Taal Volcano in Batangas. —PHOTO COURTESY OF SHIELA TAN
LUCENA CITY — Volcanic earthquakes and tremors continued to be recorded in Taal Volcano in Batangas province, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported on Monday morning, Dec. 23.
On Sunday, the Phivolcs detected four volcanic earthquakes accompanied by three tremors that lasted three to five minutes.
Six earthquakes and five volcanic tremors lasting three to six minutes were also detected the day before.
On Dec. 20, Taal recorded three volcanic tremors that lasted three to 39 minutes.
Phivolcs defines volcanic earthquakes as those “generated by magmatic processes or magma-related processes beneath or near an active volcano.”
“Unlike tectonic earthquakes that are produced by faulting, volcanic earthquakes are directly produced by many processes and are therefore much more varied in characteristics,” the agency explained.
Volcanic tremors, on the other hand, are “continuous seismic signals with regular or irregular oscillations and low frequencies (typically 0.5–5 Hz) that can last for more than a minute.”
Phivolcs added: “Tremor can be caused by different processes inside the volcano, including resonance triggered by magma or magmatic gas flowing through cracks and vents, successive overlapping low-frequency earthquakes, and eruptions of magma.”
READ: Phivolcs detects 11 tremors in Taal Volcano
In its latest update, Phivolcs also recorded the emission of 8,322 metric tons (MT) of sulfur dioxide (SO2) from Taal’s main crater, which rose 600 meters high before drifting in the southwest direction.
In an advisory on Dec. 16, Phivolcs noted that Taal Volcano has an average of about 6,057 tonnes/day for the year and has continuously degassed voluminous concentrations of SO2 since 2021.
It emphasized that 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.”
“Prolonged exposure to volcanic SO2 can cause irritation of the eyes, throat and respiratory tract.
People who may be particularly sensitive are those with health conditions such as asthma, lung disease and heart disease, the elderly, pregnant women and children,” the Phivolcs warned.
There was no upwelling of hot volcanic fluids in the Main Crater Lake on Taal Volcano Island, locally known as “Pulo,” which sits in the middle of Taal Lake, the state volcanologists recorded in its latest bulletin.
During the latest observation, the Phivolcs also reported the absence of “vog,” or volcanic smog.
The agency reminded the public that Alert Level 1 prevails over Taal Volcano, “which means that it is still in abnormal condition and should not be interpreted to have ceased unrest nor ceased the threat of eruptive activity.”
“At Alert Level 1, sudden steam-driven or phreatic or minor phreatomagmatic eruptions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within TVI (Taal Volcano Island,” the Phivolcs said.
Phivolcs reminded the public that entry to Taal Volcano Island, boating activities on Taal Lake, and flying aircraft near the volcano remain strictly prohibited. INQ