Report on Taal (Philippines) — 2 June-8 June 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 June-8 June 2010
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2010. Report on Taal (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 2 June-8 June 2010. Smithsonian Institution and US Geological Survey.
14.002°N, 120.993°E; summit elev. 311 m
All times are local (unless otherwise noted)
On 8 June, PHIVOLCS raised the Alert Level for Taal to 2 (scale is 0-5, 0 referring to No Alert status) due to changes in several monitored parameters, starting in late April. Since 26 April the number of earthquakes per day continued to increase, as well as the magnitude. Low-frequency volcanic earthquakes were detected on 2 June, and during the previous day high-frequency earthquakes were noted. In addition to increased seismicity, the temperature of the Main Crater Lake increased from 32 degrees Celsius on 11 May to 34 degrees Celsius on 24 May. Steaming from the N and NE sides of Main Crater occasionally intensified. Deformation data had shown slight inflation since 2004; measurements taken at the SE side of Taal on 7 June showed further inflation by 3 mm.
Geologic Background. 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 topography 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 has grown about 25% in area during historical time. Powerful pyroclastic flows and surges from historical eruptions have caused many fatalities.