 40 portable earthquake instruments to record aftershocks in the next few weeks to learn more about the mechanics of the main shock and to determine if stress was transferred to other faults in the region