Seismic zones of India

Also called: Earthquake hazard zones · Topic: Natural Hazards and Disaster Management in India · NCERT: Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"

Meaning

Seismic zones of India (earthquake hazard zones) are parts of the country grouped by how likely strong earthquakes are and how much damage they can cause. The official map is the Seismic Zoning Map in the BIS code IS 1893 (Part 1), which uses four zones, II to V [2]. These zones tell engineers how strongly buildings must be built in each area. They also show planners which cities and projects face the most risk.

Explanation

Why some areas shake more than others

• Plate push in the north:
• The Indian plate moves north-northeast. NCERT gives about 1 cm a year, while GPS (satellite positioning) shows about 4-5 cm a year.
• It is locked (held fast by friction) against the Eurasian plate, so strain energy builds up in the rocks.

• When the rocks can take no more, they slip suddenly. This causes earthquakes along the Himalayan arc and in the northeast, so these areas get the highest zones.

• Weak lines in the "stable" Peninsula:

• The old Peninsular shield (the hard block of the Deccan plateau) has old faults (cracks in the crust where blocks of rock move), such as the Bhima fault.
• The plate may slowly be breaking up inside the shield, so stress is released along these weak lines.

• Large dams can also set off quakes. This is reservoir-induced seismicity (earthquakes started by the weight and water pressure of a dam lake), as at Koyna.

• How zones are drawn: maps are based on the recorded history of earthquakes. NCERT's map comes from an analysis of over 1,200 earthquakes by the National Geophysical Laboratory, GSI (Geological Survey of India), IMD (India Meteorological Department) and NIDM (National Institute of Disaster Management).

NCERT's five damage-risk zones (Class 11, Fig. 6.2)

• Very high damage risk: northeastern states; areas north of Darbhanga and Araria (Bihar, along the Nepal border); Uttarakhand; western Himachal around Dharamshala; Kashmir Valley; Kachchh (Gujarat).
• High damage risk: the rest of J&K, Ladakh and Himachal; northern Punjab; eastern Haryana; Delhi; western Uttar Pradesh; northern Bihar.
• Moderate, low and very low damage risk: the rest of the country. The Deccan plateau is the safest.

BIS zoning: the official building code

• BIS (Bureau of Indian Standards) issues IS 1893 (Part 1), "Criteria for Earthquake Resistant Design of Structures". It contains the Seismic Zoning Map of India [2].
• In 2002, Zone I was merged into Zone II, leaving four zones: II, III, IV and V.

Zone	Hazard	Share of India's area
V	Highest (most active)	about 11% [3]
IV	High	about 18% [3]
III	Moderate	about 30% [3]
II	Low (least active)	about 41% [3]

• Going by recorded earthquakes, about 59% of India's land area, covering all states, is prone to earthquakes of different strengths [3].

The 2025 Zone VI revision and its withdrawal

• The 2025 revision:
• It created a new top category, Zone VI, and put the entire Himalayan arc in it.

• Only a small part of north-eastern Ladakh stayed in Zone V [2].

• The withdrawal: this revision was withdrawn in March 2026, so IS 1893 (Part 1): 2016 is again the current standard [2].

• Follow-up work: after the Himalaya was rated high-risk, the government started studies on site response (how local soil makes shaking stronger or weaker), fault mapping and regional source characterisation (finding which faults can produce quakes) [2].

Where it occurs

• Zone V (highest): the whole northeast; parts of Kashmir, Himachal Pradesh and Uttarakhand; north Bihar; Kachchh (Gujarat); the Andaman and Nicobar Islands.
• Zone IV: Delhi, along with the high-risk belt of northern Punjab, eastern Haryana, western Uttar Pradesh and northern Bihar (NCERT's high damage-risk zone).
• Most quake-prone Himalayan areas: Jammu and Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, the Darjeeling subdivision (West Bengal) and all seven northeastern states.
• Landmark quakes that match the high zones:
• 1897 Shillong (Meghalaya plateau)
• 1905 Kangra (Himachal Pradesh)
• 1934 Bihar-Nepal (north Bihar)
• 1950 Assam, M 8.6, the largest in India's recorded history [4]
• 2001 Bhuj (Kachchh, M 7.7, about 20,000 dead)

• 2005 Kashmir (near Muzaffarabad, PoK, M 7.6, over 80,000 dead)

• Lower zones that still shake:

• Latur 1993, at Killari (Maharashtra), linked to the Bhima fault

• Koyna 1967, in Satara district (Maharashtra), a reservoir-induced quake

• Central seismic gap: the stretch of the central Himalaya (Uttarakhand and western Nepal) between the 1905 Kangra and 1934 Bihar-Nepal ruptures. It has had no great quake for centuries, so strain keeps building there.

Don't confuse with

• NCERT damage-risk zones vs BIS seismic zones: NCERT names five damage-risk zones (very high to very low). The official BIS IS 1893 map has four numbered zones (II-V), because Zone I was merged into Zone II in 2002.
• Zone VI (2025) vs the current map: Zone VI put the whole Himalayan arc in a new top category, but it was withdrawn in March 2026. The 2016 map with Zones II-V applies today [2].
• Seismic zone vs seismic gap: a seismic zone is a hazard category on a map. The central seismic gap is a particular stretch of the Himalaya where no great quake has happened for centuries, so strain is still building.
• Safest zone vs quake-free: the Deccan plateau is the safest zone, but it is not quake-free. Latur 1993 and Koyna 1967 both struck there.

Prelims Hooks

• The BIS zones in use today are II, III, IV and V. Zone I was merged into Zone II in 2002.
• Zone V covers about 11% of India's area, and Zone II covers the largest share, about 41% [3].
• Delhi = Zone IV. The Andaman and Nicobar Islands = Zone V. Kachchh is Zone V, even though it lies in the Peninsula.
• Trap: the 2025 Zone VI map was withdrawn in March 2026, so IS 1893 (Part 1): 2016 still applies [2].
• About 59% of India's land, covering all states, is prone to earthquakes [3].
• NCERT's zoning is based on over 1,200 earthquakes, analysed by the National Geophysical Laboratory, GSI, IMD and NIDM. The Deccan plateau is the safest zone.

Mains Points

• Distribution of seismic risk (GS-I):
• The Indian plate is locked against the Eurasian plate, so the Himalayan arc and the northeast fall in the highest zones.
• The Peninsula is not fully safe. Old faults (Bhima), the slow breaking of the plate, and large reservoirs (Koyna) cause quakes there too.

• The central seismic gap warns of a future great quake under densely populated Uttarakhand and the Ganga plain.

• Using zones to cut deaths (GS-III):

• Latur (about M 6.2, about 10,000 dead) shows that weak houses, not magnitude alone, decide the death toll.
• Policy needs: enforce IS 1893, retrofit (strengthen) existing buildings, and make rural houses safer.

• Zone IV and V cities such as Delhi also need microzonation (detailed hazard maps at city level).

• Big projects in high zones (GS-III):

• Himalayan dams such as Tehri (on the Bhagirathi, Uttarakhand), hydro projects and fast urban growth raise the risk of reservoir-induced quakes and of heavy losses.
• The fault mapping, site-response studies and source characterisation that began after the Himalaya was rated high-risk should guide where these projects are built [2].

Related concepts

• Himalayan earthquakes
• Bhima fault
• Reservoir-induced earthquake
• Latur earthquake 1993
• Bhuj earthquake 2001
• 2005 Kashmir earthquake

Read more

• Earthquakes in India: causes, zones and landmark events