A tsunami is a series of giant ocean waves caused by something suddenly moving a huge amount of sea water — usually an underwater earthquake, but sometimes an undersea volcano or landslide. The word "tsunami" comes from Japanese and means "harbour wave".
Out in the deep ocean, a tsunami might be only a metre tall but it travels incredibly fast — up to 800 kilometres per hour, as fast as a jet plane! When it reaches shallow water near the coast, it slows down and the water piles up into enormous waves that can be taller than a house.
The 2004 Indian Ocean tsunami washing over a street in Ao Nang, Thailand. This photo was taken as the wave came ashore on December 26, 2004. See source ↓
⚠️ Nature's warning signs
Before a tsunami, the sea sometimes pulls back far from the shore, leaving the sea floor bare — this is a huge warning to run to high ground! Animals often sense danger too; in 2004, elephants in Thailand ran uphill before the waves arrived.
📜 A bit of history
After a terrible tsunami hit Hawaii in 1946, countries around the Pacific Ocean worked together to build a tsunami warning system. Today, special buoys floating in the ocean can feel a tsunami passing underneath and radio a warning to shore, saving many lives.
📚 Picture Sources
- Photo 1 — The 2004 tsunami at Ao Nang, Thailand. From Wikimedia Commons (CC BY-SA 2.5): https://commons.wikimedia.org/wiki/File:2004-tsunami.jpg
