LEGAZPI CITY (3 December 2010) — Office of the Civil Defense (OCD) regional director Rafael Alejandro IV disclosed on Thursday that during the OCD updating conference on Mt. Bulusan at Camp Simeon Ola in this city, PHIVOLCS resident volcanologist for Bicol, Eduardo P. Laguerta warned that an estimated 100,000 cubic-meters of ashfall deposits on Mt. Bulusan’s upslope threatens to inundate the four river channels at the base of the volcano once these are triggered by heavy rains.