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This is an illustration of Snell's Law. A seismic wave coming with the path of the red line would refract when it passes through the surface of medium change. Seismic waves travelling at a critical angle (blue line) will be refracted critically with an angle of refraction equal to 90°. An illustration of seismic reflection and refraction ...
S-wave refraction evaluates the shear wave generated by the seismic source located at a known distance from the array. The wave is generated by horizontally striking an object on the ground surface to induce the shear wave. Since the shear wave is the second fastest wave, it is sometimes referred to as the secondary wave. When compared to the ...
In comparison to the typical seismic reflection survey, which is restricted to relatively small incidence angles due to the limited offsets between source and receiver, wide-angle reflection and refraction (WARR) data are acquired with long offsets, allowing the recording of both refracted and wide-angle reflection arrivals. [1] [2]
Seismic waves are mechanical perturbations that travel in the Earth at a speed governed by the acoustic impedance of the medium in which they are travelling. The acoustic (or seismic) impedance, Z, is defined by the equation: = , where v is the seismic wave velocity and ρ (Greek rho) is the density of the rock.
P wave and S wave from seismograph Velocity of seismic waves in Earth versus depth. [1] The negligible S-wave velocity in the outer core occurs because it is liquid, while in the solid inner core the S-wave velocity is non-zero. A seismic wave is a mechanical wave of acoustic energy that travels through the Earth or another planetary body.
Surface waves are seismic waves that travel at the surface of the earth, along the air/earth boundary. [3] Surface waves are slower than P-waves(compressional waves) and S-waves(transverse waves). Surface waves are classified into two basic types, Rayleigh waves and Love waves. Rayleigh waves travel in a longitudinal manner (the wave motion is ...
Dispersive body waves is an important aspect of seismic theory. When a wave propagates through subsurface materials both energy dissipation and velocity dispersion takes place. Energy dissipation is frequency dependent and causes decreased resolution of the seismic images when recorded in seismic prospecting. The attendant dispersion is a ...
Seismic waves would travel in straight lines if Earth was of uniform composition, but structural, chemical, and thermal variations affect the properties of seismic waves, most importantly their velocity, leading to the reflection and refraction of these waves. The location and magnitude of variations in the subsurface can be calculated by the ...