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Galeras

earth science Maturity 7-9 Next article →

Galeras is a very active stratovolcano in Colombia.

Galerasvolcanonearpasto
Galerasvolcanonearpasto

It sits in the Nariño department near the city of Pasto. This mountain is a stratovolcano, which means it is built of layers. It is currently the most active volcano in the country. Many people live near it, including 450,000 people in Pasto. Because it is so active, experts study it very closely. It was named a Decade Volcano in 1991 to help scientists learn more.

This volcano works by having explosions from a central vent. These explosions can cause pyroclastic flows or lahars. A lahar is a type of mudflow that moves down the mountain. Sometimes, the volcano releases ash and gas into the air. In 2006, an ash column reached a height of 10 kilometers. Scientists look for special signs to see if an eruption is coming. One sign is a tornillo event, which is a low-frequency seismic event. These shakes happen before about four-fifths of the explosions at Galeras.

Galeras has been active for at least one million years. Long ago, two huge eruptions formed a large caldera. A caldera is a large crater formed when a volcano collapses. The first big collapse happened about 560,000 years ago. The second happened between 40,000 and 150,000 years ago. Since then, a smaller cone has built up inside the horseshoe shape. The indigenous Urcunina people knew this mountain long ago.

There is a long list of eruptions in the history of Galeras. The first historical eruption was recorded on December 7, 1580. Many eruptions happened in the 1800s and 1900s. In 1993, a sad eruption killed nine people. This included six scientists who were sampling gases in the crater. In November 2005, about 9,400 people had to leave their homes. In 2010, the volcano erupted ten times in just one year.

Galeras volcano
Galeras volcano

You can see how the volcano affects daily life in Colombia. When ash falls, people in Pasto must wear goggles and masks. In 2009, ash was so thick that water plants had to shut down. Scientists use tools like a seismograph to watch for ground shakes. They also use the Deep Earth Carbon Degassing Project to monitor it. Studying these patterns helps keep the people living nearby safe. Even when the volcano is quiet, experts keep a close watch.

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File:Galerasvolcanonearpasto.png
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Galeras volcano.jpg
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