Thursday, October 27, 2011

Hudson Volcano (Cerro Hudson) Eruption in Chile

As if Chile hadn't experienced enough disaster within recent years from Chaiten to Puyehue-Cordón Caulle, another massive volcano was sent into red alert yesterday on Oct 26th, 2011. Cerro Hudson in southern Chile erupted with a bang, causing avalanches and prompting evacuations as this relatively newly discovered volcano popped its top again.

The below is information from the Smithsonian Global Volcanism Program (GVP):

"The ice-filled, 10-km-wide caldera of the remote Cerro Hudson volcano was not recognized until its first 20th-century eruption in 1971. Cerro Hudson is the southernmost volcano in the Chilean Andes related to subduction of the Nazca plate beneath the South American plate. The massive, 1905-m-high Cerro Hudson covers an area of 300 sq km. The compound caldera is drained through a breach on its NW rim, which has been the source of mudflows down the Río de Los Huemeles. Two cinder cones occur north of the volcano and others occupy the SW and SE flanks. Hudson has been the source of several major Holocene explosive eruptions. An eruption about 6700 years ago was one of the largest known in the southern Andes during the Holocene; another eruption about 3600 years ago also produced more than 10 cu km of tephra. An eruption in 1991 was Chile's second largest of the 20th century and formed a new 800-m-wide crater in the SW part of the caldera."

Add Oct 26th's eruption to the list now!

Looking at the volcano on Google Earth (Seen Below) shows that this is a massive caldera containing stratovolcano. This is a dangerous volcano, like most of the Andes range volcanoes, so authorities in the area are taking exactly zero chances.

The Below picture is from USGS, and was taken yesterday I believe.

Mount Hudson. Aerial photo by Norm Banks,U.S. Geological Survey

When Chaiten volcano blew up after more than 8,000 or so years of dormancy, it took Chile by surprise. The volcano had shown little or no warning signs prior to the eruption. Years later, Puyehue-Cordón Caulle began an eruptive phase that spread tephra and ash to the east covering neighboring Argentina with a gray ash cloud that forced airports closed, and caused lots of damage to livestock, crops and the economy.

Time will tell what Cerro Hudson has in store for Chile, but if the eruptions of its neighbors are any indication, we could be seeing activity from this volcano for months, maybe years. The Andes range volcanoes tend to be quiet for a very long time, and erupt suddenly. The eruption at Chaiten and Puyehue-Cordón Caulle are still ongoing. Chaiten erupted in 2008 and has not ceased its eruptive phase as of this writing. So Hudson could be active for a long time to come.

More information on this eruption can be found here at one of Chile's English language news sites.

I'll post some updates as they become available!

As of right now, the volcano has erupted up to three separate columns of steam and ash in the main caldera. The ash/steam emissions have reached 3 miles high, although a major eruption is not expected to be imminent, as per a statement by ONEMI (Ministerio del Interior y Seguridad Pública). People have been evacuated, and given the volcanoes past two eruptions since 1971, they are taking no chances.

Previous eruptions devastated livestock and piled ash as much as 18 inches high. Since this volcano is covered by glaciers, if a full blown eruption does in fact take place, lahars and pyroclastic flow are a serious possibility. Lahars would most likely be first on the menu, and when the volcanoes top is clear of ice, the ash and gas could pose a very real hazard.

Air traffic is very likely to be affected in Chile and Argentina as a result of this eruption if it increases in scale. For now it is mostly fine ash, steam, and gas.

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