Report on Taal (Philippines) — 10 March-16 March 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
10 March-16 March 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, 10 March-16 March 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 during 10-13 March there were around 51-55 volcanic earthquakes recorded daily at Taal, and about 23-49 periods of volcanic tremor with variable durations. One hybrid earthquake was recorded during 11-12 March. Diffuse steam plumes from fumarolic vents in Main Crater rose only 5 m. Sulfur dioxide emissions were 1,327 tonnes per day on 10 March, and fluctuated between 518 and 795 tonnes per day through 14 March. At 1411 on 12 March a short-lived (2.5 minutes) burst of steam-rich gas from Main Crater generated white plumes that rose 400-500 m. Diffuse steam plumes rose 50 m above fumarolic vents on the inner N and E walls during the rest of the day.
The number of volcanic earthquakes per day rose to 74 during 13-14 March and to 252 during 15-16 March. Episodes of tremor persisted, with 17-46 periods recorded per day. Five hybrid events were detected during 14-15 March. An episode of high-temperature gas upwelling to the crater lake’s surface occurred during 1830-2045 on 14 March. Sulfur dioxide emissions were 1,216 tonnes per day on 15 March. Steam emissions rose 10 km during 15-16 March. The seismic network recorded 42 volcanic earthquakes and 34 periods of tremor. 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.