Amazing pictures of 'hole in the clouds' from volcano eruption

Thursday, June 25, 2009

A chance recording by astronauts on the International Space Station has captured the moment a volcano explosively erupted, sending massive shockwaves through the atmosphere.

Sarychev Peak, one of the most active volcanoes in the world, had been sitting quietly in the Kuril Island chain near Japan for 20 years, when it suddenly sprang to life on June 12.

Fortuitously, the International Space Station was flying overhead at the time, and managed to capture this spectacular image of the ash-cloud tearing through the atmosphere, sending clouds scattering in its wake in a perfect circle.

The station, which orbits the earth from a height of 220 miles, makes nearly 16 orbits of our planet every 24 hours, and happened to be in the perfect spot to see the dramatic eruption.

The unique images have provided a wealth of new information about the eruption process, and volcanologists are now excitedly poring over the data.

Most unique is the mist-like 'roof' to the cloud, believed to be either steam or condensing water pushed ahead of the advancing cloud of ash. Known as a 'pileus cloud', it lasts just moments, making this a rare snapshot.

Also visible, far below on the hillside, is the thunderous pyroclastic flow of super-heated rock as it cascades down the mountainside. When most people picture volcanoes, they imagine red-hot lava flows. Pyrochastic flows are their deadlier older brother. Appearing at the start of an explosive eruption, they can travel at 130mph, meaning there's nearly no escape for anyone or anything caught in its path.

But the most stunning aspect of the picture is the effect on the clouds: As the ash column punches its way towards the top of the atmosphere, the shockwave causes the clouds to scatter.

An alternative theory, one which these pictures is helping to test, is that as the ash rises, the surrounding air is pushed down, where it warms, and the increased heat causes the clouds to evaporate.

As the ISS continued its orbits over the next days, the astronauts could follow the plume as it drifted away from the island, incidentally causing disruption on nearby flight paths.

The volcano is part of a seismically active cluster of islands running North East from Japan's Hokkaido Island, and up towards Russia's Kamchatka Peninsula.

There are disputes between Russia and Japan over who owns which islands, but Matua Island, where the volcano is located, is generally agreed to be Russian territory. The Japanese call it Matsuwa Island.

The last explosive eruption from Sarychev happened in 1989, with eruptions in 1986, 1976, 1954, and 1946 also producing lava flows.

Ash from the eruptions has been recorded to reach more than 1,500miles from the volcano and commercial airline flights have been disrupted.

The height of the plume was measured at five miles high - a huge distance into the sky, although not enough to worry the astronauts peering down from above.

The International Space Station was first constructed in 1998 and is scheduled to be completed in 2011.


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