Report on Taal (Philippines) — 4 October-10 October 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 October-10 October 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Taal (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 4 October-10 October 2006. 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 ongoing seismic unrest at Taal on 26 September. During 25-26 September, 29 volcanic earthquakes occurred with five felt Modified Mercalli intensities of II to III. Epicenters were dispersed NE, N, and NW. Approximately five seismic events in a 24-hour period is typical during quiet periods.
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 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.