The USGS reported that seismic tremor levels at Anatahan were relatively low during 8-13 February, except for short-lived increases during 8-9 and 12-13 February. On 9 February, a diffuse steam plume that possibly contained ash was observed on satellite imagery and drifted W. The Washington VAAC reported that more steam plumes possibly containing some ash were visible on satellite imagery on 11, 12, and 13 February and drifted NW and SE. On 13 February, vog (volcanic fog) was also observed N and W of Saipan. Emissions of sulfur dioxide were detected by the satellite-based Ozone Monitoring Instrument (OMI). The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.
Sources: Emergency Management Office of the Commonwealth of the Mariana Islands and the US Geological Survey Hawaiian Volcano Observatory, Washington Volcanic Ash Advisory Center (VAAC) - “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”