MANILA, Philippines —  Mayon Volcano has been emitting an "effusive or gentle burst," indicating an increasing tendency toward a hazardous eruption, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Wednesday. Phivocs Director Teresito Bacolcol told The Manila Times via Viber that this was the reason why the alert level has been raised from 2 to 3, reiterating that the six-kilometer danger zone remained in place and warned residents of impending hazards in the area. The effusive eruption that began around 7:28 p.m. was a gentle release of magma from the volcano’s edifice and the hazardous pyroclastic density currents (PDCs), or "uson" has spread along Bonga Gully, the Phivolcs chief said. An explosive or major eruption involves a forceful ejection of lava into the air, he said.