600 Aftershocks Rattle Island Chain

More than 600 aftershocks have jolted a chain of islands in southern Japan in a 36-hour period, authorities said Friday.

The strongest struck early Friday morning with a preliminary magnitude of 5.2, powerful enough to rattle windows and topple books from shelves. It was followed six hours later with a 4.9-magnitude jolt.

Two-thirds of temblors were strong enough to be felt, but there were no reports of damage or injuries on the Amami islands, 750 miles southwest of Tokyo.