Detection of a thin layer by seismic reflection with different geophones at a site in Liangzhu, Southeastern China

摘要

Geophone properties are important factors for high-resolution seismic exploration and greatly influence the quality of data. In this study, we will address the problems of ultra-shallow seismic data acquisition and processing. The purpose of our study is to evaluate the applicability of using different seismic geophones and processing techniques to detect a thin soil layer that is approximately 20 cm in thickness at a depth of approximately 2 m in the Liangzhu archaeological site in southeastern China. We collected seismic data using two types of geophones: normal geophones with different natural frequencies inserted into the ground and towable cable geophones contacting the earth's surface. We considered combining the frequency advantages of these two different types of geophones to broaden the effective bandwidth of the acquired data. To achieve this, we designed a partial frequency match filtering method for data processing, which helps to improve the resolution of the reflected seismic data. The stacking profile results show that match filtering is effective in detecting a thin layer compared to drilling samples and GPR data the velocity of the thin bed is 350ms while from seismic section interval velocity of the contact between clayey soils and rammed sandy soils about 600 ms.