PHIVOLCS reported that sulfur dioxide emissions at Taal averaged 8,854 tonnes/day beginning on 27 September, and peaked on 5 October at 25,456 tonnes/day which was the highest ever sulfur dioxide gas flux recorded at the volcano. On 27 September the number of daily volcanic earthquakes significantly decreased. During 27 September-5 October upwelling of hot volcanic fluids in the lake was visible and gas-and-steam plumes rose as high as 3 km above the lake. The report noted that a sudden increase in inflation below Taal Volcano Island was recorded in August. 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 that boating on Taal Lake was 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)