Natural Hazards in India | Additional Study Material for UPSC PDF Download

India: Vulnerability Profile

• India is one of the world's ten most disaster-prone nations. 

Its unique geo-climatic and socio-economic conditions are vulnerable to a wide range of natural and man-made disasters. 

• 27 of the country's 35 states and union territories are disaster-prone.
• The five distinctive regions of the country i.e. Himalayan region, the alluvial plains, the hilly part of the peninsula, and the coastal zone have their specific problems. While on the one hand the Himalayan region is prone to disasters like earthquakes and landslides, the plain is affected by floods almost every year. The desert part of the country is affected by droughts and famine while the coastal zone susceptible to cyclones and storms.

Within the vulnerable groups, elderly persons, women, children— especially women rendered destitute, children orphaned on account of disasters and differently-abled persons are exposed to higher risks.
Besides the natural factors, various human-induced activities like increasing demographic pressure, deteriorating environmental conditions, deforestation, unscientific development, faulty agricultural practices and grazing, unplanned urbanisation, and large dams on river channels etc. are also responsible for accelerated impact and increase in frequency of disasters in the country. Building Material and Technology Promotion Council (BMTPC) has come out with Vulnerability Atlas of India.

Economic loss due to disasters

As per World Bank, economic loss accounted for 2% of the GDP due to disasters.

Natural Disasters

What is an Earthquake?

• An earthquake is the sudden shaking of the earth crust. An earthquake's impact is sudden and there is hardly any warning, making it impossible to predict.

Cause of Earthquake

It happens due to movements along the plates' boundaries when the plates ride up over the mobile mantle. When these plates contact each other, stress arises in the crust. These stresses are classified according to the type of movement along the plate's boundaries:

• Pulling away from each other (Divergent),
• Pushing against one another (Convergent)and
• Sliding sideways relative to each other (Transform)

The areas of stress at plate boundaries which release accumulated energy by slipping or rupturing are known as' faults'. A rupture then occurs along the fault and the rock rebounds under its own elastic stresses until the strain is relieved. The fault rupture generates vibration called seismic waves.
Earthquakes can be measured by using two distinctively different scales of measurement demonstrating magnitude (by Richter scale) and intensity (by Mercalli Scale). Although some scientists claim ability to predict earthquakes, accurate and exact predictions of such sudden incidents are still not possible.

Earthquake Risk in India

• Six major earthquakes have struck different parts of India over a span of the last 15 years.
• The increase in earthquake risk is due to a spurt in developmental activities driven by urbanization, economic development and the globalization of India's economy. India has highly populous cities, and these cities' constructions are not earthquake resistant. Regulatory mechanisms are weak, thus any earthquake striking in one of these cities would turn into a major disaster.

Distribution Pattern of Earthquakes in India

India falls prominently on the' Alpine - Himalayan Belt'. This belt is the line along which the Indian plate meets the Eurasian plate. Being a convergent plate, the Indian plate is thrusting underneath the Eurasian plate at a speed of 5 cm per year. The movement gives rise to tremendous stress that keeps accumulating in the rocks and is released from time to time in earthquakes.

• According to the maximum intensity of earthquake expected, India has been divided into four seismic zones. Of these, zone V is the most active, comprised of Northeast India, the northern portion of Bihar, Uttarakhand, Himachal Pradesh, J&K, Gujarat and Andaman & Nicobar Islands. The entire Himalayan Region is vulnerable to high intensity earthquakes of a magnitude exceeding 8.0 on the Richter scale. Much of India lies in zone III and zone II.

Consequences of an Earthquake

Primary damage: Damage occurs to human settlement, buildings, structures and infrastructure, especially bridges, elevated roads, railways, water towers, pipelines, electrical generating facilities. Aftershocks of an earthquake can cause much greater damage to already weakened structures.
Secondary effects include fires, dam failure, and landslides, which may block waterways and cause flooding, landslides, Tsunami, chemical spills, breakdown of communication facilities, and human loss. There is also a huge loss to the public health system, transport and water supply in the affected areas.
Tertiary impact of earthquake includes Post Trauma Stress Disorder (PTSD), long term psychological issues, loss of livelihood, disruption of social capital due to relocation related issues, etc.

Earthquake Hazard Mitigation

Since earthquake also destroys most of the transport and communication links, providing timely relief to the victims becomes difficult. It is not possible to prevent an earthquake; hence, the next best option is to emphasize disaster preparedness and mitigation rather than curative measures.

