Report on Taal (Philippines) — 21 July-27 July 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
21 July-27 July 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Taal (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 21 July-27 July 2021. Smithsonian Institution and US Geological Survey.
14.002°N, 120.993°E; summit elev. 311 m
All times are local (unless otherwise noted)
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 of its most powerful historical eruptions. Though not topographically prominent, its prehistorical eruptions have greatly changed the landscape of SW Luzon. 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, and several eruptive centers lie submerged beneath the lake. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all historical eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones that have grown about 25% in area during historical time. Powerful pyroclastic flows and surges from historical eruptions have caused many fatalities.