Mayon Volcano Bulletin

08 August 2006

9:00 AM

Three more explosions occurred at Mayon Volcano (13.2576°N, 123.6856°E) last night. Instruments recorded the explosions at 10:36PM, 10:46PM and then at 10:49PM. This latest explosive episode brings to nine (9) the total explosion events over the past 24-hour period. The nighttime explosions were accompanied by incandescent ejections of lava fragments and significant brightening of the summit area as hot ash, gas and steam were released. Meanwhile, lava continued to flow also from the summit crater forming another short stubby deposit on the upper southeast slopes. Falling lava fragments generated 344 episodes of tremor. From within the volcano, 109 earthquakes were recorded, which reflects the very high state of unrest of Mayon.

Along with lava extrusion and ash explosions, the emission rate of Sulfur Dioxide (SO₂) shot up to another high of 12,745 tonnes per day (t/d). The elevated SO₂ emission rate is again due to degassing of gas-rich magma. Consequently, PHIVOLCS anticipates an escalation of volcanic unrest. Thus, explosive eruptions may occur at any time.

Measurements of the dimensions of the advancing lava flow in the vicinity of the Mabinit channel was suspended due to increasing risk of pyroclastic flows. It is anticipated, however, that this lava flow shall advance only slightly (a hundred meters per day at most) because a significant amount of lavas are now flowing towards other directions within the southern sector of the volcano.

In summary, Alert Level 4 is in effect, which means that a hazardous explosive eruption is imminent within the coming days. Due to adverse effects of a highly explosive eruption, the EXTENDED DANGER ZONE (EDZ), defined as an area within eight (8) kilometers from the summit crater located in the general southeast sector, should be observed. At other areas around the volcano, this EDZ is seven (7) kilometers from the summit crater.

Areas recommended for evacuation have been identified in coordination with the appropriate authorities. At this stage of volcanic activity, no other significant changes in evacuation policy or plan is required. Areas outside of the EDZ are advised to be on the alert for updates regarding their potential evacuation. Residents of these areas are further advised to be prepared for possible evacuation in case volcanic activity escalates.