Report on Ahyi (United States) — 9 November-15 November 2022
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 9 November-15 November 2022
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2022. Report on Ahyi (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 9 November-15 November 2022. Smithsonian Institution and US Geological Survey.
20.42°N, 145.03°E; summit elev. -75 m
All times are local (unless otherwise noted)
On 15 November the USGS reported that hydroacoustic sensors at Wake Island began to record signals in mid-October that are consistent with submarine volcanic activity. A combined analysis of the hydroacoustic signals and seismic data from stations on Guam and Chichijima Island, Japan, suggest the source of this activity is at or near Ahyi seamount. Contrary to initial observations of there being discoloration on the water’s surface, a reanalysis of satellite imagery from 6 November showed no evidence of water discoloration at the ocean surface.
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.