密集台阵主动源与被动源联合探测珠三角地壳结构  

Passive and active source imaging of the deep structure in the Pearl River Delta using a dense nodal array

作　　者：魏运浩 杨海燕[2] 李玮 王高春 Wei Yunhao;Yang Haiyan;Li Wei;Wang Gaochun(Chinese Academy of Geological Sciences,Beijing 100037,China;School of Earth Sciences,Yunnan University,Kunming 650091,China;School of Geophysics and Geomaties,China University of Geosciences(Wuhan),Wuhan 430074,China;School of Ecology and Environment,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]中国地质科学院,北京100037 [2]云南大学地球科学学院,昆明650091 [3]中国地质大学(武汉)地球物理与空间信息学院,武汉430074 [4]郑州大学生态与环境学院,郑州450001

出　　处：《地球与行星物理论评（中英文）》2025年第2期193-200,共8页Reviews of Geophysics and Planetary Physics

基　　金：国家自然科学基金资助项目(42174067);国家自然科学基金青年基金资助项目(41604048)。

摘　　要：基于密集台阵的远震接收函数探测与人工地震测深使用相同的观测系统、观测仪器,人工地震测深的优势在于构建地壳上地幔精细速度结构模型,密集台阵接收函数成像的优势在于构建地壳几何结构模型,密集台阵主动源与被动源的联合探测方法可以有效地扩展和提升深部探测的成果和认识.本研究使用珠三角地区人工地震测深L1测线的连续数据,开展了被动源远震接收函数成像研究,联合人工地震测深获得的地壳P波速度结构模型,构建了L1测线下方的地壳几何结构模型以及地壳平均波速比分布,揭示了珠三角西岸的地壳结构和断裂带的特征,主要包括:(1)地壳厚度28~30 km,过吴川—四会断裂后向东南方向减薄;(2)地壳平均波速比在测线中部吴川—四会断裂附近为~1.73,两侧小于1.70;(3)中地壳内存在低速构造,横向上被恩平—开平断裂带分隔.基于上述结果认为珠三角地区的地壳经历过明显的减薄作用,偏低的地壳平均波速比和下地壳V_(P)说明主要由下地壳减薄导致,推测吴川—四会断裂和恩平—开平断裂深部向东倾斜,并深切至Moho面,断裂带的形成演化受控于区域岩石圈地幔的热隆作用以及东南向的伸展作用.基于密集台阵的主动源与被动源联合探测方法,能为认识精细的地壳上地幔结构特征提供多参数、多尺度的约束,对刻画界面属性、断裂延伸、流熔体分布等都有重要指示意义,在深部结构探测和矿产资源勘查等领域具有广阔的应用前景.The methods of deep seismic sounding(DSS)and dense nodal array(DNA)are based on the same observation systems and instruments.DSS offers advantages in constructing velocity models of the crust and upper mantle,whereas DNA is used to build crustal geometric models.Combining DSS and DNA can effectively enhance the deep earth exploration techniques.This study provides an example of such integration.We applied the teleseismic receiver function imaging method to the continuously recorded data from the DSS profile L1 and constructed a crustal geometric structure model for the Pearl River Delta.The study revealed the following characteristics of the crustal structure and fault zone:(1)the crustal thickness is 28–30 km,thinning gradually southeast of the Wuchuan-Sihui fault;(2)the average crustal V_(P)/VS is~1.73 near the Wuchuan-Sihui fault,but<1.70 in other segments;and(3)a low-velocity zone exists in the upper to middle crust,horizontally separated by the Enping-Kaiping fault zone.These results suggest that the crust of the Pearl River Delta region has undergone significant thinning.The low average crustal V_(P)/VS and lower crustal V_(P) indicate that this is mainly caused by the lower crust thinning.We propose that the Wuchuan-Sihui and Enping-Kaiping faults dip eastward into the deep crust and may penetrate the Moho.The formation and evolution of these faults are controlled by thermal uplift and the southeastern extension of the lithospheric mantle.Joint exploration using DSS and DNA provides multi-parameter and multiscale constraints on the crust and upper mantle structures,offering significant insights into the interface properties,fault extension,and melt flow distribution.The combined DSS and DNA techniques has broad applications in deep structural probing and mineral resource exploration.

关 键 词：人工地震测深 短周期密集台阵 珠三角地区 

分 类 号：P315[天文地球—地震学]