中国近海新构造活动断裂调查与地震勘探方法

Seismic survey and exploration methods for Neotectonic active faults in the area off China continent

  • 摘要: 中国近海处于大洋板块与大陆板块作用的关键区域,新构造运动频繁,活动断裂是其主要的表现形式之一。浅地层剖面仪测量、单道地震、多道地震和海底地震仪探测(OBS)等海洋地震勘探方法是调查研究海域活动断裂的主要地球物理手段,各自具有不同技术优势和探测功能,在海域活动断裂调查研究中发挥了重要作用。通过OBS广角反射/折射深地震探测和长排列多道地震勘探,获得了中国近海的区域深大断裂展布特征,深化了深大断裂形成与演化的深部动力学机理的认识,进而分析了其对活动断裂控制与约束关系。根据活动断裂时代新、埋藏浅的特点,综合利用浅地层剖面仪测量、单道地震和高分辨率多道地震方法,获得了中国近海海域活动断裂的分布、走向和差异升降等特征,分析了新构造运动的演化规律。本文综述了海洋地震勘探技术方法的主要特点和功能,及其在海域活动断裂调查中的功能和作用,总结了利用地震勘探技术方法在中国近海新构造活动断裂调查研究中取得的主要成果,提出了在未来的海域新构造运动地震调查研究中,应采用多技术方法组合系统调查与研究的思路,着力提高地震勘探的精度,探索应用横波地震勘探和海底可控震源等新技术的建议。

     

    Abstract: Located in the key area of land-ocean plate interaction, offshore China is an area frequently suffered from neotectonic movement-caused disasters, and active faults are one of their main triggers. Marine seismic exploration methods such as sub-bottom profiler, single channel seismic, multi-channel seismic and ocean bottom seismometer (OBS) are the main geophysical tools used to investigate active faults offshore. Each of them has its own technical advantages and detection ranges to play roles in the investigation and study of active faults offshore. Recently, through OBS wide-angle reflection/refraction deep seismic exploration and long spread multi-channel seismic exploration, we have been able to gain the distribution patterns of regional deep-large faults in China offshore area, and the understanding of deep dynamic mechanism of the formation and evolution of deep-large faults is greatly deepened. Upon the basis, we analyzed the control and constraint relationship of active faults in this paper. Newly buried active faults are young in age and shallow in burial depth. According to the features as such, we studied in this paper the distribution pattern, strike and differential rise and fall of active faults in China offshore area with such methods as sub-bottom profiler, single-channel seismic and high-resolution multi-channel seismic. And the main characteristics and functions of marine seismic exploration techniques and methods, as well as their functions and effects in the investigation of active faults in the sea area, are summarized in addition to the main achievements obtained in the researches. It is concluded that for future marine neotectonic seismic prospecting and research, it is necessary to insist on the idea of multi-technology methods and systematic investigation, focus more on improving the accuracy of seismic exploration, and explore the application of new technology such as S-wave seismic exploration and seabed vibrator.

     

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