Prelims – location
Location:
- High-altitude desert plateau (~5,000 m above sea level) in the eastern Ladakh region.
- Lies at the junction of India (Ladakh) and China (Xinjiang–Tibet region).
Geography
- Cold desert, barren, and sparsely populated.
- Source region of rivers like Sutlej and Indus tributaries.
- Important passes nearby: Karakoram Pass.
GS 1 – Geography
Earthquakes
- Sudden shaking of the Earth’s surface caused by the release of energy from the Earth’s crust.
- Energy travels in the form of seismic waves.
Key Terms
- Focus (Hypocenter) – Point inside the Earth where the quake originates.
- Epicenter – Point on the surface directly above the focus.
- Seismic Waves –
- P-waves (Primary, fastest, travel through solids & liquids).
- S-waves (Secondary, slower, travel only through solids).
- Surface waves (cause maximum damage).
- Magnitude – Measured by Richter Scale (energy released).
- Intensity – Measured by Mercalli Scale (impact on people & structures).
Causes
- Tectonic movements – plate boundaries, subduction, collision.
- Volcanic activity – magma movement.
- Collapse earthquakes – underground mines, caves.
- Artificial/induced – reservoirs, nuclear explosions.
Distribution (World)
- Circum-Pacific Belt (Ring of Fire) – most active.
- Mid-Atlantic Ridge.
- Himalayan Belt (Alpine-Himalayan).
Earthquake Zones in India
- India is divided into 4 seismic zones – Zone II, III, IV, V.
- Zone I (no risk) does not exist in India.
Zones:
- Zone II (Low risk): Most of Peninsular India – Karnataka, MP, Chhattisgarh, interior TN.
- Zone III (Moderate risk): Kerala, Goa, plains of UP, Bihar, Odisha, parts of Maharashtra. Cities: Chennai, Bengaluru, Kolkata.
- Zone IV (High risk): Delhi, parts of Haryana, Punjab, UP, Bihar, West Bengal.
- Zone V (Very high risk): Entire Northeast, J&K, Himachal, Uttarakhand, north Bihar, Andaman & Nicobar.