The US Geological Survey said the quake hit at 1:15 am (1715 GMT Monday), 26 kilometres (16 miles) northwest of Olongapo, a coastal city of more than 200,000 people, at a depth of 61 kilometres.
The Philippines sits on the Pacific "Ring of Fire" -- a belt around the Pacific Ocean dotted by active volcanoes and tectonic trenches, where frequent eruptions and earthquakes take place. (*)
Editor: Kunto Wibisono
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