THE Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday lowered the status of Taal Volcano in Batangas to Alert Level 1 due to reduced volcanic activity.
However, Phivolcs said the downgrade to Level 1 (low-level unrest), from Level 2 (decreased unrest), does not necessarily mean the threat of eruption is already gone.
“Alert Level 1 means that the volcano is still in abnormal condition and should not be interpreted that unrest has ceased or that the threat of an eruption has disappeared,” Phivolcs said in an advisory.
It said Alert Level 2 may be restored “should an uptrend or pronounced change in monitored parameters forewarn of renewed unrest.”
“Conversely, should there be a return of monitoring parameters to baseline levels after a sufficient observation period, the alert level will be further lowered to Alert Level 0 (normal),” it added.
Phivolcs raised Alert Level 3 in Taal Volcano in March after a series of phreatic or steam-driven eruptions. It lowered the status to Level 2 after a month due to improved condition.
In further lowering the alert status yesterday, Phivolcs said: “Taal Volcano’s condition in the past two months has been characterized by baseline volcanic earthquake activity, stabilizing ground deformation of the Taal Caldera and Taal Volcano Island (TVI) edifices and weak degassing and surface activity at the main crater.”
Phivolcs said these observations were supported by four monitoring parameters, including daily volcanic earthquakes which is now zero since June 13, from seven covering the period of January 1 to May 31.
Phivolcs also said Taal’s surface activity showed “weak emission of 300 to 2,400-meter tall steam reach plumes from fumaroles or active gas vents on the main crater.”
It said the last significant surface activities of Taal was on February 2, February 10 and March 26 when the volcano spewed 300 to 3,000-meter plumes.
“Since then, background hydrothermal activity in the Main Crater Lake has been quietly transpiring,” it also said.
While Taal is already at Alert Level 1, Phivolcs said “sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within TVI.”
It said entry to the TVI, the permanent danger zone, especially in the vicinity of the main crater and the Daang Kastila fissure, should be prohibited.
Phivolcs also urged civil aviation authorities to advise pilots to avoid flying close to the volcano “as airborne ash and ballistic fragments from sudden explosions and wind-remobilized ash may pose hazards to aircraft.”
