Geography · Ch 6 — Natural Hazards and Disasters
Effects of Earthquakes
Effects of Earthquakes
| On Ground | On Manmade Structures | On Water |
|---|---|---|
| Fissures | Cracking | Waves |
| Settlements | Slidings | Hydro-Dynamic Pressure |
| Landslides | Overturning | Tsunami |
| Liquefaction | Buckling | |
| Earth Pressure | Collapse |
The map is a thematic map of India, coloured to show five distinct earthquake hazard zones based on the MSK (Medvedev–Sponheuer–Karnik) intensity scale. Each zone is labelled with both a damage-risk category and its corresponding MSK intensity: Very High (MSK IX), High (MSK VIII), Moderate (MSK VII), Low (MSK VI), and Very Low (MSK V). The legend on the map pairs each category with a shade, so the eye can immediately pick out the most dangerous regions.
The very-high-risk zones (MSK IX) are not scattered randomly — they trace the active tectonic boundaries. The most prominent band runs along the Kashmir and Himalayan belt, following the collision zone where the Indian plate pushes into Eurasia. A second major concentration covers the entire Northeast, and smaller patches appear in the Rann of Kutch in Gujarat and across the Andaman & Nicobar Islands. These are precisely the areas where plate movement is most intense, so the map visually links earthquake hazard with tectonic setting.
In contrast, a broad low-risk belt (MSK VI) runs diagonally through central-northern India and across much of the peninsula. Between the extremes lie the moderate (MSK VII) and high (MSK VIII) zones, which form transitional bands. The overall layout teaches a key geographical lesson: earthquake risk in India is not uniform — it is highest where the Indian plate is actively colliding or subducting, and lowest in the stable, older cratonic interiors of the peninsula. …
An earthquake does not end when the shaking stops. Its true impact unfolds in the destruction it leaves behind — collapsed buildings, broken ground, and a chain of secondary disasters that can be worse than the tremor itself. The effects are all-encompassing, meaning they touch every part of the affected area: the land, the water, and the lives of the people living there.
The most direct and visible effects are the fissures that open up on the upper layers of the earth's crust. These cracks are not just empty gaps — through them, water and other volatile materials gush out, flooding the neighbouring areas. This is why an earthquake can turn a dry region into a waterlogged one within minutes.
Beyond the ground itself, earthquakes trigger landslides, especially in hilly or mountainous terrain. These landslides are not merely a local problem; they often block the natural flow of rivers and channels. When a river's path is obstructed, water accumulates behind the blockage, forming reservoirs where none existed before. In some cases, the river does not simply get blocked — it changes its course entirely. A river that shifts its path can cause floods and other calamities in areas that were previously safe, destroying settlements and farmland that had never been at risk before. …
Earthquakes have serious environmental consequences like landslides, soil liquefaction, ground subsidence, fires and structural collapse. Table 6.2 outlines the important effects of earthquakes on land, …