• Earthquake monitoring centres (seismological centres) for regular monitoring and fast dissemination of information among the people in the vulnerable areas should be established. Currently, Centre for Seismology (CS) is the government of India's nodal agency responsible for monitoring seismic activity in and around the country.
• A vulnerability map of the country along with dissemination of vulnerability risk information among the people can be done to minimize the adverse impacts.
• Planning: The Bureau of Indian Standards has published building codes and guidelines for safe construction of buildings against earthquakes. According to the laid-down by-laws, the building plans have to be checked by the Municipality before the buildings are constructed.
• Important buildings such as hospitals, schools and fire stations need to be upgraded by retrofitting techniques.
• Community preparedness and public education on causes and characteristics of an earthquake and preparedness measures is important. It can be created through sensitization and training programme for community by preparing disaster management plans by schools, malls, hospitals, etc. and carrying out mock drills by preparing documentation on lessons from previous earthquakes and widely disseminating it.
• Engineered structures: The soil type should be analysed before construction. Building structures on soft soil should be avoided. Similar problems persist in the buildings constructed on the river banks which have alluvial soil.
• Encouraging use of Indigenous methods - Indigenous earthquake-resistant houses like the bhongas in the Kutch Region of Gujarat, dhajji diwari buildings in Jammu & Kashmir, brick-nogged wood frame constructions in Himachal Pradesh and ekra constructions made of bamboo in Assam are increasingly being replaced with modern Reinforced Cement Concrete (RCC) buildings, often without incorporating earthquake resistant features and without compliance to building codes and bye-laws. It is thus necessary to use indigenous technical knowledge and locally available materials in the construction of earthquake-resistant buildings in suburban and rural areas.
• Quick and effective response - Experience has shown that over 80% search and rescue is carried out by communities itself before the intervention of specialized rescue and relief forces. Thus there is a need to give basic training to the community members as it is always the first responder after any disaster.
• Early Earthquake Warning and Security System -Chennai-based Structural Engineering Research Centre (CSIR- SERC), a pioneer advanced seismic testing and research laboratory under the Council of Scientific & Industrial Research (CSIR), has completed the testing of the German-developed "Early Earthquake Warning and Security System", which was launched for the first time in India recently.
• A pilot project on Earthquake Early Warning (EEW) system is under implementation for northern India (Uttarakhand) by Indian Institute of Technology (NT) Roorkee which is funded by the Ministry of Earth Sciences (MoES).
• Insurance & Risk transfer instruments - These should be developed in collaboration with the insurance companies and financial institutions.

National Earthquake Risk Mitigation Project

A National Earthquake Risk Mitigation (Preparatory phase) was approved as a Centrally Sponsored Plan Scheme in 2013. The project is to be implemented by NDMA in coordination with the State Governments/UT that lie in seismic zones IV & V in the country. It aims to increase awareness of the key stakeholders on adopting model building by-laws and earthquake-resistant construction and planning standards.

National Building Code

The National Building Code of India (NBC) provides guidelines for regulating the building construction activities on different materials, planning, design and construction practices of buildings. It lays down provisions designed to protect the public's safety about structural sufficiency, fire hazards, and buildings' health aspect.
A building collapsed in Lalita Park, Laxmi Nagar, East Delhi in November 2010 in which 71 people lost their lives. It was reported that builders in the area were violating building laws by adding extra floors for additional rental incomes and encroaching road space. An inquiry commission, headed by retired justice Lokeshwar Prasad reported that most of the buildings in East Delhi were unsafe due to the inferior construction material used. In July 2017 another four-storey building collapsed in the same Lakshmi Nagar area hinting at poor enforcement of the National Building Code.

Critical Existing Challenges for Earthquake Mitigation in India

• Inadequate enforcement of earthquake-resistant building codes and town planning bye-laws;
• Absence of earthquake-resistant features in constructions in urban and rural areas.
• Lack of formal training among professionals in earthquake-resistant construction practices.
• Lack of adequate preparedness and poor response capacity of various stakeholder groups.
• Lack of awareness among various stakeholders about the seismic risk;
• Absence of systems of licensing of engineers and masons.

NDMA Guidelines on Earthquake Management Guidelines issued by NDMA rest on six pillars of seismic safety for improving the effectiveness of earthquake management in India:

1. Earthquake Resistant Construction of New Structures: All central ministries and departments and state governments will facilitate the implementation of relevant standards for seismically safe design and construction of buildings and other lifeline and commercially important structures falling within their administrative control such as bridges, flyovers, ports, harbours etc.
2. Selective Seismic strengthening & Retrofitting of existing Priority structures and Lifeline Structures: All central ministries and state governments are required to draw up programs for seismic strengthening of priority structures through ULBs and PRIs. Buildings of national importance such as Raj Bhavans, Legislatures, Courts, critical buildings like academic institutions, public utility structures like reservoirs, dams and multi-storeyed buildings with five or more floors. The responsibility to identify these structures rests with the State Governments.
3. Regulation and Enforcement: State Governments are responsible for establishing mechanisms to implement Building Codes and other safety codes to ensure that all stakeholders like builders, architects, engineers, government departments adhere to seismic safety in all design and construction activities. The Home Ministry had constituted a national level expert group which recommended modifications to the town and country planning Acts, land use and zoning regulations, DCRs and building bye-laws which are technically rigorous and conform to globally accepted norms.
4. Awareness & Preparedness: NDMA acknowledges that all stakeholders' sensitization is one of the most challenging tasks in earthquake preparedness and mitigation. It recommends preparation of handbooks on earthquake safety, homeowner's seismic safety manuals, a manual on structural safety audit and video films for the general public. It also highlights the need to create vulnerability maps of land areas and streamlining of NGOs and Volunteer Groups.
5. Capacity Development (Education, Training, R&D, Capacity Building and Documentation): The target groups for capcity development include elected representatives and government, officials, professionals in visual and print media, urban planners, engineers, architects and builders, NGOs, Community Based Organisations (CBOs), social activists, social scientists, schoolteachers, and schoolchildren
6. Emergency Response: All response activities are undertaken through Incident Command System coordinated by the local administration. It includes involvement of community, corporate sector and specialized teams.

Tsunami

What is a Tsunami?

• Tsunami (soo-NAH-mee) is a Japanese word meaning 'harbour' wave. A tsunami is a series of large waves of extremely long wavelength and period usually generated by an undersea disturbance or activity near the coast or in the ocean.

How Tsunami is generated?

• Tsunamis are generated by a large, impulsive displacement of the sea bed level. Earthquakes generate tsunamis by vertical movement of the sea floor. Landslides can also trigger tsunamis into or under the water surface, volcanic activity and meteorite impacts. Landslide triggered tsunamis can be a possible scenario in the Bay of Bengal and the Arabian Sea due to the Ganges and Indus Rivers' huge sediment deposition.

