Anatahan
Stratovolcano in United States
Key Facts
Elevation
790 m (2,592 ft)
Type
Stratovolcano
Location
16.350°, 145.670°
Region
Mariana Volcanic Arc
Rock Type
Andesite / Basaltic Andesite
Tectonic Setting
Subduction zone
Location
Loading map...
Overview
The elongate, 9-km-long island of Anatahan in the central Mariana Islands consists of a large stratovolcano with a 2. 3 x 5 km compound summit caldera. The larger western portion of the caldera is 2.
3 x 3 km wide, and its western rim forms the island's high point. Ponded lava flows overlain by pyroclastic deposits fill the floor of the western caldera, whose SW side is cut by a fresh-looking smaller crater. The 2-km-wide eastern portion of the caldera contained a steep-walled inner crater whose floor prior to the 2003 eruption was only 68 m above sea level.
A submarine cone, named NE Anatahan, rises to within 460 m of the sea surface on the NE flank, and numerous other submarine vents are found on the NE-to-SE flanks. Sparseness of vegetation on the most recent lava flows had indicated that they were of Holocene age, but the first historical eruption did not occur until May 2003, when a large explosive eruption took place forming a new crater inside the eastern caldera.
Volcanic Hazards & Risk Assessment
Primary Hazards
- Pyroclastic flows
- Lava flows
- Volcanic bombs and ballistics
- Lahars and mudflows
Risk Level
Geological Composition & Structure
Rock Types
Tectonic Setting
Age & Formation
Eruption Statistics & Analysis
| Metric | Value | Global Ranking | Significance |
|---|---|---|---|
| Total Recorded Eruptions | Unknown | Low | Moderately active volcano |
| Maximum VEI | VEI Unknown | Minor | Local impact potential |
| Recent Activity | 18 years ago | Recent | Recently active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in Northwestern Pacific Volcanic Regions
Quick Info
- •Smithsonian ID: 284200
- •Evidence: Eruption Observed
- •Epoch: Holocene
About the Photo
The two coalescing volcanoes forming the elongate 9-km-long island of Anatahan in the central Mariana Islands are seen here from the S. The low point in the center of the island results in part from overlapping 2.3 x 5 km calderas, the largest in the Mariana Islands. The larger western caldera is 2.3 x 3 km and extends eastward from the summit of the western volcano (left). The volcano's first historical eruption in 2003 took place from a small crater within the 2-km-wide eastern caldera.
Photo courtesy of U.S. Geological Survey, 1994.
Authority Sources
Related Volcanoes
Basic Information
This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.