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.