Mayon spews ash; nearby residents told to prepare

Four months after state volcanologists raised the alert level for it, Mayon Volcano in Bicol exploded before dawn Wednesday, spewing ash reaching over 1000 meters up in the air. But while Philippine Institute of Volcanology and Seismology (Phivolcs) head Renato Solidum Jr. said it was the most powerful explosion since July, the alert level for Mayon remained at “2." “It is one of the scenarios we expected under Alert Level 2 – which includes spewing of ash and rocks. But these materials reached only two kilometers away around the upper slopes of the Volcano. However, there were traces of ash going to the southwest direction, reaching up to Camalig town in Albay," Solidum said in an interview on dzBB radio.

While he said Phivolcs has no immediate plans to raise the alert level for the volcano, he advised residents to be ready to evacuate once the need arises. “Wala pa po (None yet)," he said when asked if Phivolcs will raise the alert level to 3. Under Alert Level 3, there is an increased tendency towards eruption, with relatively high unrest. Also under such alert, volcanic quakes and tremor may become more frequent, there is a further increase in sulfur dioxide flux and occurrence of rock falls around the summit area, a vigorous steaming and/or sustained crater glow, and persistent swelling of edifice. Eruption possible “Magma is close to the crater. If the trend is one of increasing unrest, eruption is possible within weeks. [An] extension of [the] danger zone ... will be considered," Phivolcs said. Citing reports reaching him, Solidum said there are still some residents located north side of the volcano. "What is important is that residents should be ready if we raise the alert level to 3. Once we do, the local government of Albay would implement plans to evacuate residents," he said. In a separate interview on dzXL radio, Solidum said another explosion is possible, and that they are looking into whether a new batch of magma is making its way up the volcano. Solidum said the rumbling was audible to local residents and observers, and that Phivolvcs have recorded the explosion despite cloud cover. He said the explosion occurred at 1:58 a.m. and lasted for three minutes, but added there had been no follow-up explosions since. "Compared to the two past explosions since we placed Mayon under Alert Level 2, this one was more powerful, lasting three minutes," he said. On the other hand, Solidum said there is no need to expand the 6-km permanent danger zone (PDZ), saying Wednesday’s explosion was "relatively weak." “Those outside the 6-km PDZ are safe," he added. Phivolcs Bicol-based resident volcanologists Arnel Aquino said they recorded 19 high-frequency volcanic quakes and one low-frequency quake Wednesday. Aquino said a crater glow was observed, with the ash explosion reaching one kilometer. Albay evacuation plans Shortly after Phivolcs raised the alert level at Mayon, provincial officials in Albay mapped out evacuation plans, including for forced evacuation of residents near the area. Cedric Daep, head of the Albay Public Safety and Emergency Management Office (APSEMO), said Governor Jose Salceda also banned mountain-climbing activities on Mayon. In an interview last July 10, Daep said evacuation plans will be undertaken the moment Alert Level 3 is raised. "Once Mayon is placed under Alert Level 3, we will execute mandatory evacuation. Under mandatory evacuation, there will be a 24-hour curfew there, and we will place security personnel there," he said. Alert levels Phivolcs’ alert levels on volcanoes: Level 0: No Alert, Quiet; All monitored parameters within background levels and no eruption in foreseeable future. But entry in the 6-km radius Permanent Danger Zone (PDZ) is not advised because phreatic explosions and ash puffs may occur without precursors. Level 1: Abnormal, Low level unrest; Slight increase in seismicity. Slight increase in SO2 gas output above the background level, very faint glow of the crater may occur but no conclusive evidence of magma ascent, phreatic explosion or ash puffs may occur. No eruption imminent. Activity may be hydrothermal, magmatic or tectonic in origin. No entry in the 6-km radius PDZ. Level 2: Increasing unrest, moderate unrest. Low to moderate level of seismic activity, episodes of harmonic tremor, increasing SO2 flux, faint/intermittent crater glow. Swelling of edifice may be detected. Confirmed reports of decrease in flow of wells and springs during rainy season. Unrest probably of magmatic origin; could eventually lead to eruption. The 6-km radius Danger Zone may be extended to 7 km in the sector where the crater rim is low. Level 3: Increased Tendency Towards Eruption, relatively high unrest. Volcanic quakes and tremor may become more frequent, further increase in SO2 flux, occurrence of rockfalls in summit area, vigorous steaming/sustained crater glow, persistent swelling of edifice. Magma is close to the crater. If trend is one of increasing unrest, eruption is possible within weeks. Extension of Danger Zone in the sector where the crater rim is low will be considered. Level 4: Hazardous Eruption Imminent, intense unrest. Persistent tremor, many “low frequency"-type earthquakes, SO2 emission level may show sustained increase or abrupt decrease. Intense crater glow, incandescent lava fragments in the summit area, hazardous eruption is possible within days. Extension of Danger zone to 8 km or more in the sector where the crater rim is low will be recommended. Level 5: Hazardous Eruption Ongoing. Occurrence of pyroclastic flows, tall eruption columns and extensive ash fall. Pyroclastic flows may sweep down along gullies and channels, especially along those fronting the low part(s) of the crater rim. Additional danger areas may be identified as eruption progresses. Danger to aircraft, by way of ash cloud encounter, depending on height of eruption column and/or wind drift. - GMANews.TV