| 唐山7.8级地震三维地表形变和断层运动特征 |
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| 引用本文： | 畅柳,武艳强,杨博,金涛. 唐山7.8级地震三维地表形变和断层运动特征[J]. 武汉大学学报(信息科学版), 2022, 47(6): 916-926. DOI: 10.13203/j.whugis20220159 |
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| 作者姓名： | 畅柳 武艳强 杨博 金涛 |
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| 作者单位： | 1.中国地震局第一监测中心, 天津，300180 |
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| 基金项目： | 中国地震局地震科技星火计划XH22019YA科技部基础性工作专项课题2015FY210403 |
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| 摘 要： | 通过系统收集整理1976年唐山7.8级地震前后区域水准和边角网观测资料，在研究发展动态平差程序的基础上，解算得到了唐山地震震前和同震三维形变定量结果与误差分布，并反演得到了断层面同震滑动分布。结果显示，震前阶段丰润-唐山-唐海-昌黎-迁安一带整体隆升，隆升高值区位于唐山附近，震中区的水平形变量不大，唐山菱形地块相对于周围地块逆时针扭转；同震阶段唐山断裂以右旋错动为主，并呈现西升东降的垂向变形特征；反演结果表明多段断层参与了唐山7.8级地震的应变释放，主震发震断层的南段破裂主要发生在深度约6~18 km、长轴约50 km范围，北段破裂主要发生在深度约7~17 km、长轴约30 km范围，滦县地震断层也发生了少量滑动；主震断层最大水平位错为7.82 m、最大垂直位错为2.04 m，等效震级为Mw 7.58。挖掘得到的唐山震前和同震三维形变场定量结果为深入研究该地震的孕育发生机制及地震影响提供了珍贵资料。
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| 关 键 词： | 唐山地震 传统大地测量资料 三维形变场 断层位错反演 |
| 收稿时间： | 2022-05-16 |
Characteristics of 3D Surface Deformation Characteristics and Seismogenic Fault Inversion of 1976 Tangshan Ms 7.8 Earthquake |
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| Affiliation: | 1.The First Monitoring and Application Center, China Earthquake Administration, Tianjin 300180, China |
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| Abstract: | Objectives On July 28, 1976, a strong Ms 7.8 earthquake sequence occurred in Tangshan, and the influence of this earthquake continues to now. Methods In order to study the deformation characteristics and seismogenic fault activities of Tangshan Ms 7.8 earthquake in 1976, we calculate quantitative results and error distribution of three-dimensional deformation before and after the 1976 Tangshan earthquake by dynamic adjustment method. And the coseismic slip distribution on the fault plane is also inversed in this paper. Results The deformation results show that before the 1976 Tangshan earthquake, an overall uplift area appeares near the epicenter and the peak area of uplift which is located near Tangshan, the horizontal deformation of the epicenter area is small, and the Tangshan rhombic block rotates counterclockwise relative to the surrounding block. In the coseismic period, the Tangshan fault is dominated by right-lateral strike slip, with the vertical deformation characteristics of rising in the west and falling in the east. The inversion results show that multi-segment faults participate in the energy release of Tangshan Ms 7.8 earthquake. The distribution of seismic slip is mainly distributed in 6-18 km depth and 50 km width in the southern segment, and 7-17 km depth and 50 km width in the northern segment.The fault of Luanxian earthquake also experiences little sliding. The maximum horizontal dislocation is 7.82 m, the maximum vertical dislocation is 2.04 m, and the equivalent magnitude is Mw 7.58. Conclusions The results of three-dimensional deformation field before and after the Tangshan earthquake provide valuable data for the in-depth study of the preparation and occurrence mechanism of the Tangshan earthquake and its impact. |
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