Rapid fire air gun
Recoil reducing system for gas guns
Removable piston bore liner for hydraulically actuated seismic v
Repetitive detonation seismic surveying method and apparatus
Rotary air modulator
Rotary seismic shear-wave source
Rotatable horizontal vibrator
Rotating eccentric weight apparatus and method for generating co
Rotating eccentric weight seismic sources and a seismic explorat