Report on Kanlaon (Philippines) — October 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 10 (October 1989)
Managing Editor: Lindsay McClelland.
Kanlaon (Philippines) Mild ash ejections to 1,200 m
Please cite this report as:
Global Volcanism Program, 1989. Report on Kanlaon (Philippines) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 14:10. Smithsonian Institution.
10.412°N, 123.132°E; summit elev. 2435 m
All times are local (unless otherwise noted)
Since 25 October, mildly explosive ash ejections, to as much as 1,200 m above the summit, have occurred almost daily. As of 3 November, 29 voluminous gray plumes had deposited ash over the entire crater area and the upper SW and S slopes. No significant seismicity preceded emissions, which were accompanied by small-amplitude explosion earthquakes and tremor episodes. Iseismicity;explosion earthquake Total sulfate concentrations of hot springs NW of the crater have increased since March, from 90 to 135 ppm in the aquapool, 300 to 365 ppm in the mudpool, and 180 to 250 ppm in the sulfur spring.
Geological Summary. Kanlaon volcano (also spelled Canlaon), the most active of the central Philippines, forms the highest point on the island of Negros. The massive andesitic stratovolcano is dotted with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller, but higher, historically active vent, Lugud crater, to the south. Historical eruptions, recorded since 1866, have typically consisted of phreatic explosions of small-to-moderate size that produce minor ashfalls near the volcano.
Information Contacts: PHIVOLCS.