Mayon Volcano Bulletin

11 September 2006

8:00 AM

In the past 24 hours, there were some 6 volcanic earthquakes and 206 tremor episodes detected.  The Sulfur Dioxide emission rate from the crater was estimated at about 1,500 tonnes per day with plume drifts varying from northeast to east-northeast.  Ground deformation measurements indicated an overall deflation of the edifice.

These observations generally show an elevated state of unrest, although there is an apparent decline of activity since late August.  PHIVOLCS is presently undertaking an assessment  on the possibility of lowering  the alert status of Mayon and results of this evaluation shall be presented as soon as possible.

In the meantime, PHIVOLCS reminds the public to observed precautions attached with Alert Level 4.  This means that the 8-kilometer radius Extended Danger Zone (EDZ) for the southeast portion of the volcano should remain off-limits. At other areas, the EDZ is defined to be 7 kilometers from the summit. It is important  to remain vigilant because even a small explosion, if caused by a brief outburst from the summit crater, could generate life-threatening pyroclastic flows.  In the southeast, caution is also advised against approaching the still-hot lava deposits whose slopes remain unstable at this stage.