The Philippine Institute of Volcanology and Seismology (Phivolcs) on Tuesday recorded a total of 340 rockfall events from midnight of 19 January to 12 a.m. on 20 January, the highest since Alert Level 3 was raised at Mayon Volcano.

Phivolcs Director Teresito Bacolcol said the data indicate intensified volcanic activity.

“Ibig sabihin nito, nagtaas ang activity ng bulkan, nagtuloy ang dome lava activity kaya tuloy din ang rockfall at pagbagsak ng PDCs,” Bacolcol said in an interview.

Latest monitoring data showed 45 pyroclastic density currents (PDCs) and 13 volcanic earthquakes recorded over the 24-hour period. Bacolcol said overall parameters remain within expectations for Alert Level 3.

“If we look at the overall parameters, seismicity, ground information, gas emission, at surface activity, nasa loob pa rin ito ng inaasahang conditions sa Alert Level 3,” he added.

Phivolcs said it continues to closely monitor the number of volcanic earthquakes, dome collapse events, and “abnormal changes in gas emissions.”

During the 24-hour observation period, crater glow remained visible to the naked eye. Sulfur dioxide flux was measured at 3,061 tons on 19 January, while volcanic plumes were observed. The agency also noted inflation of the volcanic edifice.

Under Alert Level 3, Phivolcs reiterated that entry into the six-kilometer Permanent Danger Zone (PDZ) and entry without vigilance into the Extended Danger Zone (EDZ) are prohibited, including flying aircraft close to the volcano.

“Ito ang lugar na pwedeng tamaan (6 kilometer PDZ) ng pinakamabilis at pinakadelikadong hazard, particularly ang PDC. Ang uson, ay napakabilis at napakainit nito so kapag andun ka na, halos wala ka nang oras na tatakbo,” Bacolcol explained.

According to the latest Phivolcs bulletin, possible hazards include rockfalls, landslides or avalanches, ballistic fragments, lava flows and lava fountaining, pyroclastic density currents, moderate-sized explosions, and lahars during heavy and prolonged rainfall.

Bacolcol urged residents near the Permanent Danger Zone to remain alert and maintain “heightened vigilance.”