Tsunami Risks in India

• A few devastating tsunamis have occurred in the Indian Ocean and in the Mediterranean Sea in the past. The most significant tsunami in the region of the Indian Ocean was the one associated with the violent explosion of the volcanic island of Krakatoa in August 1883. Even though tsunamis occur very rarely in the Indian Ocean region, in the last 300 years, this region recorded 13 tsunamis and 3 of them occurred in the Andaman and Nicobar region. The Indian Ocean Tsunami of 26th December 2004 is one of the most destructive Tsunamis known to have hit India.

Distribution Pattern of Tsunami in India

Both East and West Indian shorelines are vulnerable to tsunami wave action. It has more than 2200 heavily populated km shoreline. For a tsunami to hit Indian coastline, a tsunamigenic earthquake of magnitude greater than 6.5 must occur. Actual tsunami hazard of a coastline depends on its bathymetry and coastal topography.

Consequences of Tsunami Disaster

The effects of the tsunami can range from destruction and damage, death, diseases, injury, millions of dollars in financial loss, and long lasting psychological problems for the region's inhabitants.

Indian Ocean tsunami of December 2004 along the Indian coast highlighted that the maximum damage had occurred in low-lying areas near the coast and high casualties were found in thickly populated areas. Mangroves, forests, sand dunes and coastal cliffs provided the best natural barriers to reduce the impact of the tsunami and heavy damage was reported in areas where sand dunes were heavily mined.

Tsunami Predictability
Since scientists cannot exactly predict earthquakes, they also cannot exactly predict when a tsunami will be generated. There are two distinct types of tsunami warning:
a) International tsunami warning systems and
b) Regional warning systems.

Present status of Tsunami Warnings in India:

The Indian Tsunami Early Warning Centre (ITEWC), which is based at and operated by Indian National Centre for Ocean Information Services (INCOIS), Hyderabad has all necessary infrastructure and capabilities to give tsunami advisories to India as well as to Indian Ocean countries. Towards early warning of tsunamis, real-time continuous seismic waveform data of three IMD stations, viz., Portblair, Minicoy, and Shillong, is also shared with the Center's global community for Seismology (CS), IMD.
ITEWC has been designated as one of the Regional Tsunami Service Providers for the entire Indian Ocean Region by the Intergovernmental Oceanographic Commission (IOC) of United Nations Educational, Scientific and Cultural Organization (UNESCO). It is providing tsunami warnings and related services to all countries in the Indian Ocean Rim (24 Countries) beyond fully serving the India's coastline / Islands.
The centre is capable of detecting tsunami-genic earthquakes occurring in the Indian Ocean as well as in the Global Oceans within 10 minutes of their occurrence and disseminates the advisories to the concerned authorities within 20 minutes through email, fax, SMS, Global Telecommunication System (GTS) and website.
The ITEWC consists of national and international observational network of seismic stations, sea level gauge stations and tsunami buoys around the Indian and Pacific Oceans. Data from approximately 400 seismometers is being received in real-time and processed automatically to detect an earthquake of magnitude 4.0 and above anywhere globally. As soon as the earthquake is detected, warning centre transmits the first bulletin

based on seismic data describing the location of earthquake, its magnitude, depth and other characters of the event. After issuing the first bulletin, seismic data are further analysed to improve earthquake parameters' accuracy (magnitude, depth and location). The processing of seismic data is optimized to detect and characterize large earthquakes within earliest possible time.

Volcano

What is a Volcano?

• A volcano is a vent in the earth crust that lets out hot lava, gasses, rocks, volcanic ash and steam from a magma chamber underneath the earth's surface. They are called active if they erupt regularly. Dormant or inactive volcanoes have erupted in the past times but are now quiet while the volcanoes that have not erupted since ages are termed extinct.

Causes of Volcano

Volcanic eruptions predominantly occur in areas with vibration activities or weak zones, for example, where the continental plates of the earth pull apart or collide. It also occurs where the earth's crust constantly melts.

Volcano risks in India

• India's only live volcano is the Barren Island volcano in the Andaman and Nicobar Islands, which had started showing activity in the year 1991 after being dormant for over 150 years.
• It has once again started spewing ash in January 2017. The volcanic island is uninhabited and the northern part of the island is barren and devoid of vegetation.

Floods

What is Flood?

Flood is a state of high water level along a river channel or on the coast that leads to inundation of land. India is highly vulnerable to floods. Out of the total geographical area of 329 million hectares, Rashtriya Barh Ayog (RBA) has assessed that more than 40 million hectare area is flood prone

What are Flash Floods?

• Flash floods are characterized by very fast rise and recession of small volume flow and high discharge, which causes high damages because of suddenness.
• This occurs in hilly and sloping lands where heavy rainfall and thunderstorms or cloudbursts are common.
• Depression and cyclonic storms in the eastern coastal areas may also cause flash floods.
• Sudden release of waters from upstream reservoirs, breaches in dams and embankments on the rivers' banks also leads to floods.
• Flash floods warning systems and forecasting is done using Doppler radars.

Causes of Floods

Inadequate capacity of the rivers to contain the high flows brought down from the upper catchment areas following heavy rainfall, leads to flooding.

