“
“Tsunami are commonly caused by undersea earthquakes that displace the seafloor, resulting in a disturbance at the ocean surface. The volume of water displaced now has potential energy to be transferred away from the source. Because the vertical seafloor displacement results in the deformation of the overlying water surface, large earthquakes (with moment magnitude MW>7MW>7) have the potential for generating tsunami. Surface waves in the ocean are characterised by periods of seconds and wavelengths of about 10–100 m. Tidal movement is characterized by a time scale of 12 h and a wavelength set by the size of the local basin (e.g., 100 km).

In comparison, the typical period and wavelength of a tsunami Z-VAD-FMK cell line are intermediate, between ocean waves and tides (e.g., 2400 s). Moreover, the characteristics of tsunami change significantly as they propagate across oceans, with amplitudes of a few centimetres offshore and wavelengths tending to be much longer than the water depth (e.g., 200 km). When they move into the coastal region, the wavelength decreases significantly (e.g., 20 km) and the wave height increases, sometimes reaching 10–15 m. The energy of a tsunami is conserved as they move towards the coast because the dissipation caused by drag on the ocean floor is negligible. In most inhabited coastal regions

the slope of Gemcitabine solubility dmso the land is small, and 15 m of height corresponds to a large distance inland (e.g., 1.5 km for 1:100). The potential for ingress into land and damage to infrastructure is http://www.selleckchem.com/products/AZD6244.html significant. A variety of wave forms and wave trains have been observed in the past, with either leading elevated waves or leading depressed waves. A measure of the potential for an incident wave to ingress inland is the runup height R ( Fig. 1). Runup is defined as the maximum inundation point above

sea level of a wave incident to a beach. It is extensively used, compared to other wave characteristics, as an indicator of a wave’s potential coastal impact. Given the difficulty of incorporating complex bathymetry and coastal features in numerical models, simplified runup expressions are used for example within the insurance and risk assessment community to estimate the coastal impact of tsunami. A critical review of the runup relationships shows that several approaches have been used to develop runup equations. Some existing studies (e.g., Plafker, 1965) have tried to relate runup to the initial disturbance that creates a tsunami, such as the vertical displacement of the sea floor. However, most past studies have correlated runup with the wave amplitude; the latter parameter being determined mainly through experiments or in a few cases from historical data.