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Alamagan

Stratovolcano · United States · 744m

Alamagan, seen here from the W with two peaks on either side of a roughly 350-m-deep summit crater, is the emergent summit of a large submarine volcano. The exposed cone is largely Holocene in age and the SW flank contains a 1 x 1.6 km graben. Pyroclastic flow deposits have been dated at about 1,000 years old.
Alamagan, seen here from the W with two peaks on either side of a roughly 350-m-deep summit crater, is the emergent summit of a large submarine volcano. The exposed cone is largely Holocene in age and the SW flank contains a 1 x 1.6 km graben. Pyroclastic flow deposits have been dated at about 1,000 years old. · Photo: Photo by Norm Banks, 1981 (U.S. Geological Survey). · Wikimedia Commons
Type
Stratovolcano
Country
United States
Region
Northwestern Pacific Volcanic Regions / Mariana Volcanic Arc
Elevation
744m
Coordinates
17.600, 145.830
Last eruption
870
Tectonic setting
Subduction zone / Crustal thickness unknown
Landform
Composite
Major rock type
Andesite / Basaltic Andesite
Geological summary

Alamagan is the emergent summit of a large stratovolcano in the central Mariana Islands with a roughly 350-m-deep summit crater east of the center of the island. The exposed cone is largely Holocene in age. A 1.6 x 1 km graben cuts the SW flank. An extensive basaltic andesite lava flow has extended the northern coast of the island, and a lava platform also occurs on the S flank. Pyroclastic-flow deposits erupted about 1000 years ago have been dated, but reports of historical eruptions were considered invalid (Moore and Trusdell, 1993).

From Wikipedia

Alamagan is an island in the Northern Mariana Islands in the Pacific Ocean, 30 kilometres (16 nmi) north of Guguan, 250 kilometres (135 nmi) north of Saipan, and 60 kilometres (32 nmi) south of Pagan. It is currently undergoing resettlement since 2018, with a few people living there. The project was coordinated by the Northern Islands Mayor's office and the people there have radio contact with the mainland.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
540~675 · 1 eruptions · max VEI ?809~944 · 1 eruptions · max VEI 41752~1887 · 2 eruptions · max VEI ?540809121414831752

Detailed timeline

  1. 1887VEI ?Geological estimate
    1887-11-29 – Ongoing
  2. 1864VEI ?Geological estimate
    1864-01 – Ongoing
  3. 870 (±100 yrs)VEI 4Geological estimate
    870 – Ongoing
  4. 540 (±75 yrs)VEI ?Geological estimate
    540 – Ongoing

External links

⚠ For reference only. Not for emergency response.