HONG KONG, July 14 (Xinhua) -- A moderate earthquake measuring 5.5 on the Richter scale struck northern Sumatra, Indonesia at 0450 GMT Monday, the Hong Kong Observatory said in a bulletin released here Monday afternoon.

    The epicenter was initially determined by the Hong Kong Observatory at 2.3 degrees north latitude and 96.6 degrees east longitude, about 270 kilometers west-southwest of Medan, Indonesia.

    There has been no immediate casualty report.