According to B. B. Lal, former DG of ASI, Kalibangan site shows that an earthquake occured around 2600 BC, which brought to an end the Early Indus settlement at the site. It is perhaps the earliest archaeologically recorded earthquake.
The Capital of Magadh empire was situates at Rajgriha or Girivraja. The city was almost impregnable as it was surrounded by five hills, the openings in which were closed by stone walls on all sides.