Mayon volcano 06 22 01

As of the 22nd of June, the Philippines Volcanology Society (PHIVOLCS) has reported that this Bulletin is issued to call attention to further significant progress of volcanic activity. The main portion of lavas from the summit is being discharged in the general direction of Mabinit and as of latest visual observation yesterday the toe or lowermost lava flow has descended about 300 meters from the 1,500-meter elevation record of 20 June 2001 and has now reached the 1,200-meter elevation. PHIVOLCS notes that lava is descending rapidly, partly because it is very hot and fluid and the supply of magma to the crater is apparently voluminous. The latest arrival of magma to the surface contains high amounts of gases as reflected by very high Sulfur Dioxide (SO2) emission rates of 9,450 tonnes/day. Tremor continues to be recorded athough explosion signals which signify imminent explosive eruption have not been recorded. Thus with large volumes of gas emission, the potential for buildup of gases in the magma inside the volcano is still inadequate to drive a major explosive eruption.

After consideration of recent and ongoing unrest at Mayon, the Eruption Assessment Team has concluded that Alert Level 3 (Hazardous Eruption Possible Within Weeks) is appropriate for the next day or so. Although lava is flowing along the Bonga Gully, critical indicators for a hazardous eruption are still insufficient. If in the following days, successive explosions, increasing or abrupt changes in Sulfur Dioxide gas emission or lava fountaining, etc. become evident then PHIVOLCS will declare Alert Level 4 over the volcano. Alert Level 4 means that the off-limits six (6) kilometer radius Permanent Danger Zone (PDZ) will be extended to seven (7) kilometers for limited areas in the southeast due to probable pyroclastic flows and other life-threatening volcanic phenomena. The areas at high risk are those fronting and in the vicinity of Miisi, Mabinit, Buyuan and Bonga Gullies.

From 8:30 AM yesterday, continuous rolling of incandescent materials occurred along Bonga Gully. At 1:30 PM yesterday, lava front was observed to have reached 1,200 meters elevation.

Alert Level 3 (Hazardous Eruption possible in Weeks) is still in effect but may be raised to Alert Level 5 (Hazardous Eruption in Progress) if sudden explosions produce life-threatening volcanic flows.

-- PHO (owennos@bigfoot.com), June 22, 2001