Quetrupillán facts for kids

Kids Encyclopedia Facts

Quick facts for kids Quetrupillán
Quetrupillán with Lanín in the background
Highest point
Elevation	2,360 m (7,740 ft)
Geography
Location	Chile
Parent range	Andes
Geology
Age of rock	Pleistocene-Holocene
Mountain type	Stratovolcano
Volcanic arc/belt	South Volcanic Zone
Last eruption	June 1872
Climbing
Easiest route	Palguín - Laguna Azul

Quetrupillán (also called Ketropillán) is a large, cone-shaped volcano located in the Los Ríos Region of Chile. It sits between two other famous volcanoes, Villarrica and Lanín, inside the beautiful Villarrica National Park. This volcano is built on a block of Earth's crust, located between two major fault lines called the Liquiñe-Ofqui Fault and the Reigolil-Pirihueico Fault.

Quetrupillán is a type of volcano known as a stratovolcano. It has a bowl-shaped hollow at its top called a caldera. The volcano first became active a very long time ago, during the late Pleistocene period. It also had some big eruptions during the Holocene period, which is the time we live in now.

Where is Quetrupillán Located?
When Did Quetrupillán Erupt?
Volcanoes in Mapuche Stories
Plants Around Quetrupillán
See also

Where is Quetrupillán Located?

This volcano is found in the areas of Curarrehue, Pucón, and Panguipulli in Chile. Towns close to Quetrupillán include Catripulli, Currarehue, and Puesco. Experts consider it to be the 21st most dangerous volcano in Chile.

How Plate Tectonics Shape the Region

Off the western coast of South America, a huge piece of the Earth's crust called the Nazca Plate is slowly sliding under the South American Plate. This process is called subduction. As the Nazca Plate goes deeper, it releases water, which causes the rock in the Earth's mantle to melt. This melted rock, or magma, then rises to the surface, creating the Southern Volcanic Zone of the Andes mountains.

The way these plates move has changed over millions of years. For the last six million years, the plates have been sliding past each other at an angle. This movement has created a large crack in the Earth's crust called the Liquiñe-Ofqui Fault. This fault is very important for how the volcanoes in the area behave.

Quetrupillán is located in the Southern Volcanic Zone, right on the border between the Los Ríos Region and the Araucanía Region. It lines up with Villarrica and Lanín volcanoes in a northwest-southeast direction. This line of volcanoes follows another fault line called the Mocha-Villarrica fault. Other volcanoes in this zone, like Nevados de Chillán and Puyehue-Cordón Caulle, also show similar alignments. Compared to Villarrica, Quetrupillán has been less active, and its eruptions were smaller.

What Does Quetrupillán Look Like?

Quetrupillán is a tall stratovolcano, standing about 2,360 meters (7,743 feet) high. It used to have a larger glacier on top, but it is now shrinking. The volcano is shaped like a long oval, stretching from north to south, and covers an area of about 107 square kilometers (41 square miles).

Around the main volcano, there are many smaller volcanic features. These include lava domes (mounds of thick lava), maars (wide, flat craters formed by explosions), and pyroclastic cones (small, steep hills made of volcanic rock fragments). These smaller vents cover an area of about 400 square kilometers (154 square miles). Some of these smaller vents are Huililco, Volcanes de Llancahue, and Volcanoes de Reyehueico.

There are 16 side vents on the volcano, with 12 of them found in a volcanic field south of Quetrupillán. Cracks in the ground, called fissure vents, also exist on the southern side. The main volcano itself is not very large, but the many widespread vents might be because of how the volcano interacts with the Liquiñe-Ofqui fault and other local cracks in the Earth. On the southern side of the volcano, there are two lakes: Laguna Azul to the southwest and Laguna Blanca to the southeast.

Some of the rocks from Quetrupillán show signs of interacting with ice or water. For example, tuff rings and maars formed when hot magma met groundwater. A hidden magnetic area deep underground south of the volcano might be a large body of magma, or pluton, that could be pushing up the ground. Huililco, a small scoria cone, has produced two lava flows and is also part of the Quetrupillán volcanic system.

