Geophysical Phenomena and Changes in Geographical Features

What the official syllabus says

General Studies-I (Paper III), Main Written Examination:

• Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc., geographical features and their location -changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.

Topics in detail

Earthquakes

• Causes, focus and epicentre, seismic waves, magnitude and intensity
• World distribution along plate boundaries
• India’s seismic zoning map and major earthquakes (for example Bhuj, 2001)

Tsunamis

• Causes (undersea earthquakes, landslides, volcanoes) and behaviour
• The Indian Ocean tsunami of 2004; warning systems

Volcanic activity

• Types of volcanoes and eruptions; volcanic landforms
• World distribution (the Pacific ‘Ring of Fire’); India’s Barren Island

Cyclones and other hazards

• Tropical cyclones: formation, structure, naming; the Bay of Bengal and Arabian Sea compared
• Temperate cyclones
• Landslides, cloudbursts, floods, droughts, heat waves, cold waves

Geographical features and their location

• Map knowledge: mountain ranges, peaks, rivers, lakes, straits, gulfs, islands, plateaus and deserts of the world and of India
• Places in the news and why they matter

Changes in critical features

• Retreating glaciers (the Himalaya) and melting polar ice caps; sea-level rise
• Shrinking or changing water bodies (for example the Aral Sea, Lake Chad) and wetlands
• Desertification and land degradation
• Changes in flora and fauna: coral bleaching, shifting ranges of species, invasive species, loss of biodiversity
• Effects of these changes on people, water, food and settlements

Further points

• Reducing earthquake risk: earthquake-resistant building codes, retrofitting, microzonation
• India’s tsunami early-warning centre at INCOIS, Hyderabad
• Hot spots and plumes (Hawaii); the Deccan Traps
• Cyclone warnings and the naming of cyclones in the north Indian Ocean; storm surges
• Glacial lake outburst floods and the thawing of permafrost
• Sundarbans mangroves and other coastal wetlands under threat
• Shifting treelines and species moving to higher altitudes in the Himalaya
• Effects on people: displacement, migration, food and water security

Overlaps

• Disaster management and environment: HCS Mains: General Studies III.
• Earthquake, flood and drought risk in Haryana: Haryana: Geography and Natural Resources.