Buildings collapsed at the foothills of the Himalayas

Buildings collapsed at the foothills of the Himalayas because of an earthquake before collapsing they were moving forward and backward give geographical reason

The Himalayas are prone to earthquakes. During an earthquake, energy is released from the interior of the earth in the form of waves. The primary or the P waves are the first to reach the surface of the earth. They move forward and backward. It is because of these waves that buildings move forward and backward.