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Beerenberg, a stratovolcano, is the northern-most active subaerial volcano on Earth. The volcano, mostly covered by glaciers, forms the north-end of Jan Mayen Island, 375 miles (600 km) north-northeast of Iceland. Jan Mayan is 54 km long and has an area of 145 square miles (380 square km). The island is less than 700,000 years old. The south part of the island is a mountainous ridge made of scoria craters, scoria mounds, and trachytic domes. Map based on Sylvester (1975).
Picture of Beerenberg copyrighted by Heilund.
Beerenberg is a large 2277-m-high glacier-covered stratovolcano with a 1-km-wide summit crater and numerous cinder cones that were erupted along flank fissures. It is composed primarily of basaltic lava flows with minor amounts of tephra. It is located in a farirly unusual tectonic setting near the intersection of the Jan Mayen Fracture Zone (a transfrom fault) and the Mohns mid-ocean ridge. The Kolbiensey Ridge is 105 miles (170 km) to the east. Map based on Sylvester (1975).
Beerenberg has erupted six times between 1732 and 1985. All of these eruptions were on flank vents and produced lava flows and scoria cones. The most recent eruptions were in 1970, 1973, and 1985. Map based on Imsland (1986).
Bam is a stratovolcano a few miles (km) northeast of Papua New Guinea. It has erupted at least 16 times since about 1872, most recently in 1960. Eruptions are explosive and small in size.
Photo courtesy of Jack Lockwood, U.S. Geological Survey.
Azuma is made of overlapping stratovolcanoes. All eight of the historic eruptions have been at the Issaikyo vent. Unconfirmed historic eruptions were reported for 1331 and 1711. The first confirmed historic eruption was in 1889. Most of the historic eruptions have been small to moderate in size (VEI=1-2) and about half are phreatic.
In 1893, two geologists were killed at Azuma by falling stones. The most recent eruption was in 1977. It was small and lasted less than one day.
Image credit: Leslie Sonnenschein. Note hiker at the edge of the crater.
Sources of Information:
Simkin, T., and Siebert, L., 1994, Volcanoes of the World: Geoscience Press, Tucson, Arizona, 349 p.
Ayelu is a stratovolcano in the Ethiopian rift valley. The volcano has no historic eruptions but probably has erupted sometime in the last ten thousand years; unconfirmed activity is reported from 1928.
Source of Information
Richard JJ Neumann van Padang M, 1957, Africa and the Red Sea: Catalog of Active Volcanoes of the World, Rome: IAVCEI 4:p23-24.
Figure 3. Recent tephra deposited below the Mount Awu lava dome, 12 June 2004. For scale, note the backpack-clad person standing on fresh tephra and amid stripped vegetation in the right-central foregound. Courtesy of A. Solihin, VSI, Directorate of Volcanology and Geological Hazard Mitigation (DVMBG).
Awu volcano forms the northern end of Sangihe Island in Indonesia. The volcano is a large stratovolcano that has a historical record of violent and deadly eruptions. Both pyroclastic flows and lahars have been common during many of the historical eruptions, flowing down the deep channels that have dissected the volcano. A 4.5-km-wide summit caldera is present that has at times contained a lake. Prior to the current activity the last major eruption was in 1966, however at least one small phreatic explosion did occur in 1992. During the 1966 eruption lahars and pyroclastic flows killed more than 8000 people.
Avachinsky (on the right) is one of the most active stratovolcanoes on the Kamchatka peninsula. It consists of a younger cone inside the rim of an older caldera. Avachinsky has been classified as a Somma volcano based on its similarities with Vesuvius.
Avachinsky has erupted at least 16 times since 1737. A large (VEI=4) explosive eruption occurred at Avachinsky in 1945. The most recent eruption was in 1991 and produced lava flows, a dome, and mudflows. Koryaksky is on the left.
Photograph by Jack Lockwood, U.S. Geological Survey.
Astonupuri is a stratovolcano with two historic eruptions in 1812 and 1932. Both eruptions were small (VEI = 1 and 2, respectively).
The southern Kurile Islands consist of Kunashir, Iturup, Urup, Chirppi, and Broutona islands.
The volcanoes that make the islands are:
|1. Golovnin||6. Bogatyr Ridge||11. Demon|
|2. Mendeleev||6.1 Unnamed||11.1. Ivao Group|
|2.1.Smirnov||7. Grozny Group||11.2 Rudakov|
|3. Tiatia||8. Baransky||11.3. Tri Sestry|
|4. Berutarube||9. Chirip||12. Kolokol Group|
|4.1. Lvinaya Past||9.1. Golets-Tornyi Group||13. Unnamed|
|5. Astonupuri||10. Medvezhia|
Lake Atitlan (center), San Pedro (left), Toliman (right background), and Atitlan (right foreground). View is to the northeast.
Image Credit: Steve O'Meara of Volcano Watch International.
Volcanic activity began in the Lake Atitlan area about 11-12 million years ago. The present-day stratovolcanoes and caldera represent the most recent of four periods of volcano growth and caldera collapse. This recent period of activity began about 1.8 million years ago. A large explosive eruption about 84,000 years ago formed the most recent Atitlan caldera.
Lake Atitlan fills part of the caldera.
A view of Askja, a huge caldera in a mountain area called Dyngjufjoll. Notice the different levels of the small crater (right) and the lake which is collapsed ground filled with ground water. The lake has been formed after a big eruption of the crater in front in 1875. The name of the lake is Oeskjuvatn, the crater itself is called viti (hell). A spring can be found on the left side. - Image Credit: Uli Wagemann
Ascension Island is a Holocene stratovolcano with no known historic eruptions. Space Shuttle photo STS070-0712-0086.
The following photographs are of lava fields on Ascension. They were provided and copyrighted by Olivier Staiger.
Sources of Information:
Neumann van Padang, M., Richards, A.F., Machado, F., Bravo, T., Baker, E., Le Maitre, W., 1967, Part XXI, Atlantic Ocean: Catalogue of the active volcanoes of the world, International Association of Volcanology, Rome, Italy, 128 p.