JAKARTA, Feb 1 (Reuters) - A moderate earthquake shook the southern part of Indonesia's Java island early on Thursday, but there were no immediate reports of casualties or damage, an official said. The 5.9 magnitude quake was centred in the sea 147 km (91 miles) southwest of Sukabumi in West Java, Suharjono, chief of the Meteorology and Geophysics Agency in Jakarta, told Reuters. "It did not have a tsunami potential and no casualties have been reported so far," he said, adding that the quake was felt along a wide stretch of the southern Java coast. The U.S. Geological Survey put the quake magnitude at 5.8 and said it hit at 3.31 a.m. local time (2031 GMT). Indonesia sits atop Asia's so-called "Ring of Fire" where continental plates collide and earthquakes and volcanic eruptions are frequent.
