Tiêu đề Prahaar Summary 2025_Geography and DM_E-Book.pdf ✅

CONTENTS 1. Geomorphology ........................................................................................................ 3 2. Climatology .............................................................................................................. 4 3. Oceanography .......................................................................................................... 6 4. Indian Climate.......................................................................................................... 7 5. Population and Migration in India .......................................................................... 10 6. Human Settlements and Associated Issues............................................................. 12 7. Land Use Pattern.................................................................................................... 13 8. Location of Primary, Secondary and Tertiary Sector Industries ............................... 14 9. Minerals and Energy Resources.............................................................................. 19 10. Water Resources and Their Management in India ................................................... 23 11. Transport and Communication in India .................................................................. 25 12. Geographical Perspective to Disasters in India........................................................ 28

4 Prahaar Summary 2025 Ê Convergent Boundaries: Oceanic-Continental: Oceanic plate subducts, forming trenches and volcanic chains (e.g., Cascades). Oceanic-Oceanic: Denser plate subducts, forming trenches and island arcs (e.g., Japan). Continental-Continental: Collisions form mountains (e.g., Himalayas). Ê Transform Boundaries: Plates slide horizontally, creating transform faults (e.g., San Andreas Fault). Seismicity and Earthquakes- Earthquakes result from sudden energy release in the lithosphere, with energy originating at the hypocenter. Underwater quakes can trigger tsunamis. Ê Causes: Plate movement, volcanic eruptions, meteor impacts, nuclear tests. Types of Seismic Waves Ê P-Waves: Fastest, pass through solids, liquids, gases. Ê S-Waves: Move particles perpendicularly, only through solids. Ê Surface Waves (L): Slowest, most destructive, rolling motion. Shadow Zones- Ê P-waves pass through the liquid core; S-waves do not, creating shadow zones. Seismic wave behavior confirms Earth’s layered structure. P-wave shadow zone: 105°–142° S-wave shadow zone: 105°–180° Recording Earthquakes- Ê Seismographs: Record ground motion.; Richter Scale: Magnitude (0–10).; Mercalli Scale: Intensity (1–12). Global Distribution of Earthquakes Ê Ring of Fire: 81% of major quakes along the Pacific rim. Ê Alpide Belt: Java to Himalayas, 17% of quakes. Ê Mid-Atlantic Ridge: Divergent boundary quakes. Ê Seismic Mapping of India- ~59% of India’s land is quake-prone. Zones: V (most active, 11%), IV (18%), III (30%), II (least). Ê Consequences of Earthquakes- Ground rupture, landslides, fires, soil liquefaction, tsunamis, floods, and loss of life. Ê Case Study: Sinking of Joshimath- Joshimath (Uttarakhand) faces land subsidence due to natural and human-induced activities. Volcanoes- Openings in Earth’s crust emitting lava, gases, and ash. Magma rises from chambers through conduits and vents. Parts: Magma chamber, conduit, vent, crater, slopes. Types of Volcanoes Ê Composite: Felsic/intermediate lava, explosive. Ê Shield: Fluid lava, non-explosive. Ê Caldera: Collapse after massive eruptions. Ê Cinder Cones: Small conical structures. Ê Mid-Ocean Ridge: Frequent oceanic eruptions. Distribution of Volcanoes Ê Volcanoes are primarily distributed along tectonic plate boundaries. Ê The most active volcanic belt is the Pacific Ring of Fire, encircling the Pacific Ocean. Ê Other major zones include the Mid-Atlantic Ridge and the Mediterranean-Asian Belt. Isolated volcanoes also occur at hotspots like Hawaii and Iceland. Landforms and Their Evolution- Natural features like mountains, valleys shaped by wind, water, glaciers, etc. Wind/Aeolian Landforms- Ê Erosional: Ventifacts, yardangs, deflation hollows, mushroom rocks, zeugen, inselbergs. Ê Depositional: Sand dunes (crescentic, linear, star, parabolic, dome) and loess (e.g., Mississippi valley). Glacial Landforms- Erosional: Ê Cirques, nunataks, arêtes, horns, crevasses, fjords.; Ê Depositional: Moraines, till, glacial flour, erratics.; Ê Significance: Reveal past climates (e.g., Talcher boulders). Karst Topography- Ê Erosional: Sinkholes, dolines, uvalas, poljes, disappearing streams.; Ê Depositional: Stalactites, stalagmites, pillars.; Significance: Preserve artifacts, unique ecosystems. Fluvial Landforms- Ê Erosional: Waterfalls, canyons, gorges, river valleys, potholes.; Ê Depositional: Alluvial fans, levees, floodplains, channels, deltas.; Significance: Fertile plains, mineral-rich deposits. Coastal Landforms- Ê Erosional: Headlands, bays, cliffs, caves, arches, stacks, stumps.; Ê Depositional: Beaches, spits, bars, lagoons.; Ê Significance: Tourism, minerals (gold—Subarnarekha, thorium—Kerala).; Ê Coastal Erosion: Threatens 33.6% of India’s coastline (e.g., Odisha—28%).; Ê Government Efforts: Mangroves, geo-tubes, resettlement (₹2500 crore under 15th Finance Commission). 2.CLIMATOLOGY Atmosphere- A gaseous layer, mostly Nitrogen and Oxygen, surrounds Earth.; Shape: Wider at equator, slightly flattened at poles due to rotation and gravity.; Divided into layers with varying temperature and composition, held by gravity. Earth’s Atmosphere- 99% Nitrogen and Oxygen; remainder includes argon, CO2, hydrogen, neon, helium.; Composition changes by time and place. Structure of Atmosphere Ê Troposphere: 0–13 km; weather phenomena; temp drops (1°C/165 m); tropopause (~-45°C to -80°C).