LAHAR WALL In this photo taken in 2018, grass, small trees and other plants sprouting on a lahar wall provide a little color to the path leading to the village of Inararo in Porac, Pampanga, where a community of Aetas was devastated by the eruption of Mt. Pinatubo in 1991. —RICHARD BALONGLONG
CITY OF SAN FERNANDO—A low level of unrest due to hardly felt earthquakes beneath Mt. Pinatubo has prompted the Philippine Institute of Volcanology and Seismology (Phivolcs) to place it on Alert Level 1, indicating a low-level unrest, on Thursday.
State volcanologists, however, said there were no signs of an imminent eruption despite the seismic activity around the volcano.
This was the first time since 1996 that Pinatubo was placed on this elevated alert status. The volcano, which is part of the Zambales mountain range straddling the boundaries of the provinces of Pampanga, Tarlac, Zambales and Bataan, was previously on Alert Level 0, or normal status.
Pinatubo last erupted on June 15, 1991, following 10 weeks of unrest. Its explosion was accompanied by Typhoon “Diding” (international name: Yunya) that dispersed ash up to Indonesia.
Phivolcs said since Jan. 20, the Pinatubo Volcano Network had detected 1,722 imperceptible quakes beneath the volcano’s edifice.
The first cluster of quakes between Jan. 20 and Jan. 26 happened along Sacobia Lineament, a fault that was last active following Pinatubo’s massive eruption in 1991.
These were recorded at depths of 15 to 28 kilometers and ranged between magnitudes 1 and 2.5.Phivolcs said these were followed by a more persistent cluster of quakes, with a depth of 10 to 35 km, beneath the center of the volcano. These quakes were stronger, with magnitudes ranging between 0.5 to 2.8.Extreme caution
“All earthquakes recorded are associated with rock fracturing processes,” volcanologists said in a bulletin on Thursday.
Phivolcs said entry into the Pinatubo crater area should be done with extreme caution, and should be avoided if possible. Local governments and communities surrounding the volcano were reminded to be prepared for both earthquake and volcanic hazards.
Visits to the crater lake were discouraged while the Philippine Air Force secured the entry to the volcano in the village of Sta. Juliana in Capas, Tarlac.
The Aeta communities that are closest to the volcano are found in the village of Inararo in Porac town, Pampanga province; Sitio (subvillage) Tarukan in the village of Sta. Juliana in Capas, Tarlac; and Sitio Lomboy in San Marcelino town, Zambales province.
Disaster preparedness
People living near Pinatubo were also advised to “review, prepare and strengthen their contingency, emergency and other disaster preparedness plans.”
The Pampanga provincial disaster risk reduction and management council (PDRRMC) has readied earth-moving equipment on upper lahar channels in response to Phivolcs’ advisory.
Angelina Blanco, PDRRMC officer, said they had also set up permanent and temporary evacuation centers by district and prepared food and other items.