Magma movement stops but Mayon still restive–Phivolcs

Mayon Volcano. MARK ALVIC ESPLANA/INQUIRER SOUTHERN LUZON

LEGAZPI CITY, Philippines—The rise of magma in Mayon Volcano appears to have stopped temporarily, but this does not mean the volcano has calmed down, a volcanologist said here Saturday.

Eduardo Laguerta, resident volcanologist of the Philippine Institute of Volcanology and Seismology, said at a press briefing Saturday a decrease in the number of volcanic quakes and rockfall events was noted during the past 24-hour observation period, indicating that upward movement of magma has stopped. Pressure from within pushes magma up a volcano’s vent until it spills over as lava.

Laguerta said, however, that the fact the volcano’s magma was not rising did not mean that Mayon had calmed down. It was likely that pressure was still building up for an eruption, he said.

In its bulletin on Saturday morning, Phivolcs said it recorded 4 volcanic quakes and 22 rockfall events Saturday compared to Friday’s 22 volcanic quakes and 70 rockfall events. On Thursday, there were 142 volcanic quakes and 251 rockfalls.

Phivolcs noted, however, that the emission of sulfur dioxide had increased to an average of 1,290 tons per day on Friday compared to 757 tons per day on Wednesday.

“When the magma becomes stationary, the rockfall events will also stop also but this does not mean that it (magma) will not move again,” he said.

Laguerta said the magma might have hardened at the upper portion of the magma chamber that would contribute to the “inflation” of the volcano and added pressure inside.

Phivolcs raised alert level 3 over Mayon on Monday, indicating that magma was rising to the top and a hazardous eruption could happen within a matter of weeks.

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