Effects of earthquakes
Topic: Natural Hazards and Disaster Management in India · NCERT: Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"; Class 11, Ch 3 "Interior of the Earth"
Meaning
NCERT (Class 11 Table 6.2) groups the effects of earthquakes into three kinds:
- On the ground: fissures (deep cracks), settling, landslides, liquefaction (wet sand flowing like a liquid) and earth pressure.
- On structures: cracking, sliding, overturning, buckling and collapse.
- On water: waves, hydrodynamic pressure (the force of moving water) and tsunamis.
These can set off chain effects, where one effect causes the next. Fissures can let water gush out and flood nearby land. Landslides can block rivers into lakes or shift their courses, which causes floods. Quakes are most deadly in crowded areas, and broken roads and phone links delay relief.
Example
The 1950 Assam earthquake (about magnitude 8.6) changed the courses of Brahmaputra tributaries. In the 2001 Bhuj earthquake in Kachchh, Gujarat, the ground liquefied and buildings collapsed.