地震研究

岩石力学性质实验显示,岩石破坏前会出现扩容现象,可用累积视体积的变化来度量岩体体积的变化。结合岩石破坏前应力-应变关系,通过对滇西南块体震源参数的计算,探讨2014年景谷MS6.6和2018年墨江MS5.9地震前后,震源区及邻区视应力、视体积的变化特征。结果表明:该区的地震视应力与震级、地震矩的皮尔逊相关系数r分别为0.73,0.58,视应力与震级的相关性较大,与地震矩存在正相关关系; 景谷MS6.6地震前8.4个月和墨江MS5.9地震前4.2个月,视应力和归准化视应力均出现高值异常,累积视体积增长,且增长速率增大。景谷地震前其震源区、墨江地震前震源区同一断裂带南段为视应力高值区域。

According to the experiment of rock mechanical properties,before rock failure,volume expansion phenomenon is expected to occur.We use the change of cumulative apparent volume to measure the change of rock volume.Combining stress-strain relationship before failure of rock,based on the calculation of the focal parameters of the southwest Yunnan block,we examined the temporal evolution of apparent stress,apparent volume,the characteristics of other source parameters,and spatial apparent stress before the 2014 Jinggu MS6.6 earthquake and the 2018 Mojiang MS5.9 earthquake.The results show that the Pearson correlation coefficients of apparent stress with magnitude,moment are 0.73,0.58,respectively.The apparent stress is highly correlated with the magnitude and has a positive correlation with the moment.In the 8.4 months before the 2014 Jinggu MS 6.6 earthquake and 4.2 months before the 2018 Mojiang MS 5.9 earthquake,the apparent stress and normalized apparent stress were abnormal with a high value,and the cumulative apparent volume increased at a large rate.The focal area before Jinggu earthquake and the southern segment of the seismogenic fault zone before the Mojiang earthquake are the location of a higher apparent stress.

引言
1 研究区概况
2 资料选取与计算方法
3 结果分析
4 结论与讨论

图1 研究区3.0级以上地震、台站分布及地质构造图(据安晓文等,2018修改)<br/>Fig.1 Map showing the distributions of earthquakes, seismic stations and tectonics(modified from the An et al,2018)

图1 研究区3.0级以上地震、台站分布及地质构造图(据安晓文等,2018修改)
Fig.1 Map showing the distributions of earthquakes, seismic stations and tectonics(modified from the An et al,2018)

图2 震级(a)、地震辐射能量(b)与视应力之间的定标关系及视应力(c)和折合能量(d)与地震矩之间的定标关系<br/>Fig.2 The scaling law between magnitude(a),earthquake radiation energy(b)and apparent stress and the scaling law between apparent stress(c),reduced energy(d)and seismic moment

图2 震级(a)、地震辐射能量(b)与视应力之间的定标关系及视应力(c)和折合能量(d)与地震矩之间的定标关系
Fig.2 The scaling law between magnitude(a),earthquake radiation energy(b)and apparent stress and the scaling law between apparent stress(c),reduced energy(d)and seismic moment

图3 地震视应力(a)和归准化视应力(b)滑动平均值以及震级、累积视体积(c)随时间的变化关系<br/>Fig.3 The temporal process based on 10 apparent stress(a),normalized apparent stress(b)values moving average and the relationship chart between magnitude,apparent volume and time(c)

图3 地震视应力(a)和归准化视应力(b)滑动平均值以及震级、累积视体积(c)随时间的变化关系
Fig.3 The temporal process based on 10 apparent stress(a),normalized apparent stress(b)values moving average and the relationship chart between magnitude,apparent volume and time(c)

图4 岩石全应力应变曲线(据蔡美峰等,2002)(a)及相应的体应变与法向应变的关系(b)<br/>Fig.4 Total stress-strain curve of rock(based on Cai et al,2002)(a)and the relationship between bulk strain and normal strain(b)

图4 岩石全应力应变曲线(据蔡美峰等,2002)(a)及相应的体应变与法向应变的关系(b)
Fig.4 Total stress-strain curve of rock(based on Cai et al,2002)(a)and the relationship between bulk strain and normal strain(b)

图5 景谷(a)、墨江(b)地震前研究区归准化视应力空间分布(断裂同图 1)<br/>Fig.5 Map of the normalized apparent stress prior to the Jinggu mainshock(a), Mojiang mainshock(b)(the fault is same as shown in Fig .1)

图5 景谷(a)、墨江(b)地震前研究区归准化视应力空间分布(断裂同图 1)
Fig.5 Map of the normalized apparent stress prior to the Jinggu mainshock(a), Mojiang mainshock(b)(the fault is same as shown in Fig .1)

