Earth ChangesS


Bizarro Earth

New Zealand: Canterbury Fault Had Not Ruptured For At Least 16,000 Years

Wellington, NZPA - The fault that ruptured and produced the magnitude 7.1 earthquake in Canterbury on Saturday appears not to have ruptured for at least 16,000 years, scientists said today.

The earthquake produced a 22km-long surface rupture and up to 4m of horizontal displacement in alluvial terraces that were deposited about 16,000 years ago at the end of the last glaciation.

When the last ice-age ended, rivers brought large amounts of gravel from the high country and distributed it throughout Canterbury, many metres thick in some places.

"Before Saturday, there was nothing in the landscape that would have suggested there was an active fault beneath the Darfield and Rolleston areas," manager of the Natural Hazards Platform at GNS Science Kelvin Berryman said.

Geologists had no information on when the fault last ruptured as it was unknown until last weekend.

"All we can say at this stage is that this newly revealed fault has not ruptured since the gravels were deposited about 16,000 years ago."

Dr Berryman said it was highly likely there were other "hidden" faults around New Zealand which might be capable of producing large earthquakes in the future.

The fault had been accumulating stress for thousands of years and failed catastrophically when the stresses exceeded a certain threshold.

Better Earth

Giant Iceberg Enters Nares Strait

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© ESA
ESA's Envisat satellite has been tracking the progression of the giant iceberg that calved from Greenland's Petermann glacier on 4 August 2010.

This animation shows that the iceberg, the largest in the northern hemisphere, is now entering Nares Strait - a stretch of water that connects the Lincoln Sea and Arctic Ocean with Baffin Bay.

The Petermann glacier in northern Greenland is one of the largest of the country's glaciers - and until August it had a 70 km tongue of floating ice extending out into the sea.

The glacier regularly advances towards the sea at about 1 km per year. Earlier this year, satellite images revealed that several cracks had appeared. Envisat radar images showed that the ice tongue was still intact on 3 August but, on 4 August, a huge chunk had detached.

Calvings from the Petermann glacier are quite common, but one of this magnitude is rare. Less significant events took place in 2001, in 2008 when a 27 sq km iceberg made its way south to Davis Strait, and in 2009.

Bizarro Earth

Guatemala mudslides kill at least 38; 2 buses hit

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© Associated PressPeople stand in front of a bus partially covered by a landslide, due to heavy rains, on the Pan-American highway at Tecpan, Guatemala, Saturday Sept. 4, 2010.
Nahuala - Torrential rains from a tropical depression caused landslides that have killed at least 38 people in Guatemala - some of them rescuers trying to save people already buried under a wall of mud.

In the village of Nahuala, about 200 rescue workers searched through mud and rocks for bodies Sunday after two slides in the same spot killed at least 20 along a highway leading northwest of the capital toward Mexico. Another slide closer to Guatemala City killed at least 12.

Suagustino Pascual Tuy, a Nahuala police officer, said he and several others rushed to the highway with picks and shovels after hearing radio reports of the fallen earth, which had buried two pickup trucks and a bus at kilometer 171 of the Inter-American highway.

Pascual Tuy said the crowds were able to rescue several people alive including his nephew, who was driving one of the pickups.

"He is in critical condition, but thank God we were able to get him out alive," he said.

Pascual Tuy said people were still digging through the rubble when the mountain above them began crackling. He shouted a warning, but moments later the second slide buried a number of rescuers. Pascual Tuy ran for his life and the slide only caught his legs.

Cloud Lightning

Heavy rains trigger flooding in Australia

Victoria flooding
© UnknownThunderstorms and heavy rains have triggered flooding in most areas of Victoria
Thunderstorms and heavy downpours have triggered massive flooding in Australia's Victoria State, threatening the safety of hundreds of homes.

"Many communities and individuals across the state have been affected by flooding from heavy rain over this weekend," said Victoria Premier John Brumby on Sunday.

The State Emergency Services say the army has been called in to help assess the damage inflicted by the floods.

This is while residents are working together to sandbag businesses and homes to protect them against rising floodwaters.

Arrow Up

New Zealand earthquake: ground moved by 11ft

Christchurch earthquake
© EPAA taxi is covered in rubble on Manchester St, Christchurch
A massive earthquake caused the ground beneath the New Zealand city of Christchurch to shift up to 11 feet.

The magnitude 7.1 quake on Friday night in New Zealand was larger than the one that killed 200,000 people in Haiti this year and appeared to have opened a new fault line.

Mark Quigley, a geology professor leading a team investigating the cause of the quake, said: "One side of the earth has lurched to the right."

Much of the centre of Christchurch remained sealed off and under curfew for a second night on Sunday.

More than 500 buildings have been badly damaged. Two men were seriously hurt by falling masonry but there have been no reports of deaths.

Bizarro Earth

20 Killed in Guatemala Floods, President Alvaro Colom Declares Emergency

At least 20 people were killed in Guatemala in landslides triggered by weeks of driving rains, according to figures released by national emergency and rescue services.

