2021年6月10日和6月12日，云南地区先后发生双柏MS 5.1和盈江MS 5.0地震，距5月21日云南漾濞MS 6.4地震发生不足1个月，文中系统总结2次地震前出现的地震活动和地球物理观测异常，其中：地震活动方面：震前存在中等调制地震集中、地震条带等中短期异常；地球物理观测方面：2次地震发生前，震中附近存在形变、电磁和流体等多项异常，其中双柏MS 5.1地震以形变学科趋势异常为主，盈江MS 5.0地震以流体异常为主。对2次地震序列跟踪分析，发现双柏MS 5.1地震余震较为丰富，震后半年内共记录ML 3.0以上地震7次，最大震级为ML 4.8，计算得到地震序列活动参数为：h值=1.23，b值=0.85；盈江MS 5.0地震发生后半年内仅记录ML 3.0以上余震4次，最大余震为ML 3.3地震，计算得到地震序列活动参数为：h值=2.45、b值=1.04。综合分析认为，2021年6月云南地区2次5级以上地震与漾濞MS 6.4地震形成5、6级地震连发态势，区域地震活动水平较强，多项具有中短期意义的地球物理观测异常仍在持续。
On June 10 and June 12, 2021, Shuangbai MS 5.1 and Yingjiang MS 5.0 earthquakes occurred successively in Yunnan. It was less than one month after the Yunnan Yangbi MS 6.4 earthquake on May 21. This paper systematically summarizes the seismicity and geophysical observation anomalies before the Shuangbai MS 5.1 and Yingjiang MS 5.0 earthquakes. In terms of seismicity, there are medium and short-term anomalies such as medium modulation earthquake concentration and M 4.0 earthquake belt before the earthquakes. In terms of geophysical observation, there were many anomalies in deformation, electromagnetic, and fluid observations near the epicenter of the two earthquakes before the occurrence. Deformation anomalies were mainly near the epicenter of the Shuangbai MS 5.1 earthquake and fluid anomalies were mainly near the epicenter of the Yingjiang MS 5.0 earthquake. After analyzing the sequence tracking of the two earthquakes, it is found that there are abundant aftershocks after the Shuangbai MS 5.1 earthquake. Seven aftershocks above ML 3.0 have been recorded in half a year, and the maximum magnitude is ML 4.8. The calculated sequence hvalue is 1.23 and b value is 0.85. Four aftershocks above ML 3.0 were recorded within half a year after the Yingjiang MS 5.0 earthquake, with the maximum magnitude of ML 3.3. The calculated sequence h value is 2.45 and b value is 1.04. Comprehensive analysis shows that in June 2021, two MS ≥ 5.0 earthquakes and the Yangbi MS 6.4 earthquake in Yunnan formed a continuous occurrence trend of M ≥ 5-6 earthquakes, the regional seismicity level is high, a number of geophysical observation anomalies with medium and short-term significance are still continuing.
2022,43（5）: 151-168 收稿日期：2022-08-10
DOI：10.3969/j.issn.1003-3246.2022.05.020
基金项目：国家重点研发计划（项目编号：2018YFE0109700）；中国地震台网中心青年基金（项目编号：QNJJ-202102）；国家自然科学基金联合基金（项目编号：U2039205）
作者简介：于晨(1988-),男,主要从事地震电磁学研究工作。E-mail:yuchen@seis.ac.cn
参考文献：
安晓文,常祖峰,陈宇军,等.云南第四纪活动断裂暨《云南第四纪活动断裂分布图》[M]. 北京:地震出版社,2018:51-320.
常祖峰,常昊,李鉴林,等.楚雄-南华断裂晚第四纪活动与1680年楚雄6¾级地震[J].中国地震,2015,31(3):492-500.
杜学彬. 在地震预报中的两类视电阻率变化[J]. 中国科学:地球科学,2010,40(10):1321-1330
韩颜颜,孟令媛,刘桂萍,等.西北地区中强震前固体潮调制比时空特征分析[J].地震学报,2017,39(5):738-750.
