用会聚束电子衍射对SiC中位错的研究   总被引：1，自引：0，他引：1  

边为民 《矿物学报》1987,(3)

本文用会聚束电子衍射对SiC中的全位错和不全位错进行研究。由于晶体中位错的存在,晶体内原子位移引起畸变产生应变场,导致了CBED花样中高边反射和菊池线发生分裂;而在无畸变的反射面上与完整晶体一致,高边反射和菊池线将不分裂。只要在CBED图中找到两个或更多的不分裂的反射,用g_1×g_2即可算出柏氏矢量b的方向。与传统的电子显微分析中的位错线消失的双束法比较,本法更为方便和准确。  相似文献   

辉钼矿位错结构的TEM研究   总被引：2，自引：0，他引：2  

余行祯  李佩兰 《矿物学报》1987,(4)

文中应用透射电子显微镜薄膜晶体技术,研究了江西西华山、荡坪W-Be-Mo-Bi矿床中辉钼矿的位错结构,揭示了该矿床形成过程中所经历的应力及热学史,为矿床的矿化特征提供了一种微观依据。  相似文献   

Green's functions of coseismic strain changes and investigation of effects of Earth's spherical curvature and radial heterogeneity   总被引：2，自引：0，他引：2  

Wenke Sun  Shuhei Okubo  Guangyu Fu 《Geophysical Journal International》2006,167(3):1273-1291

  相似文献   

Co-seismic displacements associated to the Molise (Southern Italy) earthquake sequence of October–November 2002 inferred from GPS measurements     

R. Giuliani  M. Anzidei  L. Bonci  S. Calcaterra  N. D'Agostino  M. Mattone  G. Pietrantonio  F. Riguzzi  G. Selvaggi 《Tectonophysics》2007,432(1-4):21-35

The 2002 earthquake sequence of October 31 and November 1 (main shocks Mw = 5.7) struck an area of the Molise region in Southern Italy. In this paper we analyzed the co-seismic deformation related to the Molise seismic sequence, inferred from GPS data collected before and after the earthquake, that ruptured a rather deep portion of crust releasing a moderate amount of seismic energy with no surface rupture. The GPS data have been reduced using two different processing strategies and softwares (Bernese and GIPSY) to have an increased control over the result accuracy, since the expected surface displacements induced by the Molise earthquake are in the order of the GPS reliability. The surface deformations obtained from the two approaches are statistically equivalent and show a displacement field consistent with the expected deformation mechanism and with no rupture at the surface. In order to relate this observation with the seismic source, an elastic modeling of fault dislocation rupture has been performed using seismological parameters as constraints to the model input and comparing calculated surface displacements with the observed ones. The sum of the seismic moments (8.9 × 10¹⁷ Nm) of the two main events have been used as a constraint for the size and amount of slip on the model fault while its geometry has been constrained using the focal mechanisms and aftershocks locations. Since the two main shocks exhibit the same fault parameters (strike of the plane, dip and co-seismic slip), we modelled a single square fault, size of 15 km × 15 km, assumed to accommodate the whole rupture of both events of the seismic sequence. A vertical E–W trending fault (strike = 266°) has been modeled, with a horizontal slip of 120 mm. Sensitivity tests have been performed to infer the slip distribution at depth. The comparison between GPS observations and displacement vectors predicted by the dislocation model is consistent with a source fault placed between 5 and 20 km of depth with a constant pure right-lateral strike-slip in agreement with fault slip distribution analyses using seismological information. The GPS strain field obtained doesn't require a geodetic moment release larger than the one inferred from the seismological information ruling out significant post-seismic deformation or geodetic deformation released at frequencies not detectable by seismic instruments. The Molise sequence has a critical seismotectonic significance because it occurred in an area where no historical seismicity or seismogenic faults are reported. The focal location of the sequence and the strike-slip kinematics of main shocks allow to distinguish it from the shallower and extensional seismicity of the southern Apennines being more likely related to the decoupling of the southern Adriatic block from the northern one.  相似文献   

Fault slip in the 1997 Manyi, Tibet earthquake from linear elastic modelling of InSAR displacements   总被引：4，自引：0，他引：4  

Gareth J. Funning  Barry Parsons  Tim J. Wright 《Geophysical Journal International》2007,169(3):988-1008

