Taal Volcano Seismic Activity Surges Post-Eruption, Alert Level 1 Remains

Taal Volcano in Batangas showed renewed signs of volcanic unrest after recording a sharp increase in seismic activity over the past 24 hours, following two short-lived phreatomagmatic eruptions on Tuesday, the Philippine Institute of Volcanology and Seismology (Phivolcs) said. In its Wednesday morning bulletin, Phivolcs reported 19 volcanic earthquakes and five episodes of volcanic tremor lasting from two to 10 minutes. The increase marked a significant change from the previous day’s monitoring, when no volcanic earthquakes were recorded. On June 29, the agency detected only one volcanic earthquake, while two were logged on June 28 and none on June 27. Phivolcs explained that volcanic earthquakes are generated by magma-related processes occurring beneath or near an active volcano. On the other hand, volcanic tremors are continuous low-frequency seismic signals that may persist for more than a minute. The heightened seismic activity followed two phreatomagmatic eruptions recorded on June 30, bringing the total number of such eruptive events at Taal Volcano to five last month. The first eruption occurred at 7:13 a.m. and lasted four minutes, producing a plume that rose about 450 meters above the main crater. A second eruption followed at 2:24 p.m. and lasted four and a half minutes. Consisting of three pulses, it generated dark gray ash jets and steam-rich plumes that rose about 1,200 meters above the crater. Phivolcs also recorded similar phreatomagmatic eruptions on June 4, which lasted two minutes; June 5, four minutes; and June 6, one minute. A phreatomagmatic eruption occurs when rising magma comes into explosive contact with water. It differs from a phreatic eruption, which is steam-driven and occurs when groundwater or surface water is rapidly heated by magma, lava, or hot rocks. During the latest monitoring period, Taal Volcano also emitted 881 metric tons of sulfur dioxide. The gas plume rose about 1,200 meters, an activity classified by Phivolcs as a moderate emission. No volcanic smog (vog) or upwelling of hot volcanic fluids in the main crater lake was observed during the monitoring period. Despite the increased activity, Taal Volcano remains under Alert Level 1, indicating low-level volcanic unrest. Phivolcs emphasized that the alert status does not mean volcanic unrest has ended or that the possibility of hazardous activity has disappeared. The agency reiterated that entry into Taal Volcano Island, locally known as “pulo” which sits in the middle of Taal Lake, boating on Taal Lake, and flying aircraft close to the volcano remain strictly prohibited because of the continuing risk of sudden steam-driven or phreatomagmatic eruptions, volcanic earthquakes, minor ashfall, and hazardous volcanic gas emissions./coa