Earthquake: A Natural Hazard

Let’s start from the basics.

An earthquake is nothing but the sudden shaking or trembling of the Earth’s crust.
And remember — this shaking happens suddenly; there is no prior warning, which is why it’s so dangerous and unpredictable.

Now, why does the Earth shake?

Because the outer layer of the Earth, called the crust, is not one single piece.
It is broken into large tectonic plates — imagine like a jigsaw puzzle floating over molten rock beneath.

These plates are constantly moving — very slowly, just a few centimeters every year — but when they interact at their boundaries, stress builds up.
When that stress exceeds the rocks’ capacity to hold it, the rocks break or slip suddenly, releasing massive energy in the form of seismic waves — and that’s what we feel as an earthquake.

⚙️ Types of Plate Movements Causing Earthquakes

The boundaries where plates meet can have three types of movements:

1. Divergent Boundaries – Plates move away from each other (example: Mid-Atlantic Ridge).
2. Convergent Boundaries – Plates collide or push against each other (example: Himalayas).
3. Transform Boundaries – Plates slide horizontally past one another (example: San Andreas Fault, USA).

The place where this sudden slip occurs is called a fault, and the energy released travels as seismic waves.

📏 Measuring Earthquakes

Two main scales are used:

1. Richter Scale → Measures the magnitude (energy released).
2. Mercalli Scale → Measures the intensity (damage and impact felt on the surface).

🇮🇳 Earthquake Risk in India

Now, from an Indian perspective —
India lies in one of the world’s most seismically active zones, known as the Alpine–Himalayan Belt — the line where the Indian Plate meets the Eurasian Plate.

The Indian plate is continuously pushing under the Eurasian plate at about 5 cm per year, which keeps the Himalayan and adjoining regions under constant stress — making them highly earthquake-prone.

🔹 Highly vulnerable regions include:

• The Western and Central Himalayas, Northeast India, and parts of the Indo-Gangetic plains.
• Other regions: Rann of Kutch, Gulf of Khambhat, parts of Peninsular India, and islands like Andaman & Nicobar and Lakshadweep.

🔹 India’s Seismic Zones

India is divided into four seismic zones (II to V):

• Zone V → Most active (covers Northeast, Northern Bihar, Uttarakhand, Himachal Pradesh, J&K, Gujarat, Andaman & Nicobar Islands).
• Most of India lies in Zones II and III.

🧩 Earthquakes: Prediction vs Prevention

Earthquakes cannot be predicted or prevented.
Hence, the focus of disaster management must be on mitigation, preparedness, and prevention to reduce vulnerability.

🏛️ Institutional Mechanisms for Earthquake Management

1. National Centre for Seismology (NCS) –
   Monitors seismic activity and provides hazard assessments.
2. National Earthquake Risk Mitigation Project (NERMP) –
   Works on reducing structural vulnerability, especially in high-risk districts.
3. National Building Code (NBC) –
   Provides detailed guidelines on safe construction practices.
4. Building Materials and Technology Promotion Council (BMTPC) –
   Promotes earthquake-resistant construction and retrofitting of lifeline structures.
5. NDMA Guidelines on Earthquake Management –
   NDMA (National Disaster Management Authority) has identified six pillars of earthquake management, forming the foundation of seismic safety in India.

🏗️ Six Pillars of Earthquake Management (NDMA Guidelines)

Let’s understand these one by one:

1. Earthquake-Resistant Construction of New Structures

All new buildings — especially lifeline structures like bridges, flyovers, hospitals, ports, etc. — must strictly follow seismic safety standards during design and construction.
Responsibility lies with Central Ministries and State Governments.

2. Selective Seismic Strengthening and Retrofitting

Existing priority and lifeline structures (e.g., Raj Bhavans, Legislatures, Courts, schools, hospitals, dams) need to be retrofitted — strengthened to withstand future earthquakes.
Identification of such structures is to be done by State Governments, and implementation through Urban Local Bodies (ULBs) and Panchayati Raj Institutions (PRIs).

3. Regulation and Enforcement

Rules are useless without enforcement.
So, State Governments must ensure strict compliance with Building Codes, Zoning Regulations, and Town Planning Acts.
Builders, architects, engineers — all must adhere to seismic safety norms.
The Home Ministry’s expert group also suggested updating planning laws to global standards.

4. Awareness and Preparedness

This is the heart of disaster management — making people aware.

NDMA recommends:

• Handbooks and safety manuals for homeowners.
• Structural safety audit guidelines.
• Earthquake awareness videos for public education.
• Use of vulnerability maps to identify risk-prone areas.
• Active participation of NGOs and volunteer groups.

Also note: NCS has launched the ‘India Quake’ App, which provides real-time alerts on earthquake parameters like time, location, and magnitude.

5. Capacity Development

This means building human and institutional capabilities.
Training programs, research, and documentation for:

• Government officials and elected representatives,
• Engineers, architects, urban planners, builders,
• Teachers, students, media, NGOs, and communities.

6. Emergency Response

When a disaster occurs, response is coordinated through the Incident Command System and Emergency Operations Centres.
It involves local administration, community, corporate sector, and specialized rescue teams.

⚠️ Critical Challenges in India’s Earthquake Mitigation

1. Weak enforcement of building codes.
2. Lack of earthquake-resistant design in many urban and rural constructions.
3. Poor training among engineers and masons.
4. Limited preparedness and coordination during emergencies.
5. Low public awareness.
6. No standardized system for licensing engineers and builders.

🏠 National Building Code (NBC): A Cornerstone

NBC provides a comprehensive national guideline on building design, planning, and construction.

It ensures:

• Structural safety,
• Fire protection, and
• Health and sanitation standards.

It’s the technical backbone of earthquake-safe construction in India.