鄂尔多斯块体西侧地壳各向异性初步研究

地震 ›› 2017, Vol. 37 ›› Issue (1): 82-91.

鄂尔多斯块体西侧地壳各向异性初步研究

太龄雪,高原

中国地震局地震预测研究所, 北京 100036

收稿日期:2016-05-09 发布日期:2019-08-14
作者简介:太龄雪(1982-), 女, 吉林延边人, 助理研究员, 主要从事地震各向异性研究。
基金资助:
中国地震局地震预测研究所基本科研业务专项(2012IES010104)与国家自然科学基金(41474032)资助

Preliminary Study of Crustal Anisotropy in the West of Ordos Block

TAI Ling-xue,GAO Yuan

Institute of Earthquake science, CEA, Beijing 100036, China

Received:2016-05-09 Published:2019-08-14

摘要/Abstract

摘要： 利用宁夏区域台网记录的2009年1月至2014年9月的近场小震波形资料, 使用剪切波分裂系统分析方法SAM方法, 对位于青藏高原东北缘的鄂尔多斯块体西侧进行了地壳各向异性研究, 共得到7个台站记录到的19条有效数据。研究发现, 受复杂的局部构造、应力场及断裂分布的影响, 研究区地壳各向异性在空间分布上呈现出分区性特点。受区域构造应力场的控制, 台站的快剪切波偏振方向与区域构造应力的主压应力方向基本一致。在构造上, 大致以中部的三关口—牛首山NNW向断裂为界, 可以分为南北两部分。本研究显示, 以快剪切波偏振方向空间分布特征为划分依据, 大致以37°N为界划分南北部, 北部区域的快剪切波偏振方向为近N-S向, 与按构造划分的青藏高原东北缘—鄂尔多斯块体西侧北部区域主压应力场一致; 南部区域的快剪切波偏振方向为近E-W向, 同样与按构造划分的区域主压应力场一致。

关键词: 快剪切波偏振方向, 慢剪切波时间延迟, 主压应力方向, 鄂尔多斯块体西侧

Abstract: Using seismic data recorded by permanent stations in Ningxia province from January 2009 to September 2014, this study analyzed the crustal anisotropy in west of the Ordos block locating at northeastern margin of Tibetan Plateau by Systematic Analysis Method (SAM method) of shear-wave splitting, and obtained 19 available data from 7 stations. The results show that, influenced by the complicated local tectonics, stress field and a large number of faults, the spatial distribution of crustal anisotropy are different in west of the Ordos block. Owing to the regional tectonic stress field, the polarization directions of fast shear-wave at most stations are consistent with the regional tectonic compressive stress field. Moreover, the distribution of polarization directions varies in different regions. Structurally, the study region can be divided into north and south parts roughly by Sanguankou-Niushoushan fault at the middle of the region. According to the spatial distribution feature of the polarization directions, we divided the research region into north and south parts roughly bounded by 37°N. In the north part, the polarization directions are nearly N-S, consistent with the regional compressive stress field at the north of west of the Ordos block, divided by tectonics. In the south part, the polarization directions are nearly E-W, consistent with the regional compressive stress field at the south west of the Ordos block, also divided by teconics.

Key words: Crustal anistropy, Shear wave splitting, Ordos block

中图分类号:

P315.7

太龄雪,高原. 鄂尔多斯块体西侧地壳各向异性初步研究[J]. 地震, 2017, 37(1): 82-91.

TAI Ling-xue,GAO Yuan. Preliminary Study of Crustal Anisotropy in the West of Ordos Block[J]. EARTHQUAKE, 2017, 37(1): 82-91.

