PHIVOLCS reported that unrest at Taal continued during 19-25 May. Low-level background tremor that had begun at 0905 on 8 April continued. During 19-21 May there were 2-30 daily low-frequency events, 10-169 daily volcanic earthquakes, and 8-139 periods of volcanic tremor with variable durations (1-37 minutes); no earthquakes were recorded during 22-25 May. Most of the earthquakes were very shallow (less than 5 km deep) beneath Taal Volcano Island (TVI) and the NE part of Taal Lake. Daily upwelling of hot volcanic fluids in the crater lake was accompanied by sometimes voluminous steam plumes that were as tall as 2 km. Sulfur dioxide emissions were 2,811-3,611 tonnes/day. Slow and steady inflation of the Taal region was recorded by multiple instruments after the January 2020 eruption. PHIVOLCS noted the continuing state of elevated unrest, reminding the public that the Alert Level for Taal remained at 2 (on a scale of 0-5). PHIVOLCS strongly recommended no entry onto the island, and access to the Main Crater, Daang Kastila fissure (along the walking trail), and boating on Taal Lake was strictly prohibited.

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)