Chapter 7
Natural Disasters and Hazards: Causes, Consequences and Management
1. 1. Find the correct answer from the following answers.
(a) Floods are frequent in which of the following states?
(1) Bihar
(2) West Bengal
(3) Assam
(4) Uttar Pradesh
Answer: (3) Assam.
(b) In which of the following districts of the Northern State, the Malpa landslide occurred?
(1) Bageshwar
(2) In Champawat
(3) Almera
(4) Pithoragarh
Answer: (4) Pithoragarh.
(c) Which of the following states also experiences floods in winter?
(1) Assam
(2) West Bengal
(3) Kerala
(4) Tamil Nadu
Answer: (4) Tamil Nadu.
(d) Majuli Island is situated in which of the following rivers?
(1) The Ganges
(2) The Brahmaputra
(3) The Godavari
(4) The Indus River
Answer: (2) The Brahmaputra.
(e) Cold storm, which of the following types of natural disasters?
(1) Atmospheric
(2) Water-related
(3) Earthly
(4) Organic
Answer: (1) Atmospheric.
2. 2. Answer the following questions in 30 words.
(1) When is a hazard called a disaster?
Answer: When the activities caused by a disaster go out of control and suddenly cause damage to people's lives and property without any warning and also cause death of many people. Such sudden events are called disasters.
(2) Why do earthquakes occur more frequently in the Himalayan region and the North East of India?
Answer: The Indian plate is moving north and northeast at a rate of 1 cm per annum and this movement is being hindered by the Eurasian plate from the north. This has caused the two plates to become trapped and the accumulated energy produces thrusts or forces that eventually break the barrier wall and the accumulated energies are suddenly released, causing earthquakes in the Himalayan bow . Therefore, earthquakes are more common in this region.
(3) What are the basic requirements for a cyclone to form?
Answer: The basic requirements for a cyclone to form are:
(c) An unstable state of air in the troposphere that causes local low pressure and which leads to the formation of a large storm .
(d) Finally, the absence of strong vertical wind wedges, which disrupt the vertical transport of latent heat.
(4) What are the differences between floods in Eastern India and floods in Western India?
The differences between floods in Eastern India and floods in Western India are:
(a) Floods in Eastern India are very strong. The floods in western India are not strong.
(b) Floods in Eastern India also cause death of animals or humans. In western India, floods do not cause any damage to animals or humans. This is because the floods in Western India are not as strong as those in Eastern India.
(5) What is the reason for the prevalence of drought in central and western India?
Answer:
3. 3. Give the answers in 125 words.
(1) Identify landslide prone areas in India and suggest ways to mitigate them.
Answer: Landslide prone areas in India are-
(a) Very high prone zone: The areas included in this zone are New Himalayas, Andaman and Nicobar Islands, steep slopes of Western Ghats and Nilgiris with high rainfall, North Eastern region, earthquake prone areas and areas of high human activity like road construction.
(b) High inclination zone: Areas in very high inclination zone are also considered within this zone. The only difference between the two is the pair or strength and bar of controlling factors. The states of the Himalayan region and the regions of the North East, excluding the Assam plain, fall within this zone.
(c) Moderate to Low Prone Zone: Areas with low rainfall like Ladakh, Spiti rugged but stable topography, low rainfall Arabli region, rain shadow region of Western Ghats and Eastern Ghats, Southern Plateau, Jharkhand, Orissa, Chhattisgarh, Madhya Pradesh, Maharashtra, Andhra Pradesh, Karnataka, Tamil Nadu, Goa and Kerala are considered to be included in this zone.
(d) Other areas: Coastal areas of Rajasthan, Haryana, Uttar Pradesh, Bihar, West Bengal, Assam and southern states are free of landslides. These areas are considered among others.
(2) What does penetration mean? Classify India into natural disaster prone zones based on drought and suggest some ways to mitigate it.
Answer: Earthquakes cannot be stopped because they are natural disasters. So we must be prepared before disaster strikes. Vulnerability is a mechanism that communicates news of danger or disaster to people.
The natural disaster prone zones of India based on weather are-
(a) Very Dry Zone: This zone covers most of the parts of Rajasthan especially the western part of the Aravali Mountains such as the deserts and the Kachchh region of Gujarat.
(b) Highly arid zone: Eastern part of Rajasthan, most of Madhya Pradesh, eastern part of Maharashtra, interior of Andhra Pradesh and Karnataka, northern interior of Tamil Nadu, southern part of Jharkhand and interior of Orissa.
(c) Moderate drought zone: Northern part of Rajasthan, Haryana, southern districts of Uttar Pradesh, Gujarat, Maharashtra excluding Kankan, Jharkhand, Coimbatore plateau of Tamil Nadu, inland areas of Karnataka belong to this zone. Other parts of India fall outside the impact of drought.
(3) When can development-oriented activities also cause disasters?
Answer: Natural forces are not the only cause of disasters. Human activities also cause disasters. Some human activities are also causes of disasters. For example, this is mentioned below:
(a) Bhopal Gas Disaster.
(b) Chernobyl nuclear hazard.
(c) War, effects of CFC gases.
(d) Increase in greenhouse gases, environmental pollution such as noise, wind, water, soil etc. Some disasters are also indirectly caused by the spread or speed of some disasters.
Such disasters are landslides and floods which are caused by indirect activities like deforestation, unscientific land use, construction in remote areas. In addition, human development-oriented activities have sometimes caused disasters much worse than natural disasters.
