Philippines

Philippines: NDCC Update - Sitrep No. 10 Mayon Volcano update

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DATE: 21 December 2009 as of 12:00 NN

Source: DOST-PHIVOLCS, OCDRC-V, ALBAY PDCC, AFP, JTF MAYON, DPWH V

I. SITUATION OVERVIEW

- Mayon volcano is under Alert Level 4 which means that a hazardous explosive eruption is possible within days. Thus areas expected to be affected by such eruption will be accordingly extended.

- To ensure the safety of the public, PHIVOLCS-DOST is recommending an extended danger zone from the summit of 8 km at the southern sector and 7 km at the northern sector.

Observations:

- Mayon Volcano activity escalated during the past 24-hour, seismic activity dramatically increased in number and size. A total of 1,942 volcanic quakes and tremors were recorded by the seismic network. Many of these volcanic earthquakes were recorded at maximum deflection and continually occurred beginning at 12:21 PM, 20 December 2009.

- Harmonic tremors were continuously recorded by the seismic instruments.

- Audible booming and rumbling sounds were first reported in the eastern flank of the volcano at about 2:55 PM yesterday then occasionally occurred beginning 11:00 PM last night.

- Intensified crater glow and rolling down of incandescent fragments from the crater was also persistent. Red hot lava continuously flowed down along the Bongo-Buyuan, Miisi and Lidong gullies.

- Lava fountains rising approximately 200 meters above the crater were observed. The lava front has now reached about 5 kilometers downslope from the summit along the Bongo-Buyuan gullies.

- Sulfur dioxide (SO2) emission rate remained very high at 6,089 tonnes per day (t/d).

Recommendations

- Since the persistent high unrest is evident and the possibility of volcanic eruption is high, PHIVOLCS strongly recommends that the 6-km radius Permanent Danger Zone (PDZ) around the volcano be extended, thus, the Extended Danger Zone (EDZ) from the summit of 8 km at the southern sector and 7 km at northern sector. This area should be free from human activity because of sudden explosions that may generate hazardous volcanic flows.

- Areas just outside of the EDZ should prepare for evacuation in the event 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.