The ground beneath Quetrupillán is made up of three different rock formations: the Panguipulli formation (from the Triassic period), the Currarehue formation (possibly from the Cretaceous period), and the Trápatrapa formation (from the Miocene period). These are made of rocks formed from magma and volcanic ash. The line of volcanoes that includes Villarrica and Quetrupillán acts like a geological border.

What is Quetrupillán Made Of?

The volcanic rocks from Quetrupillán have two main types of composition: they range from basalt (dark, fine-grained rock) to andesite (a common volcanic rock). Overall, these rocks contain more silica than the rocks from Villarrica and Lanín. Unusually for this area, a type of rock called trachydacite is also found here. These rocks contain visible crystals of plagioclase and pyroxene, along with smaller crystals of ilmenite and magnetite.

Scientists believe that the magma (melted rock) inside Quetrupillán's reservoir was like a thick slush of crystals. When new magma entered, it reheated this slush, causing magma to move and erupt. The process of fractional crystallization (where different minerals crystallize at different temperatures) of basalts created the trachytic melts. The way the Earth's plates move in this area, especially because of the Liquiñe-Ofqui Fault, might also help these magma changes happen by preventing magma from simply rising to the surface.

When Did Quetrupillán Erupt?

Quetrupillán started erupting even before the last ice ages. The first eruptions created the calderas and the main stratovolcano. Later, during the ice ages, lava flows and ignimbrites (fast-moving currents of hot gas and rock) were laid down. The current stratovolcano formed towards the end of the ice age, and smaller, side vents appeared even later, producing lava flows.

Quetrupillán has erupted pyroclastics, which are fragments of volcanic rock. These have formed flow and pumice (light, porous volcanic rock) deposits to the east of the volcano. Scientists have identified several periods of volcanic activity based on these deposits. Most of them show deposits of pumice or scoria (dark, bubbly volcanic rock) with different amounts of young lapilli (small rock fragments), lithics (older rock fragments), and ash.

Here are some of the known eruption sequences:

The Moraga sequence happened about 12,720 to 12,690 years ago during a long eruption.
The Puala sequence occurred about 10,240 years ago.
The Trancura sequence formed about 8,680 years ago and is similar to the Avutardas sequence.
The Carén sequence happened about 3,800 years ago.
The Correntoso sequence occurred about 2,930 years ago.
The Trancas Negras sequence formed about 2,060 years ago.
The Puesco sequence happened about 1,650 years ago. This was the largest known eruption of Quetrupillán. It created an eruption column 25 kilometers (15.5 miles) high and deposited about 0.26 cubic kilometers (0.06 cubic miles) of rock. This event had a volcanic explosivity index (VEI) of 4, which is a powerful eruption.
The Carén sequence (a different one) formed about 1,380 years ago. This is the most recent explosive eruption from Quetrupillán.

Additionally, three layers of volcanic ash, called tephras, found in nearby lakes might have come from Quetrupillán. They are dated to about 16,748–16,189, 15,597–12,582, and 12,708–12,567 years ago. However, they have also been linked to another volcano called Sollipulli. These tephras are made of rhyolitic to rhyodacitic rock, and the eruptions that created them had an estimated VEI of 3.

There are also reports of eruptions during the 1800s, with one eruption reported in 1872. Big explosive eruptions from Quetrupillán seem to happen about every 1,200 years. Since the last big one was a while ago, this means the volcano still poses a risk.

Volcanoes in Mapuche Stories

According to a story from Mapuche mythology, there were originally only two volcanoes: Choshuenco and Lanín. Then, a powerful volcano named Ruka Pillan (Villarrica) fought against the other two for a hundred years. Eventually, Ruka Pillan won, and this story is said to match the time when the Spanish arrived in the area.

Plants Around Quetrupillán

As of 1961, the plants growing on Quetrupillán included forests of Araucaria araucana (monkey puzzle trees) and Nothofagus antarctica (Antarctic beech). There was also puna-like vegetation, which is a type of high-altitude grassland.