Promoting Resilience: UNESCO’s World Tsunami Awareness Day 2023

• UNESCO: UNESCO and partners celebrate World Tsunami Awareness Day 2023 with #GetToHighGround campaign.
• Theme: Fighting Inequality for a Resilient Future.
• Annual Event: World Tsunami Awareness Day is an annual event held on 5 November to raise awareness of the dangerous effects of tsunamis and the importance of tsunami preparedness and early warning of tsunamis.
• UN Resolution: It was first established on 22nd December 2015 by the United Nations General Assembly (UNGA) Resolution which highlighted the need for Tsunami Awareness.
• Role of UNDRR: UN Disaster Risk Reduction (UNDRR) facilitates the observance of World Tsunami Awareness Day in collaboration with the United Nations.

Understanding Tsunamis: Forces, Impacts, and Coastal Vulnerability

• Origin: The word “tsunami” comes from the Japanese words “tsu” (which means  harbour) and “nami” (which means sea waves). 
• Destructive Waves: A tsunami is a series of deadly waves created by an underwater disturbance generally linked with earthquakes and volcanoes occurring below the ocean surface.
• Causes: Volcanic eruptions, landslides, and coastal rock debris falling into the ocean can also generate a tsunami, along with a large asteroid impacting the deep ocean surface. 
• Vertical Movement: They originate from a vertical movement of the ocean floor with the consequent displacement of the water column beneath it.
• Coastline Vulnerability: Tsunami waves often look like walls of water and can attack the coastline and be dangerous for a few hours, with waves coming every 5 to 60 minutes.
• Cascading Effect: 
  • The first wave may not be the largest, and often it is the second, third or subsequent waves that are more deadly and bigger.
  • After one wave inundates, or floods inland, it recedes seaward, often as far as a person can see, so the seafloor is exposed. 
  • The next wave then reaches the shore within a few minutes and is accompanied by many floating debris.

The Dynamics of Tsunami Formation: Understanding the Coastal Impact

• Underlying Principle: A tsunami’s ability to maintain speed is directly influenced by the vertical height of the water beneath. 
• Deep Water Waves:, As  a tsunami moves through deep water at very high speeds of nearly hundreds of miles an hour, it is hardly noticeable above the waterline.
• Difficult Detection: A tsunami is typically no more than 3 feet (1 metre) high until it gets close to the coastline.
• Coastal Vulnerability: Once a tsunami gets close to the coastline then it takes its more recognizable and disastrous shape causing coastal damage..

Distinguishing Tsunamis from Tides and Wind-Generated Waves: Key Characteristics 

The Causes of Tsunamis: Earthquakes, Landslides, Volcanic Eruptions, and Extraterrestrial Collisions

• Earthquakes
  • Plate Movements: It tends to be created by developments along sensitive zones related to plate boundaries.
  • Oceanic Activity: Most seismic tremors happen in subduction zones where a sea plate slides under a mainland plate or another sea plate.
  • Conditions: All earthquakes do not cause tsunamis. There are four conditions necessary for an earthquake to cause a tsunami:
    • The earthquake must occur beneath the oceanic plate. 
    • The earthquake must be of magnitude 6.5 or more on the Richter Scale
    • The earthquake must impact the Earth’s surface and it must occur at shallow depth – generally less than 70 km below the surface of the Earth.
    • The earthquake must cause vertical disruptions in the oceanic sea floor 
• Landslides
  • Coastal Landslide: An landslide that happens along the coast can drive a lot of water into the ocean, upwelling the water and producing a tidal wave.
  • Loosened Materials: Underwater landslides can also result in tsunamis when the material loosened by the landslide moves strongly while pushing the water in front of it. 
• Volcanic eruptions
  • Impact: Strong volcanic emissions dislodge a huge volume of water and create very disastrous waves in the quick source region.
  • Example: One of the largest and most destructive tsunamis ever recorded was generated on August 26, 1883 after the explosion and collapse of the volcano of Krakatoa (Krakatau), in Indonesia. 
• Extraterrestrial collisions
  • Rare Occurence: Tsunamis caused by asteroids, meteors and other extraterrestrial collisions are a rare occurrence. 
  • Potential Hazard: No meteor/asteroid-induced tsunamis have been recorded till date however scientists believe that if these celestial bodies strike the ocean then a large volume of water would be displaced to cause a tsunami.

