MANILA - The state seismology bureau on Thursday raised alert level 1 over Mt. Pinatubo due to the "persistence of seismic activity."
"This means that there is low-level unrest that may be related to tectonic processes beneath the volcano and that no imminent eruption is foreseen," the Philippine Institute of Volcanology and Seismology said in its latest bulletin.
A total of 1,722 "imperceptible" earthquakes were recorded in the vicinity of Pinatubo in Central Luzon since Jan. 20, the agency said.
The first cluster of earthquakes, which ranged between magnitudes 1 to 2.5, were generated along a segment of the Sacobia Lineament. This is a fault that was last active in the wake of the volcano's cataclysmic eruption in June 1991.
State volcanologists said this was followed by a "more persistent cluster of earthquakes" that took place beneath the center of the edifice itself. It ranged between 0.5 to 2.8 in magnitude.
Phivolcs advised locals that entry into the Pinatubo crater area must be conducted with extreme caution and should be avoided if possible.
"Communities and local government units surrounding Pinatubo are reminded to be always prepared for both earthquake and volcanic hazards and to review, prepare and strengthen their contingency, emergency and other disaster preparedness plans," the agency added.
Its most destructive eruption was in June 1991 where it killed at least 847 people, displaced nearly 250,000 families, and caused P12.5 billion worth of damage to properties, agriculture, and infrastructure.
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