关键词: 地震勘探, 隐伏断裂, 上断点, 影响因素

Abstract: Urban areas are mostly covered by thick Quaternary loose sediments in China. Many sizable hidden faults are developed in this loose layer. These hidden faults can be detected by using seismic method. Whether or not the upper offset points of the hidden faults detected by seismic method represent the real upper offset points of the faults? On the basis of the discussion on resolution of seismic records,the influence of S/N ratio of seismic records,the seismo-geological conditions and the data processing and interpretation methods on the seismic exploration results is analyzed in this paper. Study results show that appropriate technical measures are necessary for improving the S/N ratio and resolution of seismic records. For example,seismic profiles shall be laid vertical to fault strike during the data acquisition. Under conditions of guaranteed seismic records with high signal-to-noise ratio,the use of the methods with appropriate fold number and small group interval will help to get reflections from shallower wave impedance interfaces. In the course of seismic data processing and interpretation,it would be helpful to improve the effect of detecting the upper offset point of buried fault by obtaining accurate reflected wave velocity and adopting the processing technology that can enhance resolution and S/N ratio of seismic records as well as abandoning some mixed wave processing methods. It is difficult to detect with seismic method the interfaces in stratum without wave impedance difference,including the interface broken by buried fault.Even though the upper offset point of buried fault detected by seismic method is not necessarily the upper offset point in a real sense,the seismic prospecting result still provides scientific basis for the layout of drill hole profile,design of drilling depth,and the determination of fault activity.

Key words: seismic exploration, buried fault, upper offset point, influence factor