简体中文
By APD writer Melo M. Acuña
MANILA, Jan. 26 (APD) – The Philippine Institute of Volcanology and Seismology has lowered Taal Volcano’s alert level from hazardous eruption imminent to a decreased tendency towards hazardous eruption.
In an official release Sunday, PHIVOLCS said Taal Volcano’s condition during the past two weeks after its main eruptive phase from January 12-23, has “generally declined into less frequent volcanic earthquake activity. They also noted a decelerated ground deformation of the Taal Caldera and Taal Volcano Island structures accompanied by weak steam/gas emissions at the main crater.
Earthquakes recorded by the Philippine Seismic Network (PSN) across the Taal region declined from 959 to 27 events per day with peak magnitudes of M 4.1 to M2.1 from January 12 to 24.
The Global Positioning System or GPS data recorded ground deformation after the main eruptive phase which included the sudden widening of Taal Caldera by a meter and uplift of its northwestern sector by 20 centimeters accompanied by subsidence of the southwestern part of the Taal Volcano Island by one meter.
Government scientists said after the main eruptive phase, the activity in the Taal Main Crater diminished to infrequent weak ash eruptions and longer episodes of degassing or steaming that generated steam-laden plumes of less than 1,000 meters tall. The Sulfur dioxide emission fluctuated from ahigh or -5,300 tonnes per day last January 13 to a low of -140 tonnes per day on January 22 but averaged at 250 tonnes per day during the last five days.
Private vehicles are being checked by expressway authorities as they join other groups in delivering relief goods to Taal volcano victims early Sunday morning. (MMA photo)
“This low concentration average is consistent with a progressively degassed shallow magma source and diminished plume activity,” the statement added.
With all these factors taken into consideration, PHIVOLCS said they are lowering the alert status from Alert Level 4 to Alert Level 3 “to reflect the overall decrease in the level of monitoring parameters.”
However, they added the lowering of alert status “should not be interpreted that unrest has ceased or that the threat of a hazardous eruption has disappeared.” Should there be an increase or pronounced change in monitored parameters, it ought to be considered a potentially hazardous explosive eruption, they will immediately increase the alert level.
Residents in areas considered high risk to base surges who have returned after the alert level was decreased should and must be prepared for a quick and organized evacuation.
They called on local officials to strongly implement the ban on entry into the Permanent Danger Zone and areas over Taal Lake and communities west of the volcano island within the seven-kilometer radius from the main crater.
Batangas Governor Hermilando I. Mandanas said residents may opt to return to their homes except those from the towns of Agoncillo and Laurel. He said nobody is allowed to return to the volcano island which has been frequented by domestic and foreign tourists as the possibility exists Taal Volcano may still erupt. He called on residents who would return to their homes to prepare to evacuate within an hour should the alert level be increased to Alert Level 4.
Meanwhile, local government units and non-government organizations including private individuals outside Batangas Province have continued to bring relief goods to the displaced residents.
It is a common sight to see the convoy of both government and private vehicles along the South Luzon Expressway loaded with food and clothing as well as prime commodities up for distribution in evacuation centers composed of public school buildings and Catholic churches.
(ASIA PACIFIC DAILY)
