Bulusan Volcano and Mt. Pinatubo have logged 35 and 33 volcanic earthquakes, respectively, in the last 24 hours, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Friday, May 28.

Phivolcs said Bulusan Volcano in Sorsogon also had "very weak" emission of white steam-laden plumes from the lower southeast vent.

Moreover, sulfur dioxide (SO2) emission was measured at an average of 48 tonnes per day on May 20.

Phivolcs said that ground deformation data from real-time electronic tilt monitoring also recorded sustained inflation of the upper slopes that began on March 6, 2021, which is consistent with short-term inflation of the edifice measured by continuous GPS monitoring since February 2021.

"These parameters generally indicate that shallow hydrothermal processes are occurring beneath the edifice," Phivolcs said.

It said that Bulusan Volcano remains under Alert Level 1, which means that it is currently in an abnormal condition.

Local government units and the public were advised to prevent from entering the four-kilometer radius permanent danger zone (PDZ).

Phivolcs said the public should also remain vigilant when entering the two-kilometer extended danger zone on the southeast sector due to increased possibilities of sudden and hazardous phreatic eruptions.

Likewise, Alert Level 1 is maintained over Mt. Pinatubo in Central Luzon, which means that there is low-level unrest that may be related to tectonic processes beneath its edifice.

However, Phivolcs pointed out that "no imminent eruption is foreseen."

"Entry into the Pinatubo Crater area must be conducted with extreme caution and should be avoided if possible," Phivolcs advised.