Mount Maipo

Mount Maipo, among the most active border stratovolcanoes in the south-central Andes, sits mightily on the Chile-Argentina borders.  This volcano partially fills the Pleistocene Diamante caldera, and is elevated nearly 1900 meters above the caldera’s floor as a result of strombonian-vulcanian activity.  Its aesthetic appeal comes mostly from the luscious layer of ash and glacial deposits which neatly blanket Maipo’s surface.  This ash comes from the last significant eruption which occurred in 1826, with the explosive emission of lava and other volcanic material.  Other than that, Maipo’s eruption level has diminished to mild explosions here and there, most of which barely reach a VEI of 2.  The latest dish on activity  on Maipo is the claim of of a landslide or avalanche in 2004 just to the east of its peak, as a result of the season’s increasing temperature.  Besides this and the last recorded eruption, which occurred in 1912, Maipo’s active calderas merely continue to rest peacefully.

The Copahue Volcano

-Photo by bqviajes.com

Located in the Andes, amidst the central area of the Argentina-Chilean border, lies the breathtaking Mount Copahue.  This stratovolcano with a 8 km-wide caldera came into existence about a half a million years ago near the Pliocene Caviahue caldera.  There is particularly frequent fumarolic activity in the eastern summit crater, as well as intense acidity in the hot springs below the eastern crater lake.  However, Mount Copahue itself is not very active in terms of volcanic eruptions, as the number of recorded eruptions since the 18th century have been scant and few.  Though the last eruption there occurred in as recently as July of 2000, and its strength marked a record high for the volcano’s eruption history.  Smithsonian’s Global Volcanism program reported that ash deposits 3-5 cm thick coated the surrounding village, a sulfurous odor littered the air, and the acidic waters of Copahue’s crater lake poisoned the freshwater in Rio Lomin.  So, too, did the phreatic explosions and pyroclastic flows contribute greatly to the overall destruction of this eruption in 2000.  Since then, Copahue has been relatively quiet, with only mild fumarolic activity disturbing its peace.

San Pedro

           -Photo from letsgochile.com

 Behold the tranquil, picturesque image of Mount San Pedro nestled beautifully on the edge of the Atacama Desert in northern Chile.  It is also one of the tallest volcanoes in the world, with a staggering altitude of 6,145 meters.  This volcano features two, large peaks, San Pedro is the western summit and San Pablo is the eastern.  Notice the shadow this massive basaltic andesite-to-dacitic mountain casts on its twin, Mount San Pablo.  Exploration from world renowed, Australian scientist John Seach confirms the thick avalanche of debris that coats the western slope of San Pedro.  This material resulted from the collapse of an older edifice, which then formed the youngest cone in the volcano’s crater.   There’s not much significant activity these days to alter the material on San Pedro’s surface, as the last eruption was recorded on December 2, 1960, with a mere VEI of 2.  Thus for now, this intimidatingly tall volcano, sits quietly, a mere image of (non-dangerous) beauty.

Mount Láscar

-photo from Smithsonian/Global Volcanism Program

Mount Láscar  is situated on the northern end of the Chilean Andes and is the most active stratovolcano there.  This means that Láscar is capable of emitting both pyroclastic and magmatic material.  Very frequently, too, do phreatic eruptions occur there in which hot water and even hotter volcanic rock come together and cause an explosive eruption of pulverized rock, but no magma.  Recent reports on Láscar’s eruption activity indicate that little more is occurring than explosive, central vent eruptions, which dwarf in comparison to Láscar’s most massive, historical eruption to date.  This is, of course, the 1993 eruption, which including phreatic eruptions, pyroclastic flows and an extrusion of the volcano’s dome structure; this eruption was also reported of having a VEI of 4.  The photo above shows smooth, light-colored deposits left over from the pyroclastic flow.  The column of erupted matter exceeded the volcano’s 5km altitude by an additional 12 km, emitting as much as 0.1 cubic kilometers of volcanic material.  Láscar is yet to experience an eruption quite as massive since then, but with magma flows and explosive rock bursting from its craters so often, who’s to say what’s cooking inside of her.

El Solo

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Embedded in the northern borderline between Argentina and Chile lies El Solo, also known as Cerro Solo,  a large startovolcano composed of nine eruptive centers.   Light-colored rhydodacitic pyroclastic-flow deposit lie atop the stratovolcano in the Ojos del Salado region.  A light blanket of snow caps the summit of El Solo as well.  It juts more than 6190 meters into the sky and is  the sight of major pyroclastic flows that flow into adjacent valleys as well as holocene eruptions.  It’s massive structure and beauty are emanate, however, its activity is virtually nonexistent.  It’s last recorded eruption is completely unknown and the stratovolcano remains positively quiescent.

Alexis Franklin

March 2, 2011