Experimental study of multicomponent shallow seismic exploration: a case study of Quaternary in Tianjin City, China

Abstract

As the quick urbanization and construction requirement, investigating and identifying the different scale faults and fractures and fluid related layers in shallow urban subsurface are of great significance. However, the conventional P-wave only module may present limited resolution in shallow layers and difficult to identify the fluid layers alone, thus unable to satisfy some high-resolution urban shallow engineering work. To ameliorate this problem and test the real effectiveness, we present experimental study of seismic multicomponent exploration in Tianjin City. P-wave vibroseis for excitation and three-component detectors for receiving are carried out for three survey lines. From the data analysis, we find generally the layers in the P-wave profile have a good match to the ones in the converted profiles. Furthermore, small-scale structures including faults are presenting in the converted profiles, while they are unable to recognize in the conventional P-wave profile. The deduced fluid layer presents in the P-wave profile while disappearing in the converted profiles, the layer is thus conjectured to be fluid relative. Limited by the resolution, the P-wave profile is unable to separate the shallow formation, while the converted profiles have this ability and can separate it clearly. These results show the converted wave profiles ravel higher resolution and thus have obvious advantages in uncovering the small-scale structures including faults and fractures, and thin layers. Integrating the three-component data are helpful and can effectively mitigate ambiguity of seismic interpretation work. It can be an effective supplementary method for major urban engineering work such as infrastructure site selection and dam survey.