Why in news?

• Following strong earthquakes in Japan, including a preliminary one of 7.6 magnitude, both North and South Korea as well as Russia have issued a tsunami warning.
• Tsunami waves also hit several parts of Japan’s coastal areas and urgent evacuation warnings were issued.

What’s in today’s article?

• Tsunami
• Why is Japan prone to earthquakes and tsunamis?
• 2011 Earthquake and tsunami in Japan

Tsunami

• About
  • Tsunami is a series of giant ocean waves caused by earthquakes or volcanic eruptions under the ocean.
  • Basically, it is a series of ocean waves with extremely long wavelengths and high energy.
  • Tsunamis can travel across entire ocean basins and can cause widespread destruction when they reach coastlines.
  • Tsunami waves can be hundreds of feet tall and can travel as fast as jet planes over deep waters while slowing down when reaching shallow waters.
• Primary factors behind the creation of tsunamis
  • Underwater Earthquakes
    • When tectonic plates beneath the Earth's surface shift, they can generate seismic waves that propagate through the water, creating a tsunami.
  • Volcanic Eruptions
    • Volcanic activity, especially if it occurs beneath the ocean, can displace a large volume of water, triggering a tsunami.
    • This can happen when there is a sudden collapse of a volcanic island or an explosive eruption.
  • Landslides
    • Underwater landslides, whether caused by volcanic activity, coastal erosion, or other factors, can displace a significant amount of water and generate tsunami waves.
  • Meteorite Impact
    • Although rare, the impact of a large meteorite or asteroid in the ocean can displace water and create tsunami-like waves.
  • Underwater Explosions
    • Human activities, such as underwater explosions, can also potentially generate tsunamis.
• Devastation caused
• Once generated, the tsunami waves can travel across the open ocean at high speeds, reaching coastal areas with devastating force.
• The energy and wavelength of these waves make them different from typical ocean waves, and they can cause widespread damage when they inundate coastlines.
• Tsunami preparedness
  • Early warning systems and preparedness measures are crucial for minimizing the impact of tsunamis on coastal communities.

Tsunami preparedness in India

• Part of the Indian Ocean Tsunami Warning System
  • India is a part of the Indian Ocean Tsunami Warning System (IOTWS).
  • The TEWS includes a network of seismic and sea-level sensors strategically placed to detect underwater earthquakes and monitor sea level changes.
  • The information collected is used to issue timely warnings to coastal communities.
• Early Warning Centre
  • India's Tsunami Early Warning Centre (ITEWC) is located at the Indian National Centre for Ocean Information Services (INCOIS) in Hyderabad.
  • The ITEWC provides tsunami advisories to stakeholders.
• Public Awareness and Education
  • In coordination with the National Disaster Management Authority(NDMA), INCOIS conducts mock drills as well as organises workshops/trainings on tsunami awareness and preparedness.
• Enhancing community preparedness
  • To enhance community preparedness, INCOIS is also coordinating the implementation of the UNESCO-IOC "Tsunami Ready" initiative.
  • Venkatraipur and Noliasahi villages of Odisha have been recognised as Tsunami ready communities by the UNESCO-IOC.
    • India is the first country in the Indian Ocean region to achieve this distinction.
• Software for monitoring earthquakes and multimode dissemination of early warning of tsunamis
  • The required software for monitoring earthquakes and multimode dissemination of early warning of tsunamis is already in place at INCOIS.
  • INCOIS has also developed Decision Support System software for automatically generating and disseminating warnings for effective dissemination of tsunami early waning information.
    • E.g., INCOIS has developed interfaces to the NDMA Common Alert Protocol (CAP) system.
    • It has also developed the INCOIS mobile application known as “SAMUDRA – Smart Access to Marine Users for ocean Data Resources and Advisories”.

Why is Japan prone to earthquakes and tsunamis?

• Japan is situated along the ‘Pacific Ring of Fire’, which is the most active earthquake tectonic belt in the world.
  • The ‘ring’ refers to “an imaginary horseshoe-shaped zone that follows the rim of the Pacific Ocean.
  • This is the area where many of the world’s earthquakes and volcanic eruptions occur.
• Within the Ring of Fire, there are different tectonic belts, including the Pacific Plate, Eurasian Plate, and Indo-Australian Plate.
• These plates keep meshing and colliding with each other, causing earthquakes, volcanic eruptions and tsunamis.

2011 Earthquake and tsunami in Japan

• In 2011, Japan was hit by a 9.0 magnitude earthquake and a resulting tsunami which devastated its northeastern coastal communities, killing around 18,000 people and displacing tens of thousands.
• Those tsunami waves led to a nuclear meltdown at the Fukushima power plant, causing the most severe nuclear accident since the 1986 Chernobyl disaster in the Soviet Union.