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RE: Augustine Volcano
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Evidence of Augustine Volcano eruptions stretches back 4,200 years

Augustine Volcano sits alone, a 4,000-foot pyramid on its own island in Cook Inlet. Like many volcanoes, it has a tendency to become top-heavy. When gravity acts on Augustine's steep dome, rockslides spill into the ocean. A scientist recently found new evidence of an Augustine-generated tsunami dating back to the time when Egyptian pharaohs built their own pyramids.
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Augustine Volcano doubles as tsunami generator

Augustine Volcano, which erupted explosively at the beginning of 2006, also erupted in 1883. But there was a dramatic difference.
In 1883 part of the mountain tumbled into the sea and caused a tsunami that crossed Cook Inlet and bounced back again.
Because the tsunami happened at low tide in an area with some of the largest tidal ranges on Earth, the sea rising 20 feet was almost the same as if high tide returned early.

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Mount Augustine
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Researchers studying the Mount Augustine eruption in Alaska have written an article documenting the electrical activity that occurred during the January 2006 explosion.
 In an article published in the upcoming issue of the journal Science, the scientists from University of Alaska Fairbanks (UAF) wrote that while it has long been known that volcanic eruptions can produce vigorous lightning, there are few direct observations of the phenomena.
 Following the initial eruptions of 11 and 13 January 2006, two of which produced lightning, two electromagnetic lightning detectors were set up in Homer about 60 miles from Augustine.
 A couple of days later, the volcano erupted again, with the first of four eruptions producing a "spectacular lightning sequence".

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Alaska’s Augustine Volcano started 2006 with a bang, producing explosive eruptions in mid-January. The volcano had quieted by March 2006, although the Alaska Volcano Observatory (AVO) warned that explosive eruptions could still occur at any time. The volcano continued a fairly similar behaviour pattern in April.

The Terra satellite captured this image on April 18, 2006. According to the AVO, Augustine’s seismic activity jumped that day. The volcano continued its customary steam plume, and light winds allowed the plume to rise directly above the summit about 300 to 600 meters. This image shows the steam plume flowing from the summit in the south. The cloudy form to the north could be cloud, or a steam plume from the volcano’s pyroclastic flow deposits—hot rock fragments and ash.



Augustine Volcano is considered the most active volcano in the eastern Aleutian arc. Its biggest historical eruption occurred in 1883 when the volcano’s dome collapsed. The volcano erupted again in 1986, producing an avalanche of ash, rock fragments, and gas. Augustine’s activity spans a longer time span than historical records cover, and its oldest dated volcanic rocks are more than 40,000 years old.

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Augustine Volcano kicked back to life this weekend, with four eruptions over a 12-hour period Friday night and Saturday morning -- then went at it again Saturday afternoon, spewing a steady stream of ash that scientists characterized as a "small discrete explosion."

The new activity from Southcentral Alaska's most active volcano disrupted airlines' schedules and dusted communities to the south with a light coat of ash. Wind directions once again spared Anchorage from the annoyances of the gray, gritty ash.
The volcano, located on an uninhabited Cook Inlet island 180 miles southwest of Anchorage, ended 10 days of relative calm with a nine-minute burst Friday night that flung steam and ash to 30,000 feet. Three more eruptions of two to three minutes each were recorded before the sun rose Saturday, venting their own helpings of steam and ash.
Then, around 2:30 p.m. Saturday, the fifth event began: a seismically smaller disturbance but one that lasted much longer than the others, sending a stream of ash boiling from the mountain for hours.
The afternoon activity marked the first time since Augustine started its current eruption cycle in early January that its ash plume did not immediately separate from the volcano and get carried away by the wind, officials said.

"It's just a little different than the previous ones. It's certainly capable of putting out ash in a more quiet and passive way" - seismologist Stephanie Prejean.

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After 10 days of relative calm, Alaska's Augustine volcano has roared back to life, shooting a cloud of ash 12 kilometres into the sky.

It is the 10th explosion since January 11, when the 1,260-metre volcano in southern Cook Inlet began an eruptive phase.
So far, there have been no reports of ash settling onto any of the nearby communities.
However, some ash is expected to drift onto Kodiak Island, south-east of the peak.
Augustine is located about 280 kilometres south-west of Anchorage.
The conical-shaped peak forms its own uninhabited island in Cook Inlet, the channel that runs from the Anchorage area to the Gulf of Alaska. It is the most active of Cook Inlet's volcanoes.

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Augustine Volcano in the Gulf of Alaska erupted on December 12, 2005, sending a plume of ash and steam approximately 80 kilometres toward the southeast. The Aqua satellite captured this image the same day. In the image, the volcanic plume streams from the tiny, snow-capped volcanic island and dissipates over the ocean.



According to news reports, the eruption was not a big surprise. Augustine Volcano is closely monitored using geodetic equipment that records ground movement, and the volcano had shown seismic activity earlier in December 2005. Authorities had raised its alert level to yellow, or “restless” by the time it erupted. As activity ramped up in early December, researchers at the Alaska Volcano Observatory made a live view of the volcano available on the Web.

Augustine Volcano is regarded as the most active volcano in the eastern Aleutian arc. Its biggest historical eruption occurred in 1883 when the volcano’s dome collapsed. Dome growth since that time has restored the volcano’s height to what it was prior to 1883. The volcano erupted again in 1986, producing an avalanche of ash, rock fragments, and gas. Augustine’s activity reaches much further back in time than historical records cover. Its oldest dated volcanic rocks are more than 40,000 years old.

-- Edited by Blobrana at 23:28, 2005-12-14

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