Mayon Volcano Bulletin

03 August  2006

9:00 AM

The main observations for Mayon Volcano (13.2576°N, 123.6856°E) during the past 24 hours are the continuing quiet extrusion of lava from the summit crater, a decrease in Sulfur Dioxide (SO₂) at 4,760 tonnes per day, a high seismic count of 51 volcanic quakes and the advance of the Mabinit lava flow near the six (6) kilometer radius Permanent Danger Zone boundary.

Since a lava flow was first seen descending into the Bonga gully last 14 July, about 17 million cubic meters have been discharged.  The bulk of this material was first funneled into the Mabinit channel south-southeast of the crater while subsequent flows have entered gullies within a broad sector of the southeast upper and middle slopes, in the general directions from Miisi to Buyoan.

Moderate to voluminous dirty white steam accompanied with bluish fumes was observed emanating from the crater during cloud breaks.  Fine ash and gases are also being produced by large lava blocks breaking on impact.  As a result, 343 tremor episodes were recorded due to continuous tumbling of lava blocks into gullies in the southern portion of the summit.  The number of earthquakes generated today inside the volcano was higher at 51 events compared to yesterday’s 16 which generally reflected ongoing intrusion and ascent of magma towards the crater.

Alert Level 3, remains in effect over Mayon, which means that the six (6) kilometer radius Permanent Danger Zone (PDZ) should be off-limits.  As the lava flow reaches the PDZ boundary in the southeast, PHIVOLCS recommends everyone to keep a safe distance because sudden collapse of the front and sides of the advancing flow deposit may produce some pyroclastic avalanches which could engulf areas well beyond the lava flow’s edge.  At this stage, the lava flow is still at some distance from Barangays Mabinit and Bonga.  However, as the flow consumes surrounding vegetation a fire hazard may be generated, amplified by surface winds.  Thus, PHIVOLCS reminds the public to be also aware of potential spread of fire in the upper reaches at Mabinit and Bonga, in addition to hazards associated with explosions from the summit. Residents of barangays within the 8-km high risk zones in the southeast sector of Mayon Volcano in the towns of Daraga and Sto. Domingo and in the City of Legaspi are therefore advised to be alert and to be prepared for evacuation if activity escalates.