安晓文,常祖峰,陈宇军,等.2018.云南第四纪活动断裂[M].北京:地震出版社,10.
蔡美峰,何满潮,刘东燕.2002.岩石力学与工程[M].北京:科学出版社.
陈浩朋,李志伟,储日升,等.2018.云南地区地壳上地幔三维S波速度与径向各向异性结构研究[J].地球物理学报,61(8):3219-3236.
陈学忠,李艳娥.2007.2006年7月4日河北文安MS5.1地震前震中周围地区小震视应力随时间的变化[J].中国地震,23(4):327-336.
华卫.2007.中小地震震源参数定标关系研究[D].北京:中国地震局地球物理研究所.
李艳娥,陈学忠,付虹.2012.2007年云南宁洱MS6.4地震前滇西南地区震源参数时空变化特征[J].地震,32(1):28-39.
刘红桂,缪发军,吴晶.2004.场地响应、震源参数与介质衰减的同时反演[J].地震,24(4):27-36.
刘红桂,王培玲,杨彩霞,等.2007.地震视应力在地震预测中的应用[J].地震学报,29(4):437-445.
彭关灵,赵小艳,刘自凤,等.2018.2018年云南通海MS 5.0地震前视应力时空特征[J].地震研究,41(4):487-493.
吴忠良.2001.由宽频带辐射能量目录和地震矩目录给出的视应力及其地震学意义[J].中国地震,17(1):8-15.
易桂喜,闻学泽,辛华,等.2011.2008年汶川MS8.0地震前龙门山—岷山构造带的地震活动性参数与地震视应力分布[J].地球物理学报,54(6):1490-1500.
张敏,徐奴文,陈文夫,等.2018.白鹤滩水电站左岸边坡开挖卸荷过程微震视应力特征研究[J].岩石力学与工程学报,37(增刊2):4133-4141.
张永兴,许明.2015.岩石力学[M].北京:中国建筑工业出版社.
赵翠萍,陈章立,华卫,等.2011.中国大陆主要地震活动区中小地震震源参数研究[J].地球物理学报,54(6):1478-1489.
Archuleta R,Cranswick E,Mueller C,et al.1982.Source parameters of the 1980 Mammoth Lakes,Callfornia,earthquakes sequence[J].J Geophys Res,87(B6):4595-4607.
Atkinson G M,Mereu R F.1992.The shape of ground motion attenuation curves in Southeastern Canada[J].Bull Seismol Soc Am,82(5):2014-2031.
Baltay A,Ide S,Prieto G,et al.2011.Variability in earthquake stress drop and apparent stress[J].Geophys Res Lett,38:L06303.
Brown L,Hudyma M.2017.Identification of stress change within a rock mass through apparent stress of local seismic events[J].Rock Mechanics and Rock Engineering,1(50):81-88.
Choy G L,Boatwright J L.1995.Global pattern of radiated seismic energy and apparent stress[J].J Geophys Res,100(B9):18205-18228.
Choy G L,Kirby S.2004.Apparent stress,fault maturity and seismic hazard for normal-fault earthquakes at subduction zones[J].Geophys J Int,159(3):991-1012.
Choy G L,McGarr A,Kirby S H,et al.2013.An overview of the global variability in radiated energy and apparent stress[M].Earthquakes:Radiated Energy and the Physics of Faulting.
Choy G L,McGarr A.2002.Strike-slip earthquakes in the oceanic lithosphere:observations of exceptionally high apparent stress[J].Geophys J Int,150(2):506-523.
Ide S,Beroza G C.2001.Does apparent stress vary with earthquake size [J].Geophys Res Lett,28(17):3349-3352.
Mayeda K,Walter W R.1996.Moment,energy,stress drop,and source spectra of western United State earthquakes from regional coda envelopes[J].J Geophys Res,101(B5):11195-11208.
Mendecki A J.1993.Real time quantitative seismology in mines [C]// Kingston,Ontario,Canada:Proceedings of Third International Symposium on Rock-bursts and Seismicity in Mines 16-18,287-295.Wyss M,Brune J N.1968.Seismic moment stress,and source dimensions for earthquakes in the California-Nevada region[J].J Geophys Res,73(22):4681-4694.
Wu Z L.2001.Scaling of apparent stress from broadband radiated energy catalogue and seismic moment catalogue and its focal mechanism dependence[J].Earth Planet Sci,53(10):943-948.
Yoo S H,Rhie J,Choi H,et al.2010.Evidence for non-self-similarity and transitional increment of scaled energy in the 2005 west off Fukuoka seismic sequence[J].J Geophys Res,115:B08308.
Wyss M,Brune J N.1968.Seismic moment stress,and source dimensions for carthquakes in th California-Nevada region[J].J aeophys Res,73,4681-4694.
Brune J N.1970.Tectonic stress and spectra of seismic shear waves from equthquakes[J].J Geophys Res,15,4897-5009.

备注

引言

1 研究区概况

2 资料选取与计算方法

3 结果分析

4 结论与讨论

期刊信息