Sunday, 15 February 2015

Eruptions on Volcán Villarrica.

The Projecto Observación Visual Volcán Villarrica recorded incandescence (glowing) around the crater of Volcán Villarrica, an active volcano in southern Chile, overnight between 4 and 5 February 2015. On 6 February tephra (hot fragmentary material) was observed being ejected from the crater, reaching a height of 65 m above the crater rim. A number of Earthquakes were also recorded beneath the volcano, as well as a number of small eruptive explosions and the presence of a lava lake in the crater. On 7 February the level of activity continued to increase, with bombs (large blocks of material) as large as 5 m across being ejected from the crater, though the activity dropped off later, with reduced seismic activity and incandescence persisting.

6 February 2015. Series of images illustrating the characteristics of the Strombolian explosions at the top. (1) The arrow indicates a splash of incandescent lava (spatter), captured about 65 m above the edges and some 200 m from its origin inside the chimney. (2) classical strombolian explosion. Exploit huge gas bubbles in the well surface lava lava ejecting splash outwards. (3 and 4) Some come to impact on the upper west side incandescent pyroclastics. Projecto Observación Visual Volcán Villarrica.

The volcanoes of Chile and the Andean region of South America in general are fed by the subduction of the Nazca Plate beneath the South American Plate along the Peru-Chile Trench, which lies offshore parallel to the west coast of South America. As the Nazca Plate sinks it is melted by the heat of the Earth's interior, and the lighter portions of it rise up through the overlying South American Plate to form volcanoes at the surface. These are dotted throughout the Andes Mountains; a range of mountains that is formed by a mixture of volcanism and crumpling of the South American Plate where is is forced against the Nazca Plate.

The subduction of the Nazca Plate beneath the South American Plate. Marot et al. (2012).

Volcán Villarrica is the westernmost of three volcanoes lying on the Gastre Fault Zone (the other two being Quetrupillán and Lanín, which are far less active) which runs toughly northwest-southeast, cutting across the Liquiñe-Ofqui Fault, which runs north-south along the Chilean Andes, and upon which the majority of the country's volcanoes sit. The Gastre Fault Zone is thought to be part of the ancient Lanalhue Fault Zone, which formed along an ancient subduction zone during the Permian (about 300-250 million years ago), during the assembly of the ancient supercontinent of Pangea.

The locations of the Gastre Fault volcanoes, Villarrica (green), Lanín (orange) and Quetrupillán (red). Google Maps.

See also...

The United States Geological Survey recorded a Magnitude 4.9 Earthquake at a depth of 51 km roughly 35 km to the west of Ovalle in the Coquimbo Region...

The United States Geological Survey recorded a Magnitude 5.1 Earthquake at a depth of 22.6 km, roughly 10 km offshore of the Chilean City of Quintero...

The United States Geological Survey recorded a Magnitude 8.2 Earthquake at a depth of 20.1 km roughly 70 km off the coast of northern Chile and 95 km to the northeast of the city of Iquique, slightly after 6.45...

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