LEGAZPI CITY, ALBAY: The Philippine Institute of Volcanology and Seismology (Phivolcs) on Friday raised the alert level at Mayon Volcano to Level 2 after detecting the formation of a new lava dome measuring 30 to 50 meters high.
Phivolcs resident volcanologist Ed Laguerta said that based on observation of Mount Mayon’s summit crater on August 12, there was swelling in the mid-slope edifice and slight increase in gas emission.
This event was preceded by inferred low-volume intrusions, signified by episodes of very slight inflation or swelling of the middle slopes of the edifice since the May 7, 2013 phreatic eruption, based on Precise Leveling, continuous tilt and continuous GPS measurements.
“The significant increases in SO2 flux beyond the baseline level of 500 tons per day, based on campaign and continuous gas measurements for the past two months,” Laguerta said.
Under the Phivolcs alert level system, Level 2 means increasing unrest which is “probably of magmatic origin” and could eventually lead to eruption.
Albay Gov. Joey Salceda immediately directed city, municipal and barangay officials to be on guard in anticipation for the possible Mt. Mayon eruption.
Salceda also debarred or enforced the no mountain climbing for Mt. Mayon specifically for mountaineers. He also ordered the suspension of the famous ATV trail beyond lava front, no orchid picking, no vegetable harvesting in the delineated 6-km radius permanent danger zone and no human activity near the perimeter of the 6-km PDZ of the volcano here.
Similarly, Salceda disallowed the visitors of Mayon Skyline Hotel situated within the North of Mt. Mayon to go up during nighttime.
Phivolcs said that monitored parameters such as the occurrence of volcanic earthquakes and rockfall, however, have remained at baseline levels, while almost no crater glow or banaag has been detected in the last four months.
“The growth of the new summit dome, slight ground deformation and increased volcanic gas emission likely signify the slow intrusion and degassing of magma,” Laguerta explained.
The absence of other outstanding precursors may be due to very low magma intrusion rates, Phivolcs official 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.
“This means that magma is intruding at depth and that current conditions may eventually lead to a larger eruption. The public is strongly advised to be vigilant and desist from entering the six kilometer-radius Permanent Danger Zone (PDZ) to minimize risks from sudden explosions, rockfall and landslides,” the Phivolcs official said.
RHAYDZ B. BARCIA