A PRELIMINARY STUDY ON UPPER CRUSTAL VELOCITY STRUCTURE IN THE THREE GORGES RESERVOIR AREA

doi:10.3969/j.issn.0253-4967.2016.02.008

Abstract

Abstract:

In this paper, using the double difference tomography method, the P wave and S wave velocity structures of the earth's crust beneath the Three Gorges Reservoir are inversed based on the high-resolution seismic data of seismological stations recorded from March 2009 to December 2010. According to the research results, the P wave and S wave crust velocity zones in the Three Gorges Reservoir area show a high V_P value area and a V_S value area with value low in the lower part and high in the upper part, distributing respectively at both sides of Shennongxi River to western Xietan in the north of Badong and near the outlet of the Xiangxi River at the northern section on Xiannvshan Fault. In the region from the two sides of Shennong River in the north of Badong to the western Xietan, microseisms are distributed in three zones in near east-west direction, with steep and north-dipping sections, spreading along the high-to-low velocity transition zone of the P and S wave. On the northern section of Xiannvshan Fault, small earthquakes are distributed along the NNW-trending Xiannvshan Fault, and the geological section reveals a steep and linear distribution along the transitional zone between the high V_P value area and the V_S value that is low in the upper and high in the lower part. Joint inversion results show a good consistency of the planes of the microseisms with the distribution of active faults.

Key words: double difference tomography, P and S-wave velocity structure, upper crust structure, Three Gorges Reservoir

摘要：

文中利用三峡加密观测台网记录的2009年3月到2010年12月高精度地震数据，使用双差层析成像方法，联合反演了三峡库区上地壳的震源位置参数和三维上地壳P波和S波速度结构。研究结果显示，三峡库区上地壳P波速度和S波速度区域出现2个高V_P值、上低下高V_S值区，分别在巴东北部神农溪两岸-泄滩西区域和仙女山断裂带北段香溪河口附近。巴东北部神农溪两岸-泄滩西区域，较小地震的平面分布呈3条近EW向的条带，剖面陡立、向N倾，沿着P波和S波高、低速过渡带分布；香溪河口附近地震沿NNW向的仙女山断裂带分布，地质剖面显示出地震陡立线性分布，沿着高V_P值、上低下高V_S值区的过渡带展布，联合反演得到的微震面与断裂构造分布具有较好的一致性。

关键词: 双差层析成像, P波速度, S波速度, 上地壳构造, 三峡水库

CLC Number:

P313.3

LUO Jia-hong, MA Wen-tao. A PRELIMINARY STUDY ON UPPER CRUSTAL VELOCITY STRUCTURE IN THE THREE GORGES RESERVOIR AREA[J]. SEISMOLOGY AND GEOLOGY, 2016, 38(2): 329-341.

罗佳宏, 马文涛. 三峡库区上地壳速度结构初步研究[J]. 地震地质, 2016, 38(2): 329-341.

