Earth quakes occur in the region of marked instability of the crust
of the earth. Most of the earth quakes in India originate in Himalayan
zone. At the western extremity, where the main Himalayas meet the
Baluchistan area of mountains, and in the eastern extremity, where
the Burmese area meets the Eastern Himalayas, the crust is most unstable.
As such, the Baluchistan and Assam areas are most susceptible to earth
movements. Another zone of instability occurs along the margin of
the Shillong plateau.