Philippines

Philippines: NDCC Update - Sitrep No. 13 Mayon Volcano update

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DATE: 23 December 2009 as of 7:00 PM

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

I. CHRONOLOGY OF EVENTS

- September 2006: Reverted to Alert Level 1 (progressively downgraded from Level 4 in July 04, 2006) and maintained since then up to July 2009

- August 10, 2009: Alert Level 1 (Minor mild explosion)

- July 10, 2009: Alert Level 2 (Due to continued state of unrest which could lead to ash explosion or eventual hazardous magmatic eruption)

- Nov. 11 - 12, 2009: Alert Level 2 (4 ash explosions, Mt. Mayon remained inflated, above normal S02 level, visible crater glow, seismic activity, 1,900 families evacuated)

- December 14,2009: Alert Level 3 (8:00 PM, 5 series of ash explosion and lava flow, increase S02 and seismic activities)

- December 20, 2009: Alert Level 4 (hazardous explosive eruption is possible within days. Thus, areas expected to be affected by such eruption will be accordingly extended)

II. SITUATION OVERVIEW

- Mayon Volcano is still under Alert Level 4. To ensure the safety of the public, PHIVOLCS-DOST is reiterating that the Extended Danger Zone from the summit of 8 km at the southern sector of the volcano and 7 km at the northern sector should be free from human activity.

Observations:

- Mayon Volcano continued to show an intense level of activity during the past 24-hour observation period.

- Seismic activity remained elevated in number and size as the seismic network detected a total of 1,059 volcanic earthquakes

- Visual observation was hampered by thick clouds covering the upper and middle slopes most of the time yesterday. During cloud breaks, a total of 66 ash explosions were observed and the maximum height attained was about 1 kilometer at 4:21 PM yesterday. However, an intense crater glow was still observed during break last night.

- Harmonic tremors were still continuously recorded by the seismic instruments

- Audible booming and rumbling sounds were still intermittently heard for the past 24 hours

- Red hot lava continued to flow down along the Bonga-Buyuan, Miisi and Lidong gullies

- The lava front has now reached about 5 kilometers downslope from the summit along the Bonga-Buyuan gully

- Sulfur dioxide (SO2) emission rate remained elevated and was measured at an average of 6,737 tonnes per day (t/d) yesterday

Recommendations

- 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

AFFECTED/DISPLACED POPULATION (Tab A)

- After validation, as of 11:00 AM, 23 December 2009, the number of evacuees decreased from 9,880 to 9,754families / 47,137 to 46,639 persons inside 26 evacuation centers

- Six days into evacuation, the PDCC projects an emergence of health related problems based on prior experiences and the current weather which is likely to contribute to the increasing risks for colds and other related diseases. Thus, the fear that zero casualty goal may be compromised by health risks and the willingness of the population-at-risk to stay in the evacuation centers.

- Consequently, PDCC Albay reported 4 cases of conjunctivitis or sore eyes in Tabaco City.