Photo courtesy of Philippine News Agency (PNA).
Seismic activity beneath Taal Volcano increased significantly after monitoring instruments detected 46 volcanic earthquakes within a 24-hour period, Phivolcs reported Friday.
The latest count was more than triple the 14 earthquakes recorded during the preceding monitoring period. Daily seismic activity from August 16 to 19 had remained in the single digits.
Two episodes of volcanic tremor were also detected. These lasted between two and 245 minutes, according to the agency’s monitoring bulletin.
Phivolcs tracks such seismic signals to assess processes occurring beneath active volcanoes. Volcanic tremors are characterized by sustained low-frequency signals, while volcanic earthquakes are associated with movements or processes within the volcanic system.
Taal’s sulfur dioxide output also climbed. The volcano released 271 metric tons on Thursday, compared with a daily measurement of 107 metric tons from August 16 to 19.
Despite the increase, Phivolcs assessed the latest sulfur dioxide emission as weak. No volcanic smog, or vog, was observed during the monitoring period.
Monitoring also showed no upwelling of hot volcanic fluids in the main crater lake on Taal Volcano Island.
Alert Level 1 remains in effect over Taal, indicating low-level unrest. Phivolcs maintained that the volcano remains abnormal and that the alert level does not rule out continued volcanic activity.