Detection of Stratigraphic Structure and Surrounding Buried Faults in Complex Urban Areas: Case Study of East Lake High-tech Zone

Geological information such as stratigraphic structure characteristics, location of hidden faults, geometric characteristics, and overburden thickness in complex urban areas is extremely important for major engineering constructions such as light rail and intercity trains. The shallow seismic reflection method can identify the geometric features of concealed faults, including their strike as well as the dip and buried depth of the upper breakpoint; additionally, it can finely delineate strata and obtain information regarding the overburden thickness. However, using vibroseis vehicles for seismic exploration in urban areas is unfeasible, thus rendering it impossible to investigate the detection of complex urban stratum structures and concealed faults. To address the practical challenges encountered in complex urban environments, seismic reflection is used and microtremor detection is performed in this study to investigate concealed faults and stratum structures in cities. By utilizing the velocity structure obtained from microtremor detection in the blind spots of seismic exploration, we can obtain insights into the underground spatial structure of urban areas, thus facilitating the assessment of the overburden thickness, the depth of highly weathered and moderately weathered bedrock, and other information. Additionally, by combining drilling data, we analyze the overburden thickness, concealed faults, and stratum structures in the target area, thus effectively avoiding urban detection blind spots and realizing entire-region and multimeans detection. This combination of technologies provides new ideas for conducting geophysical work in similar cities, thus offering scientific significance and promotional value.