Japan earthquake triggers tsunami warning: What is a tsunami, why does it keep forming in the island country?
Context- On Monday (January 1), a 7.6-magnitude earthquake rattled the north-central region of Japan, triggering tsunami waves that impacted various coastal areas of the country. In response, immediate evacuation alerts were disseminated. In a broadcasted speech, Japan’s Prime Minister Fumio Kishida urged residents to adhere strictly to the evacuation directives and cautioned that the initial earthquake and tsunami might be followed by even stronger ones.
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.