Indiscriminate deforestation, unscientific agricultural practices, disturbances along the natural drainage channels and colonisation of flood-plains and river-beds are some of the human activities that play an important role in increasing the intensity, magnitude and gravity of floods. Some of the causes of flood are as follows:

Natural causes

• Heavy rainfall: Heavy rain in the catchment area of a river causes water to over flow its banks, which results in the flooding of nearby areas.
• Sediment deposition: River beds become shallow due to sedimentation. The water carrying capacity of such river is reduced. As a result the heavy rainwater over flow the river banks.
• Cyclone: Cyclone generated sea waves of abnormal height spreads the water in the adjoining coastal areas. In October 1994 Orissa cyclone generated severe floods and caused unprecedented loss of life and property.
• Change in the river's course: Meanders, erosion of river beds and banka, and obstruction of flow due to landslides also lead to changes in river courses.
• Tsunami: Large coastal areas are flooded by rising sea water, when a tsunami strikes the coast.
• Lack of Lakes - Lakes can store the excess water and regulate water flow. When lakes become smaller, their ability to regulate the flow become less and hence flooding.

Anthropogenic causes

Deforestation: Vegetation facilitates percolation of water in the ground. As a result of deforestation, the land becomes obstructed, and water flows with greater speed into the rivers and causes flood.

• Interference in drainage system: Drainage congestion caused by badly planned construction of bridges, roads, railway tracks, canals etc. hampers the flow of water and results in floods.
• International dimension - The rivers originating in China, Nepal and Bhutan cause severe floods in Uttar Pradesh, Bihar, West Bengal, Arunachal Pradesh and Assam. For flood management (FM), cooperation with the neighbouring countries viz. China, Nepal and Bhutan is essential.
• Population pressure - Because of many people, more materials are needed, like wood, land, food, etc. This aggravates overgrazing, land encroachment, over cultivation, and soil erosion, increasing the risk of flooding.
• Poor Water and Sewerage Management - Old drainage and sewerage systems in urban areas have not been overhauled. During the rainy seasons, the drainage and sewer system collapse resulting in urban flooding.

Flood Hazard Vulnerability of India

• Floods occur in almost all the river basins of the country. Around 12 per cent (40 million hectare) of land in India is prone to floods. Our country receives an annual rainfall of 1200 mm, 85% of which is concentrated in 3-4 months i.e. June to September. Due to the intense and periodic rain, most of the rivers of the country are fed with huge quantity of water, much beyond their carrying capacity leading to mild to severe flood situations in the region Distribution Pattern of Flood Areas in India.

Consequences of Floods

• Frequent inundation of agricultural land and human settlement has serious consequences on the national economy and society.
• Floods destroy valuable crops and also damage physical infrastructure such as roads, rails, bridges and human settlements.
• Millions of people are rendered homeless and are also washed down along with their cattle in the floods.
• Spread of diseases like cholera, gastro-enteritis, hepatitis and other water-borne diseases spread in the flood- affected areas.
• Floods also make a few positive contributions. Every year, flood deposits are fertile silt over agricultural fields, which restores the soil's fertility.

NDMA Guidelines on Flood Management

The main thrust of the flood protection programme undertaken in India so far has been on structural measures.

Flood Prevention, Preparedness and Mitigation Structural Measures

• Reservoirs, Dams, Other Water Storages: By constructing reservoirs in the rivers' courses could store extra water at the time of flood. Such measures adopted till now however, have not been successful. Dams built to control floods of Damodar could not control the flood.
• Embankments/Flood Levees/Flood Walls: By building flood protection embankments, floods water can be controlled from overflowing the banks and spreading in nearby areas. Building of embankments on Yamuna, near Delhi, has successfully controlled the flood.
• Drainage improvement: Drainage system is generally choked by the construction of roads, canals railway tracks etc. Floods could be checked if the original form of drainage system is restored.
• Channel Improvement/Desilting/Dredging of Rivers: A channel can be made to carry flood discharge at levels lower than its prevailing high flood level by improving its discharge carrying capacity. 
• It aims at increasing the area of flow or the velocity of flow (or both) to increase its carrying capacity. However, selective desilting/dredging at outfalls/confluences or local reaches can be adopted as a measure to tackle the problem locally.
• Diversion of Flood Water: Diverting all or a part of the discharge into a natural or artificially constructed channel, lying within or in some cases outside the flood plains is a useful means of lowering water levels in the river.
• The flood spill channel skirting Srinagar city and the supplementary drain in Delhi are examples of diverting excess water to prevent flooding of the urbanised areas.
• Catchment Area Treatment/Afforestation: Watershed management measures such as developing the vegetative cover, i.e. afforestation and conservation of soil cover, in conjunction with structural works like check dams, detention basins, etc as an effective measure in reducing flood peaks and controlling the suddenness of the runoff.

Non-Structural Measures

• Flood Plain Zoning: It is to regulate land use in the flood plains in order to restrict the damage due to floods, while deriving maximum benefits from the same.
• Flood Proofing: It helps mitigate distress and provides immediate relief to the population in flood prone areas. It is a combination of structural change and emergency Land uses increase in value as distance * action, not involving any evacuation. It includes providing from river increases raised platforms for flood shelter for men and cattle, raising the public utility installation especially the platforms for drinking water hand pumps and bore wells above flood level, promoting construction of double-storey buildings. The first floor can be used for taking shelter during floods.
• Flood Management Plans: All government departments and agencies must prepare their own FMPs.
• Integrated Water Resources Management aims to integrate water resources management at the basin or watershed scale.

Flood Forecasting and Warning in India: Real time discharge and rainfall data are the basic requirements for creating a flood forecast. Most of the hydro-meteorological data are observed and collected by the field

formations of Central Water Commission; IMD supplies the daily rainfall data.

