Geologic Background:
The highest point on the central Philippines
island of Negros, Canlaon contains a broad north crater
with a crater lake and a smaller historically active
crater to the south. The massive 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 extends 33 km SW from
Canlaon.
Historic Activity:
- Eruptions (14) have occurred in 1866, 1893, 1894,
1902, 1904-1906, 1969, 1970, and 1978. Typically
consisted of small to moderate phreatic explosions.
- Historical eruptions, recorded since 1866, have
typically been phreatic explosions of small-to-moderate
size that produce minor ashfalls near the volcano.
Recent Activity:
- Small steam and ash eruption in mid-March 1985
followed seismic activity
- During June 1986 two eruptions of ash reached heights
of 4000 m above the summit.
- Small ash eruption during April 1987 followed
increased seismicity and thermal activity.
- A series of ash ejections began on June 21,
1988.
- A series of ash ejections began on Oct. 25, 1989 and
were continuing as of early Dec.
- A mild ash emission occurred on January 8, 1992.
Volcanic tremor and earthquakes accompanied the eruption.
Geologists believe that the eruption was triggered by
ground water suddenly contacting hot rock beneath the
summit crater.
- A 1-km high ash emission and ashfall occurred on June
10, 1992.
- A mild phreatic explosion occurred on August 25, 1993
which produced a voluminous gray steam cloud to 800 m. A
second mild phreatic explosion occurred on Sept. 3 and
produced a grayish steam-and-ash column that rose 1,000 m
above the summit.
- On Aug. 10, 1996 an ash ejection emitted a
dirty-white steam-and-ash plume to 1,500 m above the
central summit crater. The ash ejection lasted about 24
minutes. Twenty-one people were in the summit area at the
time, three were killed by falling ejecta.
- Moderate earthquake activity from Jan to March
2001.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 10, No. 2 to V. 14,
No. 11)
- Global Volcanism Network (V. 16, No. 12 to V. 26, No.
10).
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