MANILA, Philippines - The Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday raised alert level 2 at Mayon Volcano in Albay after noticing the formation of a new lava dome that may lead to a larger eruption.
Visual observation of Mayon’s summit crater last Tuesday revealed the growth of a new lava dome about 30 to 50 meters high.
“Alert Level 2 means magma is intruding at depth and current conditions may eventually lead to a larger eruption,” Phivolcs said.
Before this, it noted “low-volume intrusions” signified by slight inflation or swelling of the middle slopes of the volcano since its eruption on May 7 last year, significant increases in sulfur dioxide flux beyond the baseline level of 500 tons a day and continuous gas measurements for the past two months.
Phivolcs said other parameters such as volcanic earthquakes and rock fall have remained at baseline levels.
“The growth of the new summit dome, slight ground deformation and increased volcanic gas emission likely signify the slow intrusion and degassing of magma,” it said.
The absence of other outstanding precursors may be due to low magma intrusion rates, it said.
“Based on Mayon’s behavior exhibited in recent eruptions, current observations may indicate the advent of quiet lava extrusion that may eventually lead to greater unrest,” Phivolcs said.
It said the six-kilometer radius “danger zone” may be extended to seven kilometers in the sector where the crater rim is low.
The agency advised the public to be vigilant and desist from entering the 6-km radius “permanent danger zone” to avoid risks from sudden explosions, rock fall and landslides.
Hikers banned
A few hours after the alert level was raised to 2 yesterday, the Albay government banned hikers, mountain climbers and residents from venturing into its slope.
Cedric Daep, chief of the Albay Public Safety and Emergency Management Office (Apsemo), said the ban was coordinated with local officials whose towns and cities surround Mayon.
Daep said an aerial survey to be conducted by a Philippine Air Force helicopter yesterday afternoon was aborted due to the thick sulfur dioxide emissions that mixed with clouds over Mayon.
“Air force pilots were waiting for the clouds to clear up so they could carry out the aerial survey, but Mayon was not visible until yesterday afternoon. We will just push through tomorrow,” Daep told The STAR. – Helen Flores, Cet Dematera, Celso Amo