MAYON VOLCANO BULLETIN 05 December 2014 8:00 A.M. PDF Print
Friday, 05 December 2014 06:21

Mayon Volcano’s current condition remains unstable due to slow but sustained ground deformation of the edifice caused by the movement of subsurface magma since the start of unrest this year. The latest ground deformation data based on precise leveling surveys on November 27 - 29 showed significant inflation at the base of the edifice relative to November 18 - 21 and also relative to baseline measurements beginning 2010. The large positive change in the vertical displacement indicates magma pressurization at depth. Electronic tilt data from the continuous network on the northwest flank similarly indicate continuing inflation of the edifice since August 2014, succeeding a previous inflation event in June to July 2014. The inflation events correspond to batches of magma (approximately 107 cubic meters) that have been slowly intruding at depth but that have yet to be erupted at the crater, and therefore posing threat of eventual hazardous eruption at an unknown time in the near future.

Seismic monitoring network recorded three (3) volcanic earthquakes during the past 24 hours. Emission of white steam plumes was of moderate volume that drifted west south-west and south south-west.  Crater glow was not observed due to rain clouds covering the summit.  Seismicity, visual and gas parameters, however, may suddenly change within a few hours or days as should magma breach the surface in an eventual eruption.

Mayon Volcano’s alert status remains at Alert Level 3. At this present stage, potentially eruptible magma has already been intruded and continues to be intruded beneath the edifice. At any given time in the following weeks to months, this magma can eventually be erupted quietly as lava flows or explosively as vertical eruption columns and pyroclastic flows or both. It is strongly recommended that the 6-km radius Permanent Danger Zone (PDZ) around the volcano and the 7-km Extended Danger Zone (EDZ) on the southeastern flank be enforced due to the danger of rock falls, landslides and sudden explosions or dome collapse that may generate hazardous volcanic flows. PHIVOLCS maintains close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders.