Storm surges in the marginal seas of the North Indian Ocean

One of the major natural marine hazards on the globe is the storm surge phenomenon. Large storm surges with amplitudes of up to several meters generated by tropical cyclones occur in many areas of the world, including the Gulf of Mexico and the Northern Indian Ocean. The storm surges in the marginal seas of the North Indian Ocean are discussed here. These marginal seas include the Bay of Bengal, the Arabian Sea, the Persian (Arabian) Gulf and the Red Sea. Since storm surge prediction also involves tides, some tidal regimes are also discussed. Finally, some comments are made on the possible influence of the greenhouse warming and the El Niño phenomenon on storm surges. (AU)

Storm surges in Canadian waters

Storm surges in various Canadian waters are reviewed. Following a brief discussion of the weather systems that cause surges in Canadian coastal and inland waters, the mathematical formulations to describe the development of storm surges are given. In reviewing storm surges in the different Canadian waters, particular attention is given to describe the influence of the presence of sea ice on surge development and the impact of shallow coastal areas, where the coastline configuration is itself changed by the surge, on inland penetration of the east and west coasts, the Beaufort Sea, the Gulf of St. Lawrence and the St. Lawrence estuary, Hudson Bay and the Great Lakes.(AU)

Tsunami amplification due to resonance in Alberni inlet : Normal modes

One of the best examples of tsunami amplification due to resonance is at Port Alberni which is located at the head of Alberni Inlet on Vancouver Island on the Pacific Coast of Canada. During the 1964 Alaska earthquake tsunami, the tsunami amplitude at Port Alberni was two to three times greater than the tsunami amplitude at Tofino, which is located close to the open coast. This remarkable amplification of the tsunami as it travelled a distance of about 65 km through the Alberni Inlet cat be explained by the fact that periods of the normal modes of the Alberni Inlet system agree closely with the dominant periods in the tsunami wave form from the Alaska earthquake tsunami as it reached the continental shelf off Vancouver Island (AU)

Storm surge mitigation through vegetation canopies

The paper of Reid and Whitaker (1976) on the effects of a vegetation canopy on flow of water is re-examined. Their assumptions on the equality of various drag coefficientes are replaced by more realictic calculations. A new method for calculating wind stress on water is presented for the case when the vegetation extends above the water surface. For the case of vanishingly small water depth, it is shown that the horizontal stress is approximately constant in the vertical. This results in a diagnostic relationship for the water current as a function of the wind stress and bottom roughness. A new expression for the vetically average frictional force per unit mass is derived on the assumption that the friction velocity varies linearly with height. The vertical rate of change of friction velocity depends on the mean water current, the wind stress, the bottom roughness, and the water depth. This work has a possible application in the mitigation of storm surges.(AU)

Simulation of tsunamis from great earthquakes on the cascadia subduction zone.

Large earthquakes occur episodically in the Cascadia subduction zone. A numerical model has been used to simulate and assess the hazards of a tsunami generated by a hypothetical earthquake of magnitude 8.5 associated with rupture of the northern sections of the subduction zone. Wave amplitudes on the outer coast are closely related to the magnitude of sea-bottom displacement (5.0 meters). Some amplification, up to a factor of 3, may occur in some coastal embayments. Wave amplitudes in the protected waters of Puget Sound and the Strait of Georgia are predicted to be only about one fifth of those estmated on the outer coast.

Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos.

Micro-indentation hardness studies on human bones.

Bones from different portions of human skeleton are polished and cut to suitable sizes and then subjected to micro-indentation at various loads using Vicker's diamond pyramidal indenter. The Vicker's hardness number is found to differ slightly from portion to portion of the skeleton. Interferometric studies of the indentation reveal that the applied stress of indentation causes a 'pile-up' of material near the corners of the pyramidal indents.