综合探测在小江断裂带中段西支海风园断层调查中的应用

(云南省地震局,云南 昆明 650224)

遥感技术; 高密度电法; 海风园断层; 小江断裂带

Application of the Comprehensive Detection of the Investigation of the Haifengyuan Fault in the West Branch of the Middle Segment of the Xiaojiang Fault Zone
LUO Lin,ZHUANG Ruxin,MAO Xianjin,CHEN Gang,LI Jianlin,XIE Wei

(Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)

remote sensing; high-density electrical method; the Haifengyuan Fault; the Xiaojiang Fault Zone

DOI: 10.20015/j.cnki.ISSN1000-0666.2023.0036

备注

以位于阳宗海北部地区的小江断裂带中段西支次级海风园断层为研究对象,综合利用遥感数据解译和高密度电法探测,结合野外实地调查和探槽开挖验证等技术手段揭示研究断层的空间展布位置及构造特征。结果表明:①海风园断层是一条贯通的结构单一的断层,遥感影像上断层线性特征清晰,宏观地貌显著,沿断层发育断层槽地、线性山脊、断塞塘、水系位错等活动地貌,具有强烈的左旋走滑运动特征; ②高密度电法测线反演剖面在断层破碎带附近的电性结构异常特征与探槽开挖验证确定的断层位置、断层破碎带宽度及断层倾向具有很好的一致性,断层总体走向为N20°E,倾向为SE,可识别破碎带宽度为60 m,结合野外地质调查发现海风园断层错断了上覆全新统坡积层,晚第四纪活动特征强烈,属于全新世活动断层,建设工程需要依据断层宽度进行合理避让; ③在第四系覆盖区开展活动断层探测,采用遥感定展布、物探定结构、地质定结论的综合技术手段,避免了采用单一方法在深度、广度、精度方面的不足,可极大地提高活动断层定位结果的准确性和可靠性。
The secondary Haifengyuan Fault in the west branch of the middle section of the Xiaojiang Fault Zone in the northern part of Yangzonghai is selected as the research sample.By interpretation of the multi-source,remote-sensing data and the high-density electrical detection,together with field investigation and trench excavation verification,the spatial distribution and structural characteristics of the target fault are revealed.Results show that:①The Haifengyuan Fault is basically a straight and single fault.The linear characteristics of the fault on the remote sensing image are clear,and the macroscopic geomorphology is obvious.There are active landforms such as fault troughs,linear ridges,fault plug ponds,and water system dislocations along the fault.The fault is characterized as a sinistral strike slip movement.②The electrical structure anomaly of the inverted profile of the high-density electrical survey line near the fault-fracture zone are in good agreement with the location,the fracture-zone width and the dip of the fault confirmed by trench excavation.The overall strike of the fault is N20°E and the dip is SE,and the width of the fracture zone can be identified as 60 m.The geological survey finds that the Haifengyuan Fault faulted the overlying Holocene diluvium,showing significant active characteristics in the late Quaternary.The Haifengyuan Fault belongs to the Holocene active fault,which must be kept away from by the construction projects.③To carry out an active-fault detection in quaternary-covered area,it is advisable to take the comprehensive technical means of remote sensing and geophysical exploration,to determine the distribution and structure of the fault and then draw a conclusion in a geological way.Thus,the accuracy and reliability of active-fault location can be greatly improved.