PHIVOLCS reported that unrest at Taal continued during 25-31 January, and low-level background tremor persisted. One volcanic earthquake was recorded during 25-28 January. Hot volcanic fluids were upwelling in the crater lake, and daily gas-and-steam plumes rose 1.5-2 km above the lake that drifted SW and NW. Sulfur dioxide emissions continued to be elevated, averaging 10,506-18,705 tonnes/day.

A series of nine phreatomagmatic bursts from the lake occurred between 1550 on 29 January and 0449 on 30 January. Each event was short-lived, only lasting between 10 seconds and two minutes, and recorded as trace signals in the seismic data but as distinct signals in the infrasound data. Each burst produced a steam-rich plume rising 400-900 m. Sulfur dioxide emissions averaged 4,829 tonnes per day on 30 January. Seismic data during 29-30 January consisted of 31 volcanic earthquakes and 14 tremor events with durations of 1-3 minutes, and during 30-31 January 13 volcanic earthquakes were recorded along with one tremor signal that lasted three minutes. Emissions rose as high as 1 km and drifted SW. The Volcano Alert Level remained at a 2 (on a scale of 0-5). PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and warned against extended stays on Taal Lake.

Geological Summary. Taal is one of the most active volcanoes in the Philippines and has produced some powerful eruptions. The 15 x 20 km Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2 surface lies only 3 m above sea level. The maximum depth of the lake is 160 m, with several submerged eruptive centers. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)