Bulusan Volcano Update

14 June 2006, 8:00 A.M.

Following the steam and ash explosion at 7:04 PM yesterday, small volcanic quakes occurred in Bulusan Volcano (12° 46.2’N, 124° 03’E). The nature of these micro-earthquakes suggests a shallow source beneath the volcano and may be associated with magmatic movement. Surface activity yesterday was characterized by moderate to voluminous volcanic gas emission from the western fissure but weak discharge from the active central summit vent. The release of Sulfur Dioxide contained in the volcanic plume was 423 tonnes/day (t/d), a slight increase from previous day’s 295 t/d.

Last night’s explosion and relatively voluminous ash emission indicated that Bulusan Volcano is undergoing a period of elevated unrest, distinct from the early explosions from March to May. As noted previously, Bulusan Volcano is producing more frequent outbursts in the past weeks. More ash explosions are expected in the near future considering the heightened level of activity. Alert Level 2 therefore remains in effect, which means that areas within four (4) kilometers of the summit should be avoided. PHIVOLCS suggests continuing precautions against heavy ashfall, especially on the northern portion of the volcano considering seasonal winds. As before, additional precautions should be observed for areas near river/stream channels because ash and other loose deposits from the upper slopes may be remobilized into hazardous lahars and similar volcanic flows.

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