Shimla: An earthquake of 4.3 magnitude shook Himachal Pradesh’s tribal Lahaul and Spiti district on Monday, the meteorological department said. There were no immediate reports of any casualty or damage to property, it said. The quake’s epicentre was at a depth of 20 km north-east in Lahaul and Spiti district, the department said, adding that tremors were also felt in and around the district at 9.03 am on Monday. This is the third earthquake in Himachal Pradesh in a week. Earthquakes of magnitude 4 and 3.3 shook Chamba and Kinnaur districts on July 25 and July 23 respectively.