Mayon update, 22 December 2009 22 December 2009

The latest Mayon bulletin, no. 9, reports little change in the volcano’s behaviour over the previous 24 hours:

Seismic activity remained elevated in number and size as the seismic network detected a total of 1,266 volcanic earthquakes. Many of these volcanic earthquakes were recorded at maximum deflection and have continuously occurred since 12:21 PM, 20 December 2009. Harmonic tremors were still continuously being recorded.

Sulphur dioxide emission remained high at 6,529 tonnes/day. An intensified crater glow was observed during a break in the cloud cover, and booming and rumbling noises continued to be audible. Lava continued to flow downslope to a distance of about 5 km from the crater.

The Manila Bulletin is reporting that an increase in alert level at Mayon from 4 to 5 is ‘imminent’. Level 5, the highest level, indicates that a hazardous eruption is ongoing, and presently, for all the disruption, that is not the case. There would have to be a marked upswing in activity from Mayon before level 5 would be justified – which is precisely what the Phivolcs official quoted in the story says. Meanwhile, Phivolcs has warned people to the south of the volcano to stay clear of potential lahar channels.

Fears of infectious disease among the c. 47,000 evacuees crowded into shelters have led to the deployment of extra medical teams by the Philippines Department of Health. The psychological health of the thousands of people now facing a Christmas away from their homes and in the shelters is also being considered: soldiers in Santa hats have been distributing presents to children, and an appeal has gone out for ‘clowns and actors’ to provide entertainment and lift the evacuees’ spirits. Those who have ignored the evacuation order receive no such consideration: the authorities are considering making anyone who insists on staying within the danger zone sign a waiver to the effect that anything that happens to them when the volcano erupts is their own responsibility.

For all our Mayon coverage: Mayon « The Volcanism Blog.

News
Alert level 5 for Mayon imminent – Manila Bulletin, 22 December 2009
Residents told: avoid lahar-prone areas near Mayon – Philippine Daily Inquirer, 22 December 2009
Most of 47,000 Filipinos safe from raging volcano – Associated Press, 22 December 2009
DOH deploys more medical teams to Albay – ABS-CBN News, 22 December 2009
Clowns, actors needed in Albay evacuation centers – GMANews.TV, 22 December 2009
Albay residents who refuse to leave may need to sign waiver – GMANews.TV, 22 December 2009

Information
Global Volcanism Program: Mayon – summary information for Mayon (0703-03=)
Philippine Institute of Volcanology and Seismology – website for Phivolcs

Mayon update, 21 December 2009 21 December 2009

Activity at Mayon has continued to intensify, with a dramatic upswing in seismicity over the past 24 hours, reports Phivolcs in Mayon Bulletin no. 8:

Seismic activity dramatically increased in number and size. A total of 1,942 volcanic earthquakes was detected by the seismic network. Many of these volcanic earthquakes were recorded at maximum deflection and continually occurred beginning at 1221H yesterday. Harmonic tremors were also continuously recorded.

Sulphur dioxide emissions have remained at a high level of 6,089 tonnes/day. Booming and rumbling sounds have been heard, intensified crater glow and continuous ejection of incandescent material has been visible overnight, and the advancing lava front has reached 5 km downslope of the crater. Strombolian activity has also been observed, with lava fountains reaching about 200 m above the crater.

The evacuation of at-risk populations near the volcano is into its final stages, with the authorities taking steps to remove local inhabitants who have so far refused to leave their homes and farms. The lessons of previous eruptions, particularly regarding the potential reach of pyroclastic flows and lahars, have not been lost on the Philippines authorities: ‘The probability of survival in an eruption is zero if you’re in the danger area’, Albay Governor Salceda has said, ‘The solution is obviously distance’. Phivolcs has reassured people that Mayon, with its less volatile lavas, is ‘safer’ than Pinatubo: ‘Mayon’s possible eruption would not be in the scale and intensity of Pinatubo’s eruption in 1991, considered the second largest eruption of the 20th century worldwide, although Mayon’s current activity is more energetic than when it erupted in 2006′.

Many local people have been reluctant to leave their homes and properties, with farmers proving particularly good at evading the checkpoints and returning home to check on animals and crops. The government have reassured farmers that livestock will also be evacuated to state agricultural stations where veterinary care will be available; meanwhile, the health of human evacuees, threatened by overcrowding and lack of safe drinking water, is also a concern. The authorities have made it clear that they will do everything short of using physical force to get people away from the danger zone: soldiers will be sent in to ‘nag them non-stop’ according to one disaster management official, and the deployment of clowns is being seriously considered.

For all our Mayon coverage: Mayon « The Volcanism Blog.

News
Thousands warned to flee Philippine volcano zone – AFP, 21 December 2009
Mayon ‘safer’ than Pinatubo – Manila Bulletin, 21 December 2009
Albay evacuees assured of safe drinking water – GMANews.TV, 21 December 2009
Philippine volcano gets louder, could blow up soon – Associated Press, 21 December 2009
Clowns to lure people from Mayon danger zone – Philippine Daily Inquirer, 21 December 2009

Information
Global Volcanism Program: Mayon – summary information for Mayon (0703-03=)
Philippine Institute of Volcanology and Seismology – website for Phivolcs

Mayon update, 20 December 2009: alert level raised to 4 20 December 2009

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.

News
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

Information
Global Volcanism Program: Mayon – summary information for Mayon (0703-03=)
Philippine Institute of Volcanology and Seismology – website for Phivolcs