Tampilkan postingan dengan label Icelandic volcanoes. Tampilkan semua postingan
Tampilkan postingan dengan label Icelandic volcanoes. Tampilkan semua postingan

Minggu, 22 Mei 2011

Icelandic volcano flings up ash, shuts airport

Icelandic volcano flings up ash, shuts airport


REYKJAVIK, Iceland – Iceland closed its main international airport and canceled all domestic flights Sunday as a powerful volcanic eruption sent a plume of ash, smoke and steam 12 miles (20 kilometers) into the air.

The eruption of the Grimsvotn volcano was far larger than one a year ago at another Icelandic volcano that upended travel plans for 10 million people around the world, but scientists said it was unlikely to have the same widespread effect.

University of Iceland geophysicist Magnus Tumi Gudmundsson said this eruption, which began Saturday, was Grimsvotn's largest eruption for 100 years.

"(It was) much bigger and more intensive than Eyjafjallajokull," the volcano whose April 2010 eruption shut down airspace across Europe for five days, he said.

"There is a very large area in southeast Iceland where there is almost total darkness and heavy fall of ash," he said. "But it is not spreading nearly as much. The winds are not as strong as they were in Eyjafjallajokull."

He said this ash is coarser than last year's eruption, falling to the ground more quickly instead of floating vast distances.

The ash plunged areas near the volcano in southeast Iceland into darkness Sunday and covered buildings, cars and fields in a thick layer of gray soot. Civil protection workers urged residents to wear masks and stay indoors.

Iceland's air traffic control operator ISAVIA said the Keflavik airport, the country's main hub, closed down at 0830 GMT (4:30 a.m. EDT) for the day.

Spokeswoman Hjordis Gudmundsdottir said the ash plume was covering Iceland, but "the good news is that it is not heading to Europe," blowing northwest toward Greenland instead.

President Barack Obama was flying Sunday night to Ireland, but there was no immediate word on whether the volcano would affect Air Force One's flight path.

Trans-Atlantic flights were being diverted away from Iceland, but there was no indication the eruption would cause the widespread travel disruption triggered last year by ash from Eyjafjallajokull.

In April 2010, officials closed the continent's air space for five days, fearing the ash could harm jet engines. Millions of travelers were stranded.

The Grimsvotn volcano, which lies under the uninhabited Vatnajokull glacier about 120 miles (200 kilometers) east of the capital, Reykjavik, began erupting Saturday for the first time since 2004.

Gudmundsson said the new eruption was 10 times as powerful as the one in 2004, which lasted for several days and briefly disrupted international flights. Grimsvotn also exploded in 1998, 1996 and 1993, eruptions that lasted between a day and several weeks.

Sparsely populated Iceland is one of the world's most volcanically active countries and eruptions are frequent. Grimsvotn and Iceland's other major volcanoes lie on the Atlantic Rift, the meeting of the Euro and American continental plates.

Eruptions often cause local flooding from melting glacier ice, but rarely cause deaths.

Gudmundsson said it was hard to predict how long the eruption would last, but it might already be slowing.

"There are some signs the eruption plume is getting lower now," he said. "We may be seeing the first sign that it is starting to decline. In two or three days the worst should be over."

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Jill Lawless reported from London.

http://news.yahoo.com/s/ap/20110522/ap_on_re_eu/eu_iceland_volcano

Sabtu, 17 April 2010

Ice cap thaw may awaken Icelandic volcanoes

Ice cap thaw may awaken Icelandic volcanoes


A view of the farm ThorgeirsstadirReuters – A view of the farm Thorgeirsstadir, as smoke billows from a volcano in Eyjafjallajokull, April 16, 2010. …

OSLO (Reuters) – A thaw of Iceland's ice caps in coming decades caused by climate change may trigger more volcanic eruptions by removing a vast weight and freeing magma from deep below ground, scientists said on Friday.

They said there was no sign that the current eruption from below the Eyjafjallajokull glacier that has paralysed flights over northern Europewas linked to global warming. The glacier is too small and light to affect local geology.

"Our work suggests that eventually there will be either somewhat larger eruptions or more frequent eruptions in Iceland in coming decades," said Freysteinn Sigmundsson, a vulcanologist at the University of Iceland.

"Global warming melts ice and this can influence magmatic systems," he told Reuters. The end of the Ice Age 10,000 years ago coincided with a surge in volcanic activity in Iceland, apparently because huge ice caps thinned and the land rose.

"We believe the reduction of ice has not been important in triggering this latest eruption," he said of Eyjafjallajokull. "The eruption is happening under a relatively small ice cap."

Carolina Pagli, a geophysicist at the University of Leeds in England, said there were risks that climate change could also trigger volcanic eruptions or earthquakes in places such as Mount Erebus in Antarctica, the Aleutian islands of Alaska or Patagonia in South America

.http://news.yahoo.com/video/world-15749633/19165141

MAGMA

"The effects would be biggest with ice-capped volcanoes," she said. "If you remove a load that is big enough you will also have an effect at depths on magma production."

She and Sigmundsson wrote a 2008 paper in the scientific journal Geophysical Research Letters about possible links between global warming and Icelandic volcanoes.

That report said that about 10 percent of Iceland's biggest ice cap, Vatnajokull, has melted since 1890 and the land nearby was rising about 25 millimetres (0.98 inch) a year, bringing shifts in geological stresses.

They estimated that the thaw had led to the formation of 1.4 cubic km (0.3 cubic mile) of magma deep below ground over the past century.

At high pressures such as under an ice cap, they reckon that rocks cannot expand to turn into liquid magma even if they are hot enough. "As the ice melts the rock can melt because the pressure decreases," she said.

Sigmundsson said that monitoring of the Vatnajokull volcano since 2008 suggested that the 2008 estimate for magma generation was "probably a minimum estimate. It can be somewhat larger."

He said that melting ice seemed the main way in which climate change, blamed mainly on use of fossil fuels, could have knock-on effects on geology. The U.N. climate panel says that global warming will cause more floods, droughts and rising seas.

For Reuters latest environment blogs, click on: http://blogs.reuters.com/environment/

http://news.yahoo.com/s/nm/20100416/wl_nm/us_iceland_volcano_climate