Tsunamis are massive ocean waves caused by sudden underwater movements, often triggered by earthquakes, landslides, or volcanic eruptions. These waves can grow to enormous sizes as they reach the coast, causing catastrophic damage and loss of life. The warning signs of a tsunami include a sudden and unexpected withdrawal of the sea, exposing large areas of beach and coastline. It is essential to recognize these signs and act quickly to save lives. The most accurate warnings come from tsunami warning centers, which can detect seismic waves and alert coastal residents.
Here are the key facts from the text:
1. Tsunamis are sudden and unexpected natural disasters that can grow to the size of a multi-story building and destroy everything in their path.
2. Tsunamis are not caused by monsters or popular film creatures, but by ordinary sea water that suddenly gathers into a massive wave.
3. The word "tsunami" comes from Japanese and means "wave in the harbor".
4. In the open ocean, tsunamis are usually no higher than a meter or 3.3 feet, but they can reach lengths of 100-200 kilometers or 60-120 miles.
5. Tsunamis can travel at speeds of up to 880 kilometers per hour or 547 miles per hour.
6. Tsunamis are caused by a sudden and powerful impulse from underwater, often triggered by an earthquake, volcanic eruption, landslide, or other event.
7. The main culprit behind tsunamis is seismic activity, which is responsible for 88% of all tsunamis.
8. Tsunamis can produce waves that are thousands of times larger than ordinary waves.
9. The driving energy of a tsunami passes through the water, not on top of it, making 95% of its life cycle invisible to the eye.
10. Tsunamis can be triggered by various events, including earthquakes, volcanic eruptions, landslides, and even asteroids impacting the water.
11. The world's largest tsunami occurred in Alaska, caused by 90 million tons of rock and ice falling into the bay, creating a wave that shot up 524 meters or 1720 feet into the air.
12. Tsunamis can be caused by human activities, such as underwater atomic bomb tests.
13. The rarest cause of tsunamis is asteroids with a diameter of more than one kilometer falling into the water.
14. The deadliest tsunami on record occurred near the island of Sumatra in 2004, claiming more than 200,000 lives.
15. The energy released by the earthquake that triggered the 2004 tsunami was equivalent to 20,000 atomic bombs.
16. The Pacific Ocean area known as the "Ring of Fire" is the most prone to tsunamis.
17. Even in areas prone to tsunamis, small waves usually occur no more than four times a year, and record-breaking waves occur only once a decade.