Búa tạo xung bề mặt Geotomographie Sledge Hammer
The sledge hammer is used to generate seismic waves (P- or S-waves) at the surface. A piezotrigger element is attached to the hammer. The output piezo signal is transformed to a TTL pulse by a small box to provide an exact time break to the seismograph.
It is a suitable source for shallow downhole surveys up to a depth of 100 m.