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 south flank. Pyroclastic-flow deposits erupted about 1000 years ago have been dated, but reports of historical eruptions were considered invalid. From the
Smithsonian Global Volcanism Program.
Location:
Latitude: 17.6° N
Longitude: 145.83° E
Elevation:
744 (m)
2,441 (f)
Volcano type: Stratovolcano
Composition: Andesite - Basalt
Most recent eruption: 870 CE
Threat Potential: Moderate
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