During the past 24-hour observation period, the seismic network around Mayon detected two high-frequency and four low-frequency volcanic earthquakes and 25 high-frequency, short-duration harmonic tremors which volcanologists associated with the rolling of incandescent volcanic materials down Bonga Gully.
The summit lava dome was seen to glow moderately between 7:40 p.m. Sunday and 2:13 a.m. yesterday, they said.
Sulfur dioxide emission was recorded at 5,756 tons per day, exceeding the baseline level of 500 tons per day and suggesting continuing ascent of magma into the lava dome, volcanologists said.
Alert level 3 remains in effect around Mayon, meaning an explosive eruption may occur within weeks should there be a rapid rate of magma supply. Residents are still warned not to venture into the six-kilometer permanent danger zone.  Felix de los Santos