Bella Tuvianosa, Phivolcs resident volcanologist, said that although the number of volcanic quakes has lessened compared to the 59 recorded in the preceeding 24 hours, it is still high compared to the two to three quakes recorded when the volcano is in normal state.
Tuvianosa said the sulfur gas emission ranges from moderate to profuse and rising with force to reach about 300 meters from the summit and drifting towards the west-north-west and south-west direction.
Phivolcs raised the alert level to 1 on Sunday after seismic sensors around the volcano detected 73 low and high frequency volcanic quakes. Alert level 1 in a five-step alert signifies a moderate level of unrest.
The phreatic explosion which occurred at 10:50 p.m. on Wednesday was followed by a series of explosions at 11:37 p.m. as volcanic materials came into contact with water.
Ash fall accompanied by the smell of burnt sulfur were observed as far as Barangay Peñafrancia in Claveria, Masbate one hour after the ash-driven explosion, which rose about 1.5 kilometers from the volcano’s summit.
The explosion was accompanied by lightning flashes and loud rumbling sounds. One hour after the 1,600-meter volcano ejected ash, light ash falls drifted towards the north, south and west areas of the volcano and were experienced by residents in Barangay Cogon, Tinampo, Gulang-gulang, and Bolos in Irosin town, which is about six kilometers from the volcano, including Juban and neighboring sitios.
Irosin Mayor Lilia Gonzales also activated the municipal disaster coordinating council just in case the volcano intensifies.
The institute reiterates its warning to the public not to venture inside the four-kilometer permanent danger zone due to ash ejections and explosions.
With the onset of the La Niña phenomenon, Phivolcs warned residents of barangays that experienced ash falls to keep away from valley, river or stream channels during heavy rains as loose deposits on the volcano’s upper slopes could easily be transformed to life-threatening mudflows.
Sorsogon Gov. Raul Lee has ordered Noel Pura, the head of the provincial disaster management office, to activate the provincial disaster coordinating council to map out plans in case the present level of unrest intensifies in the coming days. — With Shiela Crisostomo