Seismic Activity and Gravity Anomaly Characteristics of Yutian in Xinjiang and Surrounding Regions
-
摘要: 基于最新重力场模型对2014年于田Ms7.3地震震区的重力异常特征进行分析, 并应用Crust1.0地壳模型计算得到震区的深部构造形态, 结果显示: 震中位于地壳厚度陡变带上.同2008年于田Ms7.3地震相比, 震中虽位于不同位置, 但发震机制均与深部地壳结构变化密切相关.统计研究区内历史地震活动性与重力异常之间的关系, 发现震中的自由空气异常与地形存在明显的线性相关性, 而布格异常和均衡异常的结果则明显不同.进一步地分别计算不同重力异常的水平总梯度和线性信号, 结果表明: 重力异常梯度量与地形的相关特性更明显.研究表明: Ms7.0以上大震活动与重力异常之间具有明显的统计特性学, 这可能与重力异常反映的深部结构和壳内质量分布的不均匀有关.Abstract: The latest model of the gravitational field was used in the analysis of the gravity anomaly characteristics in the Yutian seismic zone and surrounding regions. The layered crustal structure model (Crust1.0) has been applied to obtain the deep tectonic structure around the seismic zone. This epicenter occurred in the steep variations of the crustal thickness. Contrast to the Ms7.3 earthquake in 2008 in this region, although these two epicenter were located in different 3-D spaces, they are closely related to the changes in the deep crustal structures. Besides, based on the statistical analysis of the relationship between the seismicity of historical earthquakes (Ms≥5.0) and three different gravity anomalies, we found that the free-air gravity anomalies in the seismic zone are in an obvious linear correlation to the topography, while the Bouguer anomaly and isostatic anomaly are distinctly different with the topography. In addition, the total gorizontal gradient (HGM)of the anomalies were calculated and the analytical signal (ASL) was plotted, which suggest that the gradient values are more distinctly correlated. The results show that a significant statistical characteristic exists between the activities of the strong earthquakes (Ms≥7.0) and the gravity anomalies, which may be related to the mass uneven distribution of the deep structure which caused the gravity anomaly.
-
Key words:
- Yutian earthquake /
- Seismic activity /
- gravity anomaly /
- crust model /
- statistical characteristics /
- earthquake
-
图 1 新疆于田构造背景和重力异常
a.研究区地形、断裂分布及活动地块边界; b.研究区主要地震活动(1970年以来Ms5.0以上地震)与自由空气重力异常.a中红色实线为活动断裂分布，蓝色实线为行政区边界，红色和黄色分别为一级和二级活动块体；b中地震震中位置用黑色圆圈表示其大小与圆圈直径正相关，于田两次Ms7.3地震用红色五角星表示.图 1a中的地形数据来源于EGM2008模型；b中的自由空气重力异常数据来源于Topex网站最新V22.1版本数据，并经过了Guass 50 km低通滤波，重力单位mGal=10-5 m/s2
Fig. 1. The tectonic setting and gravity anomaly of Yutian in Xinjiang
图 2 研究区布格重力异常与均衡重力异常特征
a.研究区布格重力异常；b.研究区均衡重力异常.图中红色实线为活动断裂分布，本次于田两次Ms7.3地震用红色五角星表示；图a和b中的重力异常网格精度为4 km，重力单位mGal=10-5 m/s2，并统一为Guass 50 km低通滤波结果，坐标采用Lambert平面投影，中央经纬度分别为82.5°，36.1°；均衡重力异常计算中选取的地壳平均深度为30 km，壳幔密度差0.45 g/m3
Fig. 2. The Bouger gravity and isostacy gravity anomaly of the research region
图 3 跨震中南北向剖面地形起伏、深部构造和重力异常变化数据
a.剖面位置的重力异常曲线；b.剖面位置深部构造界面、地震活动及地形起伏.FGA表示自由空气重力异常BGA布格重力异常IGA均衡重力异常，重力单位mGal=10-5 m/s2；TB塔里木盆地；F1雅鲁藏布江断裂F2郭扎错断裂2008年于田M7.3地震发震断裂F3阿尔金断裂2014年于田M7.3断裂发震断裂F4矛头山断裂F5哈尔克山断裂带F6喀什河断裂以上符号和说明与下图相同；图中地形数据来源于图 1相同，地震目录由中国地震台网提供，其中部分地震没有震源深度数据统一设置为10 km
Fig. 3. The topography, deep structure and gravity anomaly data of the south-north profile through the epicenter of Yutian in Xinjiang in 2014
图 6 研究区内地震震中位置的重力异常水平总梯度与地形高程相关关系
a.自由空气重力异常水平总梯度与高程关系; b.布格重力异常水平总梯度与高程关系; c.均衡重力异常水平总梯度与高程关系.图中各符号和图标含义与图 5一致，其中重力梯度单位为10-5/s2
