Detecting buried fault structures by microtremor survey method

  • 摘要: 介绍了运用微振动勘探方法探测隐伏断裂构造的方法和思路,并对郯庐断裂带两条分支断裂进行了试验性勘探.通过与人工地震勘探结果对比分析,发现微振动勘探方法对隐伏断裂构造具有较好的空间定位能力,其对岩性差异面形成的断裂定位误差与人工地震勘探结果相当; 又因其具有较大的勘探深度,因而可以有效揭示勘探区域下方地层及断裂的空间分布特征及其接触关系,这对于识别和确定断裂构造的主破裂面具有重要意义. 但微振动勘探方法对地层或断裂构造细节特征的揭示能力较差.因此,在实际地层或断裂勘探中,宜采用人工地震勘探方法与微振动勘探方法相结合的方式确定断裂的深浅构造关系,可以用微振动勘探方法进行普查,在确定断裂初步位置及空间展布特征后,再选用人工地震勘探方法进行断裂精确定位.

     

    Abstract: The methods and schemes of detecting buried fault structures using microtremor survey method are introduced, by which two branch faults of the Tanlu fault zone are explored. Comparison with the shallow seismic exploration results indicates that the spatial locating ability of microtremor survey method is better to detect the buried fault structure, the location error of fault caused by lithological differences is close to that from the results of the shallow seismic exploration. For its deep exploration ability, the microtremor survey method can reveal the spatial distribution characteristics as well as contact relationship between the strata and the faults beneath the microtremor survey arrays, which is important to identify and confirm the main rupture surface of faults. However, the microtremor survey method is difficult to reveal or describe the detail features of faults. To explore the strata or faults, it is the best to combine the shallow seismic exploration method with the microtremor survey method to study the relationship between deep and shallow faults. The microtremor survey method can be used to detect fault roughly, and then the shallow seismic method can be used to determine accurate position of faults after knowing the general location and spatial characteristic of faults.

     

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