Causes of Tsunami: Waves, and Impacts

The term Tsunami has been derived from the Japanese term Tsu meaning ‘harbour’ and tsunami meaning ‘waves’. A tsunami refers to a series of large waves usually noticed on sea or ocean surfaces that can lead to a considerable amount of loss of life and property. 

It is a sudden displacement of water that can take place in any waterbody if underlying Causes of Tsunami are present there. These waves can travel across entire ocean basins and, upon reaching coastal areas, can Causes of Tsunami significant damage. Phenomena such as Earthquakes, landslides,  volcanic eruptions or large meteoroid impacts result in sudden displacement of ocean water.

Key Points About Tsunamis: Causes, Characteristics, and Impact

• Causes of Tsunami: Faults, Landslides, and Volcanic Eruptions

The geological movements that Causes of Tsunami are produced in three major ways:

1. 1. Fault movements on the seafloor, accompanied by an earthquake Causes of Tsunami.
   2. Landslides either occurring underwater or originating above the sea.
   3. Volcanic activity near the shore or underwater such as in 1883, the violent explosion of the Krakatoa in Indonesia, produced a tsunami measuring 40 meters which crushed Java and Sumatra.

• General Characteristics of Tsunami: Shallow Water Waves and Coastal Impact
  • Dynamics of Ocean Waves: The speed of waves in the ocean depends upon the depth of the water. 
    • • It is more in the shallow water than in the deep ocean. 
      • As a result of this, the impact of tsunami is less over the ocean and more near the coast
      • When a tsunami enters shallow water, its wavelength gets reduced and the period remains unchanged, which increases the wave height. 
      • Sometimes, this height can be up to 15m or more, which Causes of Tsunami large-scale destruction along the shores. Thus, these are also called Shallow Water Waves.
      • The impact of tsunamis is less over the ocean and more near the coast.
  • Tsunami Hotspots: Tsunamis are frequently observed along the Pacific Ring of Fire, particularly along the coast of Alaska, Japan, the Philippines and other islands of Southeast Asia, Indonesia, Malaysia, Myanmar, Sri Lanka, and India.
  • Destructive Force of Tsunami Waves: After reaching the coast, the tsunami waves release enormous energy.
    • • • Water flows turbulently onto the land destroying port cities, structures, buildings and other settlements.

Adverse Effects of Tsunami: Swift Impact, Flooding, and Disruption

• Swift and Devastating Impact: Local tsunami events or those less than 30 minutes from the source Causes of Tsunami the majority of damage.
• Flooding: During tsunamis Causes of Tsunami major destruction to the human settlements, roads and infrastructure.
  • Waves withdraw back to the ocean, sweep out the foundations of the buildings, and houses carried out to sea.
• Disruption of Ports and Airports: Damage to ports and airports may prevent the importation of needed food and medical supplies.
• Drowning and Physical Trauma: Drowning deaths occur as people are either washed away or crushed by giant waves and debris during tsunamis.
  • Basic civic facilities get hampered such as unavailability of drinking water, Damaged Sewage pipe etc.
  • May lead to crop loss, loss of livelihood like boats and nets, environmental degradation etc.

Risk Reduction Measures: Walls, Education, and Global Collaboration

• Tsunami walls: Such as Japan tsunami walls of up to 4.5m (13.5 ft) high in front of populated coastal areas.
• Flood gates and channels:  To redirect the water from incoming tsunamis.
• Site Planning and Land Management: It is an important tool in reducing tsunami risk.
• Educate the community about good construction practices such as
  • Avoid building or living in buildings within several hundred feet of the coastline.
  • Construct the structure on a higher ground level with respect to mean sea level.
  • Elevate coastal homes.
  • Construction water breakers to reduce the velocity of waves.
  • Use of water and corrosion-resistant materials for construction.
  •  Construction of community halls at higher locations, which can act as shelters at the time of a disaster.
• Flood management to mitigate flooding resulting from a tsunami.
• International Efforts and Collective Solutions: 
• The mitigation of hazards created by tsunamis is difficult.
• It is beyond the capacity of individual states or governments to mitigate the damage. 
• Hence, combined efforts at the international level are the possible ways of dealing with these disasters.
• Thus, understanding the nature and behavior of tsunamis is crucial in developing effective early warning systems and preparedness strategies to mitigate the devastation Causes of Tsunami by these powerful ocean waves.

DOWNLOAD PDF