Alert level around Mayon lowered to 3


Posted at Jan 02 2010 09:18 AM | Updated as of Jan 03 2010 06:48 AM

MANILA, Philippines - The provincial government of Albay on Saturday morning allowed more than 7,000 families from at least 20 evacuation centers to return to their houses after government volcanologists lowered the alert level around Mayon Volcano from 4 to 3.

Albay Gov. Joey Salceda said a total of 7,218 families will be brought back by military and police personnel to their homes inside the 7-kilometer to 8-kilometer extended danger zones of the volcano.

Salceda said a total of 2,728 families, whose homes are inside the 4-kilometer to 6-kilometer permanent danger zones, would have to remain in evacuation centers pending the Philippine Institute of Volcanology and Seismology (Phivolcs) decision to further lower the alert level.

He said police and military checkpoints around the volcano would be maintained to discourage farmers from returning to the permanent danger zones.

The Phivolcs' bulletin posted on its website on Saturday morning said its seismic monitoring network detected 13 volcanic earthquakes and 68 rockfall events on Friday.

It said the volcano was emitting a "weak volume of white steam." It, however, did not indicate if lava was still flowing out of the volcano's crater summit.

The Phivolcs said the volcano's sulfur dioxide emission rate was measured Friday morning at an average of 2,621 tons per day.

The agency said the volcano's activity still indicates that its state of unrest remains high, but because of its decreasing activity observed for the past 4 days, volcanologists decided to lower the alert level from 4 to 3.

It cited 3 reasons for the lowering of the alert level:

  • * No ash ejections were observed since 29 December. Steam emission was most of the time weak and white in color indicating considerable decrease in energy and absence of ash.
  • * Majority of the type of earthquakes that were recorded during the past days were associated with rockfalls and rolling down of fragments from the lava deposits along Bonga gully and the advancing lava front.
  • * Measured SO2 levels have also showed a decreasing trend from a maximum of 8,993 tons per day to 2,621 tons per day. The still high concentration of SO2 gas emission suggests that there is residual magma degassing at shallow depth.

The Phivolcs said that despite the sudden lull of the volcano, it would still continue producing earthquakes and belch large amount of gases because the whole length of the volcanic pipe and the volcano's summit remains filled with fresh magma.