Abstract: The configuration and directional orientation of natural or induced fractures in subterranean earth formations are described by introducing a liquid explosive into the fracture, detonating the explosive, and then monitoring the resulting acoustic emissions with strategically placed acoustic sensors as the explosion propagates through the fracture at a known rate.

Abstract: A detonator is positioned in the bore of, or adjacent to, a roll or coil of detonating cord, one end of which is attached to the detonator, which in turn is aligned with a shothole and with a flexible, tubular inserting device, which advances over one end of the detonator and forces it into the shothole, during which operation the cord unwinds and is drawn into the shothole at the outside of the tubular inserter. In one embodiment cylindrically-shaped coils of cord containing the detonators are fed, as needed, through a supply tube to a receptacle positioned in front of the shothole and in front of the forward end of the inserter. In another embodiment both primer caps and detonators, with cord attached, are rotatably indexible into registry with the inserting tube and a shothole.

Abstract: A method for generating and detecting seismic shear wave energy in the earth are disclosed useful for determining shear wave velocities in localized regions in the earth at sites where foundations of large civil engineering structures are proposed or earth embankments and dams have been built, thereby providing information affecting the basic dynamic design parameters for constructing or evaluating the project and obtaining earthquake resistant design. An airgun of elongated generally cylindrical configuration and having a single discharge port opening out radially on one side only for abruptly releasing compressed air in a direction perpendicular to the axis of the airgun is lowered into a borehole in a manner and by apparatus to control the direction in azimuth at which this single lateral discharge port is aimed.

Abstract: Disclosed is a seismic source forming part of a drill string which allows geological prospecting while drilling a borehole. The source includes a section of drill pipe having a spiral cam machined into its outer surface and a port for allowing mud to flow from the inside of the drill pipe into the borehole. A sleeve surrounds this section of the drill pipe and includes a cam follower, a plurality of ports, and a spring borehole contact for preventing rotation of the sleeve. The sleeve blocks flow of mud through the drill pipe port, except when a sleeve port is in alignment therewith. When the sleeve cam follower is engaged in the drill pipe cam and the drill pipe is rotated, the drill pipe port follows a helical path relative to the sleeve and sequentially passes all the ports in the sleeve. Signal wave shape is determined by the configuration of the sleeve ports and frequency is determined by the drill pipe rotation rate.

Abstract: Improved pressurized gas discharging apparatus for use as a down-bore seismic impulse source provides a compact, efficient axially stacked assembly of components within a one piece elongated tubular shell housing having removable end closures. Within the tubular housing, removable partition means define a charge chamber and an operating chamber having an operating shuttle release means therebetween for sudden release of high pressure gas present in the charge chamber through a discharge port into the surrounding environment. Gas flow passageways for the supply of high pressure gas to the chambers extend longitudinally within the wall of the tubular housing and communicate with passages in the partition means. The shuttle release means may be actuated by a solenoid valve also removably positioned within the tubular housing for controlling gas flow through passageways also located within the walls of the tubular housing and within the partition means.

Abstract: Explosive cartridges are loaded into boreholes at a rapid rate by guided descent through a retractable flexible tubing assembly through which a stream of water flows. The cartridges preferably are cut open just before their discharge from the assembly, and their passage through, or discharge from, the assembly is detected outside the borehole. The assembly is retracted incrementally until completion of the loading. Apparatus comprising a cartridge-guiding assembly through which a stream of water flows, and means associated with the assembly for sensing cartridge passage or discharge.

Abstract: Method and apparatus for logging the position of a deep borehole filled with liquid in the earth, comprising a long, continuous small diameter pipe adapted to be reeled up on a drum mounted on a vehicle, and means to insert the end of the pipe into the mouth of a borehole and to lower it to any desired depth in the earth. A plurality of geophones are positioned on the surface of the earth in the vicinity of the borehole with conventional amplifying and recording means connected thereto. Means are provided on the vehicle for compressing a liquid or gas, and injecting it into the pipe. On the bottom end of the pipe is a chamber in which this pressurized fluid can be stored. Fast acting valve means are provided which on signal can suddenly open and permit the stored fluid in the chamber to explosively expand into the liquid in the annulus of the borehole.

Abstract: A method and apparatus for determining the position of the bottom end of a long pipe in a deep water-filled borehole, comprising generating a shock wave in the water at the surface end of the pipe, timing the travel of the shock wave down the pipe to the bottom end thereof, where the shock wave will pass into the liquid in the borehole, generating an expanding seismic wave in the earth. Setting out a plurality of geophones on the earth at the surface to detect the arrival of the seismic wave. Recording the geophone signals and determining the arrival times of the seismic wave. Determining the travel times of the seismic wave to each geophone and determining the position of the end of the pipe.