Abstract: A seismic vibrator source having an hydraulic vibrator coupled to vibrate a ground pad is provided with one or more force transducers such as, for example, load cells, strain gauges, or piezoelectric elements for measuring the force applied to the earth. Signals indicative of the pressure force are applied to a controller for the hydraulic vibrator to adjust control signals to prevent decoupling of the ground pad from the earth during ground seismic operations.

Abstract: A vibratory seismic energy source capable of generating significant energy over a broad frequency band. The vibrating baseplate and associated structure are designed to have minimum weight while still retaining sufficient structural integrity to permit the use of high actuator forces. This, coupled with a large reaction mass results in the generation of significant energy levels in the earth at high frequencies.

Abstract: A dual mode vibrator (DMV), in its hydraulic cylinder, automatically provides a shorter stroke for higher frequencies and a longer stroke for lower frequencies. The cylinder contains a pair of sleeves, each sleeve having one diameter portion sufficient to slideably engage the piston and having a smaller diameter portion to slideably engage the piston rod. The sleeves themselves are moveable within the cylinder, such movement being effected by the application of high pressure on one end or the other. When the sleeves are moved together, the stroke is effectively shortened. When the sleeves are moved apart, the stroke is effectively lengthened.

Abstract: An improved suspension assembly for a seismic exploration vehicle having a substantially rigid main frame supported and moved by track assemblies disposed along opposing sides of the frame. The suspension assembly includes two bogies which engage the inner periphery of a track on one side of the vehicle and each of the two bogies is mounted on one end of a bogie arm that is pivotally connected, at the other end of the bogie arm, to a central portion of a walking beam pivotally connected to the vehicle frame. End portions of the walking beam overlay the distal ends of the bogie arms and air bags are mounted between the distal ends of the bogie arms and the ends of the walking beam to bias the bogie arms in a downward direction.

Abstract: A vibratory seismic energy source capable of generating significant energy over a broad frequency band. The vibrating baseplate and associated structure are designed to have minimum weight while still retaining sufficient structural integrity to permit the use of high actuator forces. This, coupled with a large reaction mass results in the generation of significant energy levels in the earth at high frequencies.

Abstract: A vibratory seismic energy source capable of generating significant energy over a broad frequency band. The vibrating baseplate and associated structure are designed for minimum size and weight, while retaining the structural strength to permit high actuator forces. The weight of the transport vehicle is applied to a substantially horizontal hold-down plate that is interposed between the piston-cylinder assembly and the baseplate. This horizontal plate is coupled to the baseplate through resilient means having compliance such that dynamic motion of the baseplate is decoupled from the hold-down plate and transport vehicle.

Abstract: A gyroscopic vibrator provides a new vibrational energy source for applications such as reflection seismology and shake tables. A gyroscopic mass is rotated at a high angular velocity about a shaft. A control force imparts an oscillatory angular displacement to the shaft, preferrably in a plane perpendicular to the vector direction of the desired vibratory source. The resultant gyroscopic reactionary moment in the shaft includes a force component in the direction of the desired vibratory force. One end of the shaft is constrained by a reaction mass while the other end of the shaft is mechanically coupled to the mass which is to be excited. The resultant excitational forces are substantially greater than the controlled force required to impart the angular displacement to the shaft.

Abstract: A land surface seismic prospecting cable which can be towed on the surface of the earth along seismic survey lines. The cable is used to transport, position, protect, house, or attach sensors used for making geophysical and environmental measurements. The cable apparatus may comprise a plurality of segments each interconnected by an electrical connector and each segment having a plurality of sensors associated therewith. The outputs of the signals from the sensors are carried by way of a multiconductor wire cable within the seismic cable to a seismic recorder. After an acoustic disturbance is produced and the seismic information is recorded, the towed land cable or land streamer is towed intact to the next shooting site which saves a great deal of time and allows greater areas to be covered in a predetermined time period.