Measurements of the wave shape of the seismic transient generated by dropping a weight indicate that the weight drop has a much higher efficiency than shooting dynamite. The surface wave which is generated by the weight drop is very large, but it is minimized by the use of large seismometer groups, many drops per trace, and large offset distances. For experimental studies, a special recording instrument adaptable for either shooting or weight dropping is used. The weight truck is hydraulically operated. Weight dropping versus shooting studies indicate that the quality of weight drop records is limited by the large surface wave generated by the weight impact on the ground.

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