Japan earthquake triggers tsunami warning

What’s in today’s article?

• Why in news?
• What is tsunami?
• Tsunami preparedness in India
• Why is Japan prone to earthquakes and tsunamis?
• 2011 Earthquake and tsunami in Japan

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.

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.

Q1) What is National Disaster Management Authority (NDMA)?

The National Disaster Management Authority (NDMA) is India's top body for disaster management. The NDMA was established on December 23, 2005, and is led by the Prime Minister of India.

Q2) What is Indian National Centre for Ocean Information Services (INCOIS)?

The Indian National Centre for Ocean Information Services (INCOIS) is an autonomous body under the Ministry of Earth Sciences (MoES). It was established in 1999 and is located in Pragathi Nagar, Hyderabad. INCOIS's role is to monitor and manage ocean-related events and provide information to stakeholders.

Source: Japan earthquake triggers tsunami warning: What is a tsunami, why does it keep forming in the island country? | India Environment Portal | PIB