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| 1 | 东日本大地震地震序列的震源机制解特征及其动力学意义显示文摘日本本州及其邻近区域的应力状态以及弧后盆地的演化机制一直是人们所关注的问题.本文对2011年3月11日东日本大地震地震序列(2011年3月11日至2012年3月15日)的哈佛双力偶解进行了聚类分析,得到五种类型的震源机制解:与主震类型一致的低倾角逆断层型地震;主张应力方向垂直于日本海沟走向的正断层型地震;主张应力方向平行于日本海沟走向的正断层型地震;主压应力方向平行于日本海沟走向的逆断层型地震;包括走滑型地震在内的其他类型地震.东日本大地震地震序列中发生在弧前增生楔地震的震源机制解与大地震发生之前地震的震源机制解特征有显著区别,反映出该地区的应力状态与震前相比有较大改变.东日本大地震及其前震释放了附近区域的累积弹性应力,主震破裂区附近太平洋板块和其上覆板块接近完全解耦,降低了日本海盆地、中国东北地区的近东西向挤压应力水平.不过,整个本州岛东部区域太平洋板块和其上覆板块并没有完全解耦,但应力水平并不高.我们认为,日本海及中国东北应力水平的降低会使该区域的近东西向挤压型地震的危险性降低,而使NNE-SSW走向的走滑型地震活动性增强.同时,火山活动性也会增强.尤其是本州岛地区,存在近期火山爆发的可能性.东日本大地震地震序列的震源机制解特征还提示我们,日本海的应力状态及日本海的演化可能在一定程度上取决于太平洋板块和上覆板块的耦合状态.持续的弱耦合将不仅使得弧后大范围的地区保持岩浆上涌所必须的拉伸应力环境,而且还会因弧前隆起区发育大量正断层型地震而向深部提供促使岩浆生成所必须的水,因而造成日本海的再次扩张. | 俞红玉 陶开 蔡晨 张浩 宁杰远 王彦宾 | 2013 | 地球物理学报2013，56，8： | 11 |
| 2 | 日本海沟俯冲带M_W9.0地震震源区应力场演化分析显示文摘于2011年3月11日发生在日本东北部的MW9.0级逆冲型板间地震是日本有地震记录以来震级最大的一次地震.本研究基于NIED F-net矩张量解目录中的震源机制解,选取两个长轴相互垂直的矩形区域进行应力场2D反演,获取了日本海沟俯冲带地区应力场的空间及时间分布图像.结果表明:主震前,俯冲带地区应力状态在空间上大体趋于一致,即应力轴(P轴、σ1轴及SHmax轴)系统性地倾向板块汇聚方向,P轴、σ1轴倾角整体偏缓(<30°),且远离震源区及日本海沟东侧区域内的应力轴倾角普遍大于主震震源区内应力轴倾角;主震前,受2003年5月26日在宫城县北部发生的MW7.0地震影响,位于MW9.0地震震源区西北侧的应力场出现明显扰动,σ1轴倾向顺时针偏转150°~180°,并于之后大体恢复至震前状态,同期其他地区没有明显变化,这种情况可能和主震断层局部(深部)的前兆性滑动有关;主震后,距离震源区较远处应力场变化不大,主震震源区内应力场发生显著改变,P轴及σ1轴均以大角度(>60°)倾伏于板块汇聚方向,SHmax轴顺时针偏转60°~90°且在日本海沟附近普遍平行于海沟轴.这项研究以时空图像的方式展示了大地震前应力场变化的特点,反映了大地震孕震过程中构造与地震的相互作用,对于理解大地震孕震过程有重要意义. | 杨佳佳 张永庆 谢富仁 | 2018 | 地球物理学报2018，61，4： | 10 |
| 3 | Review of the Research of the 2011 Mw9.0 Tohoku-Oki Earthquake显示文摘On March 11,2011, a M_W9.0 earthquake occurred in the Japan Trench, causing tremendous casualties,and attracting extensive concern. Based on the results of related research,this paper analyzes the observations,phenomena and understandings of the earthquake from varied aspects,and obtains four main conclusions.(1) The earthquake,occurring in the subduction zone in the Japan Trench located in the northwest boundary of the pacific plate has two zones of concentrated coseismic slip at different depths,and the slip in the deep zone is relatively small. Though there have been many M7. 0 historical earthquakes,slips in the shallow zone are large,but there have been few historical strong earthquakes.(2) Constrained by GPS data,the study of fault movement shows that fault movement in the Japan Trench has a background of widely distributed stability and locking( the locking zone is equivalent that of coseismic rupture zone). Perturbation occurred after the 2008 M8. 0 Hokkaido earthquake,several M7. 0 events had after slips larger than the coseismic slip,and two obvious slow slip events were recorded in 2008 and2011. Eventually,the March 9,2011 M7. 0 foreshock and the March 11,2011 M_W9.0 mainshock occurred. The pre-earthquake changing of the fault movement in the Japan Trench is quite clear.(3) Traditional precursory observation show no obvious anomaly,possibly due to monitoring reason. Anomaly before earthquake consists of high stress state in focal zone reflected by some seismic activity parameters,short period anomaly in regional ground motion,etc.(4) The analysis of physical property in focal zone aroused more scientific issues,for example,is there obvious difference between physical property in focal zone and its vicinity? Does frictional property of fault determine seismogenic ability and rupture process? Whether pre-earthquake fault movement include pre-slips? Could deep fluid affect fault movement in focal zone? Experience is the best teacher,and authors hope this paper could be a modest spur to induce others in basic research in earthquake forecast and prediction. | Shao Zhigang Wang Peng Li Haiyan | 2017 | Earthquake Research in China2017，31，3： | 0 |
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