The energy required to create tsunami waves is most commonly generated by underwaterearthquakes when tectonic plates suddenly slip along plate boundaries. As tectonicplates push together, the kinetic energy of the moving plates is transformed intopotential energy. This potential energy is stored at the plate boundary.
Over time, the potential energy increases so much that it overcomes the friction between the plates, which has kept them motionless. The plates can very suddenly and violently slide past one another creating earthquakes. As the plates move vertically, they transform the built-up potential energy back into the kinetic energy of movement. The upward movement of the seafloor transfers kinetic energy from the solid earth to the ocean water above. This then gives the water kinetic energy, moving water upwards. When this vertical movement reaches the ocean surface, it can be transformed into waves. These waves begin moving horizontally outward toward shorelines as a tsunami!
As waves move from the deep ocean toward the shore, their wavelengths decrease and amplitudes increase. The kinetic energy of the water is transformed to potential energy, as seen in the height of the wave. In the deep ocean, a portion of the wave energy is kinetic. Tsunamis move up to800 km/h (550 mph). The amplitude of these waves is very low. This is why tsunamiwaves can go right under boats in the open ocean without even being noticed by peopleon board.
As tsunami waves approach the shore, the seafloor causes the waves to slow down. This decrease in speed causes the waves to get closer together and taller. The waves now have a shorter wavelength and greater amplitude. As the wave height increases, the kinetic energy of the water is transformed into potential energy. Eventually, the tsunami washes onto the shore, potentially flooding low-lying areas with the strength to destroy buildings, or even causing lives to be lost.
Predicting Tsunamis
Dr. Titov has dedicated much of his career to developing a system to forecast tsunamis. As a mathematician, he has helped write computer programs with geologists, oceanographers, and other mathematicians which model tsunami formation. He uses data from tsunami events in the past to improve the models.
Vasily also collects data as earthquakes happen around the world. This data, in combination with data collected from DART® buoys, is entered into the tsunami forecast programs that highlight threatened coastal areas. Each time there is an earthquake or landslide in the ocean, he and his team are able to refine the forecasts made by the computer programs.
As more DART® buoys are deployed and faster computers are used, this will help refine the team"s forecast programs. Dr. Titov hopes this will result in a quicker and more accurate warning system that will someday be powerful enough to save every person in the path of a tsunami.
| Most of the data scientists have gathered about the interior of Earth has been collected using our understanding of earthquake waves. Mechanical waves, such as earthquake waves, are affected by the medium through which they travel, and their behavior changes as they move between different mediums. Scientists have found that the P and S waves of an earthquake do not move in a straight line through Earth. Rather, they reflect and refract as they travel through the interior. If no boundaries between the layers of Earth existed, we would not detect any changes in wave direction. This behavior has led scientists to develop a model of Earth"s interior as composed of layers of many different materials. | |