Urban Floods

What is Urban Flood?

• Area under urban settlements (7933 towns) in India has increased from 77,000 sq. km in 2001 to 1,00,000 sq. km in 2011 showing 25,000 sq.km of additional land area being brought under urban uses. 
• Unplanned development and encroachments of sprawling habitations alongside rivers and watercourses have meddled with streams' natural flow. As a result of this, the runoff has increased in proportion to urbanization of the watersheds causing urban floods.

Causes of Urban Floods

Flooding in the cities and the towns is a recent phenomenon caused by increasing incidence of heavy rainfall in a short period, indiscriminate encroachment of waterways, inadequate capacity of drains and lack of maintenance of the drainage infrastructure. There is wide variation of rainfall amongst the cities and, even in the town, rainfall shows large spatial and temporal variation; for example, in Mumbai, on 26th July 2005, Colaba recorded only 72 mm of rainfall while Santa Cruz, which is 22 km away, recorded 944 mm in 24 hours.

Urban Flood Risks in India

Urban flooding is significantly different from rural flooding as urbanization leads to developed catchments, which increases the flood peaks from 1.8 to 8 times and flood volumes by up to 6 times. These areas are densely populated centers of economic activities with vital infrastructure which needs to be protected 24x7. Floods of Chennai (December 2015), the Kashmir Floods (2014), the Surat Floods (2006) and the Mumbai Floods (2005 & 2017) reflect the vulnerability of our Cities.

Impact and Mitigation Strategies for Urban Flood

Urban Flooding has localized impacts on commercial, industrial, business, residential and institutional locations. Disruption of water supply, sewerage, power supply and communications is common. Shutdown of commercial, industrial and business activity and property loss and assets is often observed. Disruption of traffic - road, rail and air is frequent. New slums come up in areas which are not approved.

• To check the threat of urban flooding, each city should have their Flood mitigation plans (floodplain, river basin, surface water, etc.) strongly integrated with the overall land use policy and master plan of a city. The following three phases of disaster management for effective and efficient response to urban flooding include:
• Pre-Monsoon Phase (Preparedness): It involves an estimation of emergency needs, familiarization of the stakeholders, particularly the communities through training and simulation exercises, identification of Teams for maintaining the drains and roads and conducting exercises for prevention of water logging/ inundation.
• During Monsoon Phase (Early Warning & Effective Response): It includes timely, qualitative and quantitative warnings based on the intensity of rainfall to various agencies to take preventive measures.

The Response phase focuses primarily on emergency relief:

• Saving lives
• Providing first aid
• Minimizing and restoring damaged systems (communications and transportation)
• Meeting the basic life requirements of those impacted by disaster (food, water, and shelter)
• Providing mental health and spiritual support and comfort care

Post-Monsoon Phase: Restoration and Re-habilitation phase includes establishing a programme to restore both the disaster site and the damaged materials to a stable and usable condition.

Urbanization leads to an increase in rainfall: As early as 1921, scientists noted thunderstorm formation over large cities while there were none over rural areas.

The Urban Heat Island Effect can very well explain this - the rising heat induces cloud formation while the winds interact with urban induced convection to produce downwind rainfall.

Landslides 

What is a Landslide?

• A landslide is defined as a mass of rock, debris, or earth down a slope.
• Landslides are a type of "mass wasting," which denotes any down-slope movement of soil and rock under gravity's direct influence.
• Landslides are one of the natural hazards that affect at least 15 percent of our country's land area. 
• The Himalayas are formed due to collision of Indian and Eurasian plate. The northward movement of the Indian plate (@5cm/year) towards Eurasian plate causes continuous stress on the rocks rendering them friable, weak and prone to landslides and earthquakes.

Causes of Landslides

• Heavy rain: Heavy rain is the main cause of landslides.
• Deforestation: Deforestation is another major cause of landslides. Tree, brushes and grasses keep the soil particles compact. Mountain slope looses their protective cover by felling of trees. The rain water flows on such slopes with unimpeded speed.

Earthquakes and volcanic explosions: Earthquake is a common feature in the Himalaya. Tremors destabilize the mountains and the rocks tumble downwards. Volcanic explosions also trigger landslides in mountainous areas.

Building of roads: Roads are built in mountainous areas for development. During the construction of the road, a large amount of rocks and debris have to be removed.

• This process dislodges the rock structure and changes the angle of slopes. Consequently landslides are triggered.

Shifting agriculture: In the North-Eastern part of India, the number and frequency of landslides have increased due to shifting agriculture.

Construction of houses and other buildings: To give shelter to the ever-increasing population and promote tourism, more and more house and hotels are being built. In building processes large amount of debris created. This causes landslides.

Consequences of Landslide Hazard

Landslide disasters have both short-term and long-term impact on society causing an imbalance in economic and social life and the environment.
Short term impacts:
Loss of natural beauty Roadblocks, destruction of railway lines channel blocking due to rock-falls diversion of river courses due to landslides causing flood and Loss of life and property

Longterm impacts:

Changes in the landscape that can be permanent, the loss of cultivable land the environmental impact in terms of erosion and soil loss, population shift and relocation of populations and establishments drying up water sources.

