Tropical depression "Henry" was at some 400 kilometers east of Legazpi City in Albay, packing maximum center winds of 55 kilometers per hour (kph), according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration.
Henry was moving west-northwest at 30 kph and was forecast to be at 350 kilometers east-northeast of Legazpi City today and 240 kilometers northeast of Virac, Catanduanes.
Philippine Institute of Volcanology and Seismology (Phivolcs) director Renato Solidum assured Albay residents that "Henry" would not trigger lava flows around the slope of Mt. Mayon, which had been restless for the past weeks.
Solidum noted that unlike other volcanoes like Mt. Pinatubo in Zambales, Mayon does not emit pyroclastic materials or lahar, which are volcanic mudflows that can devastate entire towns.
He added that Mayon’s molten rocks or magma immediately solidify on the slopes after being spewed out by the volcano.
Phivolcs reported yesterday that some ash fell in several areas in Daraga and Legazpi City, which lie south of Mayon.
"These trace ash deposits were primarily derived from the lava flowing through the Mabinit channel. The front of this slowly moving lava mass has reached the 320-meter elevation which corresponds to approximately 5.4 aerial kilometers from the crater," Phivolcs said.
Smaller flows and incandescent blocks of lava were seen entering adjacent gullies towards the general directions of barangays Miisi, Mabinit, Bonga, Matanag and Buyoan. Residents in these villages were advised to prepare in case they need to evacuate.
Mayon’s sulfur dioxide emission rate, measured at around 6,099 tonnes per day, indicated "active degassing" from the crater area, according to Phivolcs.
Volcanologists have recorded 394 tremors and four volcanic earthquakes, indicating a continued buildup of magma inside the volcano.