At least four moderate earthquakes shook the province of Surigao del Sur on Friday, according to the Philippine Institute of Volcanology and Seismology (Phivolcs). In its bulletin, Phivolcs said the first quake with a magnitude of 5.1 occurred at 4:53 am with epicenter of the quake traced 96 kilometers northeast of Tandag town in Surigao del Sur. The quake, which was tectonic in origin, had a depth of one kilometer. The second quake with a magnitude 4.1 occurred around 5:33 am with epicenter traced some 64 kilometers northeast of Tandag and had a depth of one kilometer. On the other hand, the third tremor with a magnitude of 3.1 happened at 7:38 am hit again the province and its epicenter was also traced seven kilometers northeast of the same town and had a depth of one kilometer. The fourth earthquake struck around at 10:59 am with magnitude 4.1 and its epicenter.