What is a tsunami?

  • A tsunami, a term derived from Japanese that translates to “harbour wave”, is a sequence of massive sea waves triggered by undersea earthquakes or volcanic eruptions.
  • When an earthquake occurs beneath the ocean, it can cause a significant portion of the seafloor to shift upwards or downwards abruptly, displacing a substantial amount of water and generating tsunami waves.
  • A similar phenomenon can occur when a volcano erupts underwater. The lava expelled from the volcano displaces the surrounding water, which can form a large wave.
  • According to a NASA report, large tsunamis typically originate in the deep ocean, where a significant volume of water can be displaced. As the wave approaches the shore, it increases in height due to the decreasing depth of the ocean.
  • Tsunami waves can reach heights of hundreds of feet and can move at speeds comparable to jet aircraft over deep waters, though they slow down upon reaching shallower waters.
  • However, it’s important to note that not all earthquakes or volcanic eruptions result in tsunamis. The creation of a tsunami is influenced by several factors, including the configuration of the ocean floor and the distance and direction of the earthquake.

Why is Japan prone to earthquakes and tsunamis?

  • Japan’s geographical position along the ‘Pacific Ring of Fire’, the world’s most seismically active tectonic belt, is the reason for its frequent seismic activity.
  • The ‘Ring of Fire’ is an imaginary zone shaped like a horseshoe that traces the edge of the Pacific Ocean, and it is the site of many of the world’s earthquakes and volcanic eruptions, as reported by Live Science.
  • The Ring of Fire comprises various tectonic plates, including the Pacific Plate, Eurasian Plate, and Indo-Australian Plate. These plates continually interact and collide with each other, resulting in earthquakes, volcanic eruptions, and tsunamis.
  • In 2011, Japan experienced a devastating 9.0 magnitude earthquake, which triggered a tsunami that wreaked havoc on its northeastern coastal communities. The disaster claimed the lives of approximately 18,000 people and displaced tens of thousands.
  • The tsunami waves also caused a nuclear meltdown at the Fukushima power plant, marking the worst nuclear incident since the Chernobyl disaster in the Soviet Union in 1986.