- 行业: Mining
- Number of terms: 33118
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The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
A seismic reflection technique that involves the plotting of reflections in time and the representation of horizontal distances along the section in equivalent time units (obtained by dividing the true horizontal distance by the sub-weathering velocity as determined from first-arrival times). Once this transformation of the coordinate system is made, migration is accomplished by swinging arcs of reflection times from successive shot points and drawing lines which are tangent to the respective arcs for the same events from adjacent shot points. For the final mapping of migrated horizons in depth, the times are recorded directly beneath the shot points. These times are converted to depths by using the best available velocity information.
Industry:Mining
A seismic shooting method in which isolated profiles are shot and correlated to obtain relative structural positions of the horizons mapped. Compare: continuous profiling
Industry:Mining
A seismic technique by which energy can be sent downward into the ground without the necessity of drilling shotholes. This technique involves lifting a weight, then permitting it to fall and strike the ground. The waves from the impact are then recorded. In areas where drilling is difficult, otherwise undesirable, or unduly expensive, this technique may be highly advantageous.
Industry:Mining
A seismic technique that dispenses with the need for drilling shotholes. In this airshooting method, dynamite is exploded in arrays of simultaneous blasts with charges several feet above the ground. The principal difficulty involves the hazard of working with aboveground explosives and the damage to property or to the peace of mind of nearby inhabitants.
Industry:Mining
A seismic wave propagated from a point source whose front surfaces are concentric spheres.
Industry:Mining
A seismic wave that propagates by alternating compressions and rarefactions in an elastic medium; the motion is in the direction of propagation. It is the type that carries sound.
Industry:Mining
A seismic wave that propagates by alternating compressions and rarefactions in an elastic medium; the motion is in the direction of propagation. It is the type that carries sound.
Industry:Mining
A seismic wave that propagates by alternating compressions and rarefactions in an elastic medium; the motion is in the direction of propagation. It is the type that carries sound.
Industry:Mining
A seismic wave that propagates by alternating compressions and rarefactions in an elastic medium; the motion is in the direction of propagation. It is the type that carries sound.
Industry:Mining
A seismic wave that propagates by alternating compressions and rarefactions in an elastic medium; the motion is in the direction of propagation. It is the type that carries sound.
Industry:Mining
