Alert Level 1 remains in effect despite a “minor phreatomagmatic eruption” recorded by the Philippine Institute of Volcanology and Seismology (Phivolcs) on Saturday, Oct. 5.
In an advisory, Phivolcs stated that the eruption at the Taal Main Crater occurred at 11:32 a.m. and lasted four minutes, according to records from the Taal Volcano Network (TVN).
“The event produced a short, black jetted plume, followed by a steam-rich plume that rose 2,000 meters above the Main Crater before drifting southwest, based on IP camera monitors,” Phivolcs reported.
Before this, Phivolcs noted that phreatic events had been recorded earlier.
Additionally, trace ashfall has been reported in the Agoncillo area.
Since Sept. 22 of this year, Phivolcs reported a total of 30 minor eruptive events.
Alert Level 1
Meanwhile, Phivolcs reminded the public that Alert Level 1 prevails over Taal Volcano.
This means that Taal is still in an “abnormal condition” and should not be interpreted as having ceased unrest or the threat of eruptive activity.
“At Alert Level 1, sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within Taal Volcano Island (TVI),” Phivolcs stated.
Phivolcs also noted that the degassing of high concentrations of volcanic SO2 continues to pose the “threat of potential long-term health impacts” to communities around the Taal Caldera that are frequently exposed to volcanic gas.
Entry into TVI, Taal’s Permanent Danger Zone (PDZ), especially in the vicinities of the Main Crater and the Daang Kastila fissure, should be strictly prohibited, according to Phivolcs.
Additionally, Phivolcs advised local government units (LGUs) to “continuously monitor and assess the preparedness of their communities and undertake appropriate response measures to mitigate hazards posed by long-term degassing and related phreatic activity.”
Moreover, Phivolcs stated that civil aviation authorities “must 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.”
SO2 emissions
Phivolcs stated that sulfur dioxide (SO2) emissions averaged 3,276 tonnes/day on Oct. 4.
“Nonetheless, average SO2 emissions since January of this year remain high at 6,673 tonnes/day,” Phivolcs explained.
They added that the phreatomagmatic event was “likely driven by the sudden contact of water with a small branch of shallow magma that has been present beneath the Taal Main Crater and has been degassing sustained levels of SO2 for the past three years.”
“The background levels of volcanic earthquake activity and ground deformation detected at Taal indicate that unrest is unlikely to progress into a major magmatic eruption at this time,” Phivolcs added.