Tsunamis

What are tsunamis?

• Tsunamis are different from other waves in that they are normally caused by underground disturbances such as earthquakes.
• These are geological events brought about by earthquakes, submarine volcanic eruptions, landslides, or even asteroid impacts.
• Wavelengths of tsunamis are so long that they can travel amazing velocities across ocean basins.
• These waves can also strike the shore and are dangerous for hours, sometimes like walls of water.

Properties of Tsunami

• Tsunamis belong to shallow water waves for the simple reason that they possess really long wavelengths. The time period between any two waves of the tsunami varies from 10 minutes to 2 hours.
• Tsunamis in deep water travel at speeds up to 550 mph- 890 km/h, equaling the speed of a jet aeroplane.
• A tsunami is not a single wave; rather, it comes in series of waves that reach the shore at different intervals.
• The shoaling effect converts the very minor waves to giant surges.
• Because of long wavelengths, tsunamis travel with less energy loss and can cover significant distances without losing strength.

Sources of Tsunami

• Earthquake:
  • They originate because of displacement that takes place along the fault zones on the boundaries of plates.
• Landslides:
  • Nearshore landslides push much water into the water, stir it up, and generate a tsunami.
• Volcanic Explosion:
  • Tsunamis caused by volcanic explosions are very destructive as huge amounts of water are displaced.
• Impact of Cosmic Body:
  • Tsunami triggered by asteroid or meteor impacts is very rare, yet it is catastrophic.

Formation of Tsunami

• Displacement of water along massive geological event sets off a series of waves.
• Those huge waves then break on the shores leading to massive flooding.
  Giant waves from the ocean converge on the shores to pour in a huge flood.
• The Pacific Ocean and all its bordering seas are hit by much more frequent and, probably, larger, destructive tsunamis because of the already huge numbers of large earthquakes that are characteristic of its own margins.

Tsunami Impacts

• Injury and death:
  • tsunami waves are strong enough to wash off whole communities.
• Infection:
  • in tsunami-devastated areas, flooding and contaminated water will likely spur spreading infections.
• Environment:
  • a tsunami would have reduced the numbers of the insects, animals, plants, and natural resources.
• Costly:
  • Reconstruction and cleaning take extra money.
• Psychological Impact:
  • There are psychological problems from the people affected by the tsunami for days, years, or even permanently for some people.
    

Tsunami Risk, Hazard & Mitigation Measures

These are proactive measures such as advanced early warning systems, planning evacuations, public awareness initiatives.