STATE seismologists need more trending data before lowering the alert level for Taal Volcano, despite a seeming decrease in volcanic activity.

“It doesn’t mean we’re safe just because the sulfur dioxide level has gone down,” Ma. Antonia V. Bornas, chief science research specialist at the Philippine Institute of Volcanology and Seismology (Phivolcs), said at a briefing on Wednesday streamed on Facebook.

“It could be that the exit points for sulfur dioxide were just being blocked,” she said in Filipino.

Phivolcs measured an average of 153 tonnes of sulfur dioxide, according to an 8 a.m. report. This was lower than the 344 tonnes it measured on Tuesday morning.

Thousands of residents were forced to flee after the volcano in Batangas province emitted a thick ash column on Jan. 12. The ashfall reached as far as cities near the capital, forcing financial markets to suspend trading and the Manila airport to close.

Phivolcs has recorded “weak steam emission” for the past 24 hours from the volcano, which produced ash plumes that went as high as 500 meters.

The agency has recorded 725 volcanic earthquakes since Jan. 12, 176 of which are felt with intensities 1 to 5.

More than 71,000 families in Batangas, Quezon, Laguna and Cavite were affected by the volcano’s eruption, according to the local disaster agency’s 6 a.m. report.

About 39,000 families were taking temporary shelter in 493 evacuation centers, while 23,133 families were being served outside them, it said.

Meanwhile, the Social Welfare department had given out more than P8.5-billion worth of assistance to communities affected by eruption, the United Nations Office for the Coordination of Humanitarian Affairs said in a Jan. 21 report.

Taal Volcano remained under Alert Level 4, which means “hazardous explosive eruption is possible within hours to days.” — Genshen L. Espedido