Understand different natural disasters and their underlying causes.
Distinguish between natural hazards and natural disasters.
Analyze human impact on disaster frequency and magnitude.
Explore strategies for disaster mitigation and management.
Understand India’s vulnerability to natural disasters.
Natural hazards and disasters, whether caused by natural phenomena or human activities, have deeply impacted human life and property. This text examines the causes, consequences, and management of such disasters. Disasters may result from natural forces or human activities. Disasters caused by nature include earthquakes, floods, and landslides, while human-induced disasters result from pollution, industrial accidents, and deforestation. Understanding these phenomena allows for improved preparedness and mitigation.
Disaster and Hazard: Definitions and Differences
A disaster is an event that causes widespread damage to life, property, and societal functions, usually with little or no warning. Disasters can be natural (earthquakes, tsunamis) or human-made (industrial accidents, wars). The severity of a disaster depends on the scale of damage and the societal response. Unlike natural hazards, which are potential threats in the environment (like ocean currents or unstable structures), natural disasters are destructive, often with devastating consequences for life and property.
Important Note: Disasters can only occur when a natural hazard interacts with vulnerable human populations or infrastructure.
Key Differences:
Natural hazards have the potential to cause harm but do not always result in destruction.
Natural disasters are extreme and often lead to loss of life, property, and social order.
Hazards can be persistent or occur over long periods, while disasters are typically sudden.
Classification of Natural Disasters
Natural disasters can be categorized into four broad types:
India, with its diverse geography and socio-economic conditions, is vulnerable to most natural disasters listed above. Regular disasters in India include floods, droughts, earthquakes, and cyclones, which cause significant loss of life and property.
Important Note: India’s vulnerability to disasters is increased due to its large population, unregulated urbanization, and deforestation.
Major Natural Disasters in India
Earthquakes
Earthquakes are among the most destructive and unpredictable natural disasters. The Indian subcontinent lies on an active seismic zone due to the movement of the Indian plate towards the Eurasian plate. The collision between these plates leads to stress accumulation, which is released through earthquakes.
Tectonic Earthquakes: Most destructive, caused by the sudden release of energy along fault lines. These impact a large area and cause widespread damage.
Other Earthquake Types: Result from volcanic activity, mining activities, or the filling of reservoirs, but these tend to have a more localized impact.
Earthquake-prone zones in India:
Very High Damage Risk Zones: Jammu & Kashmir, Himachal Pradesh, Uttarakhand, the Northeastern states, and regions of Gujarat.
High Damage Risk Zones: Parts of the Himalayan belt, including Ladakh and northern Bihar.
Moderate to Low Risk Zones: Central India, the Deccan Plateau.
Important Note: India is divided into five earthquake zones based on the intensity of past seismic activities.
Mitigation Measures:
Seismological Centers: Regular monitoring of tectonic movements to provide early warnings.
Vulnerability Maps: Identification of high-risk zones and dissemination of information to the public.
Construction Codes: Use of earthquake-resistant materials in building structures.
Public Education: Training people on how to minimize the impact of earthquakes.
Tsunamis
Tsunamis are caused by undersea earthquakes, volcanic eruptions, or landslides, which displace large amounts of water. These seismic sea waves can devastate coastal regions, especially when they hit shallow waters, causing waves up to 15 meters or more.
Key Features:
Sudden Occurrence: Usually, only a single vertical wave is generated, followed by several oscillating waves.
Less Impact at Sea: Ships in deep oceans barely feel the effects of a tsunami, while the destructive power intensifies near coastal areas.
Regions prone to tsunamis include:
Pacific Ring of Fire: Coastal regions of Japan, Indonesia, and the Philippines.
Indian Ocean: Areas like the eastern coast of India, Sri Lanka, and the Maldives.
Mitigation Measures:
International Cooperation: India joined the International Tsunami Warning System after the devastating 2004 tsunami.
Coastal Preparedness: Establishment of early warning systems and evacuation plans for coastal populations.
Cyclones
Cyclones are tropical storms formed in areas of intense low pressure, particularly between 30°N and 30°S latitudes. These storms are powered by the condensation of moisture, releasing latent heat. India’s coastline, especially along the Bay of Bengal and Arabian Sea, is frequently hit by cyclones.
Cyclone Formation:
Warm, Moist Air: Continuous supply of warm air from the ocean.
Coriolis Force: This helps the cyclone spin, preventing the central low pressure from filling up.
Unstable Atmospheric Conditions: Local disturbances lead to cyclone development.
