Misti

Misti is a tall volcano.

It looks like a big cone. Snow sits on its top.

The top has two deep holes. One hole has a plug of rock inside. Hot gas comes out of the mountain. Misti sits near a big city. Many people live near the slopes.

The mountain is very famous in Peru. It is a very special place.

Misti is a famous volcano in Peru.

It rises high above the city of Arequipa. The mountain has a steep shape like a cone. At the top, there are two nested craters. A crater is a large, bowl-shaped hole.

The inner crater holds a plug of rock. Vents in this plug let out volcanic gases. Snow often covers the summit. However, the snow does not stay there. Misti does not have glaciers.

The volcano grew in four stages. In each stage, lava flows built the mountain. Then, the top collapsed to form a bowl. This happened four times. Over 50,000 years, many big eruptions happened. These eruptions spread tephra, which is broken rock. Misti is a dangerous volcano. It sits very close to Arequipa. More than one million people live nearby. Some people even live on the volcano's slopes. Even a small eruption can cover the city in ash.

Misti is a famous volcano in the southern Andes of Peru.

It rises high above Arequipa, which is the second-largest city in the country. The mountain has a steep shape like a cone. At the very top, there are two nested craters. The inner crater holds an active lava plug, which is a dome of rock. Vents in this dome let out volcanic gases.

Snow often covers the summit, but it does not stay there. Unlike some other mountains, Misti does not have glaciers.

This volcano grew through a specific way of building itself. It grew in four different stages over a long time. In each stage, lava flows and domes built up the mountain. After the lava built the peak, the summit would collapse. This collapse created a bowl-shaped depression at the top. This cycle of building and collapsing happened four times in total.

Over the last 50,000 years, many intense eruptions have happened. These eruptions spread tephra, which are rocks broken into small pieces by the explosion.

People have lived near Misti for a very long time. Settlement in this region began over 1,500 years ago. The Inca people lived here and viewed the volcano as a threat. During an eruption between 1440 and 1470 AD, they offered sacrifices on the mountain. These mummies on Misti are the largest known Inca sacrifices.

The name Misti might mean "mixed" or "white" in Quechuan. This likely refers to the snow on the mountain. Other names for the volcano include Putina or San Francisco. Some people even call it the "house mountain" of Arequipa.

Today, Misti is considered one of the most dangerous volcanoes in the world. This is because it sits so close to the city of Arequipa. More than one million people live in the city. Some neighborhoods even spread onto the slopes of the volcano. If the volcano erupts, mudflows or hot debris could travel down narrow valleys. These flows could reach the city or hit power plants. Even a moderate eruption could cover the city in ash and tephra.

Scientists work hard to keep people safe from the volcano. Before 2005, there was very little monitoring of Misti. Now, a group called INGEMMET runs a volcano observatory in Arequipa. They create hazard maps to show where danger might be. They also run campaigns to teach the public about the volcano. In the past, researchers even built a weather station on the summit. This station was once the highest inhabited place on Earth. It helped scientists study how the human body works at high altitudes.

Misti is a prominent stratovolcano located in the southern Peruvian Andes. It rises sharply above Arequipa, the second-largest city in Peru.

This volcano is part of the Andean Central Volcanic Zone, or CVZ. The CVZ is a large volcanic belt stretching through southern Peru, Bolivia, northern Argentina, and Chile. Misti is a young, symmetrical cone with slopes measuring about 30 degrees. It is a significant landmark because it is visible from the Pacific Ocean.

The mountain was built through a specific geological process involving four distinct stages. During each stage, lava flows and domes built up the mountain's structure. This was followed by a summit collapse that created a bowl-shaped depression. These cycles of growth and collapse repeated four times to form the current cone. The volcano sits atop an older, eroded stratovolcano known as Misti 1. Its surface is covered by a large fan of volcanic debris. This debris covers an area of 150 square kilometers around the volcano.

The summit of Misti features two nested craters. The outer crater is wide and deep, with a gap in its southwestern rim. The inner crater sits in the southeastern part of the outer crater. This inner crater cuts through layers of ash and scoria. It also cuts through historical lava domes. Inside this inner crater, there is an active lava plug or dome. This dome has a cracked, boulder-strewn surface. It also contains sulphur deposits and active fumaroles, which are vents that emit volcanic gases.

Geologically, Misti is driven by the movement of tectonic plates. The Nazca Plate subducts beneath the South American Plate at a rate of about 6 centimeters per year. This process, called subduction, is responsible for the volcanism in the CVZ. As the Nazca Plate descends, it releases fluids into the mantle. These fluids chemically modify the mantle to generate melt. Most volcanoes in this region produce potassium-rich andesitic magmas. This magma is created through fractional crystallization and the absorption of crustal rocks.

History shows that Misti has been active for a very long time. Over the past 50,000 years, many intense explosive eruptions have occurred. These eruptions spread tephra, which are rocks fragmented by volcanic activity. The last two major eruptions happened 2,000 years ago and between 1440 and 1470 AD.

The Inca people recognized the volcano as a threat. During the 15th-century eruption, they performed human sacrifices on the mountain. The mummies found on Misti represent the largest known Inca human sacrifices. The name "Misti" may come from Quechua, meaning "mixed," "mestizo," or "white." This likely refers to the snow that covers the summit.

Misti is considered one of the most dangerous volcanoes in the world. This danger is due to its proximity to Arequipa. The city has a population exceeding one million people. Some northeastern suburbs have even expanded onto the volcano's slopes. If Misti erupts, narrow valleys could channel mudflows or hot volcanic debris toward the city. These flows could also damage vital infrastructure, such as hydropower plants. Even a moderate eruption could cover most of the city in volcanic ash. Many dams, such as the Aguada Blanca Dam, sit near the volcano's northern side.

Scientific interest in Misti has grown significantly over the years. In 1893, Professor Solon Irving Bailey installed a weather station on the summit. This was once the highest continuously inhabited location on Earth. It allowed researchers to study the human body at high altitudes. Today, the Peruvian Geological, Mining and Metallurgical Institute (INGEMMET) monitors the volcano. They operate a volcano observatory in Arequipa to keep the public safe. They also publish hazard maps and run public awareness campaigns. This monitoring helps manage the risks posed by this massive Andean peak.