Starting at 20:35 UTC on April 23, 2014, seismic stations located on Pagan, Sarigan, Anatahan and Saipan (Commonwealth of the Northern Mariana Islands) began recording signals believed to be from an undersea volcanic source.
Hydroacoustic sensors on Wake Island suggest that the source of this seismic activity is at or near Ahyi seamount. USGS cannot locate precisely the source of the activity and it is possible that the vent is one of the other volcanic seamounts in the area.
According to latest notice from USGS issued at 18:41 UTC on April 26 the seismic activity is ongoing but satellite images show nothing out of the ordinary and they have received no reports of activity at the ocean's surface.
Aviation color code was set to yellow.
Geologic summary
Ahyi seamount is a large conical submarine volcano that rises to within 137 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 submarine volcano, and in 1979 the crew of a fishing boat felt shocks over the summit area of the seamount followed by upwelling of sulfur-bearing water.
On April 24-25, 2001 an explosive submarine eruption was detected seismically from a seismic station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi; the summit of the seamount lies within the location uncertainty. (GVP)
Source: USGS
Featured image courtesy of the NOAA Vents Program
