Agrigan
Mariana Volcanic Arc, United States. This page separates the permanent volcano catalogue, historical eruption records, and selective weekly activity reports.
- Coordinates
- 18.77° N, 145.67° E
- Elevation
- 965 m
- Last recorded eruption
- 1917 CE
- Historical eruption records
- 1
- Primary type
- Stratovolcano
- Evidence
- Eruption Observed
- GVP database
- 5.4.0
- Catalogue revision
- Revision 2
Volcano profile
- Volcanic landform
- Composite
- Tectonic setting
- Subduction zone / Crustal thickness unknown
- Geologic epoch
- Holocene
- Major rock type
- Basalt / Picro-Basalt
- Region
- Northwestern Pacific Volcanic Regions
- Subregion
- Mariana Volcanic Arc
Geological summary
The highest of the Marianas arc volcanoes, Agrigan contains a 500-m-deep, flat-floored caldera. The elliptical island is 8 km long; its summit is the top of a massive 4000-m-high submarine volcano. Deep radial valleys dissect the flanks of the thickly vegetated stratovolcano. The elongated caldera is 1 x 2 km wide and is breached to the NW, from where a prominent lava flow extends to the coast and forms a lava delta. The caldera floor is surfaced by fresh-looking lava flows and also contains two cones that may have formed during the only historical eruption in 1917. This eruption deposited large blocks and 3 m of ash and lapilli on a village on the SE coast, prompting its evacuation.
Separate activity dataset
Weekly volcanic activity reports
Smithsonian/USGS weekly reports are selective and preliminary. They are not a comprehensive list of all eruptions or volcanic activity.
No weekly report appears on this page. Absence from the weekly report does not establish an absence of volcanic activity.
Historical catalogue records
Eruption history
Dates can be approximate, incomplete, or BCE. These are historical catalogue observations, not a statement about present activity.
| Start | End | Activity | Confirmation | VEI | Evidence | Record |
|---|---|---|---|---|---|---|
| 1917-04-09 CE | Not supplied | Confirmed Eruption | Confirmed | 4 | Observations: Reported | GVP 18502Database 5.4.0 |
Source and attribution
Source: Data: Smithsonian Institution Global Volcanism Program, Volcanoes of the World.
View the original Smithsonian GVP recordGlobal Volcanism Program, 2026. Volcanoes of the World 5.4.0.
The GVP database is scientific documentation that changes as evidence is reviewed. Historical dates may be approximate or uncertain. This platform is not an official emergency-warning service.
Read the GVP terms of useData freshness
- Source updated
- Not supplied
- Retrieved
- 11 Oct 2026, 13:07 UTC
- GVP database version
- 5.4.0
- Catalogue revision
- 2
Source-update and retrieval times describe this catalogue record. Each weekly report carries its own publication date and preliminary status.