(Eagle News) — Taal’s alert level has been downgraded to 2 following what the Philippine Institute of Volcanology and Seismology said was the volcano’s decreased unrest.
According to PHIVOLCS, the “markedly declined” unrest followed the phreatomagmatic eruption of the main crater on March 26 and six weak phreatomagmatic bursts until March 31.
PHIVOLCS said this decrease in activity was supported by the following observations:
- Since the March 26 eruption, only 86 small-magnitude and imperceptible volcanic earthquakes have been recorded by the Taal Volcano Network (TVN).
- After sulfur dioxide or SO2 gas flux increased in the first three weeks of March 2022 and peaked at 21,211 tons/day on March 16, emissions suddenly dropped on April 3. According to PHIVOLCS, SO2 flux since then has averaged 240 tons/day, decreasing to 103 tons on April 8, the lowest flux recorded since unrest began in 2021.
- A general deflation of Taal centered on eastern Taal Volcano Island has been observed. PHIVOLCS said this was “broadly consistent with depressurization of the hydrothermal region beneath TVI due to continuous degassing and gas release by phreatomagmatic activity at the main crater.”
- Activity in the main crater in the past week has been characterized by occasional weak plumes and longer periods of absence
PHIVOLCS said the downgraded alert level, however, “should not be interpreted that unrest has ceased or that the threat of an eruption has disappeared.”
“Should an uptrend or pronounced change in monitored parameters occur, the Alert Level may be raised back to Alert Level 3. At such time, people residing within areas at high risk to base surges who have returned after the step-down to Alert Level 2 must therefore be prepared for a quick and organized evacuation,” PHIVOLCS said.
PHIVOLCS said entry into TVI, Taal’s Permanent Danger Zone, must still be strictly prohibited.
Local government units were also advised to continually strengthen preparedness, contingency and communication measures in case of renewed unrest.
