By Danny O. Calleja
SORSOGON CITY, Dec. 29 (PNA) -– Government scientists have warned on the risk of flashfloods and landslides down areas near the restive Bulusan Volcano as the tail-end of the cold front continued to dump heavy rains across Sorsogon province Wednesday.
“The weather situation indicates that more rains would take place over areas around the volcano and these may cause water-triggered disasters, particularly in low-lying sites,” Ed Laguerta, the resident volcanologist of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said in an advisory aired over local radio broadcasts here Wednesday morning.
Heavy rains, from intermittent to continuous, have been pelting the southeastern and central sections of the province since early this month and, although the Philippine weather bureau allayed fear of a typhoon before the end of the year, Laguerta said the situation calls for the activation of local disaster risk reduction management councils.
He said water level in all river channels emanating from the slopes of the volcano and stretching down barangays covered by the municipality of Irosin are already high and may overflow anytime, given the huge volume of rainwater still expected to be dumped the whole day by the prevailing weather condition.
Residents near river banks should be on alert and be ready to evacuate all the time, Laguerta said.
Moderate lahar flow has been taking place over these rivers, he said, adding that landslide-prone areas at the Casiguran and Juban towns sections of the volcano should stay watchful and, better still, evacuate to safer grounds.
On the abnormal condition of the volcano, Laguerta said that, although it is silent for the past two weeks, alert level number one remains in effect, which means the danger of eruptions still exists giving reasons for a ban of human activities within its four-kilometer permanent danger zone (PDZ).
The PHIVOLCS seismographs at its Mt. Bulusan Observatory in Barangay Cabid-an here, he said, have been detecting only moderate tremors around the volcano, indicating no significant volcanic movement during latest monitoring periods.
“The important thing is to observe the PDZ. Even if there is no apparent volcanic activity, sometimes, steam-driven explosions can occur and this is what people should look out for,” he added, explaining that steam-driven explosions are due to hot rocks under the volcano interacting with rainwater.
The same activity took place as Bulusan restarted acting up in the morning of October 2, sending an ash column some 600 meters from the crater, Laguerta said.
Several other similar types of explosions, characterized by massive ejection of ash and steam, followed early this month. All those eruptions were categorized as phreatic for the absence of magmatic or lava intrusion.
Those eruptions, the resident volcanologist said, are considered preparatory to major eruptions “that is why we are not letting our guard down”.
For now, there is nothing to worry about any major eruption as the volcanic materials being recovered following ash ejections are old debris that indicated no magmatic activities yet, he added.
As these developed, Jose Lopez, the Provincial Disaster Risk Management Office (PDRRMO) chief, said his office has been closely monitoring the situation and assured that evacuation operations are in place should the situation would call for it.
All municipal DRRMOs in the six towns around the volcano have already been alerted for possible rescue and relief operations, Lopez said.
Casiguran town Mayor Ester Hamor said she dispatched the local DRR team to areas near the volcano within their area of responsibility to evaluate the situation and warn residents in at least two barangays at risk of being hit by land erosions.