| Bobrof Volcano | |
|---|---|
Bobrof Island and the volcano |
|
| Elevation | 2,421 ft (738 m) [1] |
| Location | |
|
Bobrof Volcano
|
|
| Range | Aleutian Islands |
| Coordinates | [2] |
| Geology | |
| Type | Stratovolcano |
| Age of rock | Holocene |
| Volcanic arc/belt | Aleutian Islands |
Bobrof Volcano is an inactive stratovolcano in the Aleutian Islands of Alaska, USA, 1,211 miles (1,949 km) from Anchorage. It forms the small Bobrof Island, 31 miles (50 km) west of Adak, part of the local sub-archipelago, the Andreanof Islands, which extend for 275 miles (443 km).
No recorded eruptions have taken place at Bobrof or in its vicinity. It has been considered as Holocene age.
Bobrof is part of the Andreanof Islands, a smaller chain that is considered part of the Aleutian Islands.[3] It is roughly 31 miles (50 km) west of Adak and 9 miles (14 km) west of Kanaga Island.[3] The volcanic crater, or cone, has been heavily dissected.[4] Bobrof Island is small, only 3 kilometers by 4 kilometers in area.[3] Underwater deposits adjacent to the island's northeast flank suggest an immense debris-avalanche has taken place.[3]
Because of the inclusion of Alaska, the United States has the largest number of active volcanoes in the world, many of them geologically young.[5] In Alaska, at least 50 volcanoes, including those in the Aleutian archipelago, have erupted in historical time.[6] Alaska accounts for about 80% of the United States' volcanoes, excluding the seamounts in the area, about 8% of the world's volcanoes, and most of these are located among the Aleutian Islands.[6] The Aleutian Islands arc forms the northern boundary of the Pacific Ring of Fire,[6] where tectonic activity generates earthquakes and volcanic eruptions regularly.
The volcano is thought to be of Holocene age.[3] Though no historical eruptions have taken place at Bobrof, it has erupted at least once. This data can be confirmed through pyroclastic flow deposits containing andesite.[3] Once these flows were studied, at a building intended for earthquake monitoring, they confirmed that Bobrof was prone to explosive activity.[7] There are lava deposits on the mountain which also suggest activity similar to shield eruptions.[7] In collected samples, there are traces of basaltic andesite and dacite.[8] No complete publications exist for Bobrof's definite geology, just those with facts and some information.[8]