| 摘要 |
<p>The invention relates to a method and system for generating shear waves and compression waves in the earth for seismic surveying. The apparatus comprises hollow cylinder means (20) having closed upper and lower ends, an earth-contacting plate assembly (30) connected to the lower end of said cyinder means by a horizontal pivot assembly (26), said plate assembly having gripping means (156) for gripping the earth's surface (S), a reaction mass slidably contained within said cylinder means, liquid supply means (54) for introducing liquid into said cylinder means substantially filling the volume between its lower end and the reaction mass, lift means (12, 16) for raising and lowering said plate assembly and cylinder means, tilt means for inclining said cylinder means and air gun means contained within said cylinder means between its lower end and the reaction mass for repeatedly suddenly discharging an explosive-like burst of expanding pressurized gas within said liquid-filled volume.</p> |
