46 Seismic Imaging 2.4 First example of a seismic refraction application: static corrections In land seismic acquisition, the elevation differences added to lateral variations in the velocities of the shallow layers cause delays in the arrival times, which vary from trace to trace. Given that these delays are constant with time, the corrections calculated to compensate for them are referred to as “static corrections”. Figure 2.7 Static corrections. Compensation for delays caused by surface weathering. On a seismic record, the event corresponding to a reflection on a seismic horizon no longer forms a hyperbola. The associated t, x (time - distance) curve is distorted due to the surface effects. The surface layer with a variable velocity along the seismic profile is known as the WZ layer, the weathered zone or weathering (Figure 2.7).
RkJQdWJsaXNoZXIy NjA3NzQ=