Seventeen volcanic earthquakes in Taal Volcano were recorded the past 24 hours, the Philippine Institute of Volcanology and Seismology (Phivolcs) said in its bulletin on Tuesday, Aug. 16.

Of the 17 volcanic quakes, 15 tremors lasted two to 15 minutes, it said.

Phivolcs also observed a 1,500-meter tall “voluminous” plume of steam.

The upwelling of hot volcanic fluids also continued, causing volcanic smog or “vog” over the Taal Volcano and neighboring communities.

Phivolcs said that Taal’s volcanic sulfur dioxide averaged 3,802 tons per day, as of Aug. 15.

Taal Volcano remains under Alert Level 1, which means it is still in an abnormal condition and should not be interpreted to have ceased unrest nor ceased the threat of eruptive activity.

“Should an uptrend or pronounced change in monitored parameters forewarn of renewed unrest, the Alert Level may be raised back to Alert Level 2,” Phivolcs said.

“Conversely, should there be a return of monitoring parameters to baseline levels after a sufficient observation period, the Alert Level will be further lowered to Alert Level 0,” it pointed out.

Under Alert Level 1, sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within the Taal Volcano Island (TVI).

“Phivolcs strongly recommends that entry into TVI, Taal’s permanent danger zone or PDZ, especially the vicinities of the main crater and the Daang Kastila fissure, must remain strictly prohibited,” it said.