Philippines major volcanoes now all showing signs of increased unrest

Taal Volcano – Restive Taal Volcano continued to show signs of activity, as state volcanologists recorded at least five volcanic quakes there in the last 24 hours. The Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday said it also observed weak steaming activity at the thermal area of the main crater-lake. Phivolcs also reiterated its warning against carbon dioxide in the area, saying gas measurements in March amounted to 4,670 tons per day – double the 2,250 tons per day in January. “The remarkable increase in C02 [Carbon dioxide] concentration indicates anomalous gas release from the magma at depth,” it said. It added Alert Level 1 remains over Taal Volcano, saying no eruption is imminent but the public should strictly observe some safety precautions.

Bulusan Volcano – Phivolcs also recorded at least three volcanic quakes around Bulusan Volcano in Bicol in the last 24 hours. It also noted a “wispy to weak emission of white steam” at the southeast and northwest thermal vents while the summit crater was cloud-covered during the past observation period. No lahar event was reported or observed. Phivolcs said Bulusan Volcano’s status remains at Alert Level 1, meaning the source of activity is hydrothermal and shallow. “Entry to the 4-kilometer radius Permanent Danger Zone (PDZ) is strictly prohibited, since the area is at risk to sudden steam and ash explosions. Due to the prevailing wind direction, residents in the northwest and southwest sectors of the volcano are reminded to take precautions against ash falls,” it said. Civil aviation authorities were also urged to warn pilots to avoid flying close to the volcano’s summit as ejected ash and volcanic fragments from sudden explosions may be hazardous to aircraft.

Mayon Volcano – Phivolcs said Mayon Volcano in Albay did not detect any volcanic earthquake during the past 24 hours, while steam from the crater varied from wispy to weak and drifted towards west-southwest. But it said a fair crater glow (Intensity II, can be seen by naked eye) was observed Tuesday night. Alert Level 1 is also in effect over Mayon Volcano, Phivolcs said. “Although this means that no eruption is imminent, it is recommended that the public should not enter the 6-kilometer radius PDZ due to the continuing threat from sudden small explosions and rockfalls from the upper and middle slopes of the volcano,” it said. –GMA News    –April 7, 2011