The Philippine Institute of Volcanology and Seismology (Phivolcs) observed two weak phreatic events at Taal Volcano on Saturday, June 29.
Phivolcs noted that the steam-driven activity at the Taal Main Crater occurred at 2:31 p.m. and 2:39 p.m., each lasting a minute, based on visual, seismic, and infrasound records of the Taal Volcano Network (TVN).
The events produced steam-laden plumes that rose 800 meters above the Main Crater before drifting southwest, according to IP camera monitors, Phivolcs said.
Phivolcs noted that sulfur dioxide (SO2) emissions averaged 6,571 tonnes per day on June 28.
“Nonetheless, average SO2 emissions since January this year remain high at 7,895 tonnes per day,” Phivolcs explained.
State seismologists noted that the weak phreatic activity is “likely driven by the continued emission of hot volcanic gases at the Taal Main Crater and could be succeeded by similar events.”
However, the background levels of volcanic earthquake activity and ground deformation detected at Taal “indicate that unrest is unlikely to progress into a magmatic eruption,” Phivolcs said.
Alert Level 1
Meanwhile, Phivolcs reminded the public that Alert Level 1 prevails over Taal Volcano, meaning that it is still in an “abnormal condition and should not be interpreted as having ceased unrest or the threat of eruptive activity.”
Phivolcs explained that 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).
Moreover, Phivolcs noted that the degassing of high concentrations of volcanic SO2 continues to “pose the threat of potential long-term health impacts” to communities around Taal Caldera that are frequently exposed to volcanic gas.
Phivolcs strongly recommended that entry into TVI, Taal’s Permanent Danger Zone (PDZ), especially the vicinities of the Main Crater and the Daang Kastila fissure, “must remain strictly prohibited.”
Local government units (LGUs) were also advised to “continuously monitor and assess the preparedness of their communities and undertake appropriate response measures to mitigate hazards that could be posed by long-term degassing and related phreatic activity.”
Meanwhile, Phivolcs reminded civil aviation authorities to advise pilots to “avoid flying close to the volcano, as airborne ash and ballistic fragments from explosions and wind-remobilized ash may pose hazards to aircraft.”