DOUBLET. The epicenter of the magnitude 5.3 quake that struck near Jomalig town in Quezon province Wednesday (Sept. 4, 2024) morning. The Philippine Institute of Volcanology and Seismology said another quake occurred near the same town shortly before 8 a.m., calling such an occurrence a doublet, which happens when two earthquakes of nearly the same size occur close together in the same area. (Image from Phivolcs Facebook page)
MANILA – Two earthquakes with magnitudes 5.3 and 4.9 struck almost the same epicenter in Quezon province Wednesday, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
At 7:16 a.m., a magnitude 5.3 earthquake jolted 43 km. northeast of Jomalig, while a magnitude 4.9 quake struck 38 km. northeast of the same town at 7:55 a.m.
These quakes were both 1 km. deep.
Phivolcs said such an occurrence is called a doublet,
when two earthquakes of nearly the same size occur close together in the same area.
"Though they seem similar, they are actually separate events, not one triggering the other. This happens where faults are quite complicated, causing the stress to trigger a sequence of events," it said.
Intensity III was felt in Quezon City due to the magnitude 5.3 quake.
On the other hand, the magnitude 4.9 quake resulted in the following reported intensities:
Intensity IV - Polillo, Quezon
Intensity III - Guinayangan, Alabat, Tagkawayan, Calauag, and Panukulan, Quezon; Makati; Quezon City
Intensity II - Lopez, and Gumaca, Quezon
Instrumental Intensities:
Intensity IV - Jose Panganiban, Camarines Norte
Intensity III - Mauban, Alabat, Guinayangan, and General Nakar, Quezon; Daet, Camarines Norte; Tinambac, Camarines Sur
Intensity II - Daet, Camarines Norte; City of Tagaytay, Cavite; Gumaca, Mulanay, and Calauag, Quezon
Intensity I - San Rafael and Pandi, Bulacan; Calamba, Laguna; City of Antipolo and Tanay, Rizal; Tinambac, Pasacao, and Ragay, Camarines Sur; Boac, Marinduque; Pasig City.
Aftershocks are possible from the magnitude 5.3 quake, while both earthquakes are not expected to cause damages, Phivolcs said. (PNA)
