PHIVOLCS lowers alert level at Taal Volcano from 3 to 2

PHIVOLCS on Friday night downgraded the alert level at the Taal Volcano from three to two following a "cessation of eruptive activity."

In a bulletin issued at 7:30 p.m., PHIVOLCS said it observed generally declining volcanic gas emission, very slight ground deformation, and positive microgravity anomalies since July 9.

"In view of the above observations, DOST-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," PHIVOLCS said.

"Alert Level 2 means that there is decreased unrest but should not be interpreted that unrest has ceased or that the threat of an eruption has disappeared," it added.

According to PHIVOLCS, a total of 1,195 volcanic earthquakes ranging between magnitude 1.9 to magnitude 4.6 have been recorded since the Taal Volcano erupted on July 1.

The agency said most of the earthquakes occurred beneath the main crater of the Taal Volcano and the northeastern sector of the Taal Volcano Island.

Meanwhile, the volcano emitted an average of 12,161 sulfur dioxide (SO2) per day in the first week of July while its highest emission was recorded at 22,628 tonnes per day on July 4.

PHIVOLCS said the average SO2 decreased to 4,763 per day from July 8 to 22.

“The decrease in degassing activity reflects the diminishing volumes of accumulated volcanic gas beneath TVI as well as the ‘scrubbing’ effects of rainfall-fed water recharge into Taal’s hydrothermal system,” it said.

Microgravity campaigns around the caldera of the volcano also yielded positive microgravity increases with ground deflation, according to PHIVOLCS.

“These parameters are all broadly consistent with hydrothermal activity beneath the Taal Fracture Zone and magma migration from the southeast flank to other sectors beneath TVI,” it said.

“Activity in the Main Crater has been more often characterized by the generation of moderate steam-laden plumes and periodic but generally less vigorous lake upwelling, consistent with decreased magmatic degassing,” it added.

Due to these observations, PHIVOLCS recommended that entry into the Taal Volcano Island and the permanent danger zone should be strictly prohibited. —NB, GMA News