Surface wave fine detection imaging of broadband towed seismic geophones

The traditional active source surface wave instrument, employing tapered velocity geophones, suffers from narrow frequency band and low longitudinal resolution. Manual movement of geophones one by one in traditional devices for measuring points results in inefficiency and inability to rapidly acquire high-density surface wave data at low cost, leading to low lateral resolution. This paper proposes a towed seismic surface wave data acquisition method suitable for hardened roads. Linear string and array towed gravity-coupled accelerometer geophones are designed to achieve high-density data acquisition with small geophone spacing, high sampling rate, and broad bandwidth. Traditionally, the influence of sampling rate on the detection accuracy of surface waves has been neglected. This paper suggests that high sampling rates can improve the accuracy of surface wave detection. Analysis of different sampling rates between model data and measured data shows that high sampling rates can suppress noise interference, amplify low-frequency energy, and ensure sufficient investigation depth. The surface wave data collected by the geophones in this study enables detailed description of velocity layer variations and identification of potential collapse locations. The application of towed seismic geophone for urban road collapse detection showcases efficient acquisition and precise detection capabilities.