Archive for March 22, 2010

Volcanic eruption in south Iceland could spell disaster.

An Icelandic volcano, dormant for 200 years, has erupted, ripping a 1km-long fissure in a field of ice, (Saturday 20th March). The volcano near Eyjafjallajoekull glacier began to erupt just after midnight, sending lava a hundred metres high into the atmosphere.
Icelandic airspace has been closed, flights diverted and roads closed. The eruption was about 120km (75 miles) east of the capital, Reykjavik. According to Pall Einarsson “the eruption was rather small and peaceful but scientists are concerned that it could trigger an eruption at the nearby Katla volcano, a vicious volcano that could cause both local and global damage”.
Scientists say history has proven that when the Eyjafjallajokull volcano erupts, Katla follows — the only question is how soon. And Katla, which is located under the massive Myrdalsjokull icecap, threatens disastrous flooding and explosive blasts when it blows. Saturday’s eruption at Eyjafjallajokull — dormant for nearly 200 years — forced at least 500 people to evacuate. Most have returned to their homes, but authorities were waiting for scientific assessments to determine whether they were safe to stay.

Iceland’s Laki volcano erupted in 1783, freeing gases that turned into smog. The smog floated across the Jet Stream, changing weather patterns. Many died from gas poisoning in the British Isles. Crop production fell in western Europe. Famine spread. Some even linked the eruption, which helped fuel famine, to the French Revolution. Painters in the 18th century illustrated fiery sunsets in their works, including Edvard Munch who produced the paintings illustrated below.

The winter of 1784 was also one of the longest and coldest on record in North America. New England reported a record stretch of below-zero temperatures and New Jersey reported record snow accumulation. The Mississippi River also reportedly froze in New Orleans. “These are Hollywood-sort of scenarios but possible,” said Colin Macpherson, a geologist with the University of Durham. “As the melt rises, it’s a little like taking a cork out of a champagne bottle.”

Unlike the powerful volcanos along the Pacific Rim where the slow rise of magma gives scientists early seismic warnings that an eruption is imminent, Iceland’s volcanos are unique in that many erupt under ice sheets with little warning. Magnus Tumi Gudmundsson, a geologist at the University of Iceland who flew over the site Monday, said the beginning of Saturday’s eruption was so indistinct that it initially went undetected by geological instruments. Many of the tremors were below magnitude 2.6.

Using thermal cameras and radar to map the lava flow, Gudmundsson and other scientists were able to determine that the lava from Eyjafjallajokull was flowing down a gorge and not moving toward the ice caps — reducing any threat of floods. He said he and other scientists were watching Katla but Monday’s trip was meant to assess immediate risk.

“A general expectation is that because of the Eyjafjallajokull eruption, the fissure would widen and in that sense, there’s a greater risk of extending into or underneath the glaciers and prompting an eruption at Katla,” said Andy Russell with Newcastle University’s Earth Surface Processes Research Group, who went with a team to Iceland before the eruption. “From records, we know that every time Eyjafjallajokull erupts, Katla has also erupted.”

Russell said past Katla eruptions have caused floods the size of the Amazon and sent boulders as big as houses tumbling down valleys and roads. The last major eruption took place in 1918. Floods followed in as little as an hour. Those eruptions have posed risks to residents nearby, but most of Iceland’s current population of 320,000 live in the capital of Reykjavik on the western part of the island. Southern Iceland is sparely populated but has both glaciers and unstable volcanoes — a destructive combination.

The last time there was an eruption near the 100-square-mile (160 square-kilometer) Eyjafjallajokull glacier was in 1821, and that was a “lazy” eruption that lasted slowly and continuously for two years. Iceland is one of the few places in the world where a mid-ocean ridge actually rises above sea level. Many volcanic eruptions along the ocean basin often go undetected because they can’t be easily seen. First settled by Vikings in the 9th century, Iceland is known as the land of fire and ice because of its volcanos and glaciers. During the Middle Ages, Icelanders called the Hekla volcano, the country’s most active, the “Gateway to Hell,” believing that souls were dragged into the fire below. The last major volcanic eruption in Iceland occurred in 2004 with the Grimsvotn volcano.                    
Mother Nature has certainly released her fury in the last two months!!

 

March 22, 2010 at 6:56 pm 1 comment


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