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:

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

Recent earthquakes

Earthquake of 4.3 magnitude in Afghanistan

An earthquake measuring 4.3 on the Richter Scale hit parts of Afghanistan on October 26, 2023. There were no reports of damages or casualties.

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

Anuradha Ramamirtham

With 16+ years of experience in various sectors, of which more than ten years in real estate, Anuradha Ramamirtham excels in tracking property trends and simplifying housing-related topics such as Rera, housing lottery, etc. Her diverse background includes roles at Times Property, Tech Target India, Indiantelevision.com and ITNation. Anuradha holds a PG Diploma degree in Journalism from KC College and has done BSc (IT) from SIES. In her leisure time, she enjoys singing and travelling.
Email: [email protected]

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