Report on Kanlaon (Philippines) — 10 February-16 February 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 February-16 February 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Kanlaon (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 February-16 February 2021. Smithsonian Institution and US Geological Survey.
10.412°N, 123.132°E; summit elev. 2435 m
All times are local (unless otherwise noted)
PHIVOLCS reported slightly increased seismic activity and volcanic gas flux at Kanlaon. The seismic network recorded 28 volcanic earthquakes during 11-13 February with local magnitudes between 0.7 and 2.2. They were located at shallow depths around 10 km across the N to E portions of the edifice. The sulfur dioxide emission rate on 13 February was 1,130 tonnes per day, the highest value recorded this year; sulfur dioxide emissions had been higher than background levels of 300 tonnes/day since June 2020. Ground deformation data from continuous GPS and tilt measurements indicated slight inflation of the lower and middle flanks since June 2020. Increased seismic activity continued through 16 February; from 0800 on 14 February to 0800 on 16 February there were a total of 59 earthquakes. The Alert Level remained at 1 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone.
Geologic Background. 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.