Daily Dose of Destruction
Not only are earthquakes dangerous because of all the shaking that they do, but earthquakes also can produce one of the most powerful and deadly forces on Earth, tsunamis. A tsunami is an energetic wave caused by earthquakes, landslides, and underwater volcanic eruptions. When an earthquake hits under water, it can produce a landslide, or when a volcano erupts under water or collapses into water, water is displaced. Imagine yourself doing a belly flop into a calm, still pool. The reason waves are generated is because your body displaced or moved water out of the way to make room for you. The energy of you falling into the water is transferred to the water molecules and one molecule after another receives that energy. When an earthquake breaks at a fault line in the ocean, if it displaces water, then a tsunami will be generated. Seiches are lake tsunamis or large waves in lakes. Seiches can also be caused by heavy and prolongued winds on lakes.
Tsunamis can travel thousands of miles. In the open ocean you might not even feel or see the tsunami. The energy doesn't create a big wave until it gets closer to the shore line. Sensitive instruments found in the oceans near many countries can detect the energy, thereby having time to sound a tsunami warning. Tsunamis can reach 30 meters high, but there have been a few that are much much taller. Many times the ocean will recede from the shore giving a warning itself that a tsunami is on its way. Below is a video that does a great job explaining how a tsunami is formed.
Below is a list of four of the largest tsunamis to have ever been witnessed.
- Lituya Bay Alaska
- Caused part of a mountain collapsing into the bay.
- Estimated at 1720 feet, about a quarter of a mile high. Knocked trees down half way up some of the mountains.
- Spirit Lake Washington
- 853 feet
- Caused by Mount St. Helens eruption landslide
- Shoup Bay, Alaska
- Sanriku Japan
- 125 feet
- Caused by an 8.5 magnitude Earthquake
- Killed 22,000
- Two different powerful waves hit during a celebration
- Boats out in the ocean didn't even noticed. Next morning they came to shore to discover the horrific scene.
- 30 foot waves hit Hawaii killing people there as well.
Below is a documentary of the 2004 Boxing Day Tsunami that killed 250,000 people. The video contains stories of some survivors who videotaped much of it.