Land Broadband Seismic from the Receiver Perspective

The broadband capability of land receivers is reviewed. On the low-frequency side, two more octaves have been added to the signal using low dwell sweeps. These low frequencies can be recovered below the resonant frequency of the geophones by compensating for their attenuation. However, this inverse filter works well so long as there is adequate signal-to-noise ratio. To avoid amplifying instrument noise, new geophones have been developed with a higher sensitivity and a lower resonant frequency. MEMS accelerometers that display a linear response down to DC seem to be the ideal sensor to capture very low frequencies. Their limitations relating to the instrument noise may be compensated by a high spatial sampling. On the high-frequency side, progress is limited by the absorption that occurs at shallow levels and during propagation. The spurious frequency of geophones occurs above the high-cut used in most of the surveys. MEMS accelerometers benefit from a broadband response, higher sensitivity and lower instrument noise at high frequency. Therefore, the main issue is not related to the receivers but to the possibility of enhancing the signal-to-noise ratio at high frequency.