| 乳山震群震源区三维P波速度结构的层析成像 |
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| 引用本文： | 李霞,张正帅,冀东普,董晓娜,林眉,李小晗.乳山震群震源区三维P波速度结构的层析成像[J].地震学报,2020,42(5):552-566. |
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| 作者姓名： | 李霞 张正帅 冀东普 董晓娜 林眉 李小晗 |
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| 作者单位： | 中国济南 250102 山东省地震局 |
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| 基金项目： | 山东省地震局重点基金（JJ1701）资助 |
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| 摘 要： | 基于山东省地震台网固定台站及乳山台阵的流动观测资料，利用双差层析成像方法对乳山震群及附近地区地壳浅层15 km深度以内的三维P波速度结构进行了反演。结果显示，研究区内的隆起区（如垛崮山、大孤山）及海洋所镇附近的超高压岩体为高速区，连接两者之间的白沙滩呈低速特征，乳山序列即发生在高、低速过渡带偏高速区的一侧。速度结构剖面显示，乳山序列下方的地壳内存在明显的类椭圆状的相对低速区域，序列活动基本处于该低速区域与第四纪盖层之间的高速夹层。综合考虑序列展布、区域地质构造及高低速岩体间的位置关系，本文推测在区域应力调整背景下，局部介质的不稳定性在乳山序列的发生过程中起主要作用。
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| 关 键 词： | 乳山震群 双差层析成像 P波速度结构 介质属性 |
| 收稿时间： | 2019-11-04 |
Three-dimensional P-wave velocity structure tomography in the source area of Rushan earthquake swarm |
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| Affiliation: | Shandong Earthquake Agency，Ji’nan 250102，China |
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| Abstract: | Based on the observation data recorded by the fixed stations in Shandong seismic network and by portable stations of Rushan array, the three-dimensional P-wave velocity structure of the shallow crust within 15 km depth in the source region of Rushan earthquake swarm and its surrounding areas is studied by using the double difference tomographic method. The results show that the uplifted area （such as Duogushan and Dagushan） and the ultrahigh pressure rock mass near the Haiyangsuo town are high-velocity areas, and the white sand beach between the two areas is characterized by low-velocity, the Rushan sequence occurred on the side of the high-velocity of the high-low velocity transitional zone. The velocity structure section shows that the crust beneath the Rushan sequence has an obvious ellipse-like relatively low velocity region, the sequence is basically located in the high-velocity interlayer between the low-velocity area and the Quaternary cap rock. Considering the sequence distribution, regional geological structure and the position relationship between high and low velocity rock masses, it is speculated that under the background of regional stress adjustment, the instability of local medium plays an important role in the occurrence of Rushan earthquake sequence. |
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