Posts Tagged "lahar"

Calbuco Erupts a Third Time, with New Mudflows

Posted by on Apr 30, 2015 in All Posts, Featured Posts, News | 0 comments

Calbuco Erupts a Third Time, with New Mudflows

Spread the News:ShareThe glacier-covered volcano Calbuco in southern Chile has erupted for the third time today, after a few days of relative inactivity. It is sending forth a plume of ash 5 kilometers into the atmosphere, and it has created new mudslides, which are  associated with melting of glaciers as well as with recent rainfall. As in its first eruption, seismic activity resumed only briefly before the eruption itself, just after 1pm local time. Though this eruption is, at least at present, smaller than the previous ones on 22 and 23 April, it is still sizable. And it has elicited a stronger reaction, including a public announcement by President Michelle Bachelet within hours of the event. She stated, “All measures are being taken. We are committed not to rest in our efforts to attend to this emergency as quickly as possible.” Both the National Service of Geology and Mines and the National Emergency Office have issued a red alert, the highest level. 6600 local residents have been evacuated, a larger number than for the previous recent eruptions of the volcano. Non-residents have been prohibited from entering the area near the volcano as well. National police have been instructed to enforce this restriction. The new ash fall, and other volcanic debris, are likely to cause additional damage in southern Chile, which has not yet fully recovered from the ash falls of last week. The Washington Post quotes one local resident as saying,  “We were working, cleaning the ash and sand from our homes when this third eruption took place. I feel so much anger and impotence it just breaks me apart.” Meanwhile, the European MetOp satellites have been tracing the plume of aerosols from the earlier eruptions of Calbuco. As this animation shows, the aerosols have now crossed the Atlantic Ocean and have reached South Africa, where dramatic sunsets are now expected. The webcams of the National Service of Geology and Mines have images which are a bit grainy, but are striking nonetheless. For further details about the current eruption, read Erik Klemetti’s recent post  in WIRED.   Spread the...

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Eruption in Glacier-covered Volcano in Chile

Posted by on Mar 6, 2015 in All Posts, Featured Posts, News, Science | 0 comments

Eruption in Glacier-covered Volcano in Chile

Spread the News:ShareOne of South America’s most active volcanoes, Villarrica, erupted Tuesday, 3 March 2015,  around 3 a.m. local time in Chile, creating a danger that lava would interact with the large ice cap on the mountain. The volcano spewed a lava fountain 1.5 kilometers into the air, and the pillar of smoke and ash reached 6-8 kilometers in height. Fortunately, the National Emergency Office issued a red alert and ensured the evacuation of roughly 3300 people from the volcano’s vicinity, especially residents from the town of Pucón. This area experienced  many moderate to large eruptions, including events in  1640 and 1948 which appear in the historical record, and earlier ones attested to by indigenous populations of the area and by geological evidence. #Chile 's recent volcanic eruption looked absolutely stunning, & terrifying http://t.co/cE9aL6IyL3 @fcain #Volcano pic.twitter.com/YVzNwrqJnY — Pluto Major Planet (@plutosgems) March 6, 2015 The upper reaches of the volcano are covered by an ice cap about 40 square kilometers in area, including the Pichillancahue-Turbio Glacier. This 2840 meter-high mountain is a popular destination for hikers, who are fond of peering inside of the volcano. What differentiates Villarrica from many  other volcanoes is that it contains an intermittent lava lake within its crater. In fact, Villarrica volcano is composed of layers of hardened lava and volcanic ash from previous eruptions. It is capable of erupting explosively  due to high pressure that results from the release of dissolved gas as magma rises to the surface. These explosions are often accompanied by loud sounds that can be heard over great distances. The eruption can be seen in this dramatic time-lapse video, which starts in black and white, and then shifts to color. There are three major interrelated concerns about this eruption.  Firstly, the lava could melt the glacier ice and snow on the sides of the volcano, causing massive lahars (mud and debris flows), much like the ones that occurred during the eruptions of 1964 and 1971. Secondly, the noxious volcanic ashes could pervade in the air. During the 1971 eruption of Villarrica, at least 15 fatalities from the inhalation of toxic gasses were reported. Finally, there is a somewhat lower risk of a large releases of volcanic ash, which could affect human health, damage power transmission lines, and harm vegetation.  Previous eruptions of Villarrica have released smaller amounts of ash; paradoxically, these have protected the glaciers by insulating them and protecting them from incoming solar radiation. At the time of posting, the volcanic activity is diminished, with much reduced lava emissions and lesser seismic activity. Alerts remain at the orange level for the present. For other stories on volcanic eruptions near glaciers, look here and here Spread the...

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