Thursday, July 27, 2006
Mayon shows signs of a future major eruption
Phivolcs gave the assessment after noting an abrupt drop in sulfur-dioxide emission and a rise in the volume of lava flowing down the volcano’s slopes.
The same signs were observed just before Mayon erupted in 1928 and 1978, Phivolcs said.
The sulfur-dioxide emission went down to 4,550 tons Thursday from 9,275 tons Wednesday.
Lava snaking down the southeast slope was just 1.6 kilometers from the edge of the six-kilometer permanent danger zone.
“These parameters indicate that Mount Mayon’s probability to explode is higher,” Ed Laguerta, Phivolcs resident volcanologist, told The Manila Times.
Lava had moved 250 meters down the Mabinit channel, threatening the villages of Matanag, Mabinit, Bonga and other parts of Legazpi.
Laguerta said Mayon had belched more than 10 million cubic meters of lava since July 14.
Records of past eruptions show that in 1928 the volcano spewed at least 150 million cubic meters of lava and 20 million cubic meters in 1978.
“Mount Mayon may end up just emitting lava, but still the possibility to explode is higher. If the eruption is similar to the 1968 and 1984 explosions then it would be strong,” Laguerta said.
Phivolcs personnel were also watching for ground swelling on the mountain, a suggestion that magma or molten rock was rising to the surface. Phivolcs also recorded six volcanic earthquakes on Thursday, an indication that magma was making its way to the mountain’s top.
Cedric Daep, chief of the Albay Provincial Public Safety Management Office, warned residents on the southeast slope to look out for rockfalls, lava flows and pyroclastic flows.
The rains also present a danger, since they could turn the lava on the slopes into lahar, Phivolcs said.
Alert level 3 has been in force around the volcano. Once there is an eruption level 4 will be declared, calling for the mass evacuation of residents inside an expanded danger zone that will encompass most of Legazpi.
Phivolcs officials had predicted an eruption within two weeks.
Most of the villagers living on Mayon’s slopes have refused to evacuate, because they cannot leave their crops untended.
Many who evacuated were returning to their homes, Laguerta said.
Last Saturday, some 400 families in the villages of Santo Domingo town just outside the danger zone fled because of heavy ashfalls.
Residents staying at evacuation centers are allowed to return to their homes during the day, Daep said.
Gov. Fernando Gonzales of Albay reiterated his appeal for residents to leave the exclusion zone and not wait for alert level 4.
Gonzales will ask the police to set up a checkpoint in the area once level 4 is raised