Four earthquakes shook national capital Delhi within a period of 3 hours early today.

The first quake measuring 3.1 on Richter scale occurred at 12.41 AM, an Indian Meteorological Department report said.

This was followed by three more tremors of 3.3, 2.5 and 2.8 magnitude at 1.41, 1.55 and 3.40 AM, the report said.