Tsunami ( UPSC Prelims)

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News Context

A powerful 8.8 magnitude earthquake hit Russia's Kamchatka Peninsula, causing tsunami waves to form near the Kuril Islands in the Pacific Ocean.

About Tsunami

• A series of very long waves generated by a significant and abrupt displacement of the ocean, typically due to an earthquake occurring beneath or close to the ocean floor, such as the Indian Ocean Tsunami in 2004.
 • Causes include earthquakes, landslides, volcanic eruptions, meteorites, and underwater explosions (including nuclear).
 • These phenomena are often observed along the Pacific Ring of Fire, a zone of active and dormant volcanoes encircling the Pacific Ocean.

Characteristics of Tsunami Waves:

 ● Wavelength: The speed and wavelength are mainly influenced by the depth of the ocean rather than the distance from the wave's origin.  
        ○ In the deep ocean, the wavelength is approximately 200 km, but it decreases to less than 20 km as it nears the coast due to shoaling.
  ● Wave Height (Amplitude): Ships in deep oceans do not notice the waves because their amplitude is minimal.  
        ○ As waves move into shallow water, their amplitude increases.

NDMA Guidelines for Tsunami

• Mandate a multi-tiered institutional structure comprising NDMA, SDMAs, and DDMAs.
 • Establish early warning systems and conduct hazard and vulnerability assessments.
 • Implement mitigation measures such as creating natural buffers like bio shields and promoting mangrove regeneration.