Seismic waves are distinguished from seismic noise (ambient vibration), which is persistent low-amplitude vibration arising from a variety of natural and anthropogenic sources. The propagation velocity of a seismic wave depends on density and elasticity of …

Seismic velocity structure is the distribution and variation of seismic wave speeds within Earth's and other planetary bodies' subsurface. It is reflective of subsurface properties such as material composition, density, porosity, and temperature. [ 1 ]

2016年8月31日 · seismic velocity: The speed with which an elastic wave propagates through a medium. For non-dispersive body waves, the seismic velocity is equal to both the phase and group velocities; for dispersive surface waves, the seismic velocity is …

P waves are the faster of the two, with velocities typically 50% higher than those for associated S waves. The wave velocities V p and V s are related to the elastic moduli (Young's modulus (E), Poisson's ratio (n), and Bulk modulus (k)) and the density r as follows.

Seismic refraction surveys are used to map the depth to bedrock and to provide information on the compressional and shear wave velocities of the various units overlying bedrock. Velocity information also can be used to calcu-late in place small-strain dynamic properties of these units.

struct and solve the seismic wave equation for elastic wave propagation in a uniform whole space. We will show that two types of solutions are possible, corresponding to compressional (P) and shear (S) waves, and we will derive the equations for their velocities that we presented in the last chapter. This will involve vector calculus

2024年12月28日 · In the Earth, P waves travel at speeds from about 6 km (3.7 miles) per second in surface rock to about 10.4 km (6.5 miles) per second near the Earth’s core some 2,900 km (1,800 miles) below the surface. As the waves enter the core, the velocity drops to about 8 km (5 miles) per second.

2025年1月24日 · In environmental geophysics seismic energy sources are typically a small explosion or a hammer blow, which generate three fundamental types of elastic waves: P (primary, compressional) waves; S (secondary, shear) waves, and surface waves.

Seismic velocities are usually considered to be seismic properties. In the Earth's upper crust, however, these are influenced strongly by confining stresses, pore pressures, fluid saturations, temperature, and porosity, to name only a few.

For example, we've shown that reflected waves can be generated from a planar boundary in seismic wave speed that can be recorded at the Earth's surface. How do these velocity variations relate to properties of the rocks or soils through which the waves are propagating?