| 鄂尔多斯活动地块西缘强震间库仑应力作用 |
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| 引用本文： | 张瑞, 张竹琪, 郑德文, 刘兴旺, 雷启云, 邵延秀. 2021. 鄂尔多斯活动地块西缘强震间库仑应力作用. 地球物理学报, 64(10): 3576-3599, doi: 10.6038/cjg2021P0008 |
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| 作者姓名： | 张瑞 张竹琪 郑德文 刘兴旺 雷启云 邵延秀 |
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| 作者单位： | 1. 中国地震局地质研究所 地震动力学国家重点实验室, 北京 100029; 2. 中国科学院广州地球化学研究所 同位素地球化学国家重点实验室, 广州 510640; 3. 中国地震局兰州地震研究所, 兰州 730000; 4. 宁夏回族自治区地震局, 银川 750001; 5. 天津大学 表层地球系统科学研究院, 天津 300072 |
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| 基金项目： | 国家重点研发计划;次青藏高原科学考察综合研究专题;中卫市沙坡头区活断层探测项目 |
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| 摘 要： | 本文在梳理相关历史地震和活动构造研究的基础上，详细厘定了鄂尔多斯活动地块西缘1219—1920年10个M≥6½的历史强震的震源参数，建立了相应的黏弹性位错模型，计算分析了强震的同震和震后库仑应力变化与迁移，及其对后续强震断层面上应力作用特征.结果表明，公元1495—1920年间的7个强震存在明显的应力触发关系：随着前序强震的发生与作用，直至后序强震发生前，其断层面整体的累积库仑应力变化都出现了由缓慢变化到快速升高现象，其增长速率相差几倍到几十倍不等.与该现象相反，公元1495年前的强震间累积库仑应力变化以负值为主，没有显示出明显的触发关系.进一步的模拟研究还显示，这些早期的强震对1495及其后强震的发震断层所受到的库仑应力作用的极性和大小影响都不明显.整体上看，1495年前后强震间的库仑应力作用特点与同时期该地区地震应变能释放的相对缓慢和相对快速的两个阶段存在一致性，这种一致性指示出强震引起的库仑应力变化与迁移对鄂尔多斯活动地块西缘边界带可能存在的强震丛集发挥了重要作用.本研究所展示的强震间库仑应力变化的演化特点为进一步揭示强震间触发机制及其演化趋势提供了依据.
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| 关 键 词： | 鄂尔多斯活动地块西缘 库仑应力变化与迁移 应变能 强震丛集 |
| 收稿时间： | 2021-01-04 |
| 修稿时间： | 2021-06-07 |
Coulomb stress transfer of strong earthquakes within tectonic belts near western Ordos block |
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| ZHANG Rui, ZHANG ZhuQi, ZHENG DeWen, LIU XingWang, LEI QiYun, SHAO YanXiu. 2021. Coulomb stress transfer of strong earthquakes within tectonic belts near western Ordos block. Chinese Journal of Geophysics (in Chinese), 64(10): 3576-3599, doi: 10.6038/cjg2021P0008 |
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| Authors: | ZHANG Rui ZHANG ZhuQi ZHENG DeWen LIU XingWang LEI QiYun SHAO YanXiu |
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| Affiliation: | 1. State Key Laboratory Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China; 2. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; 3. Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China; 4. Earthquake Administration of Ningxia Hui Autonomous Region, Yinchuan 750001, China; 5. Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China |
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| Abstract: | From 1219 to 1920 A.D., ten M≥6½ earthquakes occurred successively within the tectonic belt along the western boundary of active Ordos block (WBO). Static source parameters of these earthquakes are synthetically assessed with aid of previous studies of historical earthquakes and active tectonics. Then the corresponding viscoelastic dislocation models are built to investigate the co-seismic and post-seismic Coulomb stress transfer among the earthquakes. Specifically, the temporal and spatial stressing processes on fault plane are analyzed in attempt to hunt diagnostic signs indicating a major earthquake be triggered or not. For the sequence between 1495 and 1920 A.D., our results reveal that the accelerative promotion of Coulomb stress due to preceding events gradually occurs in most area on the source planes of subsequent earthquakes before their occurrence, and the rates of Coulomb stress increase in the late phase could be several times or even several tens times faster than that in the earlier stage. In contrast, however, for those events before 1495 A.D., their source planes receive mainly negative accumulative Coulomb stress change, showing no significant triggering occurred among them. Furthermore, the exclusion of events before 1495 A.D. retrieves weak impacts on the polarities and magnitudes of stress transfer received by the later events. In addition, the overall rate of accumulative strain energy released by the strong earthquakes before 1495 A.D. is relatively slower than that in the later period, which on the whole agrees with the distinct modes of Coulomb stress transfer in respective periods. Such agreement probably indicates that the Coulomb stress transfer among strong earthquakes contributes a lot to the clustering of these earthquakes within the belt along WBO. As presented in this study, the characteristic development of Coulomb stress transfer on fault plane could provide clues to unveil the triggering mechanisms among strong earthquakes and to predict the trend of future events. |
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| Keywords: | The western boundary of active Ordos block Coulomb stress transfer Strain energy Clustering |
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