|Mayon Volcano Bulletin 5|
|Saturday, 19 December 2009 12:04|
19 December 2009
Mayon Volcano (13.2576 N, 123.6856 E) continued to exhibit intensified activity for the past observation period. A total of one hundred ninety seven (197) volcanic quakes and tremors were recorded by the seismic network. Eighteen (18) of these events were explosion type, however, only fifteen (15) were observed during times of good visibility. These explosions produced dirty white to grayish ash columns that reached height from 100 to 2000m above the summit before drifting towards southwest. Harmonic tremors were continuously recorded by the seismic instruments.
During cloud break this morning, steaming activity ranged from dirty white to light brown in color. Night observation showed an intensified crater glow and continuous rolling down of incandescent materials from the crater.
The advancing lava flow has now reached approximately 4 kilometers downslope from the crater along Bonga Gully. Sulfur Dioxide (SO2) emission increased from 1,065 to 2,034 tonnes per day (t/d).
Alert Level 3 remained hoisted over Mayon Volcano. Since persistent high unrest is evident at present, the possibility of hazardous volcanic eruption is high. Thus, PHIVOLCS-DOST recommends that the 6-km radius Permanent Danger Zone (PDZ) around the volcano and the 7-km Extended Danger Zone (EDZ) on the southeast flank of the volcano should be free from human activity because of sudden explosions that may generate hazardous volcanic flows. In addition, areas in the south that are outside the 7 kilometer danger zone but within 8 kilometers of the crater should be extra alert for increased volcanic activity. 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.