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PHIVOLCS Website
LOCATION:
NEGROS ISLAND, Central Visayas (10°24.7'N - 123°7.9'E)
PHYSICAL CHARACTERISTICS:
Height: 2,435 m asl
Craters: 5
major vents aligned NNE with the present active crater
Type of Volcano:
Stratovolcano
Summit Caldera:
15 kmē
Types of Deposits:
lava flows, pyroclastic flows, lahars, ballistic blocks (near
summit), airfall ash
Composition of Lava:
Andesitic
HISTORICAL ERUPTIONS:
No. of Recorded Eruptions: 27 since 1866, no recorded
destructive eruption
Latest Eruption:
10 August 1996
Eruption Types:
Phreatic - steam-driven explosion (e.g. 1985, 1992, 1993,1994 &
1996 eruptions)
Phreato-magmatic - steam-driven with magma involced (e.g. 1884
eruption)
Strombolian - quiet emission of lava (e.g. 1902 eruption)
Precursors to
Eruptions:
Increase in frequency of volcanic tremors/quakes
Inflationary trend for geodetic measurements
Increased steaming activity
Sulfur stench observed at Cabagnaan and Mambucal
Increased chloride concentration and lowering of pH at Mambucal hot
springs
MONITORING TECHNIQUES:
Monitoring Methods:
A. Geophysical Method - seismic monitoring
B. Geodetic Method - ground deformation
Electronic Distance Measurement
Precise leveling
Tilt measurements (wet and dry)
C. Visual Observations
D. Geochemical methods (temporarily stopped since 1991 until
Canlaon shows signs of
renewed activity)
Monitoring Station:
Canlaon City Observatory - 8.7 km ESE of the summit
Cabagnaan Observatory - 5.5 km S of the summit
DANGER ZONES:
Permanent Danger Zone - 4 to 8 km radius from summit as
determined shortly before crises,
includes 19 barangays of the town of Castellana and cities of La
Carlota and Canlaon.
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