AFTERSHOCKS of the 6.9 magnitude earthquake on September 30 near Bogo City, Cebu, and the 7.4 and 6.8 magnitude doublet earthquakes near Manay, Davao Oriental, on October 10, continue to rock the two coastal towns, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.
Since Day 1, Phivolcs said it has recorded a total of 12,079 aftershocks attributed to the Cebu earthquake. Of these, a total of 2,139 were plotted and 46 were felt.
The magnitude of these aftershocks ranged from 1 to 5.8.
In the doublet earthquakes near Manay, Phivolcs said it has so far recorded 1,303 aftershocks, of which 618 were plotted and 18 were felt. The magnitudes of these aftershocks range from 1.2 to 5.8.
In Manay, Davao Oriental, three strong aftershocks were recorded on Monday morning.
The first occurred at exactly 10 a.m. The aftershock determined to be magnitude 5.6. At exactly 10:19 a.m., another strong aftershock occurred with a magnitude of 4.7. Another aftershock with a magnitude of 4.9 rocked Manay anew. It was magnitude 4.9.
Aftershocks such as these can cause further damage and endanger lives, as they can cause buildings that already sustained damage to collapse, Phivolcs said.
Phivolcs said aftershocks happen when the rocks start to adjust. Generally, aftershocks weakens in time but sometimes, they also generate strong tremors, the agency added.