What are Tsunamis? How and where are they formed? What are their consequences? Explain with examples. (Answer in 150 words)

A tsunami is a series of long-period sea waves produced by sudden displacement of a large volume of water, most commonly during submarine earthquakes.

Formation and setting

• At convergent plate margins, a thrust earthquake may abruptly uplift or depress the sea floor.
• Underwater landslides, volcanic eruptions and, rarely, meteorite impacts can also displace water.
• Waves travel rapidly in deep water with low amplitude; near shallow coasts they slow, shorten and rise dramatically.

Consequences

• Multiple waves cause drowning, debris impact, building collapse, coastal erosion and salt-water contamination.
• Ports, fisheries, tourism, roads and power systems suffer cascading economic losses.
• The 2004 Indian Ocean tsunami devastated Aceh and affected India’s Andaman–Nicobar Islands and eastern coast.

Risk reduction

Seismic monitoring, ocean buoys, rapid warnings, evacuation routes, coastal zoning, mangrove restoration and public drills reduce mortality. Because the first wave may not be the largest, communities must remain inland until official clearance.

Keywords: subduction, sea-floor displacement, shoaling, run-up, early warning, evacuation.