应用深地震反射技术揭示喀斯特地区深部地质结构特征

The application of deep seismic reflection methods to the detection of deep geological structures beneath karst areas

本文以广西南盘江—桂中坳陷为例介绍了喀斯特地貌区的深地震反射采集方法技术,来揭示地表喀斯特地貌发育的广西南盘江—桂中坳陷下深部结构。为了获得高信噪比的深地震反射资料,针对该区地表及深部复杂性情况,采取以下六个技术措施:高精度多方法联合测量技术,干扰波特性分析及压制,面向目标的观测系统设计,加强炮检点的选点工作,加大试验力度选取适合的激发和接收参数,多种针对性静校正处理方法。其中,干扰波特性分析及压制方法和技术实施是获取喀斯特地区深部结构的技术难点,也是前提和保证;多种针对性静校正处理方法是后期室内处理改善深部结构资料品质的关键。通过采取以上技术措施将大大提高了资料信噪比,改善了资料的品质,获得了广西南盘江—桂中坳陷下的较为清晰的深部结构特征。这为此类地区的地震探测提供了采集实例和探测方法依据。

Surface karst features in Panjiang-Guizhong depression make up a good example for applying the data acquisition technique in the karst area to studying deep structures beneath the depression. To probe into some problems related to complex karst features in the Panjiang-Guizhong depression, such techniques as high- resolution multiple-means survey, analysis and suppression of interference waves, objective-facing design for the observational system, and selection of shot and geophone position seem to be the key methods. The authors conducted many experiments to choose congruent explosive and record parameters. The noise analysis and elimination and many kinds of static correction means make up the crux of the technologies. The reflection image of the profile has good signal-to-noise ratio as well as high quality of profile and single-shot data. Based on these techniques, this paper has discussed some deep structures beneath the depression as a real example of karst features.