A moderate earthquake measuring 5.1 on the Richter Scale shook the Arunachal Pradesh border early on Saturday morning.The quake hit Eastern Xizang on the Arunachal borders at 03:05 am, the MeT Department said.There were no immediate reports of damage or casualty.The epicentre of the tremor was located at a latitude of 29.4 degree North and a longitude of 96.4 degree East, it said.