Tsunamis, capable of devastating entire settlements, originate from subtle water fluctuations in the ocean, and here are eight lesser-known facts about waves. These facts cover various aspects, from the highest recorded wave to the energy they carry and the science behind their formation.
The highest wave ever recorded at sea was measured at 29.1 meters (approximately 95 feet) by the British vessel “Discovery” in the Atlantic Ocean in 2000. This remains the maximum recorded height for a wind wave in the open ocean.
The highest tsunami in recorded history reached a staggering height of 520 meters (1706 feet) in Lituya Bay, Alaska, on July 9, 1958. Triggered by an earthquake and subsequent landslide, approximately 30 million cubic meters of rock plunged into the bay, creating a colossal splash. This immense wave swept trees from the mountainsides.
The most devastating tsunami in terms of human life occurred on December 26, 2004, off the coast of Indonesia, claiming an estimated 230,000 lives. Caused by a powerful earthquake, the tsunami traversed the entire Indian Ocean, reaching the shores of Africa, thousands of kilometers from the epicenter, resulting in casualties even there.
Tsunamis can travel at an average speed of approximately 720 km/h (447 mph) at a depth of 4 kilometers (2.5 miles). In the open ocean, a tsunami’s height is only tens of centimeters, and its length extends up to hundreds of kilometers, often making it go unnoticed. The wave becomes dangerous as it nears the shore, slowing down and rising sharply into a wall of water. For example, the 2004 tsunami took 8.3 hours to travel from Indonesia to Africa.
Tidal waves, one of the longest waves in the world, constantly move across the planet’s surface, reaching lengths of up to 20,000 kilometers (12,427 miles). These waves are caused by the gravitational pull of the Moon and influence the Earth’s rotation, causing low and high tides.
Ocean waves carry an immense amount of energy, with approximately 2 trillion watts reaching the shores of the seas daily. This amount is roughly equivalent to the total energy generated by all the power plants worldwide.
The growth and decay of waves are influenced by their “age,” which is determined by the ratio between the wave’s speed and the tailwind speed. Waves moving at 78% of the tailwind speed stop growing. “Young” waves (with an age of 0.4-0.5) gain strength the fastest, while “old” waves (above 0.8) gradually fade.
Waves turn into foam when they reach a steepness of 1:7, meaning their height is one-seventh of their length. At this point, the crest becomes unstable and falls forward, creating surges, areas of water with white foam and eddies that occur when a wave breaks.