Velocity continuation is an imaginary continuous process of seismic image transformation in the postmigration domain. It generalizes the concepts of residual and cascaded migrations. Understanding the laws of velocity continuation is crucially important for a successful application of time-migration velocity analysis. These laws predict the changes in the geometry and intensity of reflection ev...

Three-dimensional seismic wavefields may be extrapolated in depth, one frequency at a time by two-dimensional convolution with a circularly symmetric, frequencyand velocity-dependent filter. This depth extrapolation, performed for each frequency independently, lies at the heart of 3-D finite-difference depth migration. The computational efficiency of 3-D depth migration depends directly on the ...

Complex seismic signatures are generated due to the complexity of the subsurface which is difficult to interpret. In the present study, an attempt has been made to model the complex subsurface using the Ray tracing modeling technique. Add to this, for the imaging of these geological features, Kirchhoff’s prestack depth migration is applied over the synthetic common shot gather dataset. It is fo...

In this pedagogically motivated work, the process of migration in reflection seismics has been considered from a rigorously mathematical viewpoint. An inclined subsurface reflector with a constant dipping angle has been shown to cause a shift in the normal moveout equation, with the peak of the moveout curve tracing an elliptic locus. Since any subsurface reflector actually has a non-uniform sp...

A B S T R A C T A new type of seismic imaging, based on Feynman path integrals for waveform modelling , is capable of producing accurate subsurface images without any need for a reference velocity model. Instead of the usual optimization for traveltime curves with maximal signal semblance, a weighted summation over all representative curves avoids the need for velocity analysis, with its common...

The cataclysmic 18 May 1980 eruption at Mount St. Helens was preceded by intense seismic activity marking the mechanical response of the volcanic edifice to interior pressurisation. This seismicity is analysed to yield the temporal change in the seismic scaling exponent, D, inferred from the seismic b-value, that in-turn is related to the seismic moment of an earthquake. Time evolution of D pre...

Fractures and faults riddle the Earth's crust on all scales, and the deformation associated with them is presumed to have had significant effects on its petrological and structural evolution. However, despite the abundance of directly observable earthquake activity, unequivocal evidence for seismic slip rates along ancient faults is rare and usually related to frictional melting and the formati...

[1] The increasing power of computers and numerical methods (like spectral element methods) allows continuously improving modelization of the propagation of seismic waves in heterogeneous media and the development of new applications in particular time reversal in the three-dimensional Earth. The concept of time-reversal (hereafter referred to as TR) was previously successfully applied for acou...

We analyze seismic waves excited by small Strombolian explosions to understand the source process of volcanic explosions. deployed five broadband seismometers at only 100–300 m away from active craters Stromboli volcano, Italy. Moment tensor inversion entire signals in 0.05–0.2 Hz band locates a depth 170 and 150–200 west/southwest crater where acoustic are excited. Contrary, sources 0.2–0.5 0....

Imaging subsalt structures under the complex overburdens is a challenging task in seismic exploration due to the poor illumination of seismic waves. To solve the illumination problem, geophysicists designed the wide azimuth acquisition. Moreover, WAZ acquisition improves the signal to noise ratio by increasing the azimuthal fold, and reduces multiple interferences in the final images (Etgen, 20...