So far this is the highest SO2 reading since the volcano in Albay started spewing lava on July 14.
Alex Baloloy, the volcanologist-in-charge of SO2 measurement on Mayon, said that although the volcano’s reading dropped from 7,020 tons on Sunday to 5,885 tons the other day, it again rose to over 9,000 yesterday.
"Very high volumes of SO2 emission mean that the fresh magma is undergoing massive degassing activities which include (its) pushing towards the upper magma chamber," he told The STAR yesterday.
Baloloy said the very high SO2 emissions could be attributed to the building up of fresh magma as high SO2 emissions usually originate from the volcano’s chamber.
Baloloy said that during Mayon’s latest eruption, SO2 emissions were measured at 3,714 on Feb. 25, and 3,800 tons in the morning and 4,800 tons in the afternoon the next day, and then it went to 14,000 tons on Feb. 28, which was immediately followed by the first big explosion on the same day.
Mayon had recorded an SO2 emission of 9,448 tons on June 21, then the reading quickly dropped to 904 tons on June 24 followed again by another explosion, he added.
Baloloy said, based on this pattern, Mayon is likely to erupt whenever its SO2 emission continuously rises or after a sudden drop from the very high SO2 emission takes place.
"So Mayon follows two patterns here, one, it first emits SO2 very high volumes in several days then follows an eruption, or two, it emits a very high SO2, drops on the next day, then follows an eruption," he said.
Meanwhile, chairman Daniel Nuñez of Barangay Mabinit near Mayon said lava from the volcano had already burned the vegetation as well as trees in the area fronting the barangay, which is located about eight kilometers from the volcano’s crater.
"We can already see the burning on the area where villagers here gather firewood and tend vegetable crops," he told The STAR yesterday.
"But what is happening at Mayon is already normal to us."
Nuñez said once Mayon erupts, the 314 families or 1,394 residents near the volcano will be taken to the San Roque Evacuation Center.
Most residents of Mabinit have not worked since 40 percent or 400 villagers are dependent on their livelihood tending crash crops like petchay, string beans, chili, tomatoes and ampalaya at the slopes of Mayon, he added.
Maria Salome Villanueva, Sto. Domingo town municipal social welfare development officer, said 620 families or 2,935 persons who have left their homes in Barangays Sta. Misericordia, Fidel Surtida, Lidong and San Isidro and are now staying as "voluntary evacuees" at the San Andres and Bicol Evacuation Centers.
"Most of the evacuees return to their homes except the children and elderly," she said.
Toilets and water facilities are now being constructed at the evacuations centers to serve the needs of the evacuees, she added.
Phivolcs said that the lava flow had already advanced by about 300 meters for the past 24 hours.
"These tremors are associated with the movement of flowing lava and falling rocks," the bulletin said.
However, the lava flow and rockfall activity are still confined within the six-kilometer radius of the permanent danger zone.
The incandescent fragments were picked up by the seismic network around the 2,462-meter volcano which recorded 564 tremor episodes, from the 324 recorded Monday as well as 12 volcanic quakes compared to 11 the day previous. — With Celso Amo