Casiguran Mayor Edwin Hamor said 96 families have left their homes in Barangay Mabini.
According to the civil defense office, a total of 359 families or 1,840 people are now staying in evacuation centers in Casiguran, Irosin and Juban towns.
The weather bureau has raised public storm warning signal No. 1 over Sorsogon and other Bicol provinces and Eastern Visayas.
Government volcanologists warned that heavy rains could loosen ashes deposited on Bulusan’s slopes and trigger hazardous lahar flows.
Bulusan continued to be "quiet," with generally weak to moderate and sometimes voluminous steaming, during the past 24-hour observation period. Four low-frequency volcanic quakes were recorded.
Meanwhile, Mt. Kanlaon in Negros Oriental had two mild ash emissions the other day as part of its "ongoing low-level unrest," the Philippine Institute of Volcanology and Seismology (Phivolcs) said in a bulletin. — With Sheila Crisostomo