On 25 September PHIVOLCS warned of potential lahars around Taal due to intense rains from a typhoon expected during 25-26 September, with a particular focus on the western part of the caldera where ash deposits could become remobilized and affect the communities of Agoncillo and Laurel, Batangas Province. The report also warned that the ground cracks formed during the 2020 eruption on the NE and SW sectors of Taal Caldera may become enlarged or eroded and cause damage to buildings and houses. The ground cracks were located in the municipalities of Agoncillo, San Nicolas, Lemery, and Taal on the SW part of the caldera, and in the cities of Talisay and Tanauan on the NE side.

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)