A method for seismic exploration of a subsurface formation with a seismic survey system includes directly receiving a message, at a first fleet of seismic sources, from a second fleet; storing the message at the first fleet; verifying one or more constraints related to the first and second fleets, at the first fleet; initiating a triggering sequence of the seismic sources of the first fleet, upon verification of the one or more constraints, with no input from a central unit of the seismic survey system; and performing a sweep based on the triggering sequence.

The present application provides a seafloor multi-wave seismic source including: a pressure chamber mechanism; a high-voltage pulse generator with four discharge pathways; a thrust mechanism with a thrust rod and a thrust head; four vibrators are evenly distributed around a periphery of the thrust head, and each vibrator is connected with one discharge pathway of the high-voltage pulse generator; a power supply unit to power the seismic source; and a processor, a memory and a program, wherein the program is stored in the memory and configured to be executed by the processor; and the program includes: pulse emission instructions generated by the processor based on user settings and received by the high-voltage pulse generator, for switching on four or any two of the four discharge pathways at the same time, to enable the corresponding vibrators to vibrate to excite seismic waves in compression wave mode or shear wave mode.

Methods of identifying a subterranean tunnel using digital imaging that may include: obtaining data of a propagating wavefield through a propagating volume that includes a portion of the earth's subsurface; obtaining a reference digital image of the propagating volume; selecting a holographic computational method of wavefield imaging; selecting a wavefield based on one or more parameters; calculating a sampling ratio by dividing a number of data samples in the data subset by a number of image samples in the data subset; decimating the data subset; generating a new digital image based on the selected holographic computational method of imaging, the decimated data subset, and parameters corresponding to the data subset; determining a quantitative difference measure between the reference digital image and the new digital image, and image quality; and identifying the subterranean tunnel.

Methods to estimate formation shear wave slowness from multi-firings of different types of acoustic sources and multi-mode dispersion estimation systems are presented. The method includes obtaining waveform data of waves traversing through a downhole formation, where the waves are generated from multi-firings of different types of acoustic sources. The method also includes performing a multimode dispersion analysis of the waveform data for each firing of the multi-firings, and removing one or more tool waves generated from the multi-firings. The method further includes determining a formation type of the formation the waves traverse based properties of the waves and determining an initial shear wave slowness estimate of the waves. The method further includes generating a modeling of the waves, and reducing a mismatch between the modeling of the waves and a slowness dispersion of the waves to improve the modeling of the waves.

A seismic survey uses a central control and a seismic source. The seismic source has a vibrator that acoustically couples to the ground using a moveable pad. A method for performing a seismic survey includes sending a first message from the seismic source to the central control indicating a time at which the pad is being lowered; estimating a time at which the pad will be acoustically coupled to the ground based on the first message; and sending a message from the central control to the seismic source to begin a sweep, the sweep beginning no sooner than the estimated time. Another method includes: mapping a surface of a terrain to be traversed by the truck using at least one sensor carried by the truck; positioning a moveable pad based on the mapped surface to provide a physical gap between the surface and the moveable pad; and traversing the mapped terrain with the truck.

Methods of providing digital images of living tissue that may include: obtaining data of a propagating wavefield through living tissue; obtaining a reference digital image of the living tissue; selecting a holographic computational method of wavefield imaging; selecting a wavefield based on one or more parameters; calculating a sampling ratio by dividing a number of data samples in the data subset by a number of image samples in the data subset; decimating the data subset; generating a new digital image based on the selected holographic computational method of imaging, the decimated data subset, and parameters corresponding to the data subset; and determining a quantitative difference measure between the reference digital image and the new digital image based on the changing of one or more parameters selected from the group consisting of field sampling, imaging sampling, and image quality.

An initial gather of blended seismic signals induced in a common seismic receiver by a plurality of actual sources grouped in actual source groups is provided. Each actual source group has a linear source geometry that is the same for each actual source group. The plurality of sources in each actual source group is fired according to a pre-selected firing sequence that is the same for each actual source group. Actual shot records are created from the blended signals, and fictive shot records are created of seismic signals for fictive source groups that each have the same source geometry as the actual source groups, by interpolation of the actual shot records. Single source shot records of single source signals are separated by discrete deconvolution of the actual shot records and the fictive shot records. The output includes a seismic gather comprising a plurality of the single source shot records.

Methods of providing digital images of living tissue that may include: obtaining data of a propagating wavefield through living tissue; obtaining a reference digital image of the living tissue; selecting a holographic computational method of wavefield imaging; selecting a wavefield based on one or more parameters; calculating a sampling ratio by dividing a number of data samples in the data subset by a number of image samples in the data subset; decimating the data subset; generating a new digital image based on the selected holographic computational method of imaging, the decimated data subset, and parameters corresponding to the data subset; and determining a quantitative difference measure between the reference digital image and the new digital image based on the changing of one or more parameters selected from the group consisting of field sampling, imaging sampling, and image quality.

A technique for use in geophysical surveying includes imparting a plurality of humming seismic signals and a plurality of low-frequency seismic signals into a geological formation. The technique also includes receiving returned seismic energy of the plurality of humming seismic signals and the plurality of low-frequency seismic signals after interacting with the geological formation and recording the returned seismic energy.

A method for separating the unknown contributions of two or more sources from a commonly acquired set of wavefield signals representing a wavefield where the contributions from different sources are both encoded by means of the principles of signal apparition and as well as by means of different source encoding techniques.