Landslide Hazard Mitigation

• Hazard zones have to be identified and specific slides to be stabilized and managed in addition to monitoring and early warning systems to be placed at selected sites.
• It is always advisable to adopt area-specific measures to deal with landslides.
• Hazard mapping should be done to locate areas commonly prone to landslides.
• Restriction on the construction and other developmental activities such as roads and dams, limiting agriculture to valleys and areas with moderate slopes, and controlling the development of large settlements in the high vulnerability zones, should be enforced.
• Promote large-scale afforestation programs and construction of bunds to reduce water flow.
• Terrace farming should be encouraged in the north-eastern hill states replacing Jhumming or shifting cultivation.
• Retaining walls can be built of mountain slopes to stop land from slipping. They are treating vulnerable slopes and existing hazardous landslides.
• Restricting development in landslide-prone areas.
• Preparing codes for excavation, construction and grading.
• Protecting existing developments.
• Putting in place arrangements for landslide insurance and compensation for losses.

Existing Challenges

• Integrating landslide concerns in developing disaster management plans at different levels i.e., national, state, district, municipal/panchayat.
• Switch-over from piecemeal remediation of landslides to simultaneous and holistic implementation of control measures.
• The techno-legal regime for introducing sound slope protection, planned urbanisation, regulated land use and environment-friendly land management practices.
• Zero tolerance against deliberate environmental violence and unhealthy construction practices.
• Laws governing new constructions and alteration of existing land use on problematic slopes and in landslide-prone areas.
• Innovation in the management of multi-institutional and multi-disciplinary teams.

Establish a disaster knowledge network and disseminate information at the national level, a mechanism for international linkages, cooperation, and joint initiatives.

Drought 

What is Drought?

Droughts refer to a severe shortfall in water availability, mainly, but not exclusively, due to deficiency of rains, affecting agriculture, drinking water supply and industry. It is a slow onset disaster which evolves over months or even years and affects a large spatial extent.

Drought is a complex phenomenon as it involves elements like

• precipitation, evaporation, evapotranspiration
• ground water, soil moisture, storage and surface run-off
• agricultural practices, particularly the types of crops grown

 Socio-economic practices and ecological conditions.

Causes of Drought

The causes for droughts are increasingly attributable to the mismatch between supply and demand, particularly the demand for non-agricultural purposes. While adequate water availability is crucial to agriculture, it continues to be affected by other variables such as temperature, humidity, solar radiation and wind patterns.

Types:

The IMD recognizes five drought situations:

• 'Drought Week' when the weekly rainfall is less than half of the normal.
• 'Agricultural Drought' when four drought weeks occur consecutively during mid-June to September.
• 'Seasonal Drought' when seasonal rainfall is deficient by more than the standard deviation from the normal.
• 'Drought Year' when annual rainfall is deficient by 20 percent of normal or more.
• 'Severe Drought Year' when annual rainfall is deficient by 25 to 40 per cent of normal or more.

Drought Risks in India

Droughts in India have their own peculiarities requiring appreciation of some basic facts. These are:

• India has an average annual rainfall of around 1150 mm; no other country has such a high annual average, however, there is considerable annual variation.
• More than 80% of rainfall is received in less than 100 days during the South­west monsoon and the geographic spread is uneven.
• 21% area receives less than 700 mm rains annually making such areas the hot spots of drought.
• Inadequacy of rains coupled with adverse land-man ratio compels the farmers to practice rain-fed agriculture in large parts of the country.
• Irrigation, using groundwater aggravates the situation in the long run as ground- water withdrawal exceeds replenishment; in the peninsular region availability of surface water itself becomes scarce in years of rainfall insufficiency.
• Per capita water availability in the country is steadily declining.
• As against total annual availability 1953 km3, approximately 690 km3 of surface water and 396 km3 of ground water resources can be used. So far, a quantum of about 600 km3 has been put to use.
• The traditional water harvesting systems have been largely abandoned.

Distribution of Drought Prone Areas in India

• Droughts and floods are the two accompanying features of Indian climate. According to some estimates, nearly 19 percent of the country's total geographical area and 12 percent of its total population suffer due to drought every year. About 30 per cent of the country's total area is identified as drought prone. It is common to see flood and drought simultaneously in different regions. It is also common that same region faces drought in one season and flood in another season. This is attributed to spatial and temporal unpredictability in the monsoon behaviour.

Recently IMD has decided to drop the word 'drought' and replace it with 'deficient' to describe the bad monsoon. It said that it was never the mandate of IMD to declare drought and it is on the state government to decide as droughts are of various types - hydrological, agricultural etc. Based on severity of droughts, India can be divided into the 3 regions:

Impact of Drought as a Hazard

The impact of droughts on societies varies depending on coping capabilities and the national economies' general health. Few inevitable impacts of drought are:

Economical:

Production losses in agriculture and related sectors, especially animal husbandry, dairy, poultry, horticulture and fisheries affects livelihoods and quality of life of the population in that is dependent on agriculture a dampening impact by constricting employment avenues

All industries dependent upon the primary sector for raw materials suffer on reduced supplies and hardening prices.

Environmental:

• low water levels in ground water and surface reservoirs, lakes and ponds, reduced flows in springs, streams and rivers, loss of forest cover,
• migration of wildlife, sharpening man-animal conflicts and general stress on biodiversity
• Reduced stream flow and loss of wetlands may affect levels of salinity
• Increased groundwater depletion rates, and reduced recharge may damage aquifers and adversely affect the quality of water (e.g., salt concentration, acidity, dissolved oxygen, turbidity) which in turn may lead to a permanent loss of biological productivity of soils
• Crops failure leads to scarcity of food grains, inadequate rainfall, water shortage, and often shortage in all the three is most devastating.

