WASHINGTON - A moderate 5.6-magnitude earthquake hit northern Chile early Saturday, but there were no immediate reports of casualties or damage, according to the US government.

The epicentre of the tremor, which occurred at 1:50 am local time (0550 GMT), was located in the mountains 96 kilometres south southwest of the town of Copiao, Chile, the US Geological Survey reported.

The reading was based on the open-ended Moment Magnitude scale, now used by US seismologists, which measures the area of the fault that ruptured and the total energy released.