TSUNAMI

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TAG: GS 1: GEOGRAPHY

THE CONTEXT: Recently, the Tsunami waves hit several parts of Japan’s coastal areas and urgent evacuation warnings were issued after a 7.6-magnitude earthquake shook the country’s north-central region.

EXPLANATION:

Tsunami:

• Tsunami, derived from the Japanese term “harbour wave,”.
• It represents a series of massive ocean waves primarily triggered by seismic activities such as earthquakes or volcanic eruptions occurring beneath the ocean.
• Seismic events, including earthquakes or volcanic eruptions, create a sudden shift in the ocean floor, causing significant displacement of water.
• When an earthquake occurs underwater, the movement of the ocean floor leads to the displacement of a large volume of water, thus generating tsunami waves.
• Similarly, volcanic eruptions can also displace water, resulting in the formation of large waves.

Characteristics of Tsunamis:

• Initially emerging in the deep ocean, tsunami waves gain height and momentum as they approach shallow waters near the shore.
• These waves can reach towering heights, often hundreds of feet, and travel at high speeds comparable to jet planes over deep oceanic expanses.
• However, their speed diminishes upon reaching shallower coastal areas.

Factors Influencing Tsunami Formation:

• Not all seismic activities cause tsunamis, as the formation depends on various factors.
• These include the depth of the earthquake’s occurrence, the nature of the seafloor, the distance and direction of the earthquake from the coastline, and the magnitude of the seismic event.

Japan’s Proneness to Earthquakes and Tsunamis:

• Japan’s geographical location places it along the ‘Pacific Ring of Fire,’ a seismic hotspot marked by frequent tectonic movements and high volcanic activity.
• The ‘Ring of Fire’ encompasses an expansive area along the Pacific Ocean where significant earthquakes and volcanic eruptions occur.
• Within the ‘Pacific Ring of Fire,’ Japan experiences the convergence of several tectonic plates, including the Pacific Plate, Eurasian Plate, and Indo-Australian Plate.
• The constant collision and interaction of these plates create seismic instability, leading to earthquakes, volcanic eruptions, and subsequent tsunamis.

Historical Impact on Japan:

• Japan’s susceptibility to earthquakes and tsunamis has had devastating consequences historically.
• The 2011 Tohoku earthquake, measuring 9.0 magnitude, triggered a massive tsunami that ravaged northeastern coastal regions.
• It claimed approximately 18,000 lives, displaced tens of thousands, and caused severe damage.
• The resultant tsunami also led to the Fukushima nuclear disaster, marking one of the most significant nuclear accidents globally.

Conclusion:

• The occurrence of earthquakes and consequent tsunamis in Japan, primarily attributed to its location along the ‘Pacific Ring of Fire,’ underscores the country’s vulnerability to seismic events.
• Understanding the geological dynamics, coupled with the impact of historical tsunamis, emphasizes the critical need for preparedness, early warning systems, and strategic measures to mitigate the devastating effects of such natural disasters on Japan’s coastal communities.

SOURCE: https://indianexpress.com/article/explained/everyday-explainers/japan-tsunami-earthquake-9090621/