Mayon Volcano Update

20 August 2006

6:00 PM

No explosions occurred at Mayon Volcano (13.2576^oN, 123.6856^oE) since 6:00 AM today.  For the past 12 hours, the seismic instruments detected six (6) volcanic earthquakes and 139 tremor episodes.  The volcanic earthquakes represent magma ascent towards the crater of the volcano while the tremors were associated to the detached fragments of lava and rockfalls. The Sulfur Dioxide (SO₂) emission rate of the plume this morning remained high, measured at 5,390 tonnes per day (t/d).  This high emission rate is attributed to active magma degassing activity.  Moderate  volume of grayish steam drifting towards the northeast was observed during clear views of the crater this morning until this afternoon.

At this stage, the activity of Mayon is not yet declining, even in the absence of explosions.  Other parameters like SO₂ flux, lava extrusion, number of volcanic earthquakes and tremor episodes have not yet established a declining trend.  These will be closely observed for at least one (1) week, along with the occurrence if explosions to establish a general trend for Mayon’s activity.

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.