President Alvaro Colom has declared a national emergency in the wake of the disaster.

"Top priority at present is dealing with this emergency. There are no funds left to deal with earlier disasters like the one caused by tropical storm Agatha," in late May, Colom told reporters after a surveying tour of the country Saturday

He said damage estimates across Guatemala after weeks of rain stood at 350-500 million dollars, or 40 percent of the damage wrought by Agatha, which killed 183 people in Central America, including 165 in Guatemala earlier this year, and left thousands homeless.

Bizarro Earth

Tonga: Earthquake Magnitude 6.1

Tonga Quake_040910
© USGSEarthquake Location
Date-Time:
Saturday, September 04, 2010 at 08:52:01 UTC

Saturday, September 04, 2010 at 09:52:01 PM at epicenter

Time of Earthquake in other Time Zones

Location:
17.270°S, 174.000°W

Depth:
37.1 km (23.1 miles)

Region:
TONGA

Distances:
150 km (90 miles) S of Hihifo, Tonga

155 km (95 miles) N of Neiafu, Tonga

445 km (275 miles) NNE of NUKU'ALOFA, Tonga

2430 km (1510 miles) NNE of Auckland, New Zealand

Hourglass

Yellowstone Hot Spot Shreds Ancient Pacific Ocean

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© AGU
If you thought the geysers and overblown threat of a supervolcanic eruption in Yellowstone National Park were dramatic, you ain't seen nothing: deep beneath Earth's surface, the hot spot that feeds the park has torn an entire tectonic plate in half.

The revelation comes from a new study in the journal Geophysical Research Letters that peered into the mantle beneath the Pacific Northwest to see what happens when ancient ocean crust from the Pacific Ocean runs headlong into a churning plume of ultra-hot mantle material.

Geologically speaking, the Pacific Northwest is a peculiar place. Hot spots usually sit way out on their own in the middle of a tectonic plate (think Hawaii or the Galapagos). Not Yellowstone -- it pokes its way to the surface just a few hundred miles from the edge of the North America plate, where a giant trench sends the Juan de Fuca tectonic plate sliding underneath Washington, Oregon, and northern California.

Info

Virtual Reality Parhelic Circle

Parhelic Circle
© Spaceweather.comParhelic Circle
A parhelic circle is an unforgettable sight. Thin and pale, it circles the zenith in a majestic arc, always keeping the same distance above the horizon. "I've been looking for a parhelic circle for more than 13 years," says photographer Laurent Laveder of Pluguffan, France. "Yesterday I finally saw one." He rushed for his camera and quickly snapped enough pictures to assemble a complete 360o zenith-to-horizon composite view of the phenomenon. Click here to experience the VR parhelic circle.

Parhelic circles are caused by sunlight reflecting from the vertical faces of ice crystals--millions of them floating in thin cirrus clouds spread almost evenly across the wide blue sky. As Les Cowley notes in his authoritative web page on the subject, "the parhelic circle appears simple yet more ray paths contribute to it than in any other halo. Some are very intricate."

A striking aspect of the parhelic circle is its dual personality. At the same time it appears both circular and straight. "These two pictures (1, 2) illustrate the effect," says Laveder. More images may be found here.

Bizarro Earth

New Zealand: Earthquake Magnitude 7.0 - Christchurch

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© Screen shot, Google MapsThe quake at a depth of 34 kilometres (21.1 miles) struck six kilometres (four miles) from Christchurch at 04:05 am (1635 GMT Friday), the USGS said.
A 7.0 magnitude earthquake rocked New Zealand's second largest city Christchurch early Saturday, causing widespread damage including the collapse of some buildings and power outages, witnesses and the U.S. geological survey said. The Civil Defence ministry said the national crisis management centre had been activated. "We've had a wide range of reports of some serious damage," a civil defence spokesman said.

Although many people with minor injuries sought treatment, hospitals said there were no reports of any serious injuries although doctors were on standby because of the intensity of the quake and the damage to buildings.

The quake struck at a depth of 16.1 kilometres some 30 kilometres northwest of Christchurch at 4:35 a.m. (11:35 a.m. ET Friday), the USGS said.

Roads in the seaside suburbs were packed with cars as residents moved inland but there were no tsunami alerts issued. A swarm of aftershocks were ongoing and police said damage was widespread throughout Christchurch, with electricity supplies cut to about half of the city of about 340,000.

Sewer lines were damaged and residents were being urged to conserve water supplies. Local resident Colleen Simpson told the Stuff website that many people had run out onto the streets in fear, while the mobile phone network was failing.

"Oh my God. There is a row of shops completely demolished right in front of me," Simpson said. Kevin O'Hanlon, from Mairehau in Christchurch, said: "Just unbelievable. I was awake to go to work and then just heard this massive noise and, boom, it was like the house got hit. It just started shaking. I've never felt anything like it."