Toward the autojuggie: Planting 72 geophones in 2 sec

Shallow seismic reflection surveys require dense spatial wave-field samplin g, contributing to their high cost. To assess the feasibility of planting g eophones automatically, we planted 72 geophones in approximately 2 s in a t est line, using an 11-m-wide farm tillage tool as a planting device. Geopho nes were attached rigidly, at 15 cm intervals, to five pieces of heavy-duty channel iron bolted to the tillage-tool frame. Conventional comparison-lin e data collected about 75 cm away, parallel to the test line, were visually comparable with the seismic source 12 m distant. When the sources were pla ced Im from the geophones, a surface-wave mode was excited by the channel i ron and detected by geophones in both lines. This mode exhibited a differen t phase velocity than that of the desired seismic body-waves and could be a ttenuated by frequency-wavenumber filtering. These results suggest that aut omatic geophone placement is feasible and could decrease shallow seismic su rveying costs.