LEGAZPI CITY— Bulusan Volcano in Sorsogon recorded 438 volcanic earthquakes in 24 hours, more than double the 205 reported in the previous advisory, raising concerns over possible steam-driven eruptions. The Philippine Institute of Volcanology and Seismology (Phivolcs), in its Nov. 15 bulletin, said the earthquakes were recorded from midnight of Nov. 14 to midnight of.