![]() ![]() This class of materials is particularly interesting in that a second ‘slow’ longitudinal P2 wave, predicted by Biot (1956) and first observed by Plona (1980), exists in addition to the usual ‘fast’ P1 and the transversely polarized S modes. ![]() Often, however, the object of interest is constructed of a fluid-saturated, porous, and permeable material. Waves in such media are limited to the longitudinal P1 and transverse S modes, and at the interface the incident wave's energy is redistributed by mode conversion upon reflection and transmission. Young & Braile (1976) provide an extensive list of this literature up to the mid-1970s. Zoeppritz 1919) and two viscoelastic solids (e.g. Solutions exist for R(θ) of mechanical longitudinal and transverse plane waves for a variety of interfaces including those between a liquid and an elastic solid (e.g. Conversely, the behaviour of the reflectivity R(θ) as it varies with the angle of incidence reveals a great deal about the mechanical physical properties on either side of the interface and is now widely used to remotely probe these physical properties (e.g. However, the amplitude and phase of a wave reflected from the surface bounding two media are controlled by the contrasting physical properties and by the angle of incidence θ. Usually, seismic reflection imaging focuses on travel times and amplitudes of reflected waves. Such reflected waves are used in disciplines ranging from medical ultrasound, architectural acoustics, ultrasonic non-destructive testing, and, of course, in oceanographic sonar, seismology, and geophysical hydrocarbon exploration. Seismic reflections are created at the interface between two contrasting mechanical media. Permeability and porosity, Elasticity and anelasticity, Body waves, Seismic attenuation, Wave propagation, Acoustic properties 1 Introduction It is found that simpler elastic expressions based on equivalent-elastic solid cannot be reconciled with the observations. The observed reflectivity agrees with that predicted using the Biot-type poroelastic theory this work confirms the use of boundary conditions that allow fluid transfer across the reflecting interface. ![]() Here, the acoustic reflectivity from a water-saturated porous plate is measured as a function of the angle of incidence using a specially developed ultrasonic reflectometer. There have only been limited quantitative experimental tests of porous media reflectivity as a function of angle of incidence. However, wave propagation through, and hence reflectivity from, liquid-saturated porous solids is complicated by the presence of the slow longitudinal ( P2) wave. Such observations are almost solely interpreted assuming elastic wave theory. Angle of incidence amplitude variations of acoustic waves reflected from an interface is increasingly important in acoustic sea floor imaging and seismological studies. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |