Tsunamis derive their name from the Japanese for "harbor wave"
If an impact were to occur, three out of every four would hit the oceans. Any extraterrestrial fireball can open a depression of tens of kilometers in length, and can be as deep as five kilometers, reaching the ocean floor.
When impacting balls hit the floor, the water is emitted at a very high speed, and the seabed is cracked and melted. Because of the heat of the fireball, an immense amount of steam (vaporized water) is released into the atmosphere increasing the temperature by thousands of degrees. When the fireball stops breaking into the ocean floor, the water shoots back into its place as a wave over five kilometers high. As the wave approached the center of the circular cavity, the speed is accelerated and waves from every direction collide, forming a huge surge that shoots up water higher than the highest mountains of the planet. Finally, the sea calms down, causing huge ripples.
Tsunamis have an average speed of 750 kilometers per hour, which is nearly two-thirds of the speed of sound traveling in air. The ocean impels these huge monsters in immense heights and distance because the waves spread out in two dimensions, in a circular motion, and there is almost no loss of energy for there is no friction.
Tsunamis can be traced in history in many areas surrounding the Pacific Ocean. For example, on August 26, 1883, the Krakatau volcano in Indonesia exploded raising a 40-meter wave killing forty thousand people. Fishing boats in the harbor of Calcutta, India were sunk by the tidal waves nine hours later. A very famous site of tsunamis, are the islands of Japan. Dating back from the year 869, the Japanese people have kept records of the tsunami impacts. Some records of tsunamis include the years, 1293, 1611, 1703, 1717, 1854, 1896 and 1939, killing hundreds of thousands of citizens.
The Pacific Ocean has favored tsunamis because the Pacific Basin is surrounded by the area known as "the ring of fire," where volcanic activities are very common due to the subduction zones of plates.
However, these huge water monsters are not only present around the Pacific basin. Impacts due to earthquakes have pulled tsunamis into Jamaica, Portugal, Spain, Morocco, and in the Leeward Islands. Recently, in 1992, an earthquake off the coast of Nicaragua sent a 1 ½-meter at the port of San Juan del Sur, and an earthquake in Flores Island sent a tsunami over a populated area in Indonesia. In 1993, a 30-meter tsunami destroyed the town of Aonae, Japan.