浅层地震勘探在城市活断层探测中的应用

The Comprehensive Application of Shallow Seismic Prospecting Method to Urban Active Fault Detection

城市活断层一般是指晚更新世以来有活动的断层,活断层具有非常明显的标志,往往控制最新沉积物的分布和现今地貌的格局。活断层常构成山区和平原的分界线,对河流的走向、分布格式和拐弯具有一定的控制作用。这些断层在我国大陆内部广泛分布,尤其在我国西部地区,活断层规模大,活动性强,造成了严重的地质灾害。本文阐述了一种以SH波反射和共偏移距反射波为主的浅层地震勘探在城市活断层探测中的应用,钻探验证表明,采用合适的地震勘探方法,选择最佳的观测系统,对资料的处理和解释进行严格的管理,最终可以获得反射波信噪比高、断层显示清晰的时间剖面。通过对地震资料的综合分析和研究,可以确定勘查区断层隐伏段的位置、断层错断的层位与深度,为城市的发展规划和重大工程选址提供科学依据。

Urban active fault generally refers to the faults which have activities since late pleistocene,and active fault has very obvious signs,which often control the distribution of sediment and the latest current landscape pattern.Active fault always can form the boundary between the mountains and plains,which can often control the tendency,distribution and curve of river.These faults are widely distributed in the internal China,especially in the western region in China.The active fault scale is big with strong activity,which caused serious geological disasters.This article expounds the application of shallow seismic prospecting to urban active fault detection,and mainly SH wave reflection and common offsetreflection wave.The drilling verification shows that the use of appropriate seismic exploration method,selection of the best observation system,and strict management of the data processing and interpretation can finally get the high signal-to-noise ratio,clear fault display time section of reflection wave.Through the comprehensive analysis and study of seismic data,the location of concealed fault segments,and fault broken horizon and depth in the exploration area can be determined,which can provide a scientific basis for the development of the city planning and major project site selection.