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Ahyi

Stratovolcano · United States · 55m (submarine)

Ahyi submarine volcano is seen in a bathymetric view looking from the NE with 2x vertical exaggeration. It rises to within about 150 m of the sea surface about 18 km SE of the island of Farallon de Pajaros (Uracas) in the northern Marianas. Water discoloration has been observed over the volcano and an explosive eruption was seismically detected in April 2001.
Ahyi submarine volcano is seen in a bathymetric view looking from the NE with 2x vertical exaggeration. It rises to within about 150 m of the sea surface about 18 km SE of the island of Farallon de Pajaros (Uracas) in the northern Marianas. Water discoloration has been observed over the volcano and an explosive eruption was seismically detected in April 2001. · Photo: Image courtesy of Susan Merle (Oregon State University/NOAA Vents Program).
Type
Stratovolcano
Country
United States
Region
Northwestern Pacific Volcanic Regions / Mariana Volcanic Arc
Elevation
55m (submarine)
Coordinates
20.437, 145.030
Last eruption
2026
Tectonic setting
Subduction zone / Crustal thickness unknown
Landform
Composite
Major rock type
Andesite / Basaltic Andesite
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.

From Wikipedia

Ahyi Seamount is an active shallow submarine volcano in the Northern Mariana Islands, in the Northwestern Pacific Ocean. It has erupted 5 times since the year 2000: in 2001, 2014, 2022–23, and twice in 2024. Since 2009, it has been a part of Marianas Trench Marine National Monument of the United States.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
1934~1943 · 1 eruptions · max VEI 11961~1970 · 2 eruptions · max VEI 01970~1980 · 1 eruptions · max VEI 01980~1989 · 1 eruptions · max VEI 01989~1998 · 2 eruptions · max VEI 01998~2007 · 1 eruptions · max VEI 02007~2016 · 1 eruptions · max VEI 22016~2025 · 4 eruptions · max VEI 119341952198019982016

Detailed timeline

  1. 2025VEI ?Observed
    2025-10-20 – 2026-01-09
  2. 2024VEI 0Observed
    2024-01-01 – 2024-03-27
  3. 2024VEI 0Observed
    2024-08-05 – 2025-05-28
  4. 2022VEI 1Observed
    2022-11-18 – 2023-06-11
  5. 2014VEI 2Observed
    2014-04-24 – 2014-05-17
    Summit crater and SE slope
  6. 2001VEI 0Observed
    2001-04-24 – 2001-04-25
    S of Ahyi (20.34 N, 145.02 E)
  7. 1994VEI 0Observed
    1994-04-23 – Ongoing
  8. 1989VEI 0Observed
    1989-09-21 – 1989-12-27
    SW of Ahyi (~20.3 N, 144.9 E)
  9. 1985VEI 0Observed
    1985-08-02 – 1985-09-05
    SW of Ahyi
  10. 1979VEI 0Observed
    1979-11-15 – 1979-11-15
    Near the Ahyi summit
  11. 1969VEI 0Observed
    1969-03-11 – 1969-03-13
    S of Ahyi (20.24 N, 145.02 E)
  12. 1967VEI 0Observed
    1967-03-27 – 1967-04-10
    SW of Farallon de Pájaros
  13. 1934VEI 1Observed
    1934-07-15 – Ongoing
    Vicinity of Farallon de Pájaros

External links

⚠ For reference only. Not for emergency response.