Consequences of Cyclones:
Storm Surges: Abnormal rise in sea levels, leading to widespread flooding.
Property Destruction: Coastal regions are particularly vulnerable, with severe damage to infrastructure, agriculture, and human settlements.
Mitigation Measures:
Cyclone Shelters: Construction of emergency shelters and embankments along vulnerable coastlines.
Early Warning Systems: Use of technology to predict the path and intensity of cyclones, allowing for timely evacuations.
Floods
Floods occur when water exceeds the carrying capacity of rivers, lakes, or artificial reservoirs, leading to inundation of land. Causes of floods include excessive rainfall, snowmelt, and storm surges. Human activities such as deforestation and construction along riverbanks also contribute to flooding.
Flood-prone areas in India:
High-Risk States: Assam, Bihar, and West Bengal frequently experience floods due to overflowing rivers.
Flash Floods: Northern and Western states like Rajasthan, Gujarat, and Haryana are prone to flash floods due to heavy monsoons.
Consequences:
Loss of Life and Property: Large-scale destruction of homes, infrastructure, and agricultural fields.
Health Risks: Spread of waterborne diseases such as cholera and dysentery in the aftermath of floods.
Mitigation Measures:
Flood Control Embankments: Construction of levees and barriers to contain river flow.
Dam Construction: Building dams to regulate water flow and prevent flooding.
Afforestation: Increasing tree cover to reduce soil erosion and enhance water absorption.
Important Note: The National Flood Commission has identified 40 million hectares of land as flood-prone in India.
Droughts
A drought is a prolonged period of water shortage due to inadequate rainfall, high evaporation, or overuse of water resources. Droughts in India are particularly common due to the country’s reliance on the monsoon.
Types of Droughts:
Meteorological Drought: Caused by insufficient rainfall over an extended period.
Agricultural Drought: Occurs when soil moisture is too low to support crops.
Hydrological Drought: Affects water reservoirs and underground aquifers, leading to water shortages.
Ecological Drought: Results in ecosystem damage and reduced biodiversity.
Drought-prone areas:
Extreme Drought Areas: Rajasthan (west of the Aravallis), Kachchh region.
Severe Drought Areas: Interior Maharashtra, Andhra Pradesh, and parts of Tamil Nadu.
Moderate Drought Areas: Northern Rajasthan, southern Uttar Pradesh, and the Deccan Plateau.
Consequences:
Crop Failures: Leads to food shortages, economic losses, and rural distress.
Water Shortages: Scarcity of drinking water for both humans and livestock.
Mitigation Measures:
Rainwater Harvesting: Storing and utilizing rainwater to combat water scarcity.
Interlinking of Rivers: Transferring surplus river water to drought-prone regions.
Drought-resistant Crops: Promoting crops that require less water and can withstand dry conditions.
Landslides
Landslides involve the rapid sliding of rocks and debris down a slope, often triggered by factors such as earthquakes, heavy rainfall, or human activities like mining. Landslides are common in the Himalayas, Western Ghats, and northeastern India.
Vulnerability Zones:
Very High Vulnerability: Himalayan regions, Andaman and Nicobar Islands.
High Vulnerability: Northeastern states, Western Ghats
.
Moderate to Low Vulnerability: Deccan Plateau, parts of the Western and Eastern Ghats.
Mitigation Measures:
Slope Stabilization: Using engineering techniques to stabilize vulnerable slopes.
Afforestation: Increasing tree cover to reduce soil erosion.
Terrace Farming: Encouraging sustainable agricultural practices in hill regions.
Important Note: Landslides have far-reaching consequences, including roadblocks, destruction of infrastructure, and the redirection of rivers, which can lead to floods.
Disaster Management Strategies
Effective disaster management involves three key stages:
Pre-Disaster Preparedness:
Data Collection: Gathering information on disaster-prone areas.
Public Awareness: Educating people on disaster risks and safety measures.
Planning: Developing disaster response plans for vulnerable areas.
During the Disaster:
Rescue Operations: Evacuating people from affected areas.
Relief Efforts: Providing food, water, medical care, and temporary shelter.
Coordination: Collaborating between local and national agencies for efficient relief distribution.
Post-Disaster Recovery:
Rehabilitation: Assisting victims in rebuilding their lives and restoring infrastructure.
Capacity Building: Strengthening communities to be better prepared for future disasters.
Important Note: The Disaster Management Bill (2005) emphasizes the need for comprehensive disaster planning and preparedness, including the establishment of seismological centers and vulnerability maps.
Multi-column Table: Comparisons of Natural Disasters