青海达日断裂中段构造活动与地貌发育的响应关系探讨   总被引：12，自引：4，他引：8       下载免费PDF全文

梁明剑  周荣军  闫亮  赵国华  郭红梅 《地震地质》2014,36(1):28-38

青海达日地区发育了多条晚第四纪活动断裂带,以NW—NNW向和近SN向为主。通过航卫片解译和野外实地调查发现,达日断裂中段晚第四纪新活动性尤为显著,其性质以左旋走滑为主,至今部分地段仍保存了清晰的1947年达日7级地震地表破裂带,其破裂样式具有分段性和多样性,反映了局部构造应力的差异。达日地区作为典型的活动构造区,是研究新构造运动与地貌响应的理想场所。因此,文中采用ASTER GDEM V2数据提取了该地区的水系网络和亚流域盆地参数,计算了亚流域盆地面积-高程积分曲线和积分值(HI值),讨论了其构造活动性及地貌响应的关系。区内黄河的6个亚流域盆地的面积-高程积分曲线形态分析结果表明,这6个亚流域盆地均处于地貌演化阶段的"壮年期",其演化过程表现出很好的同步性,反映了区域性构造隆升或沉降作用的总体结果。而且,区内亚流域盆地的面积-高程积分值(HI值)分布特征表明,HI低值分布与第四纪断陷盆地和河谷盆地范围相一致,反映了局部不同构造沉降和侵蚀作用的结果;HI高值则主要出现在达日地震地表破裂带由NWW向NW转向的部位,以及早侏罗世与晚三叠世花岗闪长岩体分布的地方,也很好地反映了局部构造作用的变化和地层岩性的差异。  相似文献   

昭通-鲁甸断裂晚第四纪活动及其构造意义   总被引：12，自引：7，他引：5  

常祖峰  周荣军  安晓文  陈宇军  周青云  李鉴林 《地震地质》2014,36(4)

昭通-鲁甸断裂带主要由昭通-鲁甸、洒渔河和龙树3条右阶斜列的断裂组成。总体走向40°~60°,洒渔河和龙树断裂倾向SE,昭通-鲁甸断裂倾向NW,它们共同构成几何结构复杂的逆冲断裂系。野外考察表明:沿断裂表现为平直的断层槽地、定向排列的断层三角面、断层陡坎等地貌;大桥边、北闸镇、光明村等地断错了晚更新世—全新世地层;龙树河Ⅰ级阶地上发育高0.5~2.0m的断层陡坎。表明其最新活动时代为晚更新世—全新世,运动性质以逆冲运动为主兼有右旋走滑分量。此外,在NE向断裂间穿插发育的一些NW向断裂,同样表现出晚第四纪活动特征。在2014年鲁甸M6.5地震震区产生了NE和NW向地裂缝和地形反坎等地表形变,与NE和NW向断裂展布基本一致,反映了断裂的新活动特征。由于块体远程变形响应与能量交换传递,在川滇块体东侧形成了凉山次级活动块体,昭通-鲁甸断裂带位于凉山次级活动块体SE向运动的前缘部位。它独特的地理位置和复杂的断裂几何结构成为凉山次级块体构造变形的主要承载体之一,吸收、调节块体SE向运动应变,并构成了凉山次级活动块体的南部边界。从区域构造部位和运动特征分析,昭通-鲁甸断裂带之于凉山次级块体,正如龙门山断裂带之于巴颜喀拉块体。昭通-鲁甸断裂带在活动块体边界和区域构造格架划分上具有重要的构造意义,同时也是滇东北地区重要的地震构造。  相似文献   

不同震型地震的面波震级-体波震级标度关系研究     

钟羽云  张帆  杨钢宇 《高原地震》2005,17(1):1-8

通过研究中国大陆107次不同断层性质、不同震型、不同地区的5级以上地震的Ms与mb标度关系,用最小二乘法拟合得到:Ms=1 17mb-0 41。进一步分析发现:mb相同时,走滑断层地震的Ms大于倾滑断层地震的Ms;多震型地震的Ms大于孤立型地震的Ms。使用Ms与mb的这种关系,得到一种快速判定地震震型的方法,即对于走滑断层引起的地震,若Ms-1 17mb+0 16>0,则地震序列多数为多震型,再次发生较大或更大地震的可能性较大;对于倾滑断层引起的地震,若Ms-1 17mb+0 66<0,则地震为孤立型的可能性较大,再次发生较大或更大地震的可能性较小。  相似文献   

