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

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

in the south-western department of

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

Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...

. 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. The volcano is located near ...

, 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 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 mineral ...

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 on ...

s and formed in a

back-arc A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of ...

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 an area filled with water, localized in a Depression (geology), basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the World Ocean, oce ...

, 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 volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

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 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, they rem ...

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 the ...

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 {{Guatemala-geo-stub

See also

References