【摘要】 本文是以珠江口海区高分辨率浅层地震剖面资料为基础,用地震相分析方法来识别海底浅层断层,埋藏古河道、泥底辟、浅层气及活动沙波等不稳定地质类型,并从第四纪以来海平面的升降变化作用、海区新构造运动与海洋水动力学等方面,探讨了这些不稳定类型的可能成因以及它们与海洋石油勘探、开采有关海底工程设施的关系.更多还原

【Abstract】 The high-resolution seismic data acquired in the Pearl River mouth region in the South China Sea show the following marine instabilities: shallow faults. buried channels, gas-charged sediments, mud diapires and movable sand waves. This paper is focused on the interpretation of their depositional environments and models, on the study of dynamic characteristics of seismic facies parameters such as reflection amplitude, lineup continuity and signal frequency, and on the determination of the velocity-density properties, depths and stratification of the geological units, through the analysis of seismic facies.The causes of the marine instabilities are briefly discussed with examples in three aspects: (1) sea-level change since Quaternary; (2) neotectonic movement mainly represented by earthquakes and fractures in the region; and (3) oceanographic-hydrodynamic processes such as wave, tide and current.This paper shows that high-resolution seismic prospecting technique is a highly valuable means in discerning and studying the subbottom geohazardous events. The authors believe that it is necessary to carry out the comprehensive and multi-disciplinary study, including marine geophysics, marine geology, geotectonics and oceanology, in order to evaluate the marine engineering geological conditions more thoroughly.更多还原