The M _w 7.6 1997 Manyi earthquake occurred in an area of central northern Tibet where sparse vegetation coverage and a lack of human habitation provide excellent conditions for Interferometric Synthetic Aperture Radar (InSAR) studies. We use coseismic pairs of radar images acquired by the ESA ERS-2 satellite to construct interferograms of the surface displacement field due to the earthquake. The location and extent of the coseismic fault rupture are mapped using a combination of optical satellite imagery, high-resolution digital topography, interferometric correlation and azimuth offset measurements; in so doing, we are able to relate prominent geomorphic features in the fault zone to bends in the fault.
Using elastic dislocation models consistent with this mapped fault trace, we then test a range of fault geometries and slip conditions to find the combination which best explains the InSAR displacements. Our favoured model contains a reversal in fault dip, approximately halfway along its length, occurring at the location of a restraining bend. Slip on this model fault is heterogeneous, with two areas of peak slip of 7 m or greater, and components of dip-slip displacement which vary significantly along-strike. The success of this model in fitting the data implies that an observed asymmetry in the coseismic interferograms can be explained in terms of the local fault geometry, rather than by using non-linear elastic rheologies as suggested by earlier authors.  相似文献   

滇西区域水准观测的负位错反演与应变积累分析     

张希  江在森  张四新  王双绪 《地震研究》2007,30(3):216-222

利用1981～2006年滇西地区5个时段的区域水准观测资料,借助负位错模型反演,参考典型大震应力触发计算及跨断层等形变观测结果,研究了活动块体边界断裂应变积累的状况、分段差异性、时空演变及其与强震孕育—发生过程的关系。结果表明,该区6级以上地震多发生在断裂强锁定段或锁定程度显著加强段及其附近;目前宾川—南华以南、南涧以北,洱源、丽江一带可能反映相对较高的应变能积累背景,南定河断裂附近反映一定程度的应变积累特性。  相似文献   

巴东新城白土坡深层岩体软弱夹层地质特征   总被引：2，自引：0，他引：2  

肖拥军  殷坤龙  黄学斌  徐开祥 《水文地质工程地质》2007,34(6):72-75

巴东组第三段中的软弱夹层是白土坡斜坡的主要结构面,巴东新城白土坡深层变形监测钻孔揭露白土坡斜坡巴东组第三段厚度在270m左右,主要贯通性软弱夹层有13层,为泥质灰岩碎块石夹土、黄褐色碎石土,中上部夹层分布较密,软弱夹层的空间分布由沉积环境所决定的岩性变化控制,典型夹层露头构造分析表明夹层由于构造作用发生过层间错动,夹层的存在有利于斜坡深层变形,三峡水库蓄水后水位的抬高将会影响到斜坡岩体的深层蠕变。  相似文献   

尼泊尔M8.1地震震前卫星重力场时变特征     

邹正波  李辉  吴云龙  吴桂桔  康开轩 《大地测量与地球动力学》2015,35(4):547-551

利用多年GRACE卫星重力变化资料,给出尼泊尔及周缘地区的重力场时空变化,以探索2015-04-25尼泊尔M8.1地震震前重力变化特征;并基于球形位错理论,利用断层模型数据模拟同震重力场变化。研究表明,区域重力场变化以2008年为界存在明显的分时段特征,2003~2008年以重力增加为主,而2009~2014年以重力减少为主;且存在明显的分区性,区域重力场在尼泊尔地震震中四周呈正负相间分布;震前局部重力场变化在压缩区重力增加,拉张区重力减少,与理论同震重力变化结果一致。总结研究区域近年来M7.0以上地震震前重力变化特征发现,地震基本发生在重力变化高梯度带的过渡带及重力变化零值线附近。  相似文献   

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王宏宇  刘杰  山锋 《大地测量与地球动力学》2015,35(1):30-33

?????????????λ????????????????????????????????????????????????????????????????????巨???????????????????ú???????2001~2004???GPS?????????????????????????????з????????????????б?????????????????????????Ч??????????????????????????????  相似文献   

阿尔泰造山带内韧性剪切带的显微、超显微构造和变形机制     

张进江  曲国胜 《现代地质》1993,7(3):293-302

阿尔泰造山带的剪切带中发育大量S-C糜棱岩,其内云母产生云母鱼和扭折构造并发生边界重结晶。长石发生不同性质的系列变形,并以出熔成核为主的动态重结晶为主要变形机制,同时伴有强烈的扩散作用,属Naborrow-Herring蠕变。石英的变形呈条带状并发生完全的旋转和边界迁移动态重结晶。石英晶内变形以位错运动和动态恢复为主,形成亚颗粒构造及动态重结晶,以致产生应变弱化和超塑性变形,定量分析确定的石英变形机制主要为低温幂指数蠕变。  相似文献