The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Taal during 10-17 December. Daily emissions that were mostly diffuse rose 400-600 m above the crater rim and drifted SW and WSW. There were 3-10 daily occurrences of volcanic tremor during 10-12 December, with highly variable periods of between three minutes to six hours. Two volcanic earthquakes were recorded on 15 December. Sulfur dioxide gas emissions averaged 2,825 tonnes per day (t/d) on 11 December and 5,800 t/d on 14 December. An advisory issued at 1745 on 16 December stated that of sulfur dioxide emissions had reached 8,322 t/d, higher than the year’s average of 6,057 t/d. The Alert Level remained at 1 (on a scale of 0-5); PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain 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)