Philippine Institute of Volcanology and Seismology
27 December 2009
7:00 AM
Mayon Volcano (13.2576 N, 123.6856 E) continued to exhibit a high level of activity during the past 24-hours observation period. Nine ash explosions accompanied by rumbling sounds were observed during times of good visibility, seven of which occurred from 4:20 AM to 5:49AM today. The explosions produced dirty white to brownish ash columns with lava fragments that reached heights from 800 to 1000 meters above the summit.
The seismic network detected 44 volcanic earthquakes and 297 rock fall events related to the detachment of lava fragments at the volcano's upper slopes. Flowing red hot lava and rolling incandescent lava fragments temporarily slowed down after the 10:52 A.M. explosion earthquake yesterday and resumed early morning today after the 4:20 A.M. ash explosion. The apparent brief lull was also reflective of the decrease in the sulfur dioxide emission rate from the previous 8,993 tonnes per day to yesterday's measurement of 2,304 tonnes per day.
Electronic tilt meter measurements at the northwest slope of Mayon Volcano (elevation 800m ASL), indicate that the edifice remained inflated despite the high volume of lava extruded since the start of the eruption on December 14, 2009.
Alert Level 4 remains hoisted over Mayon Volcano, meaning a hazardous eruption is possible within days. Thus, PHIVOLCS-DOST reiterates that the Extended Danger Zone (EDZ) from the summit of 8-km on the southern sector of the volcano and 7-km on the northern sector should be free from human activity. Areas just outside of this EDZ should prepare for evacuation in the event hazardous explosive eruptions intensify. Active river channels and those perennially identified as lahar prone in the southern sector should also be avoided especially during bad weather conditions or when there is heavy and prolonged rainfall. PHIVOLCS-DOST is closely monitoring Mayon Volcano's activity and any new significant development will be immediately posted to all concerned.