以云南腾冲及邻区为研究区域,使用FMSI 方法进行应力场反演;在此基础上,进行了断层滑动趋势和地震活动性分析。结果表明:腾冲及邻区的震源机制主要以走滑型为主,最大应力主轴σ1沿 NNE—SSW 向,最小主应力轴σ3沿 NWW 向,并且最大、最小主应力轴都是近水平向。研究区域具有较强滑动趋势的断层走向范围主要为40°—80°、160°—200°、220°—260°、340°—360°;断层倾角为50°—70°,这与该地区的构造背景相符。结合该地区的断层分布分析认为,腾冲火山区附近的大盈江断裂、龙川江断裂、龙陵—瑞丽断裂未来可能具有较明显地震活动趋势。2000—2021年该区域发生了7次4.0级及以上的中强地震,且2012年之前研究区域内地震活动较多,4.0级及以上地震事件大部分都发生在2011年前后;其间,2次中强地震活动均发生在滑动趋势较强的断层周边。
In this study, the FMSI method was used to invert the stress field for Tengchong and its adjacent areas in Yunnan Province. Furthermore, fault slip tendency and seismic activity were carried out. The results show that the source mechanisms of Tengchong and its adjacent areas aremainly strike-slip types, with the maximum stress axis σ1 along the NNE-SSW direction, the minimum principal stress axis σ3 along the NWW direction, and both the maximum and minimum principal stress axes are near horizontal. The strike range of faults with strong slip tendency in the study area is mainly 40°-80°, 160°-200°, 220°-260°, and 340°-360°. The dip angle of the fault is 50°-70°, which is consistent with the tectonic setting of the area. Combined with the fault distribution analysis in this area, it is concluded that the Dayingjiang fault, Longchuanjiang fault and Longling-Ruili fault near Tengchong volcanic area may have obvious seismic activity trends in the future. From 2000 to 2021, there were 7 moderate-strong earthquakes of magnitude 4.0 or above in this area, and there were more seismic activities in the study area before 2012, with most of the seismic events of magnitude 4.0 and above occurred around 2011. Two of the seven earthquakes occurred near the faults with strong slipping tendency.
2024,45(4): 18-25 收稿日期:2024-3-18
DOI:10.3969/j.issn.1003-3246.2024.04.003
基金项目:国家自然科学基金(项目编号:41964001);云南大学大学生创新训练项目(国家级)(项目编号:202210673104)
作者简介:刘祖源(2002—),男,本科,主要从事地震学研究。E-mail:2387831494@qq.com
*通讯作者:解朝娣(1981—),女,副教授,主要从事地震学的研究。E-mail:xiecd@ynu.edu.cn
参考文献:
包林海,王成虎,王显军. 龙陵-瑞丽断裂北段现今地应力特征及其活动性分析[J]. 华南地震,2015,35(4):104-110.
常祖峰,陈刚,余建强. 大盈江断裂晚更新世以来活动的地质证据[J]. 地震地质,2011,33(4):877-888.
邓起东,张裕明,许桂林,等. 中国构造应力场特征及其与板块运动的关系[J]. 地震地质,1979,1(1):11-22.
高洋,闵照旭,徐彦. 2011年腾冲中强地震序列震源机制研究[C]//中国地球物理学会第二十八届年会. 北京:中国地球物理学会,2012.
郭祥云,蒋长胜,韩立波,等.中国大陆及邻区震源机制数据集(2009-2021年)[EB/OL]. (2022-03-16). https://data.earthquake.cn.
阚荣举,张四昌,晏凤桐,等. 我国西南地区现代构造应力场与现代构造活动特征的探讨[J]. 地球物理学报,1977,20(2):96-109.
雷兴林,苏金蓉,王志伟. 四川盆地南部持续增长的地震活动及其与工业注水活动的关联[J]. 中国科学:地球科学,2020,
50(11):1 505-1 532.
戚学祥,沈辉,任玉峰,等. 高黎贡西北缘早白垩世火山活动与怒江洋俯冲:来自流纹岩岩石地球化学,锆石U-Pb定年和Hf同位素的证据[J]. 岩石学报,2020,36(10):2 946-2 962.
钱晓东,秦嘉政,刘丽芳. 云南地区现代构造应力场研究[J]. 地震地质,2011,33(1):91-106.
盛书中,胡晓辉,王晓山,等. 云南及邻区地壳应力场研究[J]. 地球物理学报,2022,65(9):3 252-3 267.
万永革,盛书中. 中国现代构造应力场[J]. 世界地震译丛,2011,(3):18-29.
王绍晋,龙晓帆. 腾冲火山区及周围地区震源机制与构造应力场分布特征[J]. 地震研究,1998,21(4):349-357.
王绍晋,付虹,卫爱民,等. 川滇地区7级大震前中强震震源机制变化[J]. 地震研究,2001,24(2):99-108.
王晓山,吕坚,谢祖军,等. 南北地震带震源机制解与构造应力场特征[J]. 地球物理学报,2015,58(11):4 149-4 162.
王晓山,冯向东,赵英萍. 京津冀地区地壳应力场特征[J]. 地震研究,2020,43(4):610-619.
吴建平,明跃红,王椿镛. 云南地区中小地震震源机制及构造应力场研究[J]. 地震学报,2004,26(5):457-465.
杨颖,解朝娣,徐彦,等. 青藏高原西部及邻区构造应力场反演和断层滑动趋势分析[J]. 大地测量与地球动力学,2022,42(7):694-699.
AngelierJ. Tectonic analysis of fault slip data sets[J]. Journal of Geophysical Research: Solid Earth, 1984, 89(B7): 5 835-5 848.
FrohlichC, Apperson K D. Earthquake focal mechanisms, moment tensors, and the consistency of seismic activity near plate boundaries[J]. Tectonics, 1992, 11(2): 279-296.
Gephart J W, Forsyth D W. An improved method for determining the regional stress tensor using earthquake focal mechanism data: application to the San Fernando earthquake sequence[J]. Journal of Geophysical Research: Solid Earth, 1984, 89(B11): 9 305-9 320.
Hardebeck J L, Michael A J. Damped regional-scale stress inversions: Methodology and examples for southern California and the Coalinga after shock sequence[J]. Journal of Geophysical Research: Solid Earth, 2006, 111(B11): B11310.
Morris A, Ferrill D A, Henderson D B. Slip-tendency analysis and fault reactivation[J]. Geology, 1996, 24(3): 275-278.
Xu Y, Koper K D, Burlacu R, et al. A new uniform moment tensor catalog for Yunnan, China, from January 2000 through December 2014[J]. Seismological Research Letters, 2020, 91(2A): 891-900.