Report on Taal (Philippines) — 28 April-4 May 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
28 April-4 May 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, 28 April-4 May 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 reported that unrest at Taal continued during 27 April-4 May. Low-level background tremor that had begun at 0905 on 8 April continued, along with 2-26 daily low-frequency events and 5-37 daily volcanic earthquakes during 28 April-2 May. One hybrid event was detected during 28-29 April. Diffuse steam plumes from fumarolic vents in Main Crater rose 5-10 m on most days. Average daily sulfur dioxide emission rates were in the 1,452-3,191 tonnes per day range. Upwelling of hot volcanic fluids in the crater lake was accompanied by steam plumes that were 300-600 m tall on 27 April, 30 April, and 4 May. The Alert Level for Taal remained at 2 (on a scale of 0-5). PHIVOLCS strongly recommended no entry onto the island, and access to the Main Crater and Daang Kastila fissure (along the walking trail) was strictly prohibited.
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.