List of Earthquake (Seismic) Zones in India

As we know that, these days frequent tremors of the earthquake are occurring in Delhi-NCR and nearby regions. It is said that Delhi-NCR belt, mainly areas near Yamuna River etc., comes under high-risk seismic zones. Do you know about seismograph and division of seismic zones in India? Let us find out!
Created On: Jun 5, 2020 13:53 IST
Modified On: Jun 5, 2020 13:53 IST
Earthquake (Seismic) Zones in India
Earthquake (Seismic) Zones in India

An earthquake is a vibration of the surface of the earth that is caused due to the elasticity or the isostatic adjustment of the rocks under the surface of the earth. It may be caused via human as well as natural activities.

Do you know before the earthquake waves hit a region, the amount of Radon gas increases in the atmosphere of that region? The rise of Radon gas indicates that the region is going to be hit by an earthquake. Various studies are done and concluded that elevated concentrations of radon gas in soil or groundwater could be signs of an imminent earthquake.

The point where the seismic (earthquake) waves originate is called the 'focus' of the earthquake, it takes place below the surface of the earth. Whereas, the place which perpendicularly above the focus, on the surface of the earth where the tremors of the earthquake are felt for the first time is called the 'epicentre'. The energy that is dissipated from the focus is known as the ‘Elastic Energy’.

 What are Seismic Waves?

The waves which are generated during an earthquake are known as seismic waves. They are classified into 3 types:

1. Primary or Longitudinal waves are also known as P-Waves: These are longitudinal waves analogous to the sound waves.

2. Secondary or Transverse Waves are also known as S-Waves: These are transversal waves analogous to the light waves.

3. Surface or Long-period Waves are also known as L-Waves: They originate when ‘P’ wave hits the surface.

What is Seismograph?

The instrument which is sensitive to the seismic waves and helps to measure the intensity of the earthquake is called Seismograph. There are different scales that are used to measure the intensity of earthquakes namely: Rossi-Forel Scale, Mercalli Scale, and Richter Scale.

Further, let us tell you that the lines joining the regions of same seismic intensity are called Isoseismal lines and the lines joining the places which experience the tremors of the earthquake at the same time are known as Homoseismal lines.

List of Earthquake (Seismic) Zones in India

Based on the past seismic history, Bureau of Indian Standards grouped the country into four seismic zones namely Zone-II, Zone-III, Zone-IV and Zone-V. Of all these four zones, Zone-V is the most seismic active region whereas Zone-II is the least.

Seismic Zone

Intensity on M.M Scale

Zone-II (Low-Intensity Zone)

6 (or less)

Zone-III (Moderate Intensity Zone)

7

Zone-IV (Severe Intensity Zone)

8

Zone-V (Very Severe Intensity Zone)

9 (and above)

Regions that fall under the Earthquake (seismic) Zones in India

Zone-V covers entire northeastern India, some parts of Jammu and Kashmir, some parts of Ladakh, Himachal Pradesh, Uttarakhand, Rann of Kutch in Gujarat, some parts of North Bihar and Andaman & Nicobar Islands.

Zone-IV covers remaining parts of Jammu & Kashmir, Ladakh and Himachal Pradesh, Union Territory of Delhi, Sikkim, northern parts of Uttar Pradesh, Bihar and West Bengal, parts of Gujarat and small portions of Maharashtra near the west coast and Rajasthan.

Zone-III comprises of Kerala, Goa, Lakshadweep islands, remaining parts of Uttar Pradesh, Gujarat and West Bengal, parts of Punjab, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Maharashtra, Odisha, Andhra Pradesh, Tamil Nadu and Karnataka.

Zone-II covers remaining parts of the country.

Seismic zoning map of India helps in identifying the lowest, moderate as well as the highest hazardous or earthquake-prone areas in India. Also, such maps are used or looked before the construction of high rise building so as to check the level of seismology in any particular area. In the long run, this helps in saving lives.

So now you may have come to know about the Earthquake (Seismic) Zones in India.

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