Seismic magnitude scales by tectonic forces. When this stress becomes great enough to rupture the crust, or to overcome the friction that prevents one block of crust from slipping past another, energy is released, some of it in the form of various kinds of seismic waves that cause ground-shaking, or quaking. "Magnitude" is an estimate of the relative "size" or strength of an "earthquake", and thus its potential for causing ground-shaking. It is "approximately related to the released seismic energy." "Intensity" refers to the strength or force of "shaking" at a given location, and can be related to the peak ground velocity. With
Multidimensional seismic data processing seismic profile. This involves gathering seismic traces from points at the same depth and summing them. This is referred to as "Common depth-point stacking" or "Common midpoint stacking". Simply speaking, when these traces are merged, the background noise cancels itself out and the seismic signal add up, thus improving the SNR. Assuming a seismic wave formula_27 travelling upwards towards the surface, where formula_28 is the position on the surface and formula_29 is the depth. The wave's propagation is described by: formula_30 Migration refers to this wave's backward propagation. The two-dimensional Fourier transform of the wave at depth formula_31 is given