MANILA, Philippines — A 6.3 magnitude aftershock jolted Balut Island in Sarangani early Thursday, the Philippine Institution of Volcanology and Seismology (Phivolcs) reported. According to Phivolcs, the tectonic earthquake hit 99 kilometers (km) southwest of Balut Island at 5:41 a.m with a recorded depth of 10 kilometers. READ: Magnitude 6.4 quake strikes off Davao Occidental The quake reported instrumental intensities, or the measured strength of the ground shaking, over the following areas: Phivolcs said the tremor was an aftershock of the magnitude 7.8 earthquake that hit offshore Sarangani and another 6.5 magnitude quake reported offshore Davao Occidental in June. /mr...Keep on reading: Magnitude 6.3 aftershock strikes off Balut Island in Sarangani