PHIVOLCS lowered the Alert Level for Taal to 2 (on a scale of 0-5) on 23 July, noting that no eruptions had been recorded since the period of phreatomagmatic activity during 1-9 July. Additionally, an overall decrease was evident in multiple monitoring parameters. Sulfur dioxide emissions peaked at 22,628 tonnes/day on 4 July and declined to an average of 4,763 tonnes/day during 8-22 July. Steam plumes continued to be generated from the lake, rising 10-1,000 m, and lake upwelling was generally less vigorous. The DROMIC report stated that 794 people were in evacuation centers or private residences by 26 July. PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ).

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.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Disaster Response Operations Monitoring and Information Center (DROMIC)