India is no stranger to earthquakes, with several events recorded every year. Over the past decade, an average of 274 seismic events, with a magnitude of 4 or more, occurred within 300 km of its borders annually. This means the nation experiences approximately one earthquake every 1.3 days. However, what’s the cause of this frequent seismic activity, and which areas in India are the most vulnerable?
Recent Earthquake Trends
In March 2023, the country was jolted by six earthquakes, all measuring above 4 on the Richter scale. This was particularly alarming, as the northern states of India have witnessed a rise in strong seismic activities over the past two-to-three years.
On October 15, 2023, a magnitude 3.1 earthquake rocked the northern parts of India, including the capital, Delhi. The epicentre was located 9 km east of Faridabad in the Haryana state. This was the second seismic event in the span of two weeks that the national capital experienced.
Earlier in the month, on October 3, Delhi and its surrounding regions felt the tremors from two earthquakes originating in Nepal. The first of these had a magnitude of 4.6 and the second, a stronger quake, measured 6.2 on the Richter scale. Both of these quakes sent waves of panic across northern India, leading people to rush out of their homes and offices.
The Science Behind the Quakes
According to scientists, the entire stretch from the Hindu Kush mountains to the end of Arunachal Pradesh, known as the Western Himalayas, is one of the world’s most dangerous seismic zones. Earthquakes result from the movement and interaction of tectonic plates beneath the Earth’s surface. The constant interaction of these plates leads to energy being stored along the faultlines. This energy is periodically released in the form of earthquakes. The prediction is that this region might experience a major earthquake, measuring above 8 on the Richter scale, in the future.
India’s Earthquake-prone Regions
India has categorised its territories into four seismic zones:
• Zone 1: Low-intensity earthquakes; includes the Karnataka Plateau.
• Zone 2: Moderate-intensity earthquakes; covers areas such as Kerala, Goa, and the Lakshadweep Islands, as well as parts of Punjab, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Maharashtra, Odisha, and Tamil Nadu.
• Zone 3: High-intensity earthquakes; includes regions like Jammu & Kashmir, Himachal Pradesh, Delhi-NCR, Sikkim, northern parts of Uttar Pradesh, Bihar, West Bengal, and the western coasts of Maharashtra and Rajasthan.
• Zone 4: Extremely severe earthquakes; comprises North Bihar, Himachal Pradesh, Uttarakhand, the Rann of Kutch in Gujarat, and the Andaman and Nicobar Islands.
Understanding earthquakes in India involves examining both their causes and developing strategies for responding effectively. Let’s delve into both of these aspects.
Causes of Earthquakes in India:
1. Tectonic Movements: The primary cause of earthquakes is the tectonic forces generated by the movement of the Earth’s lithospheric plates. India is situated on the Indian plate that’s moving northward and is continuously colliding with the Eurasian plate, leading to the Himalayan region’s upliftment and causing significant seismic activity.
2. Fault Lines: The existence of major fault lines, such as the Himalayan Frontal Fault, Main Boundary Thrust, and the Main Central Thrust, among others, in and around India, makes it susceptible to earthquakes. The stress accumulation along these faults can lead to seismic activities when released.
3. Volcanic Activity: Although not as common in India, volcanic activities can also trigger earthquakes. The Barren Island volcano in the Andaman and Nicobar archipelago is an active volcano in India.
4. Human Activities: Activities such as mining, reservoir-induced seismicity from filling large reservoirs, and geothermal energy extraction can also induce earthquakes, though these are typically of lower magnitudes.
Best Response to Earthquakes:
1. Before an Earthquake:
• Prepare an Emergency Kit: This kit should include water, non-perishable food, a flashlight, a battery-powered radio, batteries, a first aid kit, necessary medications, important documents, and cash.
• Secure Heavy Furniture: Ensure bookshelves, refrigerators, and other heavy furniture items are anchored.
• Plan Evacuation Routes: Know how to get out of your home or building in case of an earthquake.
• Practice Drop, Cover, and Hold On: Teach everyone in the family to drop to their hands and knees, cover their head and neck with their arms, and if possible, take cover under sturdy furniture, holding on until the shaking stops.
2. During an Earthquake:
• If indoors, stay there. Move away from windows, skylights, and glass doors to prevent injury from shattered glass.
• If outdoors, find a clear spot away from buildings, trees, and streetlights and drop to the ground until the shaking stops.
• If driving, pull over to a safe place and remain inside the vehicle until the shaking ends. Avoid stopping near overpasses, bridges, power lines, and other potential hazards.
3. After an Earthquake:
• Inspect your surroundings: Check for gas leaks, damaged electrical wires, and structural damages. If you smell gas, shut off the main gas valve and open windows.
• Listen to the Radio: Stay tuned to local news and radio for updates and instructions.
• Avoid Using Phones: Unless there’s a life-threatening situation, avoid using phones to keep the lines free for emergency calls.
• Be Prepared for Aftershocks: These are smaller tremors that follow the main quake.
• Assist Neighbours: Check on your neighbours, especially if they’re elderly, have young children, or have special needs.
Having a comprehensive understanding of the causes and responses can help citizens and authorities in India be better prepared and reduce the impact of earthquakes on lives and property.
With the rising number of earthquakes, particularly in northern India, preparedness and understanding of these natural events are crucial. Researchers and scientists are working to better predict these occurrences, and citizens are urged to stay informed and be prepared for such eventualities.