Mayon update, 20 December 2009: alert level raised to 4 20 December 2009Posted by admin in activity reports, eruptions, Mayon, Philippines.
Tags: Mayon, Philippines, volcanic activity reports, volcanic eruptions
The alert level for Mayon volcano was raised on 20 December by the Philippine Institute of Volcanology and Seismology (Phivolcs) to level 4, ‘hazardous eruption imminent’. Mayon Bulletin no. 7 explains:
This is to notify the public that PHIVOLCS-DOST is now raising the alert status of Mayon Volcano (13.2576 N, 123.6856 E) from ALERT LEVEL 3 to ALERT LEVEL 4. This 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 northern sector.
Areas just outside of this Extended Danger Zone (EDZ) should prepare for evacuation in the event explosive eruptions intensify.
The previous bulletin, Mayon Bulletin no. 6, issued earlier on 20 December, reported 222 volcanic quakes and tremors over the preceding 24 hours, one of which was an explosive event that produced a 500 metre altitude grey ash column. Harmonic tremor was continually recorded. Steam plumes varied from dirty white to light brown in colour. Intensified crater glow and the continuous rolling down the slopes of incandescent material was visible at night. Lava had advanced 4.5 km downslope from the crater. Sulphur dioxide emissions were measured at 7,024 tonnes/day, a marked increase on the 2,034 tonnes/day reported in Mayon Bulletin no. 5 on 19 December.
The head of the Phivolcs volcano monitoring team has told the press that the alert level was raised on the afternoon of 20 December ‘because there was a sudden acceleration in the activity of the volcano’:
He said the number of volcanic quakes from 6:00 am Sunday (2200 GMT Saturday) increased to 463 and that the volcano was belching more sulphur dioxide into the air.
This was a sign that ‘a hazardous eruption is possible within days.’
However he would not give an estimate of when the eruption could take place.
Meanwhile, weather forecasters report that a storm is threatening the southern Philippines with heavy rains, increasing the lahar risk at Mayon. Destructive and deadly lahars have been a feature of Mayon’s history: most recently, a typhoon in November 2007 turned deposits left by the eruption of July to October 2006 into disastrous mudflows, killing and injuring thousands. It is grim experiences like this that lie behind the urgency of the current evacuation effort around Mayon.
UPDATE: A new report in the Inquirer gives Phivolcs figures of 463 earthquakes registered at Mayon between 08:00 and 14:00 on 20 December.
For all our Mayon coverage: Mayon « The Volcanism Blog.
Philippine volcano alert raised, eruption in days – govt – Philippine Daily Inquirer, 20 December 2009
Eruption within days – Manila Bulletin, 20 December 2009
Mayon alert level raised to 4; eruption seen within days – GMANews.TV, 20 December 2009
Major volcanic eruption feared in Philippines – Associated Press, 20 December 2009
Alert level 4 raised as volcano seen to erupt in days – Philippine Daily Inquirer, 20 December 2009
Global Volcanism Program: Mayon – summary information for Mayon (0703-03=)
Philippine Institute of Volcanology and Seismology – website for Phivolcs