Fig. 6. The relationship of the gravity anomaly and topography of the epicenter of earthquakes in research region
图 7 研究区内地震震中位置的重力解析信号与地形高程相关关系
a.自由空气重力异常解析信号与高程关系; b.布格重力异常解析信号与高程关系; c.均衡重力异常解析信号与高程关系.图中各符号和图标含义与图 5一致，其中重力梯度单位为10-5/s2
Fig. 7. The relationship of the gravity anomaly and topography of the epicenter of earthquakes in research region
表 1 研究区1970年以来Ms7.0以上历史地震活动
Table 1. The historical seismicity exceed Ms7.0 in related religion after 1970
编号 发震时间和名称 构造位置与震源机制 位置(经/纬) 深度(km) 震级 1 1985年8月23日乌恰地震 卡兹克阿尔特断裂带/右旋 39.53°E/75.32°N 18 7.4 2 1996年11月19日和田地震 喀喇昆仑断裂带/右旋走滑 35.43°E /78.35°N 16 7.1 3 1997年11月18日玛尼地震 茶卡-若拉错断裂/走滑 35.20°E /87.30°N 10 7.4 4 2001年11月4日昆仑山地震 东昆仑断裂带/左旋滑动 35.97°E /90.59°E 10 8.1 5 2008年3月21日于田地震 郭扎错断裂/拉张型 35.80°E /81.43°N 26 7.3 6 2014年4月12日于田地震 阿尔金断裂西段/走滑型 36.10°E /82.50°N 12 7.3 
下载: 导出CSV
-
[1] Chen, C.Y., Ren, J.W., Meng, G.J., et al., 2013. Division, Deformation and Tectonic Implication of Active Blocks in the Eastern Segment of Bayan Har Block. Chinese J. Geophys., 56(12): 4125-4141 (in Chinese with English abstract). http://www.researchgate.net/publication/283838298_Division_deformation_and_tectonic_implication_of_active_blocks_in_the_eastern_segment_of_Bayan_Har_block [2] Cui, J.W., Zhang, X.W., Li, P.W., 2002. The Altun Fault: Its Geometry, Nature and Mode of Growth. Acta Geoscientia Sinica, 23(6): 509-516 (in Chinese with English abstract). http://www.cqvip.com/QK/86253X/20012/1001445424.html [3] Fernández, M., Fullea, J., Zeyen, H., 2008. FA2BOUG—A FORTRAN 90 Code to Compute Bouguer Gravity Anomalies from Gridded Free-Air Anomalies: Application to the Atlantic-Mediterranean Transition Zone. Computers & Geosciences, 34(12): 1665-1681. doi: 10.1016/j.cageo.2008.02.018 [4] Gao, X., Deng, Q.D., 2013. Activity Analysis of Large Earthquakes in Boundary Faults around the Bayankala Faulting Block. Acta Geologica Sinica, 87(1): 9-19 (in Chinese with English abstract). http://www.researchgate.net/publication/285736964 [5] Geng, T., Tian, Q.N., Yang, H.Q., et al., 2008. Constraints of the Regional Gravitational Field on the Trend and Extension of the Southwestern Part of the Altyn Tagh Fault. Geology in China, 35(5): 841-848 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DIZI200805006.htm [6] Laske, G., Masters, G., Ma, Z., et al., 2013. Update on Crust 1.0 A 1-Degree Global Model of Earth's Crust. Geophys. Res. Abstracts, 15: 2658. http://adsabs.harvard.edu/abs/2013EGUGA..15.2658L [7] Li, Q.S., Peng, S.P., Gao, R., et al., 2003. Seismic Evidence of the Basement Uplift in the Bayan Har Tectonic Belt, Qinghai, and Its Tectonic Significance. Geological Bulletin of China, 22(10): 782-788 (in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTotal-ZQYD200310005.htm [8] Li, Y., Oldenburg, D.W., 1998. Separation of Regional and Residual Magnetic Field Data. Geophysics, 63(2): 431-439. doi: 10.1190/1.1444343 [9] Li, Z.H., Ma, H.S., Qu, Y.J., 2009. Study on Seismogenic Structure and Seismic Activity Characteristics before the Yutian Ms7.3 Earthquake on March 21, 2008, Xinjiang. Earthquake Research in China, 25(2): 199-205(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZGZD200902012.htm [10] Liu, M., Stein, S., Wang, H., 2011a., 2000 Years of Migrating Earthquakes in North China: How Earthquakes in Midcontinents Differ from Those at Plate Boundaries. Lithos, 3(2): 128-132. doi: 10.1130/L129.1 [11] Liu, M., Yang, Y., Li, Q., et al., 2011b. Parallel Finite Element Modeling of Multi-Timescale Faulting and Lithospheric Deformation in the Western US. In: Keller, R., Baru, C., eds., Cyberinfrastructure for Geosciences. Cambridge Press, London, 68-94. [12] Ren, S.M., Ge, X.H., Liu, Y.J., 2003. Progress in Altyn Fault Belts Research. Advance in Earth Sciences, 6(3): 386-391(in Chinese with English abstract). http://www.adearth.ac.cn/EN/abstract/abstract480.shtml [13] Sandwell, D.T., Garcia, E., Soofi, K., et al., 2013. Toward 1-mGal Accuracy in Global Marine Gravity from CryoSat-2, Envisat, and Jason-1. The Leading Edge, 32(8): 892-899. doi: 10.1190/tle32080892.1 [14] Sandwell, D.T., Smith, W.H.F., 1997. Marine Gravity Anomaly from Geosat and ERS 1 Satellite Altimetry. Journal of Geophysical Research: Solid Earth, 102(B5): 10039-10054. doi: 10.1029/96JB03223 [15] Sandwell, D.T., Smith, W.H.F., 2009. Global Marine Gravity from Retracked Geosat and ERS-1 Altimetry: Ridge Segmentation versus Spreading Rate. Journal of Geophysical Research, 114(B1): B01411. doi: 10.1029/2008JB006008 [16] Shen, J., Song, H.P., Chen, J.B., et al., 2013. Field Investigation on the Near-Fault Damaging Effects of the 2008 Yutian Ms7.1 Earthquake in Xinjiang, China. Earth Science Frontiers, 20(6): 85-93 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY201306015.htm [17] Smith, W.H.F., Sandwell, D.T., 1997. Global Sea Floor Topography from Satellite Altimetry and Ship Depth Soundings. Science, 277(5334): 1956-1962. doi: 10.1126/science.277.5334.1956 [18] Stein, S., Liu, M., Calais, E., et al., 2009. Mid-Continent Earthquakes as a Complex System. Seismological Research Letters, 80(4): 551-553. doi: 10.1785/gssrl.80.4.551 [19] Song, T.R.A., Simons M., 2003. Large Trench-Parallel Gravity Variations Predict Seismogenic Behavior in Subduction Zones. Science, 301(5633): 630-633. doi: 10.1126/science.1085557 [20] Wan, Y.G., Shen, Z.K., Shen, S.Z., et al., 2010. The Mechanical Effects of the 2008 Ms7.3 Yutian, Xinjiang Earthquake on the Neighboring Faults and Its Tectonic Origin of Normal Faulting Mechanism. Chinese J. Geophys, 53(2): 280-289 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DQWX201002007.htm [21] Wang, Q.S., 2003. Gravitology. Seismological Press, Beijing, 128-147 (in Chinese). [22] Wang, W.Y., 2010. Spatial Variation Law of the Extreme Value Positions of Total Horizontal Derivative for Potential Field Data. Chinese J. Geophys. , 53(9): 2257-2270 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQWX201009028.htm [23] Xu, X.W., Tan, X.B., Wu, G.D., et al., 2011. Surface Rupture Features of the Yutian Ms7.3 Earthquake and Its Tectonic Nature. Seismology and Geology, 33(2): 462-471(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DZDZ201102024.htm [24] Xu, Z.Q., Yang, J.S., Zhang, J.X., et al., 1999. A Comparison between the Tectonic Units on the Two Sides of the Altun Sinistral Strike-Slip Fault and the Mechanism of Lithospheric