Two earthquakes with magnitudes 5.3 and 4.9 struck Quezon province consecutively on Wednesday, Sept. 4, in a seismic event known as a “doublet.”
Phivolcs said the 5.3-magnitude earthquake, which occurred at 7:16 a.m., was followed by a 4.9-magnitude tremor at 7:55 a.m., with both epicenters located in Jomalig, Quezon.
Both tremors were also felt in parts of Metro Manila.
READ MORE: https://mb.com.ph/2024/9/4/5-3-magnitude-quake-jolts-quezon-province-tremors-felt-in-metro-manila
However, Phivolcs clarified that the second, weaker earthquake was not an aftershock of the first, stronger quake, making them two separate events.
“A doublet happens 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,” it said.
Phivolcs explained that doublets are a result of intricate fault systems where accumulated stress can trigger multiple seismic events in rapid succession.
The agency expects aftershocks following the 5.3-magnitude quake but does not anticipate aftershocks from the 4.9-magnitude quake.