2004年苏门答腊地震的几个断层滑动模型的全球同震位移对比   总被引：5，自引：3，他引：2       下载免费PDF全文

瞿武林  张贝  黄禄渊  尹凤玲  张怀  石耀霖 《地球物理学报》2016,59(8):2843-2858

2004年苏门答腊大地震后,不同作者根据地震波和/或GPS观测,提出了不同的断层错动模型.在利用同震位移观测资料反演断层滑动模型时,由于使用半无限空间均匀介质模型或半无限空间分层介质模型,一般只能利用近场位移GPS观测约束,无法利用远场资料,这些模型有时差别颇大,如何区别这些模型的优劣是一个仍尚未解决的问题.本文采用等效体力有限元方法,在考虑地球球形和分层的条件下,对四个不同作者提供的2004年苏门答腊地震的断层滑动模型计算全球同震位移.由于采用了球形模型,所以不仅可以把四个模型的近场位移计算结果与GPS数据进行对比,而且可以把远场位移计算结果与GPS数据进行对比.我们发现,垂直位移对断层滑动模型的依赖性小于水平位移.四个模型计算的近场位移与GPS位移符合程度均较好,但是四个模型计算的远场位移与GPS位移符合情况有很大不同,其中Chlieh等（2007）模型在近场与远场符合程度均很好,是四个模型中最好的.另外还探讨了断层反演数据资料、断层几何模型以及地球模型对计算结果的影响.对于特大地震,全球同震位移观测与计算值吻合程度的好坏是衡量断层滑动模型的合理性的一个重要依据.  相似文献   

A critical review of the Kibyra Fault (Burdur-Fethiye Shear Zone,SW Turkey)     

İrem Elitez  Cenk Yaltırak  Akın Kürçer  Ersin Özdemir  Çağıl Uygun Güldoğan 《Geodinamica Acta》2017,29(1):91-102

The Kibyra Fault is considered as the most significant evidence about the existence of the NE–SW-striking left-lateral Burdur-Fethiye Fault Zone in the south-western Anatolia in previous studies. However, recent studies show that there is a shear regime, named the Burdur-Fethiye Shear Zone, dominated by normal and left-lateral oblique normal faults in this region. A large number of ancient cities lie on this zone and many of them have been damaged by ancient earthquakes. One of these ancient cities is the ancient city of Kibyra. Most of previous studies suggest the Kibyra Fault depending on the damage in the city. However, the closest fault is located on the western side of the city and the earthquake damage was most likely caused by ground shaking. In this study, the existence of the supposed Kibyra Fault is discussed by integrating field studies, geological maps, trench data, digital elevation model and geomorphological analysis. In conclusion, it is understood that there is no evidence directly indicating a 35-km-long left-lateral fault in this region. The aim of this study is to examine the existence of the Kibyra Fault, take a different approach to the active fault studies and emphasise the importance of active faults for socio-economic conditions.  相似文献   

郯庐断裂带重岗山—王迁段晚更新世以来的活动习性   总被引：2，自引：2，他引：0  

沈小七  姚大全  郑海刚  杨源源  翟洪涛  郑颖平  王俊  赵鹏  肖伟鹏 《地震地质》2015,37(1)

活动断裂最新错动与地震事件的关系是重要的基础研究课题。文中选定郯庐断裂带泗洪县重岗山—王迁段,开挖大型探槽,识别编录晚第四纪以来变形和史前地震事件,分析其活动期次和特性。结果表明,郯庐断裂带重岗山—王迁段晚第四纪以来曾发生强烈的挤压逆冲活动,在重岗山表现为晚白垩世砖红色砂岩向西高角度逆冲于晚更新世黄褐色黏土之上,在王迁则表现为黄白色上新世砂岩向西逆覆于晚第四纪沉积之上,且存在部分张裂现象。通过14C测年分析,得到重岗山—王迁段的2次古地震事件,其年代依次为(11 755±45)~(10 525±45)a BP与(10 135±50)a BP。郯庐断裂带重岗山—王迁段晚更新世以来逆冲活动强烈,而且一直持续到全新世初期。  相似文献   

龙门山断裂带中北段的地壳电性结构及其动力学模型   总被引：1，自引：0，他引：1  

彭淼  姜枚  谭捍东  李庆庆  张立树  许乐红  张福彬  唐路特 《地震地质》2015,37(1)

2012年在四川龙门山断裂带的茂县—绵竹段进行了点距约3km、横跨断裂带的大地电磁探测,精细处理并反演获得长70km,深50km的2维电性剖面。通过与同位置的反射地震资料对比进行综合解释,刻画出龙门山断裂带中北段的地壳结构:1)四川盆地上覆地层为低阻,电性结构稳定并叠置于坚固的扬子中下地壳之上;龙门山3条主断裂均表现为低阻—中低阻,其构造形态都沿NW向倾斜,并由陡变缓向下延伸,浅部最陡处60°,深部最缓处30°。2)龙门山断裂带上地壳整体逆冲推覆于扬子板块的刚性基底之上,不仅形成由陡趋缓的3条主断裂,而且多期次的地震活动造成隐伏次级断裂发育;映秀-北川断裂之下具有明显NW倾斜且陡立的电性梯度带,2008年汶川地震余震在该区域内集中分布,其中安县-灌县断裂下盘发育大型隐伏的基底断裂,可能为发震断裂,地震能量沿隐伏次级断裂向上传递导致映秀-北川断裂遭破坏最为严重。3)青藏高原东缘的中下地壳下插,使高阻的扬子中下地壳嵌于龙门山逆冲推覆带和青藏高原东缘中下地壳之间,形成"鳄鱼口"样式的构造格架。龙门山的隆升是由上地壳的逆冲推覆脆性变形和中下地壳的壳内高导物质流的韧性变形共同作用的结果。同时提出,由于中下地壳物质流在龙门山不仅受阻于刚性的扬子块体,而且下插于扬子板块上地幔,形成一种可能的类似"传送带"的动力模式,带动了其上盘发生持续的逆冲推覆脆性变形。  相似文献   

