A.2. Tsunami

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A.2. Tsunami

A tsunami is a powerful and destructive natural phenomenon that occurs primarily in coastal areas. It is a series of ocean waves triggered by large-scale disturbances, typically earthquakes, underwater volcanic eruptions, or landslides.

The key elements and processes involved in the concept of a tsunami

Triggering Event	The most common trigger for a tsunami is an undersea earthquake. When the Earth’s tectonic plates move and shift along a fault line beneath the ocean floor, it can cause a sudden release of energy. This energy propagates through the water column, displacing a massive amount of seawater and generating powerful waves.
Wave Generation	The seismic energy released by an undersea earthquake or other triggering event creates initial waves known as “tsunamigenic waves” or “seismic sea waves.” These waves can travel at high speeds across the ocean, typically reaching velocities of several hundred kilometers per hour.
Wave Characteristics	Tsunamis are characterized by their long wavelengths, which can extend for hundreds of kilometers, and their relatively low wave heights in the deep ocean. While the height of a tsunami wave might be only a few meters, it carries an enormous amount of energy due to its massive volume of water.
Deep Ocean Propagation	In the deep ocean, tsunamis have a relatively low wave height and are hardly noticeable on the surface. Their long wavelengths enable them to travel great distances with minimal energy loss. As they propagate, the speed of a tsunami decreases while the wave amplitude (height) increases, particularly as it approaches shallower water.
Arrival at the Coast	As the tsunami approaches the coastline and encounters shallow water, the wave’s speed decreases even further, causing the wave height to increase dramatically. The leading edge of the tsunami can appear as a rapidly rising wall of water, often resulting in a sudden and devastating flood.
Inundation and Destruction	When a tsunami makes landfall, it can cause catastrophic damage due to its immense energy and the large volume of water it carries. The powerful surge of water can flood coastal areas, demolish structures, uproot trees, and sweep away everything in its path. The destructive force of a tsunami can be amplified by factors such as coastal topography and the presence of built infrastructure.
Multiple Waves	Tsunamis often arrive in a series of waves, with the initial wave not necessarily being the largest. Subsequent waves can continue to arrive for several hours, making it dangerous for people in affected areas to return prematurely, as the threat persists.

Due to the devastating nature of tsunamis, early warning systems, coastal monitoring networks, and public education programs have been established in many at-risk regions. These efforts aim to provide timely alerts and information to coastal communities, enabling them to evacuate and seek higher ground in the event of an approaching tsunami.