Social:

• Out-migration of the population from drought affected areas, rise in school dropout rates and indebtedness,
• alienation of land and livestock assets, malnutrition, starvation and loss of social status among the most vulnerable sections
• Scarcity of water compels people to consume contaminated water, resulting in many waterborne diseases like gastro-enteritis, cholera, hepatitis, etc.
• The situation of scarcity in some cases may exacerbate social tensions and lead to erosion of social capital 

How drought as a disaster is different from other disasters?

Unlike floods, earthquakes, and cyclones, droughts have certain distinct features -

• the onset is slow giving adequate warning,
• it affects livelihoods of people over a large area,
• the duration of the disaster is much longer and so the relief efforts have to be sustained over this stretched period,
• it remains basically a rural phenomenon except that very severe drought may also impact on urban water supply by drying up sources and drastically reducing water table in regions with aquifers, and
  (i) There is a possibility that drought management efforts could reduce vulnerability by improving moisture conservation and vegetal cover etc.
  (ii) This does not hold true of other natural disasters. In other words, droughts lend themselves to being managed in a manner not possible in most other disasters. All these factors necessitate 'independent consideration' drought management.

Drought Hazard Mitigation

The objectives of mitigation measures are to reduce soil erosion, augment soil moisture, restrict surface run-off of rainwater, and improve water use efficiency. It involves a wide range of soil and water conservation measures and farm practices.

• • Water Harvesting and Conservation: processes and structures of rainfall and run- off collection from large catchments area and channelling them for human consumption by using traditional methods or artificial recharge of groundwater. It helps to rejuvenate depleted high-capacity aquifers by adopting integrated groundwater recharge techniques, such as dams, tanks, anicuts, and percolation tanks, could improve water availability and create a water buffer for dealing with successive droughts.
• Drought Monitoring: It is continuous observation of the rainfall situation, availability of water in the reservoirs, lakes, rivers etc. and comparing with the existing water needs in various sectors of the society.
• Sowing drought resistant crops: By sowing drought resistant crops of cotton, Moong, pearl millet, wheat etc., the impact of drought could be mitigated to a certain extent.
• Livelihood planning identifies those livelihoods which are least affected by the drought. Some of such livelihoods include increased off-farm employment opportunities, collection of non-timber forest produce from the community forests, raising goats, carpentry etc.
• Suitable farming methods for arid areas: By adopting the following methods it is possible to mitigate the intensity of drought. The methods are: Production of coarse and hardy cereals; conservation of soil moisture by deep ploughing, storing water behind small dams, collecting water in ponds and tanks, and using sprinklers for irrigation.
• Drought planning: the basic goal of drought planning is to improve preparedness and response efforts by enhancing monitoring, mitigation and response measures.
• Small quantity of water can irrigate comparatively larger area by using drip irrigation and sprinkler methods.
• Identification of ground water potential in aquifers, transfer of river water from the surplus to the deficit areas, and particularly planning for inter-linking of rivers and construction of reservoirs and dams.
• Cloud Seeding to assess the aerosol characteristics, suitability of nuclides for cloud seeding, and alternative cloud seeding types - (ground-based or aerial, warm or cold cloud seeding, etc.). 

A cloud seeding policy needs to be formulated at National level and State level for creating required environment to regulate these measures.

Drought Crisis Management Plan, 2015

The NDMA manual sets out four important measures that a State government should take at a drought, with the Union government's help.

• MGNREGA to provide immediate employment to drought-affected people.
• The public distribution mechanism should be strengthened to provide food and fodder
• initiate actions to recharge the groundwater table by building check dams and providing pipeline water and other irrigation facilities
• The government should either waive off or defer farmer loans and arrange for crop loss compensation.

Existing Challenges in Drought Management

• Drought management encompasses three vital components namely,
• Drought intensity assessment and monitoring;
• Drought declaration and prioritization of areas for drought management and
• Development and implementation of drought management strategies

Each step in drought management lacks holistic approach to ensure effective end result.

• Development of standard procedures for drought vulnerability assessment and generation of vulnerability maps in each state needs to be done.
• Absence of Crisis Management Authority for drought to manage the various phases of drought.
• Ineffective dissemination of credible and verified information on relevant aspects of drought to the people and media.
• Ineffective monitoring and early warning system to provide accurate and timely information on rainfall, crop sown area, soil moisture, stream flow, groundwater, lake and reservoir storage.
• Half hearted attempts to detect drought conditions as early as possible to implement District Agriculture Contingency Plans and the Crisis Management Plan.
• Lack of community participation.

Heat Wave

What is a Heat Wave?

A Heat Wave is a period of abnormally high temperatures, more than the normal maximum temperature during the summer season in the North-Western parts of India. Heat Waves typically occur between March and June, and in some rare cases even extend till July.

Causes of Heat Waves

• Hot winds blowing from deserts with the dry winds on surface
• Anticyclone formations leading to no cloud formation and thunderstorm activity which fails to balance the temperature
• Rising global temperatures due to climate change and global warming
• Shifts in air currents and weather patterns due to shifting of pressure belts
• Depletion of Ozone layer
• Jet streams

Signs of Heat Waves

• Unreasonable Warmth- at least 9 degrees Celsius higher temperature than the region's average temperature.
• Humidity- presence of high moisture in the air at higher temperatures can be extremely uncomfortable.
• Duration of heat in the region for a minimum time interval of five days.
• Lack of moisture in soil

Heat Wave Risks in India

• Higher daily peak temperatures and longer, more intense heat waves are becomingly increasingly frequent globally due to climate change. India is also feeling the impact of climate change in terms of increased instances of heat waves that are more intense in nature with each passing year and have a devastating impact on human health, thereby increasing the number of heat wave casualties.

