Reflections and refractions from wide-angle, densely sampled, multi channel streamer data are transformed automatically to the slowness-depth domain using a downward continuation algorithm. The method may be used to rapidly obtain velocity functions for use in pre-stack depth migration processes. Incorporation of the reflection data has the potential to produce velocity images in complex geolog...

Sentences using ‘ought’ appear to have some kind of non-descriptive force (e.g. commending, guiding actions, committing the speaker), in which case it would seem that no ‘ought’ statement can follow logically from purely factual statements lacking such force. Yet from factual statements about slowness and liability to breakdown of alternative means of transport it seems possible validly to infe...

Is teaching impaired by gender bias? Following growing academic interest targeting bias in university curricula, we analyse the participation of literatura written women compulsory course Colombian Economic History to inquire about existence field teaching. We two categories: relevance and conclude that investigation subfield reveals existing biases economy a slowness change despite awareness i...

Pseudo interface waves can exist at the interface of a fluid and a fluid-saturated poroelastic solid. These waves are typically related to the pseudo-Rayleigh pole and the pseudo-Stoneley pole in the complex slowness plane. It is found that each of these two poles can contribute (as a residue) to a full transient wave motion when the corresponding Fourier integral is computed on the principal R...

Adjoint-state methods (ASMs) have proven successful for calculating the gradients of the functionals commonly found in geophysical inverse problems. The 3D image-domain formulation of the seismic velocity estimation problem uses imperfections in 3D migrated images to form an objective function, which is minimized using a combined ASM plus line-search approach. While image-domain methods are les...

[1] We introduce a coherence measure for seismic signal enhancement through incoherent noise attenuation. Our processing tool is designed for densely spaced arrays and identifies signals by their coherent appearance. The approach is based on the determination of the lateral phase coherence as function of distance, time, frequency, and slowness. The coherence is derived from the local phases of ...