(UPDATE) Mayon volcano showing signs of increased activity

MANILA - The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Sunday said it is studying the possibility of raising the alert level of Mayon Volcano in Albay in the Bicol region after it recently showed signs of increased activity.

PHIVOLCS said it has intensified its monitoring on the activity of Mayon Volcano.

PHIVOLCS confirmed that the crater glow of the volcano has intensified from level one to two which means the glow is visible with the naked eye.

Ed Laguerta, PHIVOLCS resident volcanologist, said the increase in the crater glow means the magma activity inside the volcano has increased.

Aside from the crater glow, Phivolcs has also noted an inflation of the volcano's edifice in the ground deformation survey conducted this June compared to the 12 millimeter deflation recorded in the survey conducted last January. The survey was conducted in Buang Leveling Line in Barangay Buang in Tabaco City.

This also indicate an abnormal activity of the volcano PHIVOLCS said.

Meanwhile for the past 24 hours, PHIVOLCS also said it has recorded four low frequency volcanic earthquake.

Alert level one however is maintained over Mayon volcano and residents and tourists are advised not to enter the seven-kilometer extended danger zone and the six-kilometer permanent danger zone. PHIVOLCS said with the recent abnormal activity of the volcano, a sudden phreatic explosion is possible.

Phreatic eruptions is desribed by US Geological Survey as steam-driven explosions that occur when water beneath the ground or on the surface is heated by magma, lava, hot rocks, or new volcanic deposits (for example, tephra and pyroclastic-flow deposits). USGS says the intense heat of such material (as high as 1,170° C for basaltic lava) may cause water to boil and flash to steam, thereby generating an explosion of steam, water, ash, blocks, and bombs.

PHIVOLCS noted that the alert level can be raised if there is a continuous increase in parameters such as seismic ground deformation and sulfur dioxide emission rate.

Mayon Volcano’s last eruption happened in July until August of 2006 which had the alert level of the volcano raised to four. No casualties were recorded in the last eruption.