How to ensure your home is earthquake proof?

In the recent past, earthquakes have been felt in parts of Rajkot, Gujarat and even in the Delhi National Capital Region (NCR) but not limited to these. Earthquakes of a higher magnitude, can cause massive destruction of property and life, which is why the structural safety of buildings and the need for the best seismographs, becomes crucial. In 2016, according to a report titled ‘Earthquake Hazard Zoning Maps’, by the Building Materials Technology Promotion Council (BMTPC), as many as 95% households in the country are vulnerable to earthquakes. The BMPTC is a government-sponsored body, for promoting appropriate building technology. Let us understand the seismic zones in India and how to build earthquake resistant house.

India’s seismic zones

About 59% of land area in India is prone to damage due to earthquakes. This land is classified into four zones.

 

Zone V

Parts of the Himalayan boundary in the north and north-east India, the Kutch region in west India, parts of Jammu and Kashmir, Himachal Pradesh, north Bihar, Andaman and Nicobar Islands and Uttaranchal, are in Zone V, which is the most active region, seismically. This zone is prone to heavy destruction due to earthquakes.

 

Zone IV

Parts of Jammu and Kashmir, Himachal Pradesh, National Capital Territory of Delhi, Sikkim, northern parts of Uttar Pradesh, West Bengal, Bihar, some parts of Maharashtra (near the west coast), Gujarat and Rajasthan, fall in Zone IV. Zone IV is less active than Zone V but the toll of destruction can still be high.

 

Zone III

Comparatively safer than Zone IV and V, Zone III comprises the remaining parts of Uttar Pradesh, West Bengal, Rajasthan, Bihar, Jharkhand, Chhattisgarh and Maharashtra that are not in the above two zones. This also includes Madhya Pradesh, Odisha, Andhra Pradesh, Tamil Nadu, Kerala, Goa, Lakshadweep and Karnataka.

 

Zone II

This is the safest or technically the least active region and covers parts of India that do not lie in any of the aforementioned zones.

 

Source: National Institute of Disaster Management (NIDM)

See also: All about Pucca house and Kutcha house

Earthquake proof house

The Bureau of Indian Standards and building codes have guidelines to construct structurally safe buildings and earthquake proof house. The following figure encapsulates the internal elements, required for an earthquake-resistant structure.

 

Source: NIDM 

How to build earthquake resistant house: Best materials to use

Wood and concrete and wood are earthquake resistant construction materials. Additional support has to be given to concrete based homes with steel slabs to make it earthquake resistant.

Earthquake proof house: Self-assess safety residential brick buildings

Here is how you can self-assess the risk of damage for your residential building or know if it is earthquake resistant house.

Number of storeys

A one or two-storeyed building, using one brick (nine inches) thick walls, will be relatively safer than a three-storeyed building. The fourth storey, if added, will be very unsafe and will make living in the lower storeys riskier.

 

Thickness of the load carrying walls in each storey

If the property uses half-bricks, of 4½-inch-thick load bearing walls, this can make the structure unsafe and if it is used in higher storeys, it could even turn catastrophic. Too many openings in a wall for windows also result in weakening the walls. The use of small piers in between openings that is less than 45 cms, will also increase the risk of destruction. The ideal combined width of the openings should be as follows:

 

Building type	Combined width of openings (for windows)
3-4-storeyed building	Less than one-third of the length of the wall
2-storeyed building	Less than 42%
1-storeyed building	Not more than 50%

 

Mortar used for construction

The stronger the mortar, the safer the building will be. The use of mortar specified for safety is 1:6 cement-sand mortar, that is, one part cement with six parts of sand. Lime-surkhi or lime-cinder mortar is much weaker, says the NIDM.

 

Horizontal seismic bands

 

Source: NIDM

Seismic safety elements are important and include the horizontal bands that are provided at the plinth level and lintel level of doors, windows and external and internal walls. These strengthen the walls against earthquake destruction and provide an earthquake-resistant home.

