Legazpi: A total of 131 rockfall events were recorded in Mayon Volcano in the past 24 hours, but raising its alert status to Level 4 is unlikely for now, the head of the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Wednesday.

According to Philippines News Agency, the latest number of rockfalls is higher than the 85 rockfall events recorded between January 5 and 6. Phivolcs Director Teresito Bacolcol explained that the sharp increase in rockfall events indicated increasing instability at the volcano's summit, a sign commonly associated with magma rising from below.

Due to elevated unrest, Phivolcs raised Mayon Volcano's alert status from Level 2, indicating increasing unrest, to Level 3, which signifies an increased tendency towards a hazardous eruption. This decision came just five days after initially placing the volcano under Alert Level 2.

During an interview on Wednesday, Bacolcol elaborated that increasing the volcano's alert status to Level 4, which suggests a hazardous eruption is imminent, is unlikely at present. He stated that other parameters such as a sudden change in sulfur dioxide emission, sustained increase in mass flux, or long lava flows need to be considered.

Other indicators before escalating to Alert Level 4 include frequent pyroclastic density currents and lava fountaining. "Minor explosions and sustained increase in volcanic earthquakes are other parameters we consider before raising the volcano's status to Alert Level 4," Bacolcol added.

He also noted that the most significant eruption of Mayon Volcano occurred in 1814. Phivolcs strongly recommends prohibiting entry into the volcano's 6-km permanent danger zone (PDZ). Bacolcol mentioned that this zone could be extended if the volcano's status is raised to Alert Level 4.