Phivolcs said the steam-driven explosion started at 9:17 p.m. and lasted for 13 minutes, although it was not visible because the summit was covered with clouds, as viewed from the Cabid-an and San Roque stations.
Affected by light ashfalls were the villages of Bacolod, Sankayon, Putting Sapa, Rangas, Mapili, Caladgao, Buraburan in Juban town and Bolos in Irosin, Phivolcs said.
Bulusan remains under alert level one although Phivolcs still expects more ash explosions, thus it warned residents against venturing into the four-kilometer radius permanent danger zone.
Meanwhile, Phivolcs recorded four high-frequency volcanic quakes in Taal Volcano in Tagaytay City from 8 a.m. last May 25 to 8 a.m. the following day, and observed "weak to moderate steaming of about 10 meters high" in the main crater.
"The main crater remains off-limits to the public because steam explosions may suddenly occur or high concentrations of toxic gases may accumulate," Phivolcs said.