T. S. Murty

Numerical Modeling of Ocean Dynamics

While there are several excellent books dealing with numerical analysis and analytical theory, students and faculty in numerical applications to ocean dynamics have to sift through hundreds of references. This monograph is an attempt to partly rectify this situation. Major chapters (II, III and IV) deal first with the basics and then go on to various applications. Instead of covering the vast field of ocean dynamics, this book focuses on transport equations (diffusion and advection), shallow water phenomena - tides, storm surges and tsunamis; three-dimensional time dependent oceanic motion; natural oscillations; and steady state phenomena. The aim of this book is two-fold; it gives an introduction to the application of finite-difference methods to ocean dynamics, and it also reviews more complex methods.

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.

Numerical simulation of two‐dimensional tsunami runup

Abstract The hydrodynamic and mathematical problems connected with discontinuity between wet and dry domains, nonlinearity, friction, and computational instability are the main problems that have to be sorted out in the runup computation. A variety of runup models are analyzed, including the boundary conditions used to move the shoreline. Based on the initial experiments one‐dimensional and two‐dimensional algorithms are constructed. These models are tested against analytical solutions obtained by others. The extent of inundation along Alaska, British Columbia, Washington, and Oregon coasts caused by the 1964 Alaska earthquake tsunami is well documented. The data gathered at Alberni Inlet, British Columbia, Canada, is used to test the numerical model and the boundary conditions set at the mouth of the inlet. The computed extent of flooding turned out to be in satisfactory agreement with the data obtained from the observations.

Influence of the Size, Shape and Orientation of the Earthquake Source Area in the Shumagin Seismic Gap on the Resulting Tsunami

Abstract The directional properties of tsunamis generated by circular and elongated sources are being studied by means of maximum amplitude contours. For the tsunami source located in the Gulf of Alaska along the Aleutian Islands, the main lobe of energy is directed towards the south and southeast. The time dependent tsunami signal over the shelf and at the open ocean depicts a considerable difference, probably a result of the shelf resonance. Coriolis effects are only noticeable over the shelf regions where the longer period tsunami waves are generated.