利用微动台阵初勘目标区断裂位置及地层分布情况——以滨海区评为例∗

Preliminary Survey of Fracture Location and Stratigraphic Distribution in Target Area using Microtremor Array: a Case Study of the Coastal Area Assessment

摘要:

在滨海某地震安全性评价项目中，针对目标区面积大、覆盖层厚度大、地下隐伏构造复杂等问题，采用微动勘探方法加密观测目标区，获得了界牌-滨淮农场断裂的空间位置、目标区三维S 波速度结构；并将微动探测结果与主动源地震勘探、剪切波速测井展开对比分析。结果表明：（1）针对界牌-滨淮农场断裂，微动探测与主动源地震勘探两种方法所揭示的断裂特征较为一致，作为初勘成果具有较强的应用价值；（2）在100 m 深度范围以内，微动探测与波速测井所获得的剪切波速度值相近，因此微动探测技术可用于场地类别的快速判定；（3）微动探测技术相比测井和主动源地震勘探，可更经济快速的探明深部地层的速度结构，为目标区地层三维建模提供拓展资料及修正依据。

Abstract:

In a seismic safety evaluation project in a coastal area, microtremor detection method wasadopted to densely observe the target area, addressing issues such as large target area, significantthickness in overburden layers, and complex subsurface concealed structures. This approach success-fully determined the spatial location of the Jiepai-Binhuai Farm Fault and the 3D S-wave velocitystructure of the target area. The microtremor detection results were analyzed and compared with datafrom active source seismic exploration and shear wave velocity logging. The results showed that: (1)For the Jiepai-Binhuai Farm Fault, the characteristics revealed by both microtremor detection and ac-tive source seismic exploration were relatively consistent, demonstrating significant application valueas preliminary exploration results; (2) Within a depth of 100 m, the shear wave velocity values ob-tained from microtremor detection were similar to those from wave velocity logging, indicating that