A record moderate aftershock of last week’s magnitude 6.5 earthquake in Leyte province struck Monday morning.
The 9:41 a.m. aftershock was a magnitude 5.4 earthquake of tectonic origin that struck 15 km east of Ormoc City with a depth of 6 km, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
“That’s the earthquake’s strongest aftershock so far,” said Phivolcs science research analyst Bong Lauron.
He said movement of Philippine Fault’s Leyte segment triggered the aftershock.
Lauron said Phivolcs already recorded, as of 10 a.m. Monday, 629 aftershocks of last week’s Leyte earthquake including the record moderate one on this day.
Those aftershocks’ magnitudes ranged from 1.5 to 5.4, he noted.
The moderate aftershock’s occurrence isn’t surprising, however, said Phivolcs Dir. and science undersecretary Renato Solidum.
Aftershocks are always of smaller size compared to the earthquake that generate these, he said.
There’s low probability for last week’s Leyte earthquake to generate aftershocks with magnitudes higher than 6.5, Phivolcs noted.
Phivolcs is expecting damages from Monday’s moderate aftershock in Leyte, however.
“The aftershock was felt at Intensity 6 in Ormoc – it was a very strong one so damages from ground-shaking there are possible,” said Lauron.
Such aftershock was also reported at Intensity 5 (Kananga, Leyte), Intensity 4 (Mayorga, Leyte and Tacloban City; Mandaue City), Intensity 3 (Loay and Jagna, Bohol; Cebu City) and Intensity 2 (Lapu-Lapu City; Cadiz City, Negros Oriental), noted Phivolcs.
Phivolcs noted the aftershock was likewise reported at instrumental Intensities 3 (Cebu City) and 2 (Palo, Leyte; Lapu-Lapu City).
Under Phivolcs’ earthquake intensity scale, 5 and 4 indicate people felt the aftershock as “strong” and “moderately strong,” respectively. (Catherine J. Teves/PNA)