 

Vertical reinforcing bars

At every corner and T-junction of the room, vertical reinforcing bars should be provided, right from the foundation to all the storeys and to the top roof slab.

What is retrofitting?

Retrofitting refers to the strengthening of the building, to avoid damage due to earthquakes. Retrofitting may be required in some buildings, because the old building bye laws may be outdated. One should hire a licensed structural engineer to study the property, before retrofitting.

What is a structural safety certificate?

This certificate confirms that the structure’s construction plan satisfies the safety requirements, vis-à-vis an earthquake or a cyclone. Usually, the civic administration issues the structural safety certificate, after a thorough inspection. The certificate is proof of the fact that the structure is fit for use and the same has been determined, after adequate verification and soil testing. In 2011, the Delhi government made the structural safety certificate mandatory for property registration.

What is on-site EWS?

On-site early earthquake warning and security system (On-site EWS) senses the primary waves of an earthquake and triggers an alarm. It can even be programmed to halt certain ongoing activity, such as elevator parking, shutting power, water and gas lines or even entry and exit gates. This can be useful for residential and commercial projects

What to do before an earthquake?

The National Disaster Management Authority (NDMA) has chalked out a detail plan on what has to be done before, during and after earthquake. Mentioned below are pointers as mentioned by the NDMA.

• Follow BIS codes relevant to your area for building standards
• If you see cracks in building foundation or ceiling, get in touch with a structural engineer and get the place repaired.
• Fasten shelves securely to walls.
• Place large or heavy objects on lower shelves.
• Get defective electrical wiring and leaky gas connections repaired as these are potential fire risks.
• Identify safe places indoors and outdoors.
• Stay away from the place where glass could shatter around windows, mirrors, pictures, or where heavy bookcases or other heavy furniture could fall over
• If in the open, be away from buildings, trees, telephone and electrical lines, flyovers and bridges
• Know emergency telephone numbers (such as those of doctors, hospitals, the police, etc)

 

Emergency kit

 

• Keep a battery operated torch with extra batteries
• Battery operated radio
• First aid kit and manual
• Emergency food (dry items) and water (packed and sealed)
• Candles and matches in a waterproof container
• Knife
• Chlorine tablets or powdered water purifiers
• Can opener.
• Essential medicines
• Cash and credit cards
• Thick ropes and cords
• Sturdy shoes

The NDMA suggests that it is a good idea to develop a plan before hand in case of family separating during the natural disaster.

What to do during an earthquake?

The NDMA mentions that some earthquakes are actually foreshocks and a larger earthquake might occur. It is better to minimise your movements and stay indoors until the shaking has stopped and you are sure exiting is safe.

 

If you are indoors

 

• Drop to the ground; take COVER by getting under a sturdy table or other piece of furniture; and HOLD ON until the shaking stops. If there is no a table or desk near you, cover your face and head with your arms and crouch in an inside corner of the building.
• Stay away from glass, windows, outside doors and walls, and anything that could fall.

If you are outdoors

• Move away from buildings, trees, streetlights and utility wires.
• If you are travelling in a vehicle, avoid roads, bridges, or ramps that might have been damaged by the earthquake.

 

If trapped under debris

• Do not light a match.
• Do not move about or kick up dust.
• Cover your mouth with a handkerchief or clothing.
• Tap on a pipe or wall so rescuers can locate you.
• Use a whistle if one is available. Shout only as a last resort. Shouting can cause you to inhale dangerous amounts of dust.

 

What to do during an earthquake?

It is always good to have an emergency plan and you should discuss this with all responsible members of your family/ building. The National Disaster Management Division has given the following plan to be followed during an earthquake:

• Turn off utilities, such as gas and the electricity fuse box.
• If you are near an exit, hold your arms to cover your head and rush out.
• If you are stuck in a staircase or a high-rise building, just ‘Drop-cover-hold’ or sit and lie down under a sturdy piece of furniture and cover as much of your upper body as possible.
• Do not use the elevators.
• If you are on the road, occupy a free space, away from structures, bridges, metro stations and power lines.
• If you are driving, you should stop and move away to a safe zone.
• Stay calm but prepare yourself in advance, in case of aftershocks.

