Report on Taal (Philippines) — 7 July-13 July 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
7 July-13 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, 7 July-13 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 reported that an eruption at Taal continued during 7-13 July. A series of short-lived phreatomagmatic explosions were recorded at 0518, 0847, 0915, 0926, 1156, and 2141 on 7 July and jetted ash plumes as high has 700 m. Another series was recorded at 0647, 1806, 2121, 2150 on 8 July and 0259 on 9 July, jetting ash 200 m high.
During 7-13 July daily plumes of steam and sulfur dioxide gas rose 1-1.5 km from the lake and drifted NW, W, and SW. Sulfur dioxide emissions averaged 4,149-11,397 tonnes/day. Low-level background tremor continued with as many as 185 volcanic earthquakes and 44 low-frequency volcanic earthquakes recorded per day. There were also 5-176 daily episodes of volcanic tremor, each lasting between 1 and 97 minutes. The network also detected 2-10 daily hybrid earthquakes during 6-9 July. The DROMIC report stated that 10,408 people were in evacuation centers or private residences by 12 July. The Alert Level remained at 3 (on a scale of 0-5) and PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and to not enter the high-risk barangays of Agoncillo and Laurel. Activities on Taal Lake were 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 observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities.