An official from the Philippine Institute of Volcanology and Seismology (Phivolcs) said that the structural integrity of infrastructures in Samar and Leyte must be checked after multiple earthquakes occurred in the waters of Eastern Samar.

Dr. Winchelle Ian Sevilla, Chief Science Research specialist of the Volcano Monitoring and Eruption Prediction Division of Phivolcs, emphasized that residents must double-check their houses to ensure that they have not been damaged by offshore earthquakes.

“Residents must be aware of the possible aftershocks, they follow the local government’s instructions and consult with the local engineers,” Sevilla said in a phone interview.

Last Sunday night, the state seismology agency logged two magnitude 4 earthquakes, which were aftershocks of the magnitude 5.3 earthquake that occurred last Friday, 14 February, night.

Initial inspection from the Local Disaster Risk Reduction and Management Office of Hernani showed minimal cracks from different establishments in the area.

Sevilla said the earthquake was caused by the Philippine trench, a 1,320-kilometer-long trench that extends from the east of Luzon to Indonesia.

“It is normal for trenches to generate earthquakes, although sometimes, more frequent earthquakes occur in fault lines,” the state seismologist added.

Since the 14 February earthquake, Phivolcs recorded 129 earthquakes, of which 74 were plotted.

The strongest aftershock occurred at 9:18 a.m. on 15 February, generating a magnitude 5.2 earthquake that was felt in the Samar provinces, Leyte, Masbate and Sorsogon.

The Phivolcs also noted that the aftershocks, which mostly occurred in the areas of Maydolong and Hernani in Eastern Samar are all tectonic in origin.