On January 19, 1993, a very bright bolide (peak magnitude −23) crossed the sky of Northern Italy, ending with an explosion approximately over the town of Lugo (Emilia Romagna, Italy). The explosion (14 kton of energy) generated shock waves which were recorded by six local seismic stations. A reanalysis of the available data leads us to the hypothesis that the meteoroid was a porous carbonaceous...

We have investigated energy amplification observed within Greater Los Angeles basin by analyzing regional waveforms recorded from several Nevada Test Site (NTS) nuclear explosions. Although the stations are located nearly at the same azimuth (distances ranging from 350 to 400 km), the seismograms recorded in Compton (the central part of the basin), Long Beach (the southern edge of the basin), a...

The shear instability mechanism for generation of surface water waves (Miles 1957) is re-examined in light of the nonnormality of the underlying linear operator. The associated eigenproblem and adjoint eigenproblem are solved numerically and a clarification to previous perturbation solutions of the eigenproblem discussed. The optimal excitation problem is solved in the asymptotic limit t → ∞ an...

geophysical fluids such as atmosphere and ocean often have stable density stratification; hence internal gravity waves are generated and propagated through them which are important in momentum and energy transfer in these media. these waves are also believed to generate layered structures in such media. recently there have been numerous theoretical, experimental and numerical studies on the way...

This paper is concerned with two-dimensional unsteady motion of water waves generated by an initial disturbance created at an ice sheet covering the water. The ice cover is modeled as a thin elastic plate. Using linear theory, the problem is formulated as an initial value problem for the velocity potential describing the motion in the liquid. In the mathematical analysis, the Laplace and Fourie...

We consider exact nonlinear solitary water waves on a shear flow with an arbitrary distribution of vorticity. Ignoring surface tension, we impose a non-constant pressure on the free surface. Starting from a uniform shear flow with a flat free surface and a supercritical wave speed, we vary the surface pressure and use a continuation argument to construct a global connected set of symmetric soli...

Waves generated by aerial and subaerial landslides are studied experimentally, theoretically and numerically. A set of experiments are done in a wave tank of 18 m long, 0.65 m wide and 1.5 m deep. Numerical simulations are in good agreement with the experiments. Based on numerical and experimental results, we derive different scaling laws which show a good agreement with the experiments and the...