An earthquake of moderate intensity measuring 5.1 in the Richter Scale shook Assam and other parts of the north-eastern region early today. Officials said in Guwahati that the epicentre of the tremor that occurred at 12.30 am was at Rangapara in central Assam's Sonitpur district. The quake was also felt in neighbouring Nagaland and Arunachal Pradesh. Sources said that no casualty, injury or loss of property was reported.