Taal Volcano’s alert level lowered

The Philippine Institute of Volcanology and Seismology (Phivolcs) has lowered Taal Volcano’s alert status, citing its decreased activity.

Phivolcs said there has been a generally declining volcanic gas emission and very slight ground deformation following the phreatomagmatic eruption of the main crater on July 1 and 19 weak phreatomagmatic bursts until July 9.

“In view of the above observations... Phivolcs is lowering the alert status of Taal Volcano from Alert Level 3 to Alert Level 2 to reflect the overall decreasing trend in the level of monitoring parameters,” the agency said in an advisory.

Phivolcs said 1,201 volcanic earthquakes, with magnitudes ranging from 1.8 to 4.6, have been recorded in the Taal Network since July 1.

A total of 789 volcanic, 365 low-frequency, 27 hybrid and eight volcano-tectonic earthquakes were generated in the shallow magma and hydrothermal region.

Sulfur dioxide emissions declined to an average of 4.763 tons per day between July 8 and 22, from a peak of 22,628 tons on July 4.

Phivolcs said a decrease in degassing activity reflects the diminishing volumes of accumulated volcanic gas beneath the island and the “scrubbing effects” of rainfall-fed water charge into its hydrothermal system.

There were also generally less vigorous lake upwelling that is consistent with decreased magmatic degassing despite the generation of moderate steam-laden plumes.

Despite the volcano’s decreased unrest, Phivolcs said the threat of an eruption remains and the alert level could be raised again should there be an uptrend in monitored parameters.

Alert Level 2 means sudden steam-driven or phreatic explosions, volcanic earthquakes, ashfall and lethal accumulations or expulsions of volcanic gas may still occur and threaten areas around Taal Volcano Island.

Phivolcs said residents returning to high-risk areas should be prepared for a quick and organized evacuation.

Communities near active river channels should remain vigilant as ash from last year’s eruption may cause lahar and sediment-laden streamflows, it added.