 

List of Indian cities in various seismic zones

Town	State/UT	Zone	Town	State/UT	Zone
Agra	Uttar Pradesh	III	Chitradurga	Karnataka	II
Ahmedabad	Gujarat	III	Coimbatore	Tamil Nadu	III
Ajmer	Rajasthan	II	Cuddalore	Tamil Nadu	III
Allahabad	Uttar Pradesh	II	Cuttack	Orissa	III
Almora	Uttarakhand	IV	Darbhanga	Bihar	V
Ambala	Haryana	IV	Darjeeling	West Bengal	IV
Amritsar	Punjab	IV	Dharwad	Karnataka	III
Asansol	West Bengal	III	Dehradun	Uttarakhand	IV
Aurangabad	Maharashtra	II	Dharmapuri	Tamil Nadu	III
Bacharach	Uttar Pradesh	IV	Delhi	Delhi	IV
Bengaluru	Karnataka	II	Durgapur	West Bengal	III
Barauni	Bihar	IV	Gangtok	Sikkim	IV
Bareilly	Uttar Pradesh	III	Guwahati	Assam	V
Belgaum	Karnataka	III	Goa	Goa	III
Bhatinda	Punjab	III	Gulbarga	Karnataka	II
Bhilai	Chattisgarh	II	Gaya	Bihar	III
Bhopal	Madhya Pradesh	II	Gorakhpur	Uttar Pradesh	IV
Bhubaneswar	Orissa	III	Hyderabad	Andhra Pradesh	II
Bhuj	Gujarat	V	Imphal	Manipur	V
Bijapur	Karnataka	III	Jabalpur	Madhya Pradesh	III
Bikaner	Rajasthan	III	Jaipur	Rajasthan	II
Bokaro	Jharkhand	III	Jamshedpur	Jharkhand	II
Bulandshahr	Uttar Pradesh	IV	Jhansi	Uttar Pradesh	II
Burdwan	West Bengal	III	Jodhpur	Rajasthan	II
Cailcut	Kerala	III	Jorhat	Assam	V
Chandigarh	Chandigarh	IV	Kakrapara	Gujarat	III
Chennai	Tamil Nadu	III	Kalapakkam	Tamil Nadu	III
Kanchipuram	Tamil Nadu	III	Pondicherry	Pondicherry	II
Kanpur	Uttar Pradesh	III	Pune	Maharashtra	III
Karwar	Karnataka	III	Raipur	Chattisgarh	II
Kohima	Nagaland	V	Rajkot	Gujarat	III
Kolkata	West Bengal	III	Ranchi	Chattisgarh	II
Kota	Rajasthan	II	Roorkee	Uttarakhand	IV
Kurnool	Andhra Pradesh	II	Rourkela	Orissa	II
Lucknow	Uttar Pradesh	III	Sadiya	Assam	V
Ludhiana	Punjab	IV	Salem	Tamil Nadu	III
Madurai	Tamil Nadu	II	Shimla	Himachal Pradesh	IV
Mandi	Himachal Pradesh	V	Sironj	Madhya Pradesh	II
Mangalore	Karnataka	III	Solapur	Maharashtra	III
Monghyr	Bihar	IV	Srinagar	Jammu & Kashmir	V
Moradabad	Uttar Pradesh	IV	Surat	Gujarat	III
Mumbai	Maharashtra	III	Tarapur	Maharashtra	III
Mysore	Karnataka	II	Tezpur	Assam	V
Nagpur	Maharashtra	II	Thane	Maharashtra	III
Nagarjunasagar	Andhra Pradesh	II	Thanjavur	Tamil Nadu	II
Nainital	Uttarakhand	IV	Thiruvananthapuram	Kerala	III
Nasik	Maharashtra	III	Tiruchirappalli	Tamil Nadu	II
Nellore	Andhra Pradesh	III	Tiruvannamalai	Tamil Nadu	III
Osmanabad	Maharashtra	III	Udaipur	Rajasthan	II
Panjim	Goa	III	Vadodara	Gujarat	III
Patiala	Punjab	III	Varanasi	Uttar Pradesh	III
Patna	Bihar	IV	Vellore	Andhra Pradesh	III
Pilibhit	Uttarakhand	IV	Vijayawada	Andhra Pradesh	III
			Visakhapatnam	Andhra Pradesh	II

