MANILA — The Philippine Institute of Volcanology and Seismology (Phivolcs) on Monday morning said it has recorded more than a hundred earthquakes as well as “moderate emissions” from Negros Island’s Kanlaon Volcano.

The 136 volcano-tectonic earthquakes were observed on the western flank of the volcano in the last 24 hours, based on Phivolcs’ 8 a.m. bulletin.

Four of the earthquakes, which struck from 1 a.m. to around 2 a.m. on Monday, were at 3.2 to 4.7 in magnitude.

“They were felt at Intensities II to V in La Carlota and Bago City, Negros Occidental and Canlaon City, Negros Oriental,” Phivolcs said.

Meanwhile, the white steam-laden plumes rose to 200 meters before drifting southwest.

Sulfur dioxide, which would signal that magma is close to the surface, was measured at an average of 438 tonnes/day more than a week ago on June 13. Phivolcs said it had also detected “slight deflation” of the volcano’s lower and mid slopes since January this year.

“These parameters indicate that hydrothermal or magmatic activity is occurring beneath the edifice,” Phivolcs said.

Kanlaon Volcano has been on Alert Level 1 since March 11 as it “entered a period of unrest.”

Entry into the 4-kilometer radius of the permanent danger zone is prohibited because of possible eruptions. Flying over the volcano is also prohibited.

- With a report from Kristine Sabillo, ABS-CBN News