A simple 2-conductor wire connects the geophones, collecting data and providing power to the units.
Near surface exploration seismic systems, sometimes called engineering seismographs, are used for earthquake site response, rippability surveys, depth-to-bedrock, groundwater exploration, geologic hazards, shallow reflection surveys, shear wave surveys and multi-channel analysis of surface waves MASW.
Exploration Seismographs, Wall-Lock
Borehole Geophones, Land Streamers

Geostuff offers a variety of wall-lock borehole geophones, both analog and digital.
Used for high productivity seismic surveys. The string of geophones is towed along the ground by hand or vehicle.
Hammer Switches