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Exams आसान है !

09 September 2022

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MAINS QUESTIONS DAILY QUESTIONS & MODEL ANSWERS

Q1. Explain about landslides, its causes and types.

Paper & Topic: GS I à Geography

Model Answer:

  • A landslide is a sudden, gravity-driven movement of rock, soil, and plants down a slope. It may be brought on by natural forces like heavy rain or earthquakes, or it may be brought on by excessive human intervention with slope stability.
  • Man breaks rocks to build houses, tunnels, railways, roads, etc. In such situations, landslides happen as a result of loose rocks.
  • Landslides can take many different forms, including earth flow, mass movement, mudflow, rotating slip, and avalanches.
  • Rarely are landslides of the same size as seismic or volcanic disasters. However, the geological structure, slope angle, type of sedimentary materials, and human contact with the slope all affect the intensity and size of the landslide.

Landslide types:

  • Falls: These occur as a result of the sudden movements of large geologic masses, such as rocks and boulders that separate from cliff faces or steep slopes.
  • Topples: This occurs as a result of a unit or units rotating forward about a pivot point that is low or below the unit, under the influence of gravity, forces from other units, or fluids in fractures.
  • Slides: In this type, soil, rocks, or other debris flow through the materials that create slopes.
  • Spread: It typically happens on flat or very gentle inclines.

Landslide causes include:

The fall of rain and snow:

  • In places of steep slopes where National Highways and roads have been built, the occurrence of strong or persistent rainfall may cause heavy landslides.
  • Landslides commonly occur in the Nashri region of Jammu and Kashmir, between Batote-Ramban-Ramsu and Banihal. The landslides in this region are particularly severe during the rainy and winter seasons when the vehicular traffic is disturbed for several days.

Volcanic eruptions and earthquakes:

  • Landslides in folded mountainous regions are primarily caused by earthquakes. In India, landslides are more common in Tertiary-era folded mountains like the Himalayas.
  • The 1905 earthquake in the Kashmir valley caused landslides in the lesser and greater Himalayas, which resulted in the deaths of many thousand people.
  • Landslides can also brought on by volcanic explosions in mountainous areas.

Road construction, mining, and quarrying:

  • Landslides can occur as a result of the ongoing mining and quarrying of coal, minerals, and stones as well as the construction of roadways by slicing through the steep slopes of folded mountains.
  • These landslides can be seen in the Eastern and Western Ghats as well as the Himalayas.

House construction-related loading:

  • Unplanned urban sprawl without rock and soil testing in steep places is a significant contributor to landslides.
  • Due to the weight of the hotels and residential buildings, the eastern slope of Nanital (Uttarakhand) is sinking.

Clearing of forests:

  • Landslides are also brought on by human activity such as deforestation. The majority of the landslides include small, up to a few metres wide, blocks. However, some are huge enough to bring about a disaster. Roads, buildings, and other structures might be buried.
  • Landslides have a negative impact that can be lessened by limiting deforestation on mountain slopes, adhering to building regulations in such places, and avoiding building on steep slopes.

Mitigation Strategy:

  • In addition to monitoring and early warning systems being installed at certain places, hazardous zones must be recognised and individual slides must be stabilised and managed.
  • Hazard mapping should be done to locate areas commonly prone to landslides. Adopting area-specific methods to combat landslides is usually advisable.
  • Limitations on building and other developmental operations, such as roads and dams, as well as restrictions on expanding major communities in vulnerable areas should all be enforced. Agriculture should also be restricted to valleys and areas with a moderate slope.

Q2. What is Miyawaki Method?

Paper & Topic: GS I à Environmental Conservation

Model Answer:

  • Akira Miyawaki, a Japanese botanist, developed the Miyawaki technique, which speeds up the process of creating dense, natural forests.
  • It has transformed backyards into little woods, revolutionising the idea of urban afforestation.
  • In order to save space, this strategy calls for planting trees (only native species) as closely as possible together in the same area. The planted saplings support one another’s growth and block sunlight from penetrating the ground, which inhibits the growth of weed.
  • After the first three years, the saplings become maintenance-free (self-sustaining).
  • According to the strategy, plant growth should be 10 times faster and the finished plantation should be 30 times denser than typical.
  • A forest can be grown using the Miyawaki method in 20 to 30 years as opposed to 200 to 300 years using traditional techniques.

Miyawaki Method:

  • The four tiers of shrub, sub-tree, tree, and canopy are used to categorise the natural trees of the area.
  • The quality of the soil is evaluated, and biomass is added to it to improve its capacity for permeability, water retention, and nitrogen retention.
  • Three to five saplings per square metre are planted in the seeds once a mound of soil has been constructed.
  • Mulch is spread out over the ground in a thick layer.

Concerns:

  • Some characteristics of natural forests, such as their capacity to produce rain and their medicinal value, are absent from such woods.
  • Such rapidly expanding plantations aren’t actually forests; rather, they are wood lots, which are parts of woodlands or forests that can be used for recreational activities like bird watching, bushwalking, and appreciating wildflowers as well as small-scale production of forest products like wood fuel, sap for maple syrup, sawlogs, and pulpwood.
  • Environmentalists have questioned the effectiveness of a technique that claims to match the intricate ecosystem of a forest while speeding up tree growth (as it is not a good idea to force plants to photosynthesize fast).

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