RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides

Go through these RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides contain important concepts so that students can score better marks in the exam.

Rajasthan Board RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides

Natural Disasters

  • The unfavourable affect of changes in Nature on human society is called natural disaster.
  • Excessive rainfall turns into a natural disaster when it takes the form of flood.
  • Rainfall in a very low quantity becomes a disaster, when it turns into drought.

Natural Disaster and Hazard

  • There is a minor difference between natural disaster and hazard.
  • The incident or the change that takes some moments for it occurrence is called natural disaster. The problems rising after the occurrence of a disaster are called as hazard.
  • The word disaster is made of two French words-Dis and Aster. Dis means ‘‘very bad” and Aster means “stars.” Hence, ‘disaster’ means ‘very bad stars’.
  • In India, natural disasters are also called the wrath of nature.
  • The natural disasters are the result of interaction with the nature in the past.

Cause of Natural Disasters

  • A combination of several factors is responsible for various natural disasters.
  • The inner and outer forces of our earth are the major causes for several natural disasters.
  • Insensible exploitation of natural resources by man is the major factor for inviting natural disasters.
  • Deforestation, land erosion and excessive urbanisation have encouraged disasters.

RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides

Classification of Natural Disasters

  • On the basis of origin, disasters have been classified into seasonal disasters, topographical disasters and man-made disasters.
  • Cyclone, floods, drought and snowfall are seasonal disasters.
  • Landslides, avalanches, earthquakes, volcanic eruptions are topographical disasters.
  • Epidemics, plague, malaria, locust attack, etc., are man-made disasters.

Natural Disasters and Management

  • All the works done for the prevention of a disaster or hazard are included in disaster management.
  • Management means to decide the responsibilities at every level to get relief from a hazard.
  • Management is influenced by various factors like-economic condition, positive thinking of man, social honesty and faith, geographical conditions, availability of means of transport and communication, and population.

Earthquake

  • Earthquake is a rapid and sudden shaking of the earth’s surface due to massive disturbance in the internal part of the earth.
  • The intensity of an earthquake is measured with an instrument named seismograph, while the intensity of waves is measured on Richter scale.
  • The intensity of earthquake is measured from 1 to 12 on Richter scale. The earthquake of 5 Richter is considered as normal, but an earthquake with intensity of more than 5 Richter is always considered as destructive.

Reasons of Earthquake’s Origin

  • Earthquakes are usually caused by plate teatonics. The reasons of breaking up of the underground rocks are folding and faulting, Plate tectonics, deprivation in earth crust, contraction in Earth, etc.
  • In the man-made reasons, insensible exploitation of resources, construction of large dams, etc. are included.
  • In India, on the basis of their nature and activeness, earthquakes are divided into imperceptible, feeble and very slight earthquakes.

RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides

Earthquake: A Hazard

  • An earthquake is such a natural disaster which produces destructive changes within a few moments.
  • An earthquake causes excessive loss of man-power. Demolition of buildings and destruction of the routes of transport, change in the flow of rivers, deaths of people are some negative effects of earthquakes.
  • In coastal areas, Tsunami waves arise due to the earthquakes, which cause excessive destruction.

Rescue from Earthquakes

  • The intensity of earthquakes may be avoided to some extent by spreading a network of seismograph instruments, making the people aware, showing unity and humanity and helping the victims.
  • As we realize about occurrence of an earthquake, we should leave our homes and come out in the open space.

Landslide

  • A landslide or landslip or mudslide is a form of mass wasting that includes a wide range of ground movement, such as rock faults, deep failure of slopes and shallow debris flow.
  • A landslide starts with a loud thundering voice and rubble falls down.

Reasons of Landslides and Landslide Affected Areas

  • Both the factors, natural as well human, are responsible for landslides.
  • In natural factors, slope of land, quantity and intensity of rainfall, weaker mountain folds and nature of rocks are responsible for landslides.
  • In human factors, unplanned development, over-exploitation of forests, construction of roads, railways, tunnels and mining process are responsible.
  • The gravitational force of earth also causes landslides.
  • In India, landslides are mainly seen in the Himalayan region, Western Ghats and on Konkan Coast.

Landslide Hazard and It’s Management

  • Landslide is a devastating disaster in which the flow of rivers, routes of transport and railways are blocked, life is disturbed, and in densely-populated areas, excessive destruction is seen all round.
  • Proper drainage system, providing support to the rocks by building strong walls, checking human settlement in landslide prone zones, providing protection to one self and others and creating awareness are included in landslide management.

RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides

Natural Disasters and Management, Earthquakes & Landslides Notes Important Terms

→ Disaster: A sudden accident or a natural catastrophe that causes great damage or loss of life and property.

→ Management: The process of dealing with a task on the basis of achievement of pre-determined objective.

→ Earthquake: A sudden violent shaking of the ground, typically causing great destruction as a result of movements within the earth’s crust or volcanic action.

→ Landslide: A landslide or landslip or mud slip or mudslide is a form of mass wasting that includes a wide range of ground movement, such as rockfalls, deep failure of slopes, and shallow debris flows.

→ Natural Disaster: A natural event such as a flood, earthquake or hurricane, that causes great damage or loss to life and property.

→ Flood: An overflow of a large amount of water beyond its normal limits, especially over what is normally dry land.

Volcano: A volcano is an opening in the earth’s crust that allows molten rock from beneath the crust to reach the surface.

→ Resources: Everything found on the earth or any other planet, useful for human being, is called resource.

→ Environment: The surrounding or conditions in which a person, animal or plant lives or operates.

→ Global warming: A gradual increase in overall temperature of the earth’s atmosphere, generally attributed to the greenhouse effects caused by increased levels of carbon dioxide.

→ Seasonal Disasters: The disasters caused by a rapid change in season are called seasonal disasters.

→ Cyclone: A system of winds rotating inwards to an area of low barometric pressure with an anticlockwise or a clockwise circulation or a depression.

→ Snowfall: A fall of snow, especially the amount of snow that falls in a single storm or in a given period.

→ Avalanches: A large amount of ice, snow, dirt, or rocks falling suddenly and quickly down the side of a mountain.

→ Transport: Take or carry (people, animals, goods,) from one place to another place by means of a vehicle, aircraft or ship.

→ Communication: The imparting or exchanging of information by speaking, writing, or using some other medium.

→ Population Density: The number of people living per unit of an area (e.g. per square km). The number of people relative to the space occupied by them.

→ Seismograph: An instrument that measures and records the magnitude of earthquakes, such as force and duration.

→ Richter scale: It is used to rate the magnitude of an earthquake, that is, the amount of energy released during an earthquake.

→ Epicentre: It is the point on the earth’s surface vertically above the hypocentre (or focus), point in the crust where a seismic rupture starts.

→ Tectonic Plates: The two sub-layers of the earth’s crust (lithosphere) that move, float, and sometimes fracture and whose interaction causes continental drift, earthquakes, volcanoes and mountainous and oceanic trenches.

→ Dynamic Equilibrium: A state of coordination between two opposite forces or effects.

→ Fault: A fracture in a rock where there has been movement and displacement. One of the major boundaries between tectonic plates on earth.

→ Dam or Embankment: A dam is any barrier that holds backwater. Dams are primarily used to save, manage, and/or prevent the flow of excess water into specific regions.

→ Peninsula: A peninsula is a piece of land which is almost entirely surrounded by water but is connected to the mainland on one side.

RBSE Class 11 Indian Geography Notes Chapter 10 Natural Disasters and Management, Earthquakes & Landslides

→ Lake: An expanse of water entirely surrounded by land and unconnected to sea except by rivers or streams.

→ Tsunami: A large wave on ocean, usually caused by an undersea earthquake, a volcanic eruption, or coastal landslide. A tsunami can travel hundreds of miles over the open sea and cause extensive damage when it encounters the land.

→ Religion : The belief and worship of superhuman controlling power, especially a personal God or Gods.

→ Self helf-group: Also known as mutual help, mutual aid, or support group, groups of people which provide mutual support to each other. In a self-helf group, the members share a common problem, often a common disease or addiction.

→ Folds: A sycline is a fold that sinks down as both sides of the rocks are pushed inwards.

→ Rain: Water that is condensed from the aqueous vapour in the atmosphere and falls to earth in the form of droplets more than 0.5 mm in diameter.

→ Vegetation: It is an assemblage of plant species and the ground cover they provide. The vegetation type is defined by characteristics of entire dominant species, such as algae, grasses, bushes, trees, etc.

→ Soil Erosion: Soil erosion is the displacement of the upper layer of soil; it is one form of soil degradation.

→ Mining: The process or industry of obtaining coal or other minerals from a mine is called mining.

→ Season: Each of the four divisions of the year (spring, summer, autumn and winter), marked by particular weather patterns and daylight hours, resulting from the earth’s changing position with regard to the sun.

→ Citizen: A legally-recognized subject or national of a state or commonwealth, either native or naturalized.

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