Search results for "Seismic wave"
showing 10 items of 19 documents
The influence of building interactions on seismic and elastic body waves
2019
We outline some recent research advances on the control of elastic waves in thin and thick plates, that have occurred since the large scale experiment [S. Brûlé, Phys. Rev. Lett. 112, 133901 (2014)] that demonstrated significant interaction of surface seismic waves with holes structuring sedimentary soils at the meter scale. We further investigate the seismic wave trajectories of compressional body waves in soils structured with buildings. A significant substitution of soils by inclusions, acting as foundations, raises the question of the effective dynamic properties of these structured soils. Buildings, in the case of perfect elastic conditions for both soil and buildings, are shown to int…
Combination of modal responses consistent with seismic input representation
2004
The well-known modal superposition method for the evaluation of seismic response by the complete quadratic modal combination rule (CQC) is revisited. The most widely used version of the CQC rule utilizes correlation coefficients derived for white-noise excitation and neglects the influence of peak factor variation on the response. Here a simplified procedure for evaluation of correlation coefficients and peak factors consistent with the power spectral density of seismic excitation is proposed. The procedure is based on an approximate analytic expression for direct evaluation of the power spectral density of the excitation consistent with any prefixed response spectrum, and the evaluation of…
Simultaneous seismic wave clustering and registration
2012
In this paper we introduce a simple procedure to identify clusters of multivariate waveforms based on a simultaneous assignation and alignment procedure. This approach is aimed at the identification of clusters of earthquakes, assuming that similarities between seismic events with respect to hypocentral parameters and focal mechanism correspond to similarities between waveforms of events. Therefore we define a distance measure between seismic curves in R^d d>=1, in order to interpret and better understand the main features of the generating seismic process.
COMPARATIVE CONSIDERATIONS ON THE ENERGY CONTENT OF SEISMIC WAVES IN CENTRAL AND LINEAR PATTERN SHOOTING*
1960
In continuation of a publication by Pierau and Mueller (1960), theoretical and experimental comparisons are made about the energy content of seismic waves for central and linear shotpoint arrangements. The following results are obtained: Using shotpoint arrangements as chosen for the investigation, the energy content of deep reflections is greater in linear than in central pattern shooting, provided that the total quantity of charge is the same in both cases. Furthermore the seismograms obtained with linear shotpoint arrays are less disturbed by surface waves than those obtained in central pattern shooting. Both effects are superimposed and improve considerably the signal-to-noise ratio, th…
Assessment of a geological model by surface wave analyses
2016
A set of horizontal to vertical spectral ratio (HVSR) and multichannel analysis of surface waves (MASW) measurements, carried out in the Altavilla Milicia (Sicily) area, is analyzed to test a geological model of the area. Statistical techniques have been used in different stages of the data analysis, to optimize the reliability of the information extracted from geophysical measurements. In particular, cluster analysis algorithms have been implemented to select the time windows of the microseismic signal to be used for calculating the spectral ratio H/V and to identify sets of spectral ratio peaks likely caused by the same underground structures. Using results of reflection seismic lines, ty…
On the Accuracy and Efficiency of Transient Spectral Element Models for Seismic Wave Problems
2016
This study concentrates on transient multiphysical wave problems for simulating seismic waves. The presented models cover the coupling between elastic wave equations in solid structures and acoustic wave equations in fluids. We focus especially on the accuracy and efficiency of the numerical solution based on higher-order discretizations. The spatial discretization is performed by the spectral element method. For time discretization we compare three different schemes. The efficiency of the higher-order time discretization schemes depends on several factors which we discuss by presenting numerical experiments with the fourth-order Runge-Kutta and the fourth-order Adams-Bashforth time-steppin…
Boundary rigidity for Randers metrics
2021
If a non-reversible Finsler norm is the sum of a reversible Finsler norm and a closed 1-form, then one can uniquely recover the 1-form up to potential fields from the boundary distance data. We also show a boundary rigidity result for Randers metrics where the reversible Finsler norm is induced by a Riemannian metric which is boundary rigid. Our theorems generalize Riemannian boundary rigidity results to some non-reversible Finsler manifolds. We provide an application to seismology where the seismic wave propagates in a moving medium.
Scattering and Localization of Classical Waves Along a Wave Guide with Disorder and Dissipation
1993
The problem of localization of classical waves has recently attracted consider-able attention.1,2 Classical waves have, of course, been the subject of extensive research already in the last century, as emphasized by Landauer in his historical sketch.3 A variety of interesting phenomena is associated with classical waves like seismic waves, tidal waves, acoustic as well as optical waves. A major topic is the transport of energy or information by these waves. The current interest in classical waves is stimulated by the development of microelectronics with its very small structures, in particular very thin wires (as connections between the components of integrated circuits) which may (or may n…
THEORETISCHE UNTERSUCHUNG UBER DIE MEHRFACHAUFSTELLUNG VON GEOPHONEN*
1958
The receiving of seismic waves by multiple geophones (geophone-group) is described by a system of coupled differential equations considering only effective resistances. For so-called symmetrical connections of the geophone-group which are used in practice nearly in all cases, a method can be given for solving this system of differential equations. The solutions so derived are valid for seismic waves of any shape. The calculation takes into account the coupling of the geophones as well as the building-up transient oscillations. A suitable measure of superposition is defined, based on the energy transferred during the receiving of the seismic waves. By this means effects similar to interferen…
THEORETISGHE UNTERSUCHUNGEN UBER DEN EINFLUSS DER VERWITTERUNGSSCHICHT AUF DAS SPEKTRUM ELASTISCHER WELLEN IN DER REFLEXIONSSEISMIK
1957
The following assumptions are made in the mathematical treatment of the problem. Below a plane earth's surface there is a three-layered elastic medium the interfaces of which are parallel to the earth's surface. The uppermost layer represents the weathered layer in which the velocity of propagation of seismic waves increases linearly with depth. The two lower layers, the so-called intermediate layer and the substratum each have a constant velocity. The surface of the earth is acted on simultaneously by a normal pressure N in the form of a Heaviside pulse. The seismic wave thus generated is propagated through the elastic media. The aim of the investigation is to study the shape of the wave 1…