Ahyi
Mariana Volcanic Arc, United States. This page separates the permanent volcano catalogue, historical eruption records, and selective weekly activity reports.
- Coordinates
- 20.44° N, 145.03° E
- Elevation
- -55 m
- Last recorded eruption
- 2026 CE
- Historical eruption records
- 13
- Primary type
- Stratovolcano
- Evidence
- Eruption Dated
- 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
- Andesite / Basaltic Andesite
- Region
- Northwestern Pacific Volcanic Regions
- Subregion
- Mariana Volcanic Arc
Geological summary
Ahyi seamount is a large conical submarine volcano ~18 km SE of the island of Farallon de Pajaros in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations.
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 |
|---|---|---|---|---|---|---|
| 2025-10-20 CE | 2026-01-09 CE | Confirmed Eruption | Confirmed | 0 | Observations: Satellite (visual) | GVP 22635Database 5.4.0 |
| 2024-01-01 CE | 2024-03-27 CE | Confirmed Eruption | Confirmed | 0 | Observations: Satellite (visual) | GVP 22557Database 5.4.0 |
| 2024-08-05 CE | 2025-05-28 CE | Confirmed Eruption | Confirmed | 0 | Observations: Reported | GVP 22595Database 5.4.0 |
| 2022-11-18 CE (day uncertainty +/- 1) | 2023-06-11 CE | Confirmed Eruption | Confirmed | 1 | Observations: Reported | GVP 22489Database 5.4.0 |
| 2014-04-24 CE | 2014-05-17 CE | Confirmed EruptionSummit crater and SE slope | Confirmed | 2 | Observations: Hydrophonic | GVP 20936Database 5.4.0 |
| 2001-04-24 CE | 2001-04-25 CE | Confirmed EruptionS of Ahyi (20.34 N, 145.02 E) | Confirmed | 0 | Observations: Hydrophonic | GVP 18474Database 5.4.0 |
| 1994-04-23 CE | Not supplied | Confirmed Eruption | Confirmed | 0 | Observations: Reported | GVP 22533Database 5.4.0 |
| 1989-09-21 CE | 1989-12-27 CE | Confirmed EruptionSW of Ahyi (~20.3 N, 144.9 E) | Confirmed | 0 | Observations: Hydrophonic | GVP 18477Database 5.4.0 |
| 1985-08-02 CE | 1985-09-05 CE | Confirmed EruptionSW of Ahyi | Confirmed | 0 | Observations: Hydrophonic | GVP 18476Database 5.4.0 |
| 1979-11-15 CE | 1979-11-15 CE | Uncertain EruptionNear the Ahyi summit | Uncertain | 0 | Observations: Reported | GVP 18470Database 5.4.0 |
| 1969-03-11 CE | 1969-03-13 CE | Confirmed EruptionS of Ahyi (20.24 N, 145.02 E) | Confirmed | 0 | Observations: Hydrophonic | GVP 18475Database 5.4.0 |
| 1967-03-27 CE | 1967-04-10 CE | Confirmed EruptionSW of Farallon de Pájaros | Confirmed | 0 | Observations: Hydrophonic | GVP 18494Database 5.4.0 |
| 1934-07-15 CE (day uncertainty +/- 45) | Not supplied | Confirmed EruptionVicinity of Farallon de Pájaros | Confirmed | 1 | Observations: Reported | GVP 18486Database 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.