Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The highest concentration of seismic zones lies in the Himalayan region in India.
Reason (R): There are many longitudinal thrust zones in the Himalayas.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Both (A) and (R) are true and (R) is the correct explanation of (A)
Assertion (A): The highest concentration of seismic zones lies in the Himalayan region in India. True. On India's seismic zone map, the Himalayan belt from Jammu and Kashmir to the North-East lies almost wholly in Zones IV and V, the zones of the highest earthquake risk.
Reason (R): There are many longitudinal thrust zones in the Himalayas. True. The Himalayas are still rising as the Indian Plate pushes against the Eurasian Plate, and the strain is taken up along long faults running parallel to the ranges, such as the Main Central Thrust and the Main Boundary Thrust.
The Reason explains the Assertion: earthquakes occur when rocks slip suddenly along such faults, so the many active thrust zones are what make the Himalayan region the most earthquake-prone part of India.