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Report on Ahyi (United States) — 22 March-28 March 2023


Ahyi

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 22 March-28 March 2023
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2023. Report on Ahyi (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 22 March-28 March 2023. Smithsonian Institution and US Geological Survey.

Weekly Report (22 March-28 March 2023)

Ahyi

United States

20.42°N, 145.03°E; summit elev. -75 m

All times are local (unless otherwise noted)


Unrest at Ahyi Seamount continued during 21-28 March. A plume of discolored water was observed in high-resolution satellite images acquired on 21 and 22 March. No observations indicated that activity has breached the ocean surface. One possible underwater explosion was detected by pressure sensors on Wake Island, 2,270 km E, during 26-27 March. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Geological Summary. Ahyi seamount is a large conical submarine volcano that rises to within 75 m of the ocean surface ~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.

Source: US Geological Survey