SEISMIC ZONES OF INDIA:-

Seismic Zones of India

India is one of the most seismically ac ve countries in the world, primarily due
to its geological features and tectonic se ngs. The country's seismic ac vity is
influenced by the interac on of the Indian Plate with the Eurasian Plate, among
others. This interac on has given rise to various seismic zones, which are
classified based on the expected intensity and frequency of earthquakes.
Tectonic Background
The Indian subcon nent is located on the Indian Plate, which is moving
northward towards the Eurasian Plate at a rate of approximately 5 cm per year.
This collision creates significant stress in the Earth's crust, resul ng in frequent
earthquakes. The Himalayas, formed by this collision, are a testament to the
tectonic ac vity in the region.
The major tectonic features affec ng seismic ac vity in India include:
1. The Himalayan Frontal Thrust: This is where the Indian Plate subducts
under the Eurasian Plate, causing significant seismic events.
2. The Indo-Burmese Arc: This area has complex tectonics leading to varying
seismic risks.
3. The Mid-Indian Ridge: This underwater ridge also influences seismic
pa erns in the region.
Classifica on of Seismic Zones in India
India has been divided into four major seismic zones, labeled as Zone I to Zone
V, based on the poten al for earthquake damage. The Bureau of Indian
Standards (BIS) has classified these zones in its code IS 1893, which focuses on
earthquake-resistant design of structures.
1. Zone I: Very Low Seismic Risk
o Descrip on: This zone experiences minimal seismic ac vity and is
generally considered safe for construc on.
o Geographic Areas: Parts of the western and southern regions, such
as Gujarat and Tamil Nadu.
 o Typical Earthquake Magnitude: Rarely exceeds magnitude 5.0.
2. Zone II: Low Seismic Risk
o Descrip on: Areas in this zone experience occasional earthquakes,
but they are typically of low intensity and infrequent.
o Geographic Areas: Parts of Punjab, Haryana, and some areas in
Rajasthan and Maharashtra.
o Typical Earthquake Magnitude: Magnitudes up to 5.5 can occur.
3. Zone III: Moderate Seismic Risk
o Descrip on: This zone has a moderate level of seismic ac vity, with
buildings requiring proper earthquake-resistant designs.
o Geographic Areas: Most of Northern India, including Delhi, parts of
Jammu & Kashmir, Himachal Pradesh, and U arakhand.
o Typical Earthquake Magnitude: Can experience earthquakes of
magnitude 6.0 or slightly higher.
4. Zone IV: High Seismic Risk
o Descrip on: Characterized by frequent seismic events, this zone
requires strict adherence to earthquake-resistant construc on
prac ces.
o Geographic Areas: Areas around the Himalayan region, including
parts of Himachal Pradesh, U arakhand, and the northeastern
states.
o Typical Earthquake Magnitude: Earthquakes can reach magnitudes
of 7.0 or more.
5. Zone V: Very High Seismic Risk
o Descrip on: This is the most seismically ac ve zone in India, with a
high likelihood of experiencing significant earthquakes.
o Geographic Areas: Primarily in the Himalayan states, including parts
of Jammu & Kashmir, Himachal Pradesh, and parts of Sikkim.
o Typical Earthquake Magnitude: Earthquakes can frequently exceed
magnitude 7.5, with the poten al for devasta ng effects.
Seismic History of India
India has a rich history of seismic ac vity, with several major earthquakes that
have caused significant damage and loss of life:
 The 1905 Kangra Earthquake: One of the most devasta ng earthquakes,
measuring 7.8 on the Richter scale, struck the Kangra Valley in Himachal
Pradesh, killing around 20,000 people.
 The 1934 Bihar-Nepal Earthquake: With a magnitude of 8.1, this
earthquake affected a vast area, resul ng in widespread destruc on in
Bihar and Nepal.
 The 1993 Latur Earthquake: This earthquake, measuring 6.4, struck
Maharashtra, leading to over 9,000 deaths and significant property
damage.
 The 2001 Gujarat Earthquake: Measuring 7.7, this earthquake struck the
Kutch region, resul ng in approximately 20,000 deaths and extensive
destruc on.
 The 2015 Nepal Earthquake: Although centered in Nepal, this earthquake
(magnitude 7.8) affected northern India, demonstra ng the cross-border
impact of seismic events.
Seismic Risk Assessment and Mi ga on
Given the poten al for earthquakes in various zones, India has implemented
several measures for seismic risk assessment and mi ga on:
1. Building Codes: The Bureau of Indian Standards has established codes
that outline guidelines for earthquake-resistant designs, par cularly for
buildings in high-risk zones.
2. Public Awareness: Educa ng the public about earthquake preparedness
and response strategies is essen al for minimizing damage and loss of life.
3. Seismic Monitoring: The Na onal Centre for Seismology (NCS) in India is
responsible for monitoring seismic ac vity and providing early warnings
for poten al earthquakes.
4. Retrofi ng: Older buildings, par cularly in high-risk zones, are being
retrofi ed to meet modern safety standards.
 5. Research and Development: Ongoing research into seismic ac vity and
building technologies aims to improve resilience against earthquakes.
Conclusion
India's seismic zones reflect the country’s complex geological history and the
ongoing tectonic interac ons. Understanding these zones is crucial for disaster
preparedness and urban planning. As urbaniza on increases, par cularly in
vulnerable regions, the need for resilient infrastructure and public awareness
becomes even more cri cal. With a proac ve approach to seismic risk
management, India can mi gate the impact of future earthquakes and protect
its popula on and infrastructure.