Shimla: An earthquake measuring 4 on the Richter scale shook the Shimla district of Himachal Pradesh on Wednesday, Indian Meteorogical Department said. The tremors felt at 9.58 am had its epicentre at Seri-majhali, about 65 km from here, and it occurred at a depth of 7 km. People felt the tremors but no damage has been reported so far.