References

陈学波, 陈步云, 张四维, 等. 1994. 长江三峡工程坝区及外围深部构造特征研究［M］. 北京:地震出版社. CHEN Xue-bo, CHEN Bu-yun, ZHANG Si-wei et al. 1994. Study of Deep Tectonic Characteristics in the Yangtze Three Gorges Dam and Adjacent Area［M］. Seismological Press, Beijing(in Chinese).
胡毓良. 1994. 诱发地震［J］. 国际地震动态. 6:37-38. HU Yu-liang. 1994. The induced earthquake［J］. Recent Developments in World Seismology, 6:37-38(in Chinese).
李峰, 韩晓玉, 但卫, 等. 2008. 三峡水库巴东地区的地震活动分析［J］. 大地测量与地球动力学, 28(4):63-67. LI Feng, HAN Xiao-yu, DAN Wei, et al. 2008. Analysis of seismicity in Badong area of Three Geoges Reservoir［J］. Journal of Geodesy and Geodynamics, 28(4):63-67(in Chinese).
李强, 赵旭, 蔡晋安, 等. 2009. 三峡水库坝址及邻区中上地壳 P 波速度结构［J］. 中国科学(D辑), 39(4):427-436. LI Qiang, ZHAO Xu, CAI Jin-an, et al. 2009. P-wave velocity structure of upper and middle crust beneath the Three Gorges reservoir dam and adjacent region［J］. Science in China(Ser D), 39(4):427-436(in Chinese).
李强, 赵旭, 蔡晋安, 等. 2011. 三峡水库坝址及邻区中上地壳S波速度结构［J］. 地震学报, 33(1):39-50. LI Qiang, ZHAO Xu, CAI Jin-an, et al. 2011. S-wave velocity structure of upper and middle crust beneath the Three Gorges reservoir dam and adjacent region［J］. Acta Seismologica Sinica, 33(1):39-50(in Chinese).
廖武林, 姚运生, 丁志峰, 等. 2007. 三峡地区 P 波速度层析成像研究［J］. 大地测量与地球动力学, 27(3):80-84. LIAO Wu-lin, YAO Yun-sheng, DING Zhi-feng, et al. 2007. Tomographic imagery of P wave velocity structure in Three Gorges region［J］. Journal of Geodesy and Geodynamics, 27(3):80-84(in Chinese).
廖武林, 张丽芬, 姚运生. 2009. 三峡水库地震活动特征研究［J］. 地震地质, 31(4):707-714. LIAO Wu-lin, ZHANG Li-fen, YAO Yun-sheng. 2009. Characteristics of seismicity in Three Gorges reservoir area［J］. Seismology and Geology, 31(4):707-714(in Chinese).
刘福田, 李强, 吴华, 等. 1989. 用于速度图像重建的层析成象法［J］. 地球物理学报, 32(1):46-61. LIU Fu-tian, LI Qiang, WU Hua, et al. 1989. On the tomographic inverse method used in velocity image reconstruction［J］. Acta Geophysica Sinica, 32(1):46-61(in Chinese).
马文涛, 徐长朋, 李海鸥, 等. 2010. 长江三峡水库诱发地震加密观测及地震成因初步分析［J］. 地震地质, 32(4):552-563. doi:10.3969/j.issn.0253-4967.2010.04.003. MA Wen-tao, XU Chang-peng, LI Hai-ou, et al. 2010. Intensive observation of reservoir-induced earthquake and preliminary analysis on the causes of earthquakes in Three Gorges Reservoir［J］. Seismology and Geology, 32(4):552-563(in Chinese).
王小龙, 马胜利, 郭志, 等. 2013. 利用地震背景噪声成像技术反演三峡库区及邻近地区地壳剪切波速度结构［J］. 地球物理学报, 56(12):4113-4124. doi:10.6038/cjg20131216. WANG Xiao-long, MA Sheng-li, GUO Zhi, et al. 2013. S-wave velocity of the crust in Three Gorges Reservoir and the adjacent region inverted from seismic ambient noise tomography［J］. Chinese Journal of Geophysics, 56(12):4113-4124(in Chinese).
王小龙, 倪四道, 刘渊源, 等. 2010. 利用远震接收函数分析三峡库区重庆段地壳厚度变化［J］. 地震地质, 32(4):543-551. doi:10.3969/j.issn.0253-4967.2010.04.002. WANG Xiao-long, NI Si-dao, LIU Yuan-yuan, et al. 2010. Study of crustal thickness variation in Chongqing section of Three Gorges Reservoir area from teleseismic receiver function method［J］. Seismology and Geology, 32(4):543-551(in Chinese).
赵凌云, 张辉, 陈俊华, 等. 2014. 基于CAP方法的2013湖北巴东5.1级地震震源机制与发震构造研究［J］. 地震工程学报, 36(4):1014-1018. ZHAO Ling-yun, ZHANG Hui, CHEN Jun-hua, et al. 2014. Focal mechanism solutions and seismogenic structure of the Badong M_S5.1 earthquake of 2013 using the CAP method［J］. China Earthquake Engineering Journal, 36(4):1014-1018(in Chinese).
