Mocho-Choshuenco (Pronounced: ) is a

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

covered compound

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

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

Los Ríos Region The Los Ríos Region (Spanish: ''Región de Los Ríos'', , ''Region of the Rivers'') is one of Chile's 16 regions, the country's first-order administrative divisions. Its capital is Valdivia. It began to operate as a region on October 2, 2007, ...

, Chile. It is made of the twin volcanoes Choshuenco in the northwest and the Mocho in the southeast. The highest parts of the volcano are part of the

Mocho-Choshuenco National Reserve The Mocho-Choshuenco National Reserve (Pronounced: ) is a natural reserve around the Mocho-Choshuenco volcano, in Los Ríos Region, southern Chile. The reserve was created by decree in March 1994 and covers distributed in Panguipulli, Los Lagos ...

while the eastern slopes are partly inside the

Huilo-Huilo Natural Reserve Huilo-Huilo Biological Reserve ( , Pronounced: ) is a private for profit natural reserve and ecotourism area in southern Chile. It is by the community of Neltume along the international road to Hua Hum Pass near the border to Argentina. The re ...

. Choshuenco, located on the northwest rim of the 4 km wide

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 ...

, is of late glacial age. It has a heavily eroded crater and is currently dormant. Mocho 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 ...

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 ...

volcano placed above the caldera. Some parasitic craters and

cinder cones A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or ...

are located on the southwest and northeast flanks of the stratovolcano. Mocho has its earliest certainly recorded eruption in 1759, older eruptions reported are uncertain due to the usage of different names and inexact maps. The northern foothills of Mocho-Choshuenco are surrounded by an arc of rivers and lakes formed by Fui, Enco and

Llanquihue River Llanquihue River ( es, Río Llanquihue) is a river in the commune of Panguipulli, southern Chile. It is formed by the union of Neltume River Neltume River ( es, Río Neltume) is a river in the commune of Panguipulli, southern Chile. It drains N ...

, and Pirihueico,

Panguipulli Panguipulli ( ; Mapudungun for "hill of the puma") is a city and commune in Valdivia Province, southern Chile, administered by the Municipality of Panguipulli. It is located on the western edge of Panguipulli Lake, and is on a moraine in the Ch ...

and

Riñihue Lake The Riñihue Lake ( es, Lago Riñihue ) is a lake of glacier, glacial origin in eastern Valdivia Province, southern Chile. It is surrounded by several mountains. The eastern side receives the waters of the Panguipulli Lake by the Enco River, its ...

s. The

Fui River Fuy River (Spanish: ''Río Fuy'') is a river in the commune of Panguipulli, southern Chile. It drains Pirihueico Lake and flows southward along the village of Neltume where it joins the Neltume River and together they create the Panguipulli La ...

has high degree of underground infiltration, such that in some years the

Huilo-Huilo Falls Huilo-Huilo Biological Reserve ( , Pronounced: ) is a private for profit natural reserve and ecotourism area in southern Chile. It is by the community of Neltume along the international road to Hua Hum Pass near the border to Argentina. The re ...

may dry out completely. As consequence of this infiltration a large

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

Cuenca del río Valdivia
is situated beneath Mocho-Choshuenco. The southern and eastern slopes drain to

Pillanleufú River Pillanleufú River ( Mapudungun for ''river of the pillán'') is a river in Futrono, southern Chile. It drains waters from the southern and eastern slopes of Mocho-Choshuenco volcano to Maihue Lake, which in turn flows by Calcurrupe River into ...

which flows south along the

Liquiñe-Ofqui Fault The Liquiñe-Ofqui Fault is major geological fault that runs a length of roughly in a NNE-SSW orientation and exhibits current seismicity. It is located in the Chilean Northern Patagonian Andes. It is a dextral intra-arc strike-slip fault. Most ...

Maihue Lake The Maihue Lake ( es, Lago Maihue, , Mapudungun for ''Wooden glass'') is a lake located east of Ranco Lake in the Andean mountains of southern Chile. The lake is of glacial origin and it is enclosed by mountain ranges of the Andes The And ...

Name

The two volcanoes have had several historical names such as Valdivia, used by

Juan Ignacio Molina Fr. Juan Ignacio Molina (; (June 24, 1740 – September 12, 1829) was a Chilean Jesuit priest, naturalist, historian, translator, geographer, botanist, ornithologist, and linguist. He is usually referred to as Abate Molina (a form of Abbot Moli ...

in 1795, and Panguipulli and Lajara, which Pedro Amadeo Pissis identified in 1875 as Choshuenco and Mocho respectively because only Choshuenco is visible from

Panguipulli Lake The Panguipulli Lake ( ; es, Lago Panguipulli) is one of the " Seven Lakes" in Panguipulli municipality, southern Chile. The lake is of glacial origin and it is enclosed by mountain ranges of the Andes, on all sides except the west, where the tow ...

