the application of nmo (normal moveout) has been recognized as an effective method of generating quasi-zero-offset traces in traditional common-midpoint processing. artifacts of the nmo method relate to the nmo-stretch effects. conventional application of normal-moveout correction to a common-midpoint (cmp) reflection generates a stretch that increases with offset and decreases with zero-offset...

A MATLAB program was developed to invert first arrival travel time picks from zero offset profiling borehole ground penetrating radar traces to obtain the electromagnetic wave propagation velocities in soil. Zero-offset profiling refers to a mode of operation wherein the centers of the bistatic antennae being lowered to the same depth below ground for each measurement. The inversion uses a simu...

the velocity data of seismic waves in a region has an important role in locating occurred events. information such as velocity ratio of vp/vs and velocity curves for pg, pn, sg, and sn phases directly affect the locating results. it is well known that the vp/vs ratio can be used to predict lithology, and that s-waves are sensitive to microcracks aligned by the present day stress field. also, th...

Time-zero adjustment or the true ground surface for penetrating radar (GPR) applications is a very important aspect and an essential factor in order to position subsurface targets, especially those located at shallow depths, their depth. As transmitted received signals from GPR antennas are affected by presence of different materials with varying electromagnetic properties, adjusting time zero ...

the purpose of velocity analysis is to extract the normal moveout velocity as a function of the zero-offset travel time at selected cdp locations along the seismic line. since results of velocity analysis depend on coherency estimator, an estimator that provides a high velocity resolution is essential. even though the conventional semblance method which is the most popular coherency estimator (...

A new ray-based approach for converting multicomponent normal moveout uncorrected offset domain prestack seismic data into angles is presented. From any two-way zero-offset time sample and a given angle of incidence, the exact ray and a few neighboring rays that contribute to the given angle of incidence are traced through the medium to their corresponding source and receiver locations to compu...

Isochron rays are lines perpendicular to isochrons, which represent surfaces of constant two-way traveltime. The image of a temporal sequence of seismic impulses is a sequence of isochrons in depth. The later the time impulse the deeper the isochron. The term isochron ray arises from an analogy between the isochron “movement” and the wave propagation. While isochrons behave as wavefronts, its p...

in exploration seismology, migration refers to a multi-channel processing step that attempts to spatially re-position events and improve focusing. before migration, seismic data is usually displayed with traces plotted at the surface location of the receivers and with a vertical time axis. this means that dipping reflections are systematically mispositioned in the lateral coordinate and the ver...