The Almolonga volcano, also called "Cerro Quemado" (Burned Mountain) or "La Muela" (The Molar) due to its distinct shape, is an

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

in the south-western department of

Quetzaltenango Quetzaltenango (, also known by its Maya name Xelajú or Xela ) is a municipality and namesake department in western Guatemala. The city is located in a mountain valley at an elevation of above sea level at its lowest part. It may reach above ...

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

. Part of the mountain range of the Sierra Madre, the volcano is located near the town of

Almolonga The Almolonga volcano, also called "Cerro Quemado" (Burned Mountain) or "La Muela" (The Molar) due to its distinct shape, is an andesitic stratovolcano in the south-western department of Quetzaltenango in Guatemala. Part of the mountain range o ...

, just south of

, Guatemala's second largest city. The volcano is set along the Zunil fault zone and has a central caldera surrounded by several

dacitic Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

and

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

s and formed in a

back-arc The back-arc region is the area behind a volcanic arc. In island arc, island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal zone, abyssal depths, which may be separated by remnant arcs, similar to island arcs. In conti ...

volcanic setting, with activity commencing 84,000BP. Almolonga

is the oldest edifice and underwent collapse prior to the caldera forming eruption of

Lake Atitlan A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

, the major chronological marker of volcanism in the region. The collapse of the stratovolcano left a

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

with a diameter of 3,3 km and a depth of 350m that was subsequently occupied by lava domes on its northern edge and covered by

tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...

layers from numerous volcanoes, both in the Almolonga field and others. Cerro Quemado is the largest (about 2 km³) and youngest lava dome complex formed by eight vents with viscous lava flows and plugs during four distinct volcanic phases - the first two involving effusion of lava and formation of new domes. Cerro Quemado underwent a flank collapse 1,150BP, generating a landslide that went 6 km SSW in the Llano de Pinal valley and occupied an area of 13 km², generating a lateral blast that affected the neighbouring

Volcán Siete Orejas Volcán Siete Orejas ( Mam: ''Wuq Xinkan'') is a stratovolcano in Guatemala located within the Quetzaltenango Department, in the municipalities of Quetzaltenango, Concepción Chiquirichapa, La Esperanza, and San Martin Sacatepequez. It is in t ...

volcano as well. A lava dome emerged inside the collapse scar subsequently. 1818 an eruption formed a block lava flow over half a year that travelled 2.5 km eastward. Lahars and further explosive activity are potential hazards from this volcano.

References

* * * Stratovolcanoes of Guatemala Subduction volcanoes Mountains of Guatemala Pleistocene stratovolcanoes Holocene stratovolcanoes North American 3000 m summits {{Guatemala-geo-stub

See also

References