Mayon Volcano Bulletin

19 August 2006

8:00 AM

Mayon Volcano (13.2576°N, 123.6856°E) produced two (2) minor explosions since 6:00 AM yesterday.  These explosions occurred at 3:35AM and 4:14AM.  In the past 24 hours, the seismic network detected 22 volcanic earthquakes and 240 tremor episodes.  The volcanic earthquakes indicate continuing ascent of magma while the tremors are associated with lava extrusion and rockfall activity  towards the southeast slopes.  The lowest tremor count correlated with an apparent fewer number of rockfall episodes.  The Sulfur Dioxide (SO₂) emission rate of the volcanic plume was 2,712 tonnes per day (t/d), which is similar to the previous reading of 2,937 t/d.  This rate reflects active magma degassing.

Last night’s observation revealed the apparent decrease in rockfall activity and a noticeable decrease in the intensity of glow from lava deposits on the middle and lower slopes of the volcano.

The estimated volume of erupted volcanic deposits is now from about 36 to 41 million cubic meters.  However, the front of lava flow deposit in the vicinity of Mabinit/Bonga gully is estimated to be still within seven (7) aerial kilometers from the crater.

PHIVOLCS maintains Alert Level 4 for Mayon Volcano.  This means that a hazardous explosive eruption may still occur anytime.  The public is reminded that the eight (8) kilometer radius - EXTENDED DANGER ZONE (EDZ) in the southeast sector of the volcano should 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.