The U.S. Geological Survey reports that a strong undersea earthquake has hit western Indonesia, but there were no immediate reports of damage or casualties.

The magnitude-6.5 quake early Thursday was centered 91 kilometers (56 miles) west of Sungaipenuh, a district town in Jambi province in Sumatra or 141 kilometers (88 miles) south of Padang, provincial capital of West Sumatra, the USGS said. It said the quake had a depth of 50.8 kilometers (31.5 miles).

Indonesia is prone to earthquakes due to its location on the Pacific "Ring of Fire," an arc of volcanoes and fault lines in the Pacific Basin. In December 2004, a massive earthquake off Sumatra island triggered a tsunami that killed 230,000 people in a dozen countries.