Seismic activity in Taal Volcano continues to rise
CLEAR VIEW A small cloud of steam rises from Taal Volcano, as seen from Tagaytay City on Monday. Three days later, on Thursday, a minor phreatic eruption from the main crater on Taal Volcano
Island was recorded by volcanologists at 7:21 a.m. —ROBERT JAWORSKI L. ABAÑO
LUCENA CITY — The Philippine Institute of Volcanology and Seismology (Phivolcs) on Thursday, May 1, reported a continued rise in seismic activity at Taal Volcano in Batangas province.
In its morning bulletin, Phivolcs said Taal recorded 64 volcanic earthquakes, accompanied by five volcanic tremors lasting one to two minutes in the past 24 hours.
On April 29, the agency recorded 53 volcanic earthquakes and 13 tremor episodes. On April 27, there were 37 earthquakes and eight tremors. On April 26, Taal registered 56 quakes and 14 tremors. Between April 8 and 26, Phivolcs logged 126 volcanic earthquakes and 34 tremor episodes.
The agency said the data suggest ongoing magmatic activity beneath or near the volcano.
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, meanwhile, 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.”
“Tremors 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,” it added.
In its latest update, Phivolcs recorded the emission of 1,213 metric tons of sulfur dioxide (SO₂) from Taal’s main crater — a significant increase from the 672 metric tons recorded the previous day. The emission was classified as “weak”
No upwelling of hot volcanic fluids was observed in the Main Crater Lake, and no volcanic smog, or “vog,” was detected during the latest monitoring period.
Taal Volcano remains under Alert Level 1, which indicates abnormal activity. Phivolcs reiterated that this status does not mean unrest has ceased or that the threat of eruption has been ruled out.
