| 摘要 |
Device for generating shear waves in the earth for seismic prospecting, comprising means for striking with a mass a target-member coupled to the earth, said means including means for lifting and shifting said mass with respect to the target member, an electromagnet for intermittently locking it in an upper position and releasing it abruptly and means for adjusting the stroke of the mass from its upper position to its lower position where it impinges the target member. |
