What Does Reflected Wave Mean?
Reflected wave is a component of the seismic trace obtained during the seismic refraction test. It can be defined as the wave energy that is reflected off the interface of two different mediums when a seismic wave travels through the earth. A reflected wave has the same angle of entry and exit when measured to the normal of the boundary.
Seismic refraction and other tests are carried out to determine the sub-surface geology and in-situ stress in rocks. Reflection seismology is also used to image the earth's sub-surface geological structure.
Trenchlesspedia Explains Reflected Wave
While conducting seismic refraction survey, low-frequency seismic energy is produced by a seismic source on the surface such as a hammer plate, buffalo gun or weight drop, depending on the depth of penetration required and prevalent site conditions. As the seismic waves propagate downward, they are reflected or refracted off layers in the subsurface. The output data is recorded on geophones and compiled and processed by a seismograph.
The seismic trace components include direct wave, reflected wave and critically refracted wave. Wave refraction occurs at interfaces where the lower layer has greater seismic velocity than the overlying layer.
In reflection seismology, an acoustic energy source transmits an acoustic signal into the earth. The transmitted wave will reflect some energy back where it meets with a geological interface.
Geophones or hydrophones detect the reflected signals which are later processed.