青藏高原东南缘及邻区地壳介质非均匀性谱结构

发布时间：2019-05-21 19:57

【摘要】：用S波包络展宽法对青藏高原东南缘及邻区地壳介质非均匀性谱结构进行了研究,并以8~16Hz非均匀性谱结构为例分析了地壳介质非均匀性空间特征及其与强震孕育之间的关系。结果表明,研究区内地壳介质呈现强烈的、复杂的横向非均匀性。上地壳上部区域,沿龙门山断裂带、安宁河断裂带北段介质非均匀性程度相对较强,非均匀体尺度相对较小;鲜水河断裂带炉霍—道孚段、安宁河断裂带南段介质非均匀性程度相对较弱,非均匀体尺度相对较大。上地壳下部区域,沿龙门山断裂带、安宁河断裂带北段、鲜水河断裂带炉霍—道孚段、莲峰断裂沿线地壳介质非均匀性程度相对较强,沿鲜水河断裂带道孚—康定地区介质非均匀性相对较弱。中地壳,汶川—都江堰段、宝兴—康定段以及康定—石棉段介质非均匀性程度相对较强,而炉霍—康定西北地区,莲峰断裂沿线介质非均匀性程度相对较弱。对比发现中强震孕育、发生与介质非均匀性具有较强的相关性,中强震震中分布在介质非均匀性强弱过渡带上。强烈的、复杂的介质非均匀性可能与区内复杂的地质构造运动、频繁的地震活动所引起深部物质破碎、熔融及其沿断裂带的上涌、运移有关。
[Abstract]:The heterogeneous spectral structure of crustal media in the southeast margin of Qinghai-Xizang Plateau and its adjacent areas is studied by using S-wave envelope broadening method. Taking 8~16Hz inhomogeneous spectral structure as an example, the spatial characteristics of inhomogeneity of crustal media and its relationship with the preparation of strong earthquakes are analyzed. The results show that the crustal media in the study area show strong and complex transverse inhomogeneity. In the upper part of the upper crust, along the Longmenshan fault zone, the inhomogeneity of the media in the northern section of the Anning River fault zone is relatively strong, and the scale of the heterogeneous body is relatively small. In the Luhuo-Daofu section of the Xianshuihe fault zone and the southern section of the Anning River fault zone, the degree of inhomogeneity of the media is relatively weak and the scale of the heterogeneous body is relatively large. In the lower part of the upper crust, along the Longmenshan fault zone, the northern section of the Anning River fault zone, the Luhuo-Daofu section of the Xianshuihe fault zone, the heterogeneity of crustal media along the Lianfeng fault is relatively strong. The inhomogeneity of media in Daofu-Kangding area along Xianshuihe fault zone is relatively weak. In the middle crust, Wenchuan-Dujiangyan section, Baoxing-Kangding section and Kangding-Shimian section, the degree of media inhomogeneity is relatively strong, while in the northwest of Luhuo-Kangding, the degree of media inhomogeneity along Lianfeng fault is relatively weak. It is found that the occurrence of moderate and strong earthquakes is strongly correlated with the inhomogeneity of the medium, and the epicenter of the medium and strong earthquakes is distributed in the transition zone of the inhomogeneity of the medium. Strong and complex media inhomogeneity may be related to the deep material breakage, melting and upwelling and migration along the fault zone caused by the complex geological tectonic movement and frequent seismic activity in the area.
【作者单位】：南京工业大学;江苏省地震局;四川省地震局;
【基金】：国家自然科学基金(41074036)资助
【分类号】：P315.2

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