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Stacking Velocity
In reflection seismology, stacking velocity, or Normal Moveout In reflection seismology, normal moveout (NMO) describes the effect that the distance between a seismic source and a receiver (the offset) has on the arrival time of a reflection in the form of an increase of time with offset. The relationship bet ... (NMO) velocity, is the value of the seismic velocity obtained from the best fit of the traveltime curve by a hyperbola.. The hyperbolic approximation to the traveltime curve (two-way travel time versus offset) is known as Normal moveout (NMO). The procedure of finding the best fit on common midpoint (CMP) seismic gathers is known as NMO velocity analysis. References Seismology {{seismology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection Seismology
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite or Tovex blast, a specialized air gun or a seismic vibrator. Reflection seismology is similar to sonar and echolocation. This article is about surface seismic surveys; for vertical seismic profiles, see VSP. History Reflections and refractions of seismic waves at geologic interfaces within the Earth were first observed on recordings of earthquake-generated seismic waves. The basic model of the Earth's deep interior is based on observations of earthquake-generated seismic waves transmitted through the Earth's interior (e.g., Mohorovičić, 1910). The use of human-generated seismic waves to map in detail the geology of the upper few kilometers of the Earth's crust followed shortly thereafter and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Moveout
In reflection seismology, normal moveout (NMO) describes the effect that the distance between a seismic source and a receiver (the offset) has on the arrival time of a reflection in the form of an increase of time with offset. The relationship between arrival time and offset is hyperbolic and it is the principal criterion that a geophysicist uses to decide whether an event is a reflection or not. It is distinguished from dip moveout (DMO), the systematic change in arrival time due to a dipping layer. The normal moveout depends on complex combination of factors including the velocity above the reflector, offset, dip of the reflector and the source receiver azimuth in relation to the dip of the reflector. For a flat, horizontal reflector, the traveltime equation is: t^2 = t_0^2 + \frac where ''x'' = offset; ''v'' = velocity of the medium above the reflecting interface; t_0 = travel time at zero offset, when the source and receiver are in the same place. According to W. Harry Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
