| 走滑断层地震地表破裂带分布影响因素数值模拟研究——以1973年炉霍MS7.6地震为例 |
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| 引用本文： | 李红, 邓志辉, 陈连旺, 周庆, 冉洪流, 邢成起. 2019. 走滑断层地震地表破裂带分布影响因素数值模拟研究——以1973年炉霍MS7.6地震为例. 地球物理学报, 62(8): 2871-2884, doi: 10.6038/cjg2019M0240 |
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| 作者姓名： | 李红 邓志辉 陈连旺 周庆 冉洪流 邢成起 |
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| 作者单位： | 1. 中国地震局地质研究所, 北京 100029; 2. 北京市地震局, 北京 100080; 3. 广东省地震局, 广州 510070; 4. 中国地震局地壳应力研究所, 北京 100085 |
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| 基金项目： | 地震动力学国家重点实验室开放基金（LED2018B06），国家自然科学基金项目（40841016），国家科技支撑项目（2012BAK15B01-10），地震科技星火计划（XH18001Y，XH19001Y）和中国地震局震情跟踪任务（2016010113）共同资助. |
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| 摘 要： | 地震后在断层两侧的强变形与破裂带是地震灾害最严重的区域.为系统、定量研究同震地表变形带特征及其影响因素，本研究建立了走滑断层的三维有限元模型，分别探讨了断层位错量、断层倾角、错动方式、上覆松散层厚度、沉积层土性等因素的影响规律.模拟结果显示：走滑断层同震地表变形表现为以断层为中心的近似对称单峰分布，强地表变形集中在断层两侧各50 m宽度范围，地表变形量峰值随位错量增加而增大，破裂带宽度也随位错量增加而增大，但增量逐渐减小，并趋于一个渐近值；断层倾角对地表变形与破裂带宽度影响表现为随倾角减小变形量峰值点向上盘小距离偏移；走滑兼正断位错引起的变形量峰值最大，但地表破裂带宽度最小，走滑兼逆断引起的变形量峰值最小，但地表破裂带宽度最大，直立纯走滑断层的两参量都居中；走滑断层地表变形量峰值随上覆松散层厚度增大而减小，但随厚度减小的速率逐渐变小，松散层厚度从5 m增加到20 m时，破裂带宽度随厚度增加而缓慢增加，但自厚度大于20 m时，破裂带宽度开始随厚度增加而逐渐下降；当不同土性覆盖层（粗砂、粉砂、黏土）厚度相同时，地震引起的地表变形量峰值自粗砂、粉砂、黏土逐次增大，当粗砂厚度为60 m以上时，3.6 m的同震水平位错已不能形成地表破裂，而粉砂的厚度为70 m以上，黏土的厚度则为75 m以上.
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| 关 键 词： | 走滑断层 地表破裂带分布 影响因素 数值模拟 |
| 收稿时间： | 2018-04-14 |
| 修稿时间： | 2018-11-04 |
Simulation study on the influencing factors of surface rupture zone distribution of strike-slip fault:take Luhuo MS7.6 earthquake in 1973 for example |
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| LI Hong, DENG ZhiHui, CHEN LianWang, ZHOU Qing, RAN HongLiu, XING ChengQi. 2019. Simulation study on the influencing factors of surface rupture zone distribution of strike-slip fault:take Luhuo MS7.6 earthquake in 1973 for example. Chinese Journal of Geophysics (in Chinese), 62(8): 2871-2884, doi: 10.6038/cjg2019M0240 |
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| Authors: | LI Hong DENG ZhiHui CHEN LianWang ZHOU Qing RAN HongLiu XING ChengQi |
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| Affiliation: | 1. Institute of Geology, China Earthquake Administration, Beijing 100029, China; 2. Beijing Earthquake Agency, Beijing 100080, China; 3. Earthquake Agency of Guangdong Province, Guangzhou 510070, Guangzhou; 4. The Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China |
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| Abstract: | The strong deformation and fracture zone on both sides of the fault is the most serious area of earthquake disaster. In order to study on the surface deformation zone characteristics of co-seismic and its influencing factors quantitatively and scientificly, a 3-D finite element model of strike-slip fault is established and the effect law of dislocations, fault dip, dislocation mode, thickness of sedimentary layer are discussed respectively. The simulation results show that the co-seismic surface deformation of the strike-slip fault is approximately symmetric single-peak distribution centered on the fault, and the strong surface deformation is concentrated in the 50 m width range on both sides of the fault. The peak value of surface deformation increases with the increase of dislocations, and the rupture zone width increases with the increase of dislocations too, but the increment decreases gradually and tends to an asymptotic value. The effect of fault dip on the surface deformation and rupture zone width is that the peak value point of deformation deviates to the hanging wall at a small distance with decreasing of fault dip. The peak value of deformation of normal strike-slip is the largest, but rupture zone width is the smallest, the peak value of deformation of thrust strike-slip is the smallest, but rupture zone width is the largest, while both parameters of vertical pure strike-slip fault are in the middle. The peak value of surface deformation of strike-slip fault decreases with the increase of the thickness of the loose sedimentary layer, but the rate decreases gradually with the increase of the thickness. When the thickness of sedimentary layer increases from 5 m to 20 m, the rupture zone width increases slowly with the increase of thickness. However the rupture zone width begins to decrease with the increase of thickness when thickness is larger than 20 m. When the thickness of different soil cover layers (coarse sand, silt, clay) is the same, the peak value of surface deformation increases successively from coarse sand, silt and clay. And when the thickness of coarse sand is more than 60 m, the horizontal co-seismic dislocation of 3.6 m can no longer form the surface rupture. The thickness of silt and clay is more than 70 m and 75 m respectively. |
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| Keywords: | Strike-slip fault Surface rupture distribution Influencing factors Simulation |
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