Understanding Tsunami Dynamics: Key Features and Implications

Impact of Tsunamis: Losses, Risks, and Long-term Consequences

• Casualties: In the past 100 years, 58 tsunamis have taken more than 260,000 lives which is more deadly than any other natural hazard.
• Coastal Destruction: The highest number of deaths in that period was in the Indian Ocean tsunami of December 2004. It caused an estimated 227,000 deaths in more than 10 countries, with Indonesia, Sri Lanka, India and Thailand hardest hit.
• Economic Losses: Tsunamis account for $280 billion in economic losses over last two decades
• Disease Spread: Water-borne diseases such as malaria arises due to congested and stagnant water
• Environmental Damage: Tsunamis have a devastating effect on insects, animals, plants, and natural resources. 
• Psychological effects: Survivors of the Sri Lankan tsunami of December 2004 were found to have PTSD (post-traumatic stress disorder) when examined by the World Health Organization (WHO)

Tsunami Mitigation Strategies: Safeguarding Coastal Communities and Infrastructure

• Revamping Coastal Infrastructure: Planting trees and mangrove plantation along the coast helps mitigate impacts of tsunami and coastal floods.
• Standard Operating Procedure: Constructing, marking, and publicising evacuation routes
• Relief Camps: Construction of evacuation structures and shelter relief camps in Coastal districts.
• Awareness: Educating the people on the risks of a tsunami and the safety tips 
• Reengineering: Redesigning Buildings on lines of Tsunami Code to ensure minimal damage.
• Mock Drills: Practising tsunami emergency drills such as moving to higher ground
• Land Use Planning: Proper land use planning and zoning regulations can help reduce the vulnerability of coastal areas to tsunamis. 
• International Collaboration: Organisations like the Pacific Tsunami Warning Center and the UNESCO Intergovernmental Oceanographic Commission coordinate efforts to mitigate the impact of tsunamis in the Pacific region and beyond.

Global Collaboration for Tsunami Preparedness and Mitigation

• Deep-Ocean Assessment and Reporting of Tsunamis (DART): 
  • Sensitive Movement Tracking: The DART system can detect a tsunami as small as a centimetre high above the sea level.
• UNESCO Intergovernmental Oceanographic Commission (IOC): 
  • Early Warning System: The IOC plays a central role in tsunami management and early warning systems, particularly in the context of the United Nations. 
  • Collaborative Approach: It supports Member States in developing and implementing tsunami warning systems and coordinates international efforts for tsunami research, monitoring, and response.
• Tsunami Management under Hyogo Framework:
  • Global Agreement: Governments adopted the 10-year Hyogo Framework for Action, the first comprehensive global agreement on disaster risk reduction.
  • Mitigation System: They created the Indian Ocean Tsunami Warning and Mitigation System, which boasts scores of seismographic and sea-level monitoring stations and disseminates alerts to national tsunami information centres.
• Sendai Framework for Disaster Risk Reduction 2015-2030
  • Risk Understanding: It promotes a greater understanding of tsunami risk to avoid future loss of life. 
  • Improve Infrastructure: It brings attention to the economic losses tsunamis can inflict as a result of damage to critical infrastructure located along vulnerable, densely populated coastlines.

Tsunami Prone Regions Along the Indian Coastline

The government has published a list of tsunami-prone locations on the coastal boundary of India. These consist of

• Orissa  –  Puri coastal areas
• Andhra Pradesh – Kakinada, Machilipatnam, Nizampatnam Vetapalem
• Tamil Nadu – Chennai, Rameshwaram, Thoothukudi
• Cuddalore-Pondicherry
• Kerala – Alappuzha-Chavara, Kochi
• Andaman & Nicobar Islands

Tsunami Preparedness Measures in India: Early Warning Systems and Community Initiatives

• Indian Tsunami Early Warning System:
  • Background: It was established in 2007 and is based at & operated by INCOIS, Hyderabad.
    • INCOIS is an autonomous body under the parent organisation Ministry of Earth Sciences (MoES).
  • Real-Time Tracking: It comprises a real-time network of seismic stations, Bottom Pressure Recorders (BPR), tide gauges and 24 X 7 operational tsunami warning centre to detect tsunamigenic earthquakes and to monitor tsunamis 
  • Use of Modelling: In order to provide timely advisories to the vulnerable community by means of the latest communication methods with back-end support of scenario database, vulnerability modelling and Decision Support System.
  • Undersea Detection: Indian scientists can detect large undersea earthquakes in the Indian Ocean in real-time and provide a tsunami warning in 10-20 minutes after the earthquake occurs.

• Tsunami-Ready Initiative:
  • Background: It is a community performance-based programme to promote tsunami preparedness through active collaboration.
  • Parent Body: UNESCO-IOC 
  • Two villages of Odisha- Venkatraipur in Ganjam district and Noliasahi in Jagatsinghpur district are now ‘Tsunami Ready’.

Conclusion:

World Tsunami Awareness Day is a reminder that Tsunamis are a real danger, and they generally occur without sufficient warning. In such cases the need for awareness, education, and preparation can help save lives and minimise the impact of devastation caused by such deadly oceanic waves.