One of the most destructive powers on Earth is water. It can cut rock, erode mountains, smash buildings, and leave utter devastation in its wake. Tsunamis have historically been some of the worst natural disasters human communities have faced, and there’s not a lot we can do to soften the blow when they strike. To understand more about them, let’s look at what causes a tsunami in the first place:
1. When the earth moves, a domino effect is triggered.
The trigger for a tsunami can be an earthquake, volcanic eruption, or an underwater landslide. Each of these events involves earth moving suddenly and with force. Earthquakes that happen under the ocean floor can generate massive waves, as can volcanic eruptions when they dump large volumes of material into the ocean. These waves then turn into tsunamis.
2. The ocean presents a wide expanse where momentum can gather.
How exactly does one event create a wave that can decimate a city? Think about the open ocean. It stretches for miles not only from coast to coast, but also from the surface to the deep. There are no obstructions that take momentum away from the building wave, allowing it to grow to incredible sizes.
3. When a wave reaches a shoreline, it breaks.
The growing wave will continue to gain energy until it finds an island, where the sea floor rises. This rise causes the tsunami wave to gain amplitude (height) in order to conserve energy, resulting in the huge and powerful waves we associate with tsunamis.