Taal Volcano in Batangas recorded 10 earthquakes in 24 hours, down from 20 the previous day, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported on Thursday, Oct. 9.
From October 1 to 9, a total of 78 volcanic earthquakes and four tremor episodes were recorded. In comparison, Phivolcs documented 189 volcanic earthquakes and 129 tremors in September.
The four tremors occurred during the two phreatic eruptions on Oct. 2.
Phivolcs defines volcanic earthquakes as those ‘generated by magmatic processes or magma-related processes beneath or near an active volcano.’ Volcanic tremors are ‘continuous seismic signals with regular or irregular oscillations and low frequencies (typically 0.5 to 5 Hz) that can last for more than a minute.’
In its latest update, Phivolcs reported the emission of 1,892 metric tons (MT) of sulfur dioxide from Taal’s main crater. The gas plume rose 600 meters before drifting southwest, which the agency classified as a ‘weak emission.’
No upwelling of hot volcanic fluids was observed in the Main Crater Lake on Taal Volcano Island (TVI), locally known as ‘Pulo,’ at the center of Taal Lake.
Phivolcs also noted the absence of ‘vog,’ or volcanic smog, during the latest observation.
The agency reminded the public that Alert Level 1 remains in effect over Taal Volcano, ‘which means that it is still in an abnormal condition and should not be interpreted as having ceased unrest or the threat of eruptive activity.’