A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism.
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 periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high to intermediate levels of silica, with lesser amounts of less viscous mafic magma. Extensive felsic lava flows are uncommon, but have traveled as far as 15 km (9 mi).
A volcanologist, or volcano scientist, is a geologist who focuses on understanding the formation and eruptive activity of volcanoes. Volcanologists frequently visit volcanoes, sometimes active ones, to observe and monitor volcanic eruptions, collect eruptive products including tephra, rock and lava samples. One major focus of inquiry in recent times is the prediction of eruptions to alleviate the impact on surrounding populations and monitor natural hazards associated with volcanic activity. Geologists who research volcanic materials that make up the solid Earth are referred to as igneous petrologists.
Catherine Joséphine "Katia" Krafft and her husband, Maurice Paul Krafft were French volcanologists and filmmakers who died in a pyroclastic flow on Mount Unzen, Nagasaki, Japan, on 3 June 1991. The Kraffts became well known as pioneers in the filming, photographing, and recording of volcanoes, often coming within feet of lava flows. Their obituary appeared in the Bulletin of Volcanology. Since their deaths, their work has been featured in two documentary films by Werner Herzog, Into the Inferno (2016) and The Fire Within: A Requiem for Katia and Maurice Krafft (2022), and a further film, Fire of Love (2022), depicted their lives, relationship and careers using their archived footage.
Mount Nyiragongo is an active stratovolcano with an elevation of 3,470 m (11,385 ft) in the Virunga Mountains associated with the Albertine Rift. It is located inside Virunga National Park, in the Democratic Republic of the Congo, about 12 km (7.5 mi) north of the town of Goma and Lake Kivu and just west of the border with Rwanda. The main crater is about two kilometres (1 mi) wide and usually contains a lava lake. The crater presently has two distinct cooled lava benches within the crater walls – one at about 3,175 m (10,417 ft) and a lower one at about 2,975 m (9,760 ft).
Mount Unzen is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island.
Santa María Volcano is a large active volcano in the western highlands of Guatemala, in the Quetzaltenango Department near the city of Quetzaltenango. It is part of the mountain range of the Sierra Madre.
Tolbachik is a volcanic complex on the Kamchatka Peninsula in the far east of Russia. It consists of two volcanoes, Plosky (flat) Tolbachik and Ostry (sharp) Tolbachik, which as the names suggest are respectively a flat-topped shield volcano and a peaked stratovolcano. As Ostry is the mountain's highest point, the entire mountain is often referred to as "Ostry Tolbachik", not to be confused with Ostry, a separate volcano to the north also on the Kamchatka Peninsula.
Galeras is an Andean stratovolcano in the Colombian department of Nariño, near the departmental capital Pasto. Its summit rises 4,276 metres (14,029 ft) above sea level. It has erupted frequently since the Spanish conquest, with its first historical eruption being recorded on December 7, 1580. A 1993 eruption killed nine people, including six scientists who had descended into the volcano's crater to sample gases and take gravity measurements in an attempt to be able to predict future eruptions. It is currently the most active volcano in Colombia.
An active volcano is a volcano that has erupted during the Holocene, is currently erupting, or has the potential to erupt in the future. A volcano that is not currently erupting but could erupt in the future is known as a dormant volcano. Volcanoes that will not erupt again are known as extinct volcanoes.
Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified.
Prediction of volcanic activity, and volcanic eruption forecasting, is an interdisciplinary monitoring and research effort to predict the time and severity of a volcano's eruption. Of particular importance is the prediction of hazardous eruptions that could lead to catastrophic loss of life, property, and disruption of human activities.
Mount Sinabung is a Pleistocene-to-Holocene stratovolcano of andesite and dacite in the Karo plateau of Karo Regency, North Sumatra, Indonesia, 40 kilometres (25 mi) from the Lake Toba supervolcano. Many old lava flows are on its flanks and the last known eruption, before recent times, occurred 1200 years before present, between 740 - 880 CE. Solfataric activities were last observed at the summit in 1912; recent documented events include an eruption in the early hours of 29 August 2010 and eruptions in September and November 2013, January, February and October 2014. The volcano has recently claimed the life of at least 23 people in a number of events since 2014. Between 2013 and 2014, the alert for a major event was increased with no significant activity. On 2 June 2015, the alert was again increased, and on 26 June 2015, at least 10,000 people were evacuated, fearing a major eruption. The long eruption of Mount Sinabung is similar to that of Mount Unzen in Japan, which erupted for five years after lying dormant for 400 years. A major eruption began on 10 August 2020.
The Harras of Dhamar is a volcanic field in Yemen.
Sierra la Primavera is a Late Pleistocene volcanic centre in Jalisco of central-western Mexico, located immediately west of Guadalajara in La Primavera Biosphere Reserve. It consists of a caldera, lava domes and lava flows that have formed in the last 200,000 years, with the latest known volcanic eruption having occurred about 30,000 years ago.
Marta Lucía Calvache Velasco is a Colombian geologist and volcanologist, best known for her work on geological hazards and risk reduction in Colombia.
