Earthquakes

Sudden movement or vibration in Earth’s crusts. It is due to the release of energy and active internal dynamism of the earth.

Types:

1. Shallow focus
2. Intermediate focus
3. Deep focus

Shallow focuses are the most destructive.

Reasons:

1. Collision of plate boundaries like Ocean – Ocean, Ocean – Continental, or Continent – Continent plates.
2. Divergent plate boundaries lead to earthquakes due to the formation of mid-ocean ridges and eruptions.
3. Transverse plate boundaries create friction between plates and lead to earthquakes.
4. Breaking of plates and frequent interaction between them.
5. Human-induced due to Mining, and the building of dams.
6. Re-emergence of old fractures.

Tsunami

The tsunami waves are created due to the energy released from plate collisions. The colliding energy is transmitted to the waves. These waves have a greater wavelength and height when they hit the coast.

The vessels in the ocean don’t feel the tsunami. Waves also have higher speeds.

Floods

Floods – Inundation of land. Indian climate where monsoon concentrated in a few months leads to the flooding situation. The reasons for a flood are heavy rainfall, poor drainage due to topography, cloud burst, siltation of river bed, and landslide in course of the river.

Human-induced reasons like deforestation, unplanned settlements, global warming and melting of glaciers, and the construction of dams.

Solution:

1. Afforestation on river banks
2. Better settlement management
3. Watershed management and rainwater harvesting

Droughts

  Rainfall is 60 – 75 cm then the place is considered drought-affected. The southern part of the Deccan plateau, Western Rajasthan and Ladakh is considered drought-prone as these have 25% variability of normal rainfall.

 In India, drought is a more complex problem. Drought is due to inadequate development. It leads to agrarian poverty and high mortality of infants and mothers.

   To resolve drought-related problems:

1. Improve agriculture irrigation facility
2. Provide alternative livelihood
3. The economic status of farmers.

Rain-fed areas where agriculture completely depends on rainfall cover 55% of the country. 50% of food grains, 90% of pulses/millets, and 66% of the livestock population reside here. However, there is low productivity, high poverty, and subsistence farming. 40% of India’s B.P.L population live here.

The following are drought-prone areas:

1. The Rainshadow region of western Ghats – doesn’t receive adequate rainfall
2. Malwa, Bundelkhand, Mewar
3. Eastern India – high rainfall but overuse and inadequate storage
4. Northeast India – wettest part of India but no availability of storage.

Solution:

1. Agricultural income should be supplemented by alternate income sources too from animal husbandry, food processing, agro-forestry, handicrafts, and tourism.
2. For availability of alternate income 24*7 electricity, transportation, and connectivity should be ensured.
3. Mostly cash crops are grown in rain-fed areas and this should be changed to less water intensive crops like millets. Agro practices should be changed like the use of drip irrigation, and sprinkler irrigation.
4. Use of Drought-resistance variety, Conservation of soil moisture – mulching, Pre-monsoon plowing and soil dressing, Deep drilling of seed and fertilizers, crop rotation.