In a special report for Taal issued on 15 November, PHIVOLCS noted that sulfur dioxide emissions were as high as 11,695 tonnes per day (t/d) and gas-and-steam plumes rose up to 1.2 km. A minor sulfur odor was reported in Banyaga, Agoncillo. High concentrations of gas had been continually emitted since March 2021; emissions averaged 6,267 t/d since September. Seismicity was at moderate levels; of the 686 earthquakes recorded during 1 September-15 November 629 were volcanic tremors associated with gas emissions. Sulfur dioxide emissions averaged 8,024 t/d on 16 November. During 16-21 November pronounced upwelling of gasses and hot fluids in the lake produced plumes that rose 500-1,200 m and drifted SW. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ).

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)