the mixture of natural and artificial seismic sources with random distributions cause diffuse wave field with random amplitudes and phases called noise. when noise is analyzed in a long-term process, it contains surface waves which are spread in all directions. thus, ambient noise contains data relevant to the surface waves. in recent years, as broadband seismic networks have been distributed v...

Structural Health Monitoring (SHM) is a multidisciplinary technology devoted to development and implementation of methods and systems that realize inspection and damage detection by integration with structures. This chapter covers the major SHM disciplines which are based on topics such as piezoelectric transducers, elastic waves propagation phenomenon, phased array techniques, damage mechanics...

RAYLEIGH waves from the Solomon Islands earthquake of July 29, 1950, recorded at Honolulu, Berkeley, Tucson, and Palisades are analyzed. Both the direct waves and those propagated through the Antipodes were observed for all stations except Honolulu. Application of a correction for land travel results in a dispersion curve for the oceanic portion of the path. It is found that the observed disper...

Aims. We suggest an explanation for the high-frequency power excess surrounding active regions known as seismic halos. Methods. We use numerical simulations of magneto-acoustic wave propagation in magnetostatic sunspot model. Results. We propose that seismic halos can be caused by the additional energy injected by high-frequency fast mode waves refracted in the higher atmosphere due to the rapi...

Among numerous sources emitting pressure waves a few are known to generate acoustic signals both in the earth, as seismic waves, and in the atmosphere, as infrasound, which were recorded over large distances. Those sources are near surface phenomena like volcanic eruptions, explosions, and ocean waves, which all occur at the boundary between the solid earth and the atmosphere, either shallow ab...

The purpose of this work is to present and analyze the results of numerical simulations related to the application of three different mathematical models in the acoustic seismic wave propagation in which only compressional waves (P-waves) are contemplated. And present the results of an investigation about how these wave equation implementations can influence the amplitudes of a migrated section...

We adopt the frozen Gaussian approximation (FGA) for modeling seismic waves. The method belongs to the category of ray-based beam methods. It decomposes seismic wavefield into a set of Gaussian functions and propagates these Gaussian functions along appropriate ray paths. As opposed to the classic Gaussian-beam method, FGA keeps the Gaussians frozen (at a fixed width) during the propagation pro...

In order to systematically reveal the dynamic response characteristics of rock mass slopes subject seismic excitation, time-domain and frequency-domain analyses are used investigate a bedded slope from multiple perspectives, using two-dimensional numerical analyses. Based on simulation results, influence weak structural planes propagation waves in is analyzed. The analysis suggests that topogra...

The way fractures affect seismic waves depends on fracture mechanical parameters, such as compliance and saturating fluid, and on their geometric properties, such as dimensions and spacing. When fractures are small relative to the seismic wavelength, waves will be weakly affected by fractures, and in effective medium theory, a zone comprised of many small fractures is equivalent to a homogeneou...