广西苍梧贺街-夏郢断裂遥感影像和小震分布

Remote Sensing Image Interpretation and Distribution of Small Earthquakes on Hejie-Xiaying Fault in Cangwu,Guangxi

采用遥感影像解译、小震精定位等方法,结合野外地震地质调查,分析了贺街-夏郢断裂附近的遥感影像特征和小震分布特征,并据此将贺街-夏郢断裂从南到北分为南段(夏郢镇毓秀-石桥镇新塘)、中段(石桥镇新塘-步头镇白石口)、北段(步头镇白石口以北)。结果显示,贺街-夏郢断裂中段卫星影像上线性特征明显,控制石桥-沙头盆地的发育,局部次级断裂控制NE向水系发育,苍梧MS5.4地震就发生在中段,附近有小震活动,初步推测中段第四纪以来有过活动;北段影像上有一定的线性特征,沿盆地边缘第四纪宽阔谷地发育,小震活动弱,初步推测北段第四纪以来可能有过活动;南段影像上线性特征不明显,多发育在基岩山体中,对沿途水系无错移,无小震活动,初步推测南段第四纪以来未曾活动。

This paper uses interpretation of remote sensing images and precise locating of small earthquakes to analyze the features of remote sensing images of Hejie-Xiaying fault and distribution of small earthquakes,and divide the fault into south segment(Yuxiu,Xiaying to Xintang,Shiqiao),middle segment(Xintang,Shiqiao to Baishikou,Butou)and north segment(northern Butou).The results show that the middle segment exhibits strong linear feature as revealed in remote sensing images,controls the growth of Shiqiao-Shatou basin with certain small earthquakes,and the Cangwu MS5.4 happened on this segment.It may be active in Quaternary period even in late Pleistocene and Holocene.Compared to the middle segment,the north segment shows linear feature to a less extent and weaker earthquake activities,it may be active in Quaternary period.The linear feature of the south segment is inconspicuous and mostly crossed bedrocks without small earthquakes,it was inactive in Quaternary period.