In India, April to June is a typical heat wave season. June is the onset month of Southwest Monsoon when summer- like conditions leave Peninsular and Central India but remains in North India. Cities are hotter than rural areas due to population density, pollution from industrial activities, and buildings' presence.
The combination of exceptional heat stress and a predominantly rural population makes India vulnerable to heat waves. Heat wave per say is more prominent in the interiors of the country. Hilly regions, Northeast India and coastal stations generally do not witness heatwave conditions. Heat waves prevail in pockets of Haryana, Delhi, Maharashtra, Telangana, Andhra Pradesh, Odisha, West Bengal, Bihar, Jharkhand, Chhattisgarh and Karnataka.

Consequences of Heat Waves

Effects on Human Health

• High moisture at high temperature doesn't let body sweat to evaporate easily to cool itself and body temperature raises eventually causing sickness.
• Heat stroke, Heat exhaustion, Heat cramps 
• S Dehydration, nausea, dizziness, headaches 
• S Diseases transmitted by chemical air
• Heat waves is one of the biggest killers amongst all natural calamities

Effects on Nature

• Heat waves can lead to droughts with decrease in moisture in the air and soil. Moisture in soil helps cool down the temperature by evaporation 
• Some species may disappear. Few new species may appear which are heat resistant.
• Adaptations in lifestyle and behaviour of few organisms 
• S Wildfires in open areas or forests become frequent due to heat waves.
• Coral bleaching in oceans can rise
• Huge damage to crops leading to food shortage

Effects on Infrastructure and Economy

• Heat tests infrastructure's ability to withstand the pressure created by increased energy demand. Electricity transmission line expands due to heat
• Transport services gets impacted
• Loss of labour efficiency

Nuclear Hazards

What is a Nuclear Hazard?

• It is a risk or danger to human health or the environment posed by radiation emanating from atomic nuclei of a given substance, or the possibility of an uncontrolled explosion originating from a fusion or fission reaction of atomic nuclei. The phenomenon is known as Radioactivity and the emission of energy released from the radioactive substance is called as "Radioactive Pollution".

Sources of Nuclear Hazard

• Natural Resources: Cosmic rays from the outer space, emissions from the radioactive materials from the earth's crust.
• Man-Made Sources: Nuclear power plants, X-Rays, nuclear bombs, nuclear accidents, nuclear weapons, mining and processing of radioactive ores.
  (i) Nuclear emergencies can also arise due to factors beyond the control of the operating agencies; e.g., human error, system failure, sabotage, earthquake, cyclone, flood, etc. Even though of very low probability, such failures may lead to an on-site or off-site emergency.
  (ii) It can also take place while using radiation sources, either at Hospitals, Industries, Agriculture or Research Institutions due to loss or misplacement or due to faulty handling.

Nuclear Hazard risk in India

India has traditionally been vulnerable to natural disasters on account of its unique geo-climatic conditions and it has, of late, like all other countries in the world, become equally vulnerable to various human-made disasters.

• Nuclear power is one of the biggest sources of electricity in India. India has a flourishing and largely indigenous nuclear power programme and expects to have 14.6 GWe nuclear capacity online by 2024 and 63 GWe by 2032. It aims to supply 25% of electricity from nuclear power by 2050. 
• Nuclear and Radiological Emergency can arise in a nuclear facility at plant level leading to plant/ site or offsite emergency depending upon its impact on the surroundings.

Impacts of Nuclear Hazard

• Death, acute or chronic debilitation, or increased risk of cancer, cataract in eyes, hair loss
• Radiation Sickness: A person's risk of getting sick depends on how much radiation the body absorbs. Radiation sickness is often fatal and can produce such symptoms as bleeding and shedding on the gastrointestinal tract's lining.
• Damage or destruction of agricultural products - animals and crops
• Degradation of environmental resources
• Devaluation or loss of use of public and private property
• Genetic changes in the generations to come by mutation

Nuclear Hazard Mitigation Strategies

• There are four ways in which people are protected from identified radiation sources:
  (i) Limiting time. In occupational situations, dose is reduced by limiting exposure time.
  (ii) Distance. The intensity of radiation decreases with distance from its source.
  (iii) Shielding. Barriers of lead, concrete or water give good protection from high levels of penetrating radiation such as gamma rays. Intensely radioactive materials are therefore often stored or handled under water, or by remote control in rooms constructed of thick concrete or lined with lead.
  (iv) Containment. Highly radioactive materials are confined and kept out of the workplace and environment. Nuclear reactors operate within closed systems with multiple barriers that keep the radioactive materials.
• Promoting flexibility in management of emergencies, for efficient use of resources.
• Maintenance of full-time capability for immediate response
• Ensuring the responders, plans, facilities, and any necessary inter-organizational coordination are sufficient to provide the desired protection.
• Appropriate steps and measures to be taken against occupational exposure and safety measures for nuclear accidents.

Steps Taken by Gol

• With increased emphasis on power generation through nuclear technology, the threat of nuclear hazards has also increased. The Department of Atomic Energy (DAE) has been identified as the country's nodal agency in respect of manmade radiological emergencies in the public domain.
• Nuclear facilities in India have adopted internationally accepted guidelines for ensuring safety to the public and environment.
• A crisis management system is also in place to take care of any nuclear hazard.
• Other types of emergency response plans in place within the facility to handle local emergencies, response plans have also been drawn up to handle such emergencies in the public domain, which are called "offsite Emergencies".
• These plans, drawn up separately in detail for each site - which are under the jurisdiction of the local district administration, cover an area of about 16 km radius around the plant or the offsite Emergency Planning Zone.