Philippines: Mayon Volcano Bulletin 16

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Philippine Institute of Volcanology and Seismology

29 December 2009
7:00 AM

Mayon Volcano (13.2576 N, 123.6856 E) continued to be restive and exhibited 9 ash explosions during the past 24 hours. The explosions produced dirty white to light brown ash columns that rose to a maximum height of about 2000 meters above the summit before drifting towards the west and southwest.

Seismic activity remained at high level as a total of 38 volcanic earthquakes and 171 rock fall events related to the detachment of lava fragments at the volcano's upper slopes was detected by the seismic network. Measurements of sulfur dioxide emission rate conducted yesterday yielded an average value of 3,416 tonnes per day (t/d).

Red hot lava continued to flow down along the Bonga-Buyuan, Miisi and Lidong gullies. At present, the lava front at Buyuan channel is approximately 5.8 kilometers downslope from the summit crater. From time to time, rolling down of incandescent lava fragments coming from the crater was observed.

The status of Mayon Volcano is maintained at Alert Level 4. 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 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. In addition, Civil Aviation Authorities must advise pilots to avoid flying close to the volcano's summit as ejected ash and volcanic fragments from sudden explosions may pose hazards to aircrafts. PHIVOLCS-DOST is closely monitoring Mayon Volcano's activity and any new significant development will be immediately posted to all concerned.