Shearing. Acta Geologica Sinica, 73(3): 193-205(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DZXE199903000.htm [25] Yang, X.Y., Chen, L.W., Yang, L.M., et al., 2013. Numerical Simulation on Strong Earthquake Dynamic Process of Bayan Har Block. Acta Seismologica Sinica, 35(3): 304-314(in Chinese with English abstract). http://www.researchgate.net/publication/289255257_Numerical_simulation_on_strong_earthquake_dynamic_process_of_Bayan_Har_block [26] Zhang, G.M., Zhang, P.Z., 1999. Recent Research Progress on the Mechanism and Forcast for Continental Strong Earthquakes. China Basic Science, (Z1): 47-58(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZGJB200403001.htm [27] Zhang, P.Z., Deng, Q.D., Zhang, G.M., et al., 2003. Strong Earthquake Activities and Continental Block of Mainland China. Science in China (Series D), 33(S1): 12-20(in Chinese). [28] Zhang, Y., Xu, L.S., Chen, Y.T., et al., 2014. Fast Inversion for the Rupture Process of the 12 February 2014 Yutian Mw6.9 Earthquake: Discussion on the Impacts of Focal Mechanisms on Rupture Process Inversions. Acta Seismologica Sinica36(2): 159-164(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DZXB201402001.htm [29] 陈长云, 任金卫, 孟国杰, 等, 2013. 巴颜喀拉块体东部活动块体的划分、形变特征及构造意义. 地球物理学报, 56(12): 4125-4141. doi: 10.6038/cjg20131217 [30] 崔军文, 张晓卫, 李朋武, 2002. 阿尔金断裂: 几何学、性质和生长方式. 地球学报, 23(6): 509-516. doi: 10.3321/j.issn:1006-3021.2002.06.005 [31] 高翔, 邓起东, 2013. 巴颜喀喇断块边界断裂强震活动分析. 地质学报, 87(1): 9-19. doi: 10.3969/j.issn.0001-5717.2013.01.002 [32] 耿涛, 田黔宁, 杨汇群, 等, 2008. 阿尔金断裂西南端走向及延伸的区域重力场制约. 中国地质, 35(5): 841-848. doi: 10.3969/j.issn.1000-3657.2008.05.005 [33] 李秋生, 彭苏萍, 高锐, 等, 2003. 青藏高原北部巴颜喀拉构造带基底隆起的地震学证据. 地质通报, 22(10): 782-788. doi: 10.3969/j.issn.1671-2552.2003.10.006 [34] 李志海, 马宏生, 曲延军, 2009.2008年3月21日新疆于田7.3级地震发震构造与震前地震活动特征研究. 中国地震, 25(2): 199-205. doi: 10.3969/j.issn.1001-4683.2009.02.011 [35] 任收麦, 葛肖虹, 刘永江, 2003. 阿尔金断裂带研究进展. 地球科学进展, 6(3): 386-391. doi: 10.3321/j.issn:1001-8166.2003.03.010 [36] 沈军, 宋和平, 陈建波, 等, 2013.2008年3月21日新疆于田7.1级地震近断层破坏作用. 地学前缘, 20(6): 89-97. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY201306015.htm [37] 万永革, 沈正康, 盛书中, 等, 2010.2008年新疆于田7.3级地震对周围断层的影响及其正断层机制的区域构造解释. 地球物理学报, 53(2): 280-289. doi: 10.3969/j.issn.0001-5733.2010.02.006 [38] 王谦身, 2003. 重力学. 北京: 地震出版社, 128-147. [39] 王万银, 2010. 位场总水平导数极值位置空间变化规律研究. 地球物理学报, 53(9): 2257-2270. doi: 10.3969/j.issn.0001-5733.2010.09.027 [40] 徐锡伟, 谭锡斌, 吴国栋, 等, 2011.2008年于田Ms7.3地震地表破裂带特征及其构造属性讨论. 地震地质, 33(2): 462-471. doi: 10.3969/j.issn.0253-4967.2011.02.019 [41] 许志琴, 杨经绥, 张建新, 等, 1999. 阿尔金断裂两侧构造单元的对比及岩石圈剪切机制. 地质学报, 73(3): 193-205. doi: 10.3321/j.issn:0001-5717.1999.03.001 [42] 杨兴悦, 陈连旺, 杨立明, 等, 2013. 巴颜喀拉块体强震动力学过程数值模拟. 地震学报, 35(3): 304-314. doi: 10.3969/j.issn.0253-3782.2013.03.003 [43] 张国民, 张培震, 1999. 近年来大陆强震机理与预测研究的主要进展中国基础科学, (Z1): 47-58. [44] 张培震, 邓起东, 张国民, 等, 2003. 中国大陆的强震活动与活动地块. 中国科学(D辑), 33(S1): 12-20. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK2003S1001.htm [45] 张勇, 许力生, 陈运泰, 等, 2014.2014年2月12日于田Mw6.9地震破裂过程初步反演: 兼论震源机制对地震破裂过程反演的影响. 地震学报, 36(2): 159-164. doi: 10.3969/j.issn.0253-3782.2014.02.001 -
点击查看大图
图(7) / 表(1)
计量
- 文章访问数: 2963
- HTML全文浏览量: 152
- PDF下载量: 593
- 被引次数: 0