参考文献

[1] Gao Y, Shi Y T, Wu J, et al. Shear-wave splitting in the crust: regional compressive stress from polarizations of fast shear-waves[J]. Earthquake Science, 2012, 25(1): 35-45.
[2] Gao Y, Wang P D, Zheng S H, et al. Temporal changes in shear-wave splitting at an isolated swarm of small earthquakes in 1992 near Dongfang, Hainan Island, southern China[J]. Geophys. J. Inter., 1998, 135(1): 102-112.
[3] 太龄雪, 高原, 曹凤娟, 等.辽宁1999年MS5.9岫岩地震的剪切波分裂特征[J].地震学报, 2008, 30(4): 340-354.
[4] 太龄雪, 高原, 马国鳳, 等.用剪切波分裂研究台湾北部地壳各向异性[J].地球物理学报, 2011, 54(9): 2233-2242.
[5] Cochran E S, Li Y G, Vidale J E. Anisotropy in the shallow crust observed around the San Andress Fault before and after the 2004 M6.0 Parkfieldearthquake[J]. Bull Seism Soc Am, 2006, 96: S364-S375.
[6] Gao Y, Wu J, Fukao Y, et al. Shear-wave splitting in the crust in North China: stress, faults and tectonic implications[J]. Geophys. J. Int., 2011, 187(2): 642-654.
[7] Shi Y T, Gao Y, Su Y J et al. Shear-wave splitting beneath Yunnan area of southwest China[J]. Earthquake Science, 2012, 25(1): 25-34.
[8] 丁志峰, 武岩, 王辉, 等. 2008年汶川地震震源区横波分裂的变化特征[J]. 中国科学D辑: 地球科学, 2008, 38: 1600-1604.
[9] 常利军, 丁志峰, 王椿镛. 2010 年玉树7.1级地震震源区横波分裂的变化特征[J]. 地球物理学报, 2010, 53: 2613-2619.
[10] Zatsepin S V, Crampin S. Modelling the compliance of crustal rock: I-response of shear-wave splitting to differential stress[J]. Geophys J Int。, 1997, 129: 477-494.
[11] Crampin S, Zatsepin S V. Changes of strain before earthquakes: the possibility of routine monitoring of both long-term and short-term precursors[J]. J Phys Earth, 1997, 45: 1-26.
[12] 高原, 石玉涛, 梁维, 等. 剪切波分裂系统分析系统SAM(2007)软件系统[J]. 中国地震, 2008, 24(4): 345-353.
[13] 马杏垣. 中国岩石圈动力学地图集[M]. 中国地图出版社, 1989, 56.
[14] 国家地震局地质研究所, 宁夏回族自治区地震局. 海原活动断裂带[M]. 地震出版社, 1990.
[15] Crampin S, Peacock S. A review of shear-wave splitting in the compliant crack-criticalanisotropic Earth[J]. Wave Motion, 2005, 41: 59-77.
[16] 张进, 马宗晋, 任文军, 等. 海原、宁夏中部牛首山地区构造特征及其地质意义[J]. 大地构造与成矿学, 2003, 27(2): 132-142.
[17] 汪一鹏, 等, 宁夏北部活动断裂的若干特点, 中国活动断裂[M]. 地震出版社, 1982.
[18] 马禾青, 丁志峰, 常利军, 等. 宁夏地区地壳介质地震各向异性特征[J]. 地球物理学进展, 2011, 26(2): 61-70.
[19] 李孟銮, 赵知军. 宁夏地区现代构造应力场及其与地震活动的关系[J]. 地震研究, 1986, 9(3): 299-314.
[20] 谢富仁, 舒塞兵, 窦素芹, 等. 海原、六盘山断裂带至银川断陷第四纪构造应力场分析[J]. 地震地质, 2000, 22(2): 139-146.
[21] 曾宪伟, 莘海亮, 蔡新华, 等. 利用小震震源机制解研究宁夏北部及邻区构造应力场[J]. 防灾减灾学报, 2013, 29(4): 25-30.
[22] 曾宪伟, 莘海亮, 陈春梅, 等. 利用小震震源机制解研究宁夏南部及邻区构造应力场[J]. 地震研究, 2015, 38(1): 51-57.
[23] 王美芳, 李慧勤. 宁夏银川盆地地震构造演化特征[J]. 科技资讯, 2008, 3: 148-149.
[24] 徐涛, 杨家喜, 刘源, 等. 宁夏南部万更新世沉积物沉积特征及其构造意义[J]. 地学前缘, 2013, 20(4): 37-45.