When it reaches shore waters, they rise to form masses of moving water known as “run-up”. This phenomenon is very many feet high and its variation depends on the strength of striking waves (NOAA, 2009). Normal run-up height is about 30 meters high although there are some extra high run-ups such as that witnessed in Alaska in 1958 which went up to 60 meters high. Run-up rush onto the sea shore and strikes the coastal areas with an intensive, destructive force. Huge earthquakes are able to send tsunami waves across oceans. For instance, recent earthquakes in both Japan and Chile send tsunami waves which struck Alaska, Hawaii, Oregon, California, and Washington causing enormous losses of life and property. Water masses subjected to tsunami waves can take hours to regain stability hence tsunami effects can experienced repeatedly.
Tsunami waves occur in phases called first, second and even the third waves. First waves are always less destructive but the second and third may have catastrophic effect depending on the magnitude of causing forces and the position of origin (NOAA, 2009). Tsunamis have very long waves and crest to crest distance may be anywhere between 10 and 2500 kilometers. It travels through the sea at a speed more than 700 km/h. A series of waves travel and arrive at the sea shore at an interval of few minutes. In most cases, tsunami waves are not noticeable like normal sea waves and tides but it possess large amount of energy than other waves. Due to its influence to entire water column, depth of water determines its force (Nelson, 2012). The long wavelengths make the first sign of tsunami waves at the sea shores to be a drawback.
Tsunami is caused by submarine earthquake, landslide, volcanic eruption or meteorites (CA, 2009). These causes have common characteristics because they occur suddenly and violently which make them to displace large amounts of water.