Definitive signs of unrest at Ahyi Seamount have been observed sporadically in satellite data over the past few weeks. Plumes of discolored water were observed drifting up to several hundred yards (meters) away from the volcano in satellite images on November 1, 10, and 19. A retrospective analysis of older satellite data shows weak activity extending back to August 5, 2024. Some of these satellite images, including the most recent one, show what might be pumice floating on the ocean surface. Nothing significant has been detected from the direction of Ahyi Seamount in hydroacoustic array data at Wake Island, although submarine plumes have been observed at the volcano in the past without clear hydroacoustic signals.
The possible presence of pumice, in addition to the plume of discolored water, suggests an ongoing submarine eruption at Ahyi Seamount. Thus, the Aviation Color Code and Volcano Alert Level are being raised to YELLOW and ADVISORY. We will continue to monitor satellite and distal hydroacoustic data for additional evidence for, or escalation of, volcanic activity.