Why are there more earthquakes in the Himalayas and in the north-eastern region of India?
The Himalayas and the north-eastern region of India experience more earthquakes due to the continuous movement of tectonic plates. The Indian plate is moving at a speed of one centimetre per year towards the north and northeastern direction.
This movement is being constantly obstructed by the Eurasian plate from the north. As a result of this collision and obstruction between the two plates, significant tectonic stress builds up in these regions. This makes the North-east states and the Himalayan region (including Uttarakhand, Western Himachal Pradesh, and Kashmir Valley) highly vulnerable to earthquakes.
These areas are classified under the Very High Damage risk zone and have experienced some of the most devastating earthquakes in India due to this ongoing tectonic activity.
Explanation
The textbook explains that the primary reason for earthquakes in the Himalayas and north-eastern region is the collision between the Indian plate and the Eurasian plate. The Indian plate's northward movement at 1 cm/year is obstructed by the Eurasian plate, creating tectonic stress. This is why these regions fall under the Very High Damage risk zone.