Alagogshak is a

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

, located on the

Alaska Peninsula The Alaska Peninsula (also called Aleut Peninsula or Aleutian Peninsula, ; Sugpiaq language, Sugpiaq: ''Aluuwiq'', ''Al'uwiq'') is a peninsula extending about to the southwest from the mainland of Alaska and ending in the Aleutian Islands. T ...

, United States, in

Katmai National Park and Preserve Katmai National Park and Preserve is a List of national parks of the United States, United States national park and National preserve, preserve in southwest Alaska, notable for the Valley of Ten Thousand Smokes and for its Alaska Peninsula brown ...

. It is the oldest of the volcanoes in the vicinity of the

Valley of Ten Thousand Smokes The Valley of Ten Thousand Smokes is a valley within Katmai National Park and Preserve in Alaska which is filled with ash flow from the eruption of Novarupta on June 6–8, 1912. Following the eruption, thousands of fumaroles vented steam fr ...

. The volcano was recognized as a separate feature from Mount Martin in 1997. The

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

Mount Martin stands partly on Alagogshak's deeply eroded edifice, about northeast of the Alagogshak vent. Alagogshak was last active in

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

time, and was active from about 680,000 years ago to about 43,000 years ago. The remnant summit crater consists of hydrothermally altered rock. It is the only member of the Katmai volcanic group that is no longer active. The name Alagogshak is an informal name given by the geological team that investigated the volcano, from nearby Alagogshak Creek, whose name comes from native Alaskan tradition. Map of Alaska Peninsula Volcanoes

References

External links

Alagogshak
at the Alaska Volcano Observatory
Alagogshak Volcano: A Pleistocene Andesite-Dacite Stratovolcano in Katmai National Park
{{Authority control Stratovolcanoes of Alaska One-thousanders of the United States Volcanoes of Lake and Peninsula Borough, Alaska Mountains of Lake and Peninsula Borough, Alaska Aleutian Range Katmai National Park and Preserve Pleistocene stratovolcanoes

See also

References

External links