Model Answer
0 min readIntroduction
Earthquakes, resulting from the sudden release of energy in the Earth’s lithosphere creating seismic waves, are among the most devastating of natural hazards. These events not only cause immediate destruction but also trigger a cascade of secondary hazards, impacting both the natural environment and human settlements. India, situated in a seismically active zone, is particularly vulnerable. Understanding the diverse hazards associated with earthquakes and implementing effective mitigation strategies are crucial for minimizing loss of life and property. The recent earthquake in Turkey and Syria (February 2023) underscored the importance of robust building codes and disaster preparedness.
Natural Hazards Due to Earthquakes
Earthquakes generate a range of natural hazards, categorized as primary, secondary, and long-term effects:
- Primary Hazards: These are direct consequences of ground shaking.
- Ground Rupture: Visible breakage of the Earth’s surface along fault lines.
- Ground Shaking: The most widespread hazard, causing building collapse and infrastructure damage. Intensity is measured using the Modified Mercalli Intensity Scale.
- Landslides & Avalanches: Triggered by ground shaking, particularly in mountainous regions.
- Secondary Hazards: These are triggered *by* the primary hazards.
- Tsunamis: Generated by underwater earthquakes, causing widespread coastal flooding. (e.g., 2004 Indian Ocean Tsunami).
- Fires: Often caused by ruptured gas lines and electrical systems.
- Floods: Dam failures due to earthquake shaking can lead to catastrophic flooding.
- Liquefaction: Saturated soil loses strength and behaves like a liquid, causing buildings to sink or tilt.
- Long-Term Hazards: These are effects that persist long after the earthquake.
- Disease Outbreaks: Disrupted sanitation and water supplies can lead to the spread of infectious diseases.
- Economic Disruption: Damage to infrastructure and businesses can have long-lasting economic consequences.
- Psychological Trauma: Earthquakes can cause significant psychological distress among survivors.
Mitigation Aspects of Earthquake Hazards
Effective earthquake hazard mitigation involves a multi-faceted approach encompassing pre-earthquake, during-earthquake, and post-earthquake measures:
Pre-Earthquake Mitigation
- Seismic Zoning: Identifying areas with varying levels of seismic risk to guide land-use planning and building codes.
- Building Codes: Implementing and enforcing stringent building codes that ensure structures can withstand earthquake forces. (e.g., IS 1893:2016 – Criteria for Earthquake Resistant Design of Structures).
- Public Awareness & Education: Educating the public about earthquake hazards and preparedness measures.
- Early Warning Systems: Developing and deploying earthquake early warning systems to provide seconds of warning before strong shaking arrives.
- Infrastructure Strengthening: Retrofitting existing vulnerable structures, such as bridges and dams.
During-Earthquake Mitigation
- Drop, Cover, and Hold On: A widely recommended safety procedure during shaking.
- Emergency Response Plans: Having well-defined emergency response plans in place at the community and national levels.
- Communication Systems: Maintaining reliable communication systems for disseminating information and coordinating rescue efforts.
Post-Earthquake Mitigation
- Search and Rescue Operations: Rapidly deploying search and rescue teams to locate and assist survivors.
- Medical Assistance: Providing immediate medical care to the injured.
- Shelter and Relief: Providing temporary shelter, food, water, and other essential supplies to those affected.
- Reconstruction and Rehabilitation: Rebuilding infrastructure and providing long-term support to help communities recover.
Table: Comparison of Seismic Zones in India
| Seismic Zone | Intensity | Areas Covered |
|---|---|---|
| Zone V | Very High | Kashmir, Western and Central Himalayas, North-Eastern India, Andaman & Nicobar Islands |
| Zone IV | High | Seismic gaps in Himalayas, States in Indo-Gangetic Plain, Godavari basin |
| Zone III | Moderate | Coastal areas of India, Gujarat, and parts of Maharashtra |
| Zone II | Low | Remaining areas of India |
Conclusion
Earthquakes pose a significant threat to life and property, particularly in seismically active regions like India. Mitigating these hazards requires a holistic approach encompassing robust building codes, effective early warning systems, comprehensive disaster preparedness plans, and swift response and recovery mechanisms. Investing in these measures is not merely a matter of economic prudence but a moral imperative to protect vulnerable populations and build resilient communities. Continuous research and development in earthquake engineering and disaster management are also vital for adapting to evolving risks and improving our ability to withstand future events.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.