PHIVOLCS reported ongoing seismic unrest at Taal on 26 September. During 25-26 September, 29 volcanic earthquakes occurred with five felt Modified Mercalli intensities of II to III. Epicenters were dispersed NE, N, and NW. Approximately five seismic events in a 24-hour period is typical during quiet periods.

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)