BACKGROUND Duration and speed of propagation of the pulse are essential factors for stability of excitation waves. We explore the propagation of excitation waves resulting from periodic stimulation of an excitable cable to determine the minimal stable pulse duration in a rate-dependent modification of a Chernyak-Starobin-Cohen reaction-diffusion model. RESULTS Various pacing rate dependent fe...

Wave propagation in disordered (random) media is the underlying theme. Many types of wave propagation problems can most conveniently be analyzed in this framework. Acoustic waves in the earth's crust and shallow water (or surface gravity) waves are two examples. The interaction of sound waves with the heterogeneities in the earth's crust is important in seismology. The interaction of surface gr...

A numerical study is presented of the dynamic response of end-bearing piles embedded in a number of idealized soil deposits and subjected to vertically propagating harmonic S-waves. Results, for both 'kinematic' and 'inertial' interaction, are offered in the form of dimensionless graphs and formulae covering a wide range of excitation frequencies and of crucial material and geometric parameters...

In this study, the effect of deep excavation on the seismic response of RC moment resisting building systems has been studied. Deep excavation can cause significant changes in the stress and strain levels of soil environment and also changes in the propagation of seismic waves. This leads to permanent displacements in the foundation system. In this study, three RC building systems, i.e. 5, 10, ...

An integrated seismic monitoring system with a total of 55 channels of accelerometers is now operating at and in the nearby free-field site of the 20-story steel-framed Atwood Building, in highly seismic Anchorage, Alaska. The building has a single-story basement and a reinforced-concrete foundation without piles. The monitoring system comprises a 32-channel structural and a 21channel site arra...

The propagation of seismic waves in an open borehole is reviewed. The principal wave types are the refracted P and S waves and the two guided waves pseudo-Rayleigh and Stoneley. The dispersion properties of the gUided waves are analyzed. An efficient method of computing synthetic microseismograms is described. The relative effects of the borehole. fluid and formation properties on the propagati...

In this work, an effective technique for the measurement of seismic wave propagation velocity in the real geological medium is presented. The propagation velocities of seismic waves vary in different types of geological media from 100 m/s to 6800 m/s. Due to this, it is necessary to evaluate the propagation of the seismic wave front between the different points in the real media. The signal tim...

High-precision modeling of seismic-wave propagation in heterogeneous media is very important to seismological investigation. However, such modeling is one of the difficult problems in the seismological research fields. For developingmethods of seismic inversion and high-resolution seismic-wave imaging, the modeling problem must be solved as perfectly as possible. Moreover, for long-term computa...

Excitations of seismic background noises are mostly related to fluid disturbances in the atmosphere, ocean and the solid Earth. Earthquakes have not been considered as a stationary excitation source because they occur intermittently. Here we report that acoustic-coupled Rayleigh waves (at 0.7-2.0 Hz) travelling in the ocean and marine sediments, retrieved by correlating ambient noise on a hydro...