钟以章. 1990. 用灰色系统理论预测锦凌水库的诱发地震［J］. 华南地震, 10(4):80-86. ZHONG Yi-zhang. 1990. Jinling Reservoir-induced seismicity predicted by gray system theory［J］. South China Journal of Seismology, 10(4):80-86(in Chinese).
邹志辉, 周华伟, 张建中. 2015. 三峡地区上地壳结构的远震虚震源反射地震成像［J］. 地球物理学报, 58(2):411-423. doi:10.6038/cjg20150206. ZOU Zhi-hui, ZHOU Hua-wei, ZHANG Jian-zhong. 2015, Imaging upper crustal structure of the Three Gorges region via teleseismic virtual reflection profiling［J］. Chinese J Geophys, 58(2):411-423(in Chinese).
Brown J, Prejean S, Zhang H, et al. 2004. Double difference earthquake relocation and tomography at Mount Spurr Volcano, Alaska, 1991 to 2004［R］. AGU Fall Meeting Abstracts. 2004, 0140.
Cuenot N, Charléty J, Dorbath L, et al. 2006. Faulting mechanisms and stress regime at the European HDR site of Soultz-sous-Forêts, France［J］. Geothermics, 35(5):561-575.
Dixit M M, Kumar S, Catchings R D, et al. 2014. Seismicity, faulting, and structure of the Koyna-Warna seismic region, Western India from local earthquake tomography and hypocenter locations［J］. Journal of Geophysical Research:Solid Earth, 119(8):6372-6398.
Gunasekera R C. 2003. Reservoir depletion at the Geysers geothermal area, California, shown by four-dimensional seismic tomography［J］. Journal of Geophysical Research, 108(B3).
Haggag H M, Bhattacharya P M, Kamal S, et al. 2009. Seismicity and 3D velocity structure in the Aswan Reservoir Lake area, Egypt［J］. Tectonophysics, 476(3-4):450-459.
Mei B, Xu Y, Zhang Y. 2013. P- and S-velocity structure beneath the Three Gorges region(central China)from local earthquake tomography［J］. Geophysical Journal International, 193(2):1035-1049.
Scarfì L, Giampiccolo E, Musumeci C, et al.. 2007. New insights on 3D crustal structure in southeastern Sicily(Italy)and tectonic implications from an adaptive mesh seismic tomography［J］. Physics of the Earth and Planetary Interiors, 161(1):74-85.
Shelly D R, Beroza G C, Ide S, et al. 2006. Low-frequency earthquakes in Shikoku, Japan, and their relationship to episodic tremor and slip［J］. Nature, 442(7099):188-191.
Waldhauser F, Ellsworth W L. 2000. A double-difference earthquake location algorithm:Method and application to the northern Hayward Fault, California［J］. Bulletin of the Seismological Society of America, 90(6):1353-1368.
Zhang H, Thurber C H. 2003. Double-difference tomography:The method and its application to the Hayward Fault, California［J］. Bulletin of the Seismological Society of America, 93(5):1875-1889.
Zhang H, Thurber C H. 2005. Adaptive mesh seismic tomography based on tetrahedral and Voronoi diagrams:Application to Parkfield, California［J］. Journal of Geophysical Research:Solid Earth, 110(B4):B04303.
Zhang H, Thurber C H, Shelly D, et al. 2004. High-resolution subducting-slab structure beneath northern Honshu, Japan, revealed by double-difference tomography［J］. Geology, 32(4):361-364.
Zhao D, Hasegawa A, Horiuchi S. 1992. Tomographic imaging of P and S wave velocity structure beneath northeastern Japan［J］. Journal of Geophysical Research, 97(B13):19909.
Zhou L, Zhao C, Chen Z, et al. 2011. Three-dimensional V_P and V_P/V_S structure in the Longtan Reservoir area by local earthquake tomography［J］. Pure and Applied Geophysics, 169(1-2):123-139.

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