季建清,钟大赉,张连生.滇西南新生代走滑断裂运动学、年代学、及对青藏高原东南部块体运动的意义[J]. 地质科学,2000,35(3):336-349
蒋海昆,代磊,侯海峰,等.余震序列性质判定单参数判据的统计研究[J]. 地震,2006,26(3):17-25.
蒋海昆,傅征祥,刘杰,等. 中国大陆地震序列研究[M]. 北京:地震出版社,2007.
李腊月,薄万举,陈宗时,等.滇西北下关跨断层场地形变异常调查与机理分析[J].大地测量与地球动力学,2019,39(1):77-83.
孟令媛,苑争一,宋治平,等. 2020年1月19日新疆伽师MS 6.4地震总结[J]. 地震地磁观测与研究,2020,41(2):63-89.
徐锡伟,于贵华,马文涛,等.中国大陆中轴构造带地壳最新构造变动样式及其动力学内涵[J]. 地学前缘,2003,10(S1):160-167.
许鑫,万永革,李振月,等. 2021年云南漾濞MS 6.4地震序列静态应力触发研究[J]. 地震工程学报,2022,44(4):970-979.
杨婷,吴建平,房立华,等. 2014年云南盈江MS 5.6和MS 6.1地震余震序列重定位[J].地震地质,2016,38(4):1 047-1 057.
张国民,李丽,黎凯武,等.强震成组活动与潮汐力调制触发[J].中国地震,2001,17(2):110-120.
张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学(D辑),2003,33(Z1):12-20.
中国地震局监测预报司.测震分析预测技术方法工作手册[M].北京:地震出版社,2020:114-138.
Marzocchi W, Sandri L. A review and new insights on the estimation of the b-value and its uncertainty[J]. Annals of Geophysics, 2003, 46(6):1 271-1 282.
Mignan A, Woessner J. Estimating the magnitude of completeness for earthquake catalogs[M/OL]. Swiss Seismological Service:ETH Zurich, 2012[2020-08-21]. http://www.corssa.org/export/sites/corssa/.galleries/articles-pdf/Mignan-Woessner-2012-CORSSA-Magnitude-of-completeness.pdf.
Mouslopoulou V, Nicol A, Little T A, et al. Displacement transfer between intersecting regionalstrike-slip and extensional fault systems[J]. Journal of Structural Geology, 2007, 29(1):100-116.
Peng Z G, Vidale J E, Ishii M, et al. Seismicity rate immediately before and after main shock rupture from high-frequency waveforms in Japan[J]. Journal of Geophysical Research-Solid Earth, 2007, 112(B3):B03306.
Tapponnier P, Peltzer G, Le Dain A Y, et al. Propagating extrusion tectonics in Asia:New insights from simple experiments with plasticine[J]. Geology, 1982, 10(12):611-616.
Wang E, Burchfiel B C, Royden L H, et al. Late Cenozoic Xianshuihe-Xiaojiang, Red River, and Dali Fault Systems of south western Sichuan and central Yunnan, China[M]. Boulder:Geological Society of America, 1998:108. doi:10.1130/SPE327.
Wiemer S, Wyss M. Minimum magnitude of completeness in earthquake catalogs:examples from Alaska, the western United States, and Japan[J]. Bull Seismol Soc Am, 2000, 90(4):859-869.
Wyss M, Hasegawa A, Wiemer S, et al. Quantitative mapping of precursory seismic quiescence before the 1989, M 7.1 off-Sanriku earthquake, Japan[J]. Annals of Geophysics, 1999, 42(5):851-869.
Yu H Z, Cheng J, Zhang X T, et al. Multi-Methods Combined Analysis of the Future Earthquake Potential[J]. Pure and Applied Geophysics, 2013, 170 (1/2):173-183.
