摘要
2016年11月25日在我国新疆克孜勒苏州阿克陶县发生M_S6.7地震(阿克陶M_S6.7地震).我们收集国内外地震资料,对主震及4级以上余震进行了重新定位和震源机制反演,对434次余震进行了双差定位,对主震震源过程进行了反演确定和复杂性分析,并基于反演确定的有限动态源模型估计了此次地震的烈度分布.结果表明:这次地震发生在当地一个近乎东西向展布的小型盆地内,很可能由一条新断层或隐伏断层的活动所致.发震断层近乎直立,近东西向展布,总体上表现为右旋走滑.破裂首先向西扩展,紧接着向东,随后向东西两个方向同时扩展,然后西侧破裂首先停止,东侧破裂继续,最后破裂在东侧停止,整个过程持续一20 s,释放地震矩1.08 X 10^(19)N·m,相当于M_w6.6.破裂过程最终形成两个位错高值区,分别位于初始破裂点的东西两侧,西侧高值区规模较小,东侧区规模较大.根据烈度估计,烈度椭圆长轴方向与主震破裂方向以及余震展布方向一致,最大烈度约为Ⅸ度,主要集中在震中以东很小的区域,Ⅷ度区呈纺锤形,分布于震中东西两侧,Ⅴ至Ⅶ度区呈椭圆形,总体上东侧烈度大于西侧.
On November 25, 2016, an MS6.7 earthquake struck Aketao county （Aketao MS6.7 earthquake）, Kizilsu Prefecture, Xinjiang Autonomous Region. With the seismic recording data collected inside and outside our country, we relocated the hypocenters of the main-shock and the aftershocks with magnitudes above ML4.0, inverted for their focal mechanisms,relocated 434 aftershocks by means of the DD method, and inverted for the spatio-temporal rupture process of the main-shock in order to analyze the source complexity, and then calculated the intensities of the epicentral area based on the inverted finite-dynamic source model. The results show that, the events occurred within a small and local basin which stretches generally from east to west, are very likely caused by a new or burried fault. The seismogenic fault is nearly vertical, strikes almost from east to west, and is of generally right-lateral strike-slip. The rupture started on the western side of the hypocenter firstly, then on the eastern side, and very soon the rupture propagated toward to both east and west simultaneously, and then the rupturing on the western side stopped firstly while the rupturing on the eastern side remained, and eventually the rupturing ended on the eastern side.The whole process lasted about 20 s, releasing scalar moment of 1.08×10^19N·m, corresponding to moment magnitude MW6.6. The rupture process resulted in two patches with higher slip values on two sides of the hypocenter, respectively, with the western one having a smaller dimension than the eastern one.From the estimated intensity pattern, the long-axis orientation of the intensity ellipse is generally consistent with the rupture-orientation of the main-shock as well as the distribution-orientation of the aftershocks, the maximal intensity is close to IX, concentrating in a small area on the eastern side, the Ⅷ-intensity area is of spindle-shape lying on both the eastern and western sides of the epicenter, respectively, and the Ⅴ-to-Ⅶ intensity areas have elliptical shapes.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第4期1411-1422,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金(41474046)
中国地震局地球物理研究所基本业务费(DQJB16B05)联合资助