基于球体位错理论的地震形变分析     

田平  金红林 《地震》2015,35(2):26-33

地震形变分布特征主要取决于地震断层破裂特征, 不同震级的地震引起的形变响应范围存在差异。 本文中, 我们基于球体位错理论, 以5 mm的形变测量值为基准, 针对逆冲型和走滑型地震断层, 分析了M_W6.0~M_W8.5地震在跨断层法方向上的形变响应范围, 提出了地震震级和响应范围的经验公式, 并与实际地震(2001年昆仑山口西地震、 2013年芦山地震等)结果进行了比较。 比较结果显示, 经验公式计算结果和实际观测值相符合, 可以用于估算M_W6.0~M_W8.5地震在跨断层法方向的形变响应范围, 同时为地震远场形变特征分析与同震、 震后形变测量点布设等方面提供参考数据。  相似文献   

Evidence of non extensivity in the evolution of seismicity along the San Andreas Fault,California, USA: An approach based on Tsallis statistical physics     

《Physics and Chemistry of the Earth》2015

We examine the nature of the seismogenetic system along the San Andreas Fault (SAF), California, USA, by searching for evidence of complexity and non-extensivity in the earthquake record. We use accurate, complete and homogeneous earthquake catalogues in which aftershocks are included (raw catalogues), or have been removed by a stochastic declustering procedure (declustered catalogues). On the basis of Non-Extensive Statistical Physics (NESP), which generalizes the Boltzmann–Gibbs formalism to non-equilibrating (complex) systems, we investigate whether earthquakes are generated by an extensive self-excited Poisson process or by a non-extensive complex process. We examine bivariate cumulative frequency distributions of earthquake magnitudes and interevent times and determine the size and time dependence of the respective magnitude and temporal entropic indices, which indicate the level on non-equilibrium (correlation). It is shown that the magnitude entropic index is very stable and corresponds to proxy b-values that are remarkably consistent with the b-values computed by conventional means. The temporal entropic index computed from the raw catalogues indicate moderately to highly correlated states during the aftershock sequences of large earthquakes, progressing to quasi-uncorrelated states as these die out and before the next large event. Conversely, the analysis of the declustered catalogues shows that background seismicity exhibits moderate to high correlation that varies significantly albeit smoothly with time. This indicates a persistent sub-extensive seismogenetic system. The degree of correlation is generally higher in the southern SAF segment, which is consistent with the observation of shorter return periods for large earthquakes. A plausible explanation is that because aftershock sequences are localized in space and time, their efficient removal unveils long-range background interactions which are obscured by their presence! Our results indicate complexity in the expression of background seismicity along the San Andreas Fault, with criticality being a very likely mechanism as a consequence of the persistent non-equilibrium inferred from the temporal entropic index. However, definite conclusions cannot be drawn until the earthquake record is exhaustively studied in all its forms.  相似文献   

Stick-slip behavior of Indian gabbro as studied using a NIED large-scale biaxial friction apparatus     

Tetsuhiro Togo  Toshihiko Shimamoto  Futoshi Yamashita  Eiichi Fukuyama  Kazuo Mizoguchi  Yumi Urata 《地震科学（英文版）》2015,28(2):97-118

This paper reports stick-slip behaviors of Indian gabbro as studied using a new large-scale biaxial friction apparatus, built in the National Research Institute for Earth Science and Disaster Prevention (NIED), Tsukuba, Japan. The apparatus consists of the existing shaking table as the shear-loading device up to 3, 600 kN, the main frame for holding two large rectangular prismatic specimens with a sliding area of 0.75 m² and for applying normal stresses σ_n up to 1.33 MPa, and a reaction force unit holding the stationary specimen to the ground. The shaking table can produce loading rates v up to 1.0 m/s, accelerations up to 9.4 m/s², and displacements d up to 0.44 m, using four servocontrolled actuators. We report results from eight preliminary experiments conducted with room humidity on the same gabbro specimens at v = 0.1-100 mm/s and σ_n = 0.66-1.33 MPa, and with d of about 0.39 m. The peak and steady-state friction coefficients were about 0.8 and 0.6, respectively, consistent with the Byerlee friction. The axial force drop or shear stress drop during an abrupt slip is linearly proportional to the amount of displacement, and the slope of this relationship determines the stiffness of the apparatus as 1.15×10⁸ N/m or 153 MPa/m for the specimens we used. This low stiffness makes fault motion very unstable and the overshooting of shear stress to a negative value was recognized in some violent stick-slip events. An abrupt slip occurred in a constant rise time of 16-18 ms despite wide variation of the stress drop, and an average velocity during an abrupt slip is linearly proportional to the stress drop. The use of a large-scale shaking table has a great potential in increasing the slip rate and total displacement in biaxial friction experiments with large specimens.  相似文献