Mayon Volcano Bulletin

20 August 2006

8:30 AM

Mayon Volcano (13.2576^oN, 123.6856^oE) did not generate any explosions for the past 24 hours. The seismic network however, recorded fifteen (15) volcanic earthquakes and 253 tremor episodes. The volcanic earthquakes where associated with the activity of magma inside the volcano while the tremors were generated by extruded lavas, rockfalls or detaching lava fragments. The Sulfur Dioxide (SO2) emission rate of the volcanic plume yesterday was still high, measured at 6,634 tonnes per day (t/d). This high emission rate is attributed to active magma degassing activity. Visuals on the summit this morning revealed moderate volume of grayish steam with northeasterly drifts.

Lack of explosion for the past 24 hours does not mean that the activity of Mayon is waning. Other parameters like elevated SO2 flux, continuous lava flow and significant number of volcanic earthquakes are indicators that the volcano is still undergoing high level of unrest.

PHIVOLCS maintains Alert Level 4 over Mayon Volcano, which means that hazardous explosive eruptions are still possible. Thus, the public is reminded that the eight (8) kilometer radius EXTENDED DANGER ZONE (EDZ) in the southeast sector of the volcano should continue to be off-limits at all times. At other areas around the volcano, this EDZ is seven (7) kilometers from the summit crater. Residents of areas just outside and adjacent to the EDZ are also advised to be on the alert for updates regarding their status for possible evacuation in case volcanic activity intensifies.