Q.On December 2004, tsunami brought havoc in 14 countries including India. Discuss the factors responsible for the occurrence of Tsunami and its effects on life and economy. In the light of guidelines of NDMA (2010) describe the mechanisms for preparedness to reduce the risk during such events.

graph TD
    TO["Tsunami Occurrence Factors"] --> SE["Submarine Earthquakes"]
    TO --> VE["Volcanic Eruptions"]
    TO --> SL["Submarine Landslides"]
    TO --> GC["Glacial Calving"]
    TO --> MI["Meteorite Impacts"]
    TO --> TPM["Tectonic Plate Movement"]

Body Analysis

Factors Responsible for the Occurrence of Tsunamis

• Submarine Earthquakes: The sudden vertical displacement of the ocean floor, typically along subduction zones, displaces massive volumes of water.
  • Example: The 2004 tsunami was caused by a megathrust earthquake (magnitude 9.1–9.3) where the Indo-Australian plate subducted beneath the Burma microplate.
• Volcanic Eruptions: Underwater volcanic explosions or the collapse of volcanic calderas can generate powerful displacement waves.
  • Example: The 1883 eruption of Krakatoa generated waves that caused widespread casualties.
• Submarine Landslides: Large-scale underwater landslides, often triggered by earthquakes, rapidly displace water columns.
  • Example: The 1929 Grand Banks earthquake triggered a massive submarine landslide and subsequent tsunami.
• Cosmic Impacts: Though rare, the impact of large meteorites or asteroids in oceans can displace immense volumes of water.
• Tectonic Plate Movements: Continuous stress accumulation and sudden release along convergent plate boundaries.
• Coastal and Oceanic Topography: Features like funnel-shaped bays can amplify tsunami wave heights as they approach shallow waters.
  • Example: The unique topography of the Bay of Bengal amplified the impact of the 2004 tsunami along India's southeastern coast.

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Effects of Tsunamis on Life and the Economy

• Loss of Life: Causes immediate, widespread casualties in densely populated coastal zones.
  • Example: The 2004 tsunami claimed over 230,000 lives globally, including more than 10,000 in India.
• Displacement of Populations: Destroys coastal settlements, leading to long-term humanitarian crises.
  • Example: Over 1.7 million people were displaced in the aftermath of the 2004 disaster.
• Economic Losses: Severely impacts key coastal sectors such as fisheries, tourism, and agriculture.
  • Example: The 2004 tsunami caused an estimated $10 billion in economic damage across affected regions.
• Environmental Degradation: Salinizes freshwater aquifers, erodes coastlines, and destroys vital ecosystems like mangroves and coral reefs.
• Psychosocial Impact: Leaves survivors with deep psychological trauma, including anxiety and PTSD.
• Infrastructure Destruction: Damages critical infrastructure like ports, roads, power grids, and communication networks.

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Mechanisms for Preparedness as per NDMA Guidelines (2010)

• Early Warning Systems: Establishing and maintaining state-of-the-art detection networks. The Indian Tsunami Early Warning Centre (ITEWC), set up in 2007, provides real-time monitoring and successfully issued alerts during the 2012 Sumatra earthquake.
• Community Awareness and Education: Conducting regular mock drills and public awareness campaigns in vulnerable coastal communities to ensure rapid evacuation.
• Coastal Zone Management: Enforcing strict land-use regulations, such as the Coastal Regulation Zone (CRZ) notifications, to restrict unsafe construction near the shoreline.
• Response Infrastructure: Enhancing the capacity of specialized response units like the NDRF through regular training and advanced equipment.
• Evacuation Planning: Mapping and clearly marking safe evacuation routes and shelters for coastal districts.
• Post-Disaster Recovery Frameworks: Implementing structured reconstruction protocols that focus on building resilient housing and restoring local livelihoods.
• International Collaboration: Participating in regional data-sharing networks like the Indian Ocean Tsunami Warning and Mitigation System (IOTWMS).