How does a tsunami start?
The vast majority of tsunamis form due to earthquakes — specifically tectonic tsunamis. As an earthquake happens, the ground beneath the water is moved up and/or down abruptly and as this movement happens, a mass of water is displaced and starts moving in all directions. This marks the start of a tsunami.
When can a tsunami occur?
Generally, an earthquake must exceed magnitude 8.0 to generate a dangerous distant tsunami. An earthquake must be big enough and close enough to the ocean floor to cause the vertical movement of the ocean floor that typically sets a tsunami in motion. As the ocean floor rises or drops, so too does the water above it.
Where do tsunamis usually start?
the Pacific Ocean
Tsunamis occur most often in the Pacific Ocean and Indonesia because the Pacific Rim bordering the Ocean has a large number of active submarine earthquake zones. However, tsunamis have also occurred recently in the Mediterranean Sea region and are expected in the Caribbean Sea as well.
When was the first tsunami in the world?
479 BC
The oldest recorded tsunami occurred in 479 BC. It destroyed a Persian army that was attacking the town of Potidaea in Greece. As early as 426 BC, the Greek historian Thucydides inquired in his book History of the Peloponnesian War (3.89. 1–6) about the causes of tsunamis.
What are the 3 types of tsunamis?
Tsunami – Information Page
- Distant tsunami: Are generated from a long way away, such as from across the Pacific in Chile.
- Regional tsunami: Are generated between one and three hours travel time away from their destination.
- Local tsunami: Are generated very close to New Zealand.
Who first discovered tsunamis?
The oldest recorded tsunami occurred in 479 BC. It destroyed a Persian army that was attacking the town of Potidaea in Greece. As early as 426 BC, the Greek historian Thucydides inquired in his book History of the Peloponnesian War (3.89. 1–6) about the causes of tsunamis.