| 摘要 |
<p>A seismic wave generator comprises a closed housing (40) adapted to be lowered into a borehole, a clamp to clamp the housing against a wall of the borehole, at least one bender arm assembly (54,56) mounted on a support secured within the housing, the assembly including a pair of piezoelectric ceramic crystals (62,64) forming an arm, and a mass (58) attached to the arm intermediate its ends, and drive means connected to energize the crystals to bend the arm to generate a seismic wave for propagation into a formation surrounding the borehole when the housing is clamped to the wall. <IMAGE></p> |