Recent earthquakes

Earthquake of 5.3 magnitude in Telangana

An earthquake measuring 5.3 on the Richter Scale hit parts of Telangana on December 5, 2024 at 7.27 AM.  The tremors of this earthquake, believed to be second biggest in 55 years were felt in many places across Telangana and Andhra Pradesh, Chhattisgarh and Maharashtra. Mulugu near Godavari riverbed was the epicentre of this earthquake.

Earthquake of 4.2 magnitude in Delhi

Following an earthquake of 4.2 magnitude in Delhi at 2.20 PM on October 3, 2023, the national capital and areas around North India experienced strong tremors after an earthquake of magnitude 6.2 shook Nepal, according to the National Centre for Seismology.

Earthquake of Magnitude:6.2, Occurred on 03-10-2023, 14:51:04 IST, Lat: 29.39 & Long: 81.23, Depth: 5 Km ,Location:Nepal for more information Download the BhooKamp App https://t.co/rBpZF2ctJG @ndmaindia @KirenRijiju @Indiametdept @Dr_Mishra1966 @Ravi_MoES pic.twitter.com/tOduckF0B9

— National Center for Seismology (@NCS_Earthquake) October 3, 2023

Earthquake of 4.4 magnitude in Jaipur 

An earthquake of 4.4 magnitude hit Rajasthan’s Jaipur, Dausa and Tonk on July 21, 2023  at 4.09 AM. This was followed by an earthquake of 3.1 and 3.4 magnitudes at 4.22 AM and 4.25 AM. While the depth of the first and the third earth quakes was recorded at 10 KM near Jaipur, the depth of the second earth quake was 5 KM.

Earthquake of Magnitude:4.4, Occurred on 21-07-2023, 04:09:38 IST, Lat: 26.88 & Long: 75.70, Depth: 10 Km ,Location: Jaipur, Rajasthan, India for more information Download the BhooKamp App https://t.co/hGAimUi1GZ @ndmaindia @Indiametdept @KirenRijiju @Dr_Mishra1966 @DDNewslive pic.twitter.com/EpQI2Ejk7Q

— National Center for Seismology (@NCS_Earthquake) July 20, 2023

FAQs

How many seismic zones are there in India?

There are four seismic zones – Zone V (very high risk zone), Zone IV (high risk zone), Zone III (moderate risk zone) and Zone II (low risk zone).

Which earthquake zone is Mumbai in?

Mumbai falls under seismic Zone III (moderate risk zone).

Which earthquake zone is Delhi in?

Delhi falls under seismic Zone IV (high risk zone).

What are the main causes of earthquakes?

Movement of Tectonic Plates, Volcanic Eruptions, Underground Explosions, Induced Quaking (Human Activities) etc. are the main causes of earthquakes.

What should you not do if you are stuck under debris?

As per NDMA, you should not shout unless there is no last resort as you may swallow dust and debris.

If you are stuck at home what should you be away from?

From windows and glass panes that may shatter.

Can you use lift during an earthquake?

No. You should not use lifts during earthquake or in case of fire.

Got any questions or point of view on our article? We would love to hear from you.Write to our Editor-in-Chief Jhumur Ghosh at jhumur.ghosh1@housing.com