. Other historical spellings and names for the volcanoes include Choshuenco-

Pillán The Pillan (of Mapudungun origin; singular ''pillán'' and plural ''pillanes'' in Spanish) is a powerful and respected male spirit in Mapuche mythology. According to legend, the Pillan are good spirits, but they can also cause disasters, since t ...

, Rauco, Penguipulli, Reñihue and Riñihue.Volcán Mocho-Choshuenco
The current name for the volcano is composed of the Spanish word ''mocho'' and the native

Mapudungun Mapuche (, Mapuche & Spanish: , or Mapudungun; from ' 'land' and ' 'speak, speech') is an Araucanian language related to Huilliche spoken in south-central Chile and west-central Argentina by the Mapuche people (from ''mapu'' 'land' and ''che ...

word ''choshuenco'' (pronounced ''choswenko''). ''Mocho'' means short cut and refers to the headless or edgeless shape of Mocho's

volcanic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and ...

. The word ''choshuenco'' may be a corruption of the ''chodhuen'' and ''co'' which means yellow earth and water respectively. Another possible etymology is ''chod-hue'' and ''co'' which would mean place where there is water to dye yellow.

Eruptions

Very little is known about eruptions before the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

epoch. This is explained by the great extent of the

Patagonian Ice Sheet upright=1.4, Map showing the extent of the Patagonian Ice Sheet in the Strait of Magellan area during the last glacial period. Selected modern settlements are shown with yellow dots. Sea level was much lower than shown here. The Patagonian Ice S ...

that covered most of the southern Andes and caught volcanic material such as ash and pyroclast. Glaciers of the ice sheet also reworked previously deposited layers. Some 10,300 years ago Choshuenco produced the

Neltume Neltume is a Chilean town in Panguipulli commune, of Los Ríos Region. It lies along the 203-CH route to Huahum Pass into Argentina. The town's main economic activities are forestry and, more recently, tourism since the Huilo-Huilo Biological ...

Pumice during a plinian eruption. The earliest historical accounts of eruptions from the Mocho-Choshuenco complex may be those in

Alonso de Ovalle Fr. Alonso de Ovalle (Santiago; July 27, 1603 – Lima; May 1651) was a Chilean Jesuit priest and chronicler of Chilean history, author of the ''Historica relacion del Reyno de Chile y de las missiones y ministerios que exercita en él la Comp ...

's map ''Tabula Geographica Regni Chile'' from 1646. Here Mocho-Choshuenco may be one of the mountains drawn as erupting volcanoes east of

Valdivia Valdivia (; Mapuche: Ainil) is a city and commune in southern Chile, administered by the Municipality of Valdivia. The city is named after its founder Pedro de Valdivia and is located at the confluence of the Calle-Calle, Valdivia, and Cau-Cau R ...

. In

's map from 1795 Mocho-choshuenco appears erupting under the name of Volcán de Valdivia, but eruption shown in this map is probably that of 1759. On November 1, of 1864 the Chaiquemahuida cinder cone erupted, the eruption eventually ended 1–3 days later. This explosive eruption originated from a vent on the southwestern flank of Mocho's edifice and produced pyroclastic flows. According to a missionary from Quinchilca, who was interviewed by Vidal Gormaz in 1869, a strong noise followed by an earthquake was felt during one of the first days of November 1864. The last reported eruption, is supposed to have occurred on June 16, 1936. Little is known about this event apart from the occurrence of

mudflow A mudflow or mud flow is a form of mass wasting involving fast-moving flow of debris that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. Mudflows contain a significa ...

s and

lahar A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extreme ...

s, this have led volcanologists to consider this eruption report as a false report just like in the case of the supposed 1906

Lanín Lanín is an ice-clad, cone-shaped stratovolcano on the border of Argentina and Chile. It forms part of two national parks: Lanín in Argentina and Villarrica in Chile. It is a symbol of the Argentine province of Neuquén, being part of its flag ...

eruption.

Glaciers

The uppermost part of Mocho-Choshuenco is covered by an

ice cap In glaciology, an ice cap is a mass of ice that covers less than of land area (usually covering a highland area). Larger ice masses covering more than are termed ice sheets. Description Ice caps are not constrained by topographical features ...

that surrounds the

of Mocho and some flanks of Choshuenco. By 2003 the ice cap had shrunk in area by a total of 40% of its area of 1976. The largest retreat by area occurred on Choshuenco Glacier in the northwest. Mocho Glacier runs from Mocho's cone to the southeast and is the largest glacier of the volcano with its 5.1 km² followed by Choshuenco Glacier (2 km²).

Name

Eruptions

Glaciers

See also