嘉峪关断层中段的新活动特征

嘉峪关断层是河西走廊盆地内部的一条重要断层,断层走向NNW向,晚第四纪以来新活动特征以挤压逆冲为主兼具有右旋走滑特征。通过野外地质调查,在嘉峪关城楼北关园子山嘉峪关断层大陡坎西侧0.5km处的Ⅲ级阶地面上,新发现一段长约1.6km保存完好的小断层陡坎,坎高0.5～2m,且有冲沟发生右旋位错现象。经探槽开挖和热释光测年确认,嘉峪关断层全新世有古地震活动。据断错地貌的差分GPS测量和测年结果,得到断裂晚第四纪晚期以来的平均滑动速率为0.52～0.56mm/a。     

西藏格林错断层带的基本特征

格林错断层带是一条晚白垩纪以前形成,第四纪以来具明显活动性质的右旋走滑断层。断层带由4条次级走滑断层呈右行右阶羽列排列而成,在两条次级走滑断层的连接部位分别形成孜桂错、格林错、瓦昂错拉分区。格林错断层带是西藏中部地区的主要发震断层之一,全新世以来,至少有4期地震地表破裂沿该断层带发生。第四纪晚期,断层具明显的分段活动性质,并且断层活动有从北西向南东、向南迁移的迹象     

敦煌三危山断层—一条无强震的第四纪活动断层

本文研究了敦煌三危山断层的第四纪活动特征及其与地震活动的关系,运用构造地貌学分析方法确定了晚更新世以来三危山地区的区域抬升期次和抬升速率。研究结果表明,敦煌三危山断层是一条晚更新世以来无强震的第四纪活动断层,早、中更新世曾发生过比较强烈的倾滑逆冲运动,晚更新世以来停止活动,代之以包括三危山断层在内的间歇性区域抬升运动。     

巴基斯坦北Potwar形变区地震的震源机制研究

巴基斯坦北Potwar形变区是西北喜马拉雅褶皱逆冲带前陆区的一部分，绘制了该区的地震活动性图. 与相邻地区比较，该区地震并不活跃，没有显示出与地表地质构造相关的清晰地震活动图象. 做出了4次地震的震源机制解. 结果表明，有3次地震是左旋走滑断层活动，另一次地震是逆断层活动. 地震震源机制解的P轴方向为NW-SE和NE-SW. 现今的构造形变很可能也包括基底的形变.      

有关1976年唐山地震发震断层的讨论

对《地震地质》刊登的两篇文章中有关唐山断裂是高角度西倾的逆冲走滑断裂及唐山市东侧付庄-西河断裂是唐山地震的发震断裂的观点进行讨论。笔者认为,如果唐山地震断层是西倾的逆冲走滑活动,需要考虑唐山逆冲断裂的活动方式与唐山市西侧第四纪凹陷之间的关系;如果付庄-西河断裂是唐山地震震源构造的地表破裂,需要解释该西倾的倾滑断裂带与唐山市内走滑地裂缝带的成因联系。此外,还需要更有说服力的证据排除该地表破裂带是次生构造破裂的可能。建议对控制草泊第四纪凹陷的活动断裂开展调查     

确定辽东半岛潜在震源区的断层活动性研究

本文讨论了在地震活动中等或较弱、而又没有发现古地震遗迹的地区(辽东半岛属于这类地区),如何利用断层活动性资料评价该区的地震危险性和确定潜在震源区的问题,并取得以下结果:1.该区发生的5级以上地震基本与晚更新世有过活动的断层有关;2.研究区活断层据其运动特性划分为以粘滑为主、蠕滑为主和粘滑、蠕滑兼有三类。6级地震发生在粘滑断层段;3.利用晚更新世活断层长度和个别断层的位移量估算了一些断层可能的最大震级     

西藏中部的发震构造

西藏中部的发震构造是晚第四纪以来强烈活动的北东、北西和近南北向的活动断层及受其控制的地堑半地堑型盆地和拉分盆地，东西向缝合线和断层晚第四纪以来的运动性不明显，对地震活动没有明显的控制作用，活动断层的规模和晚第四纪以来的运动性质对地震的震级和数量有明显的的控制作用。８级地震的发生与拉分盆地内部张剪切断层与盆地一侧新活动幅度大的次级走滑断层的相互作用密切相关。     

湖南太阳山隆起区断层活动性研究

湖南省太阳山地区是洞庭湖西缘一个晚新生代时期隆起的低山丘陵区,山体走向为北北东方向,自南向北斜列展布了太阳山低山区和凤凰山低山区,二者之间为北北东向大龙站谷地.通过对该地区现有6条断层活动性的地质调查,获得了位于大龙站谷地东侧的肖伍铺断层断错中更新世晚期,距今12.3±1.O万年地层的地质证据,为中更新世晚期至晚更新世早期有活动的断层,表现为逆冲活动的性质.根据岗市-河袱断层带发育的断层泥及其测年结果可知,该断层可能在中更新世中期有过活动.其余4条断层没有第四纪以来活动的地质地貌表现,属于前第四纪断层.上述研究结果对认识1631年太阳山63/4级地震的发震构造是有意义的.     

西秦岭北缘活断层带断层气的基本特征

通过对西秦岭北缘活断层带断层气活动基本特征的研究认为：本活断层带是本区地球排气的主要通道;在走滑断层拉分区,地球排放气体活动的强度与地震活动有密切的关系;本带东段断层排气活动比较强,西段断层排气活动比较北,并讨论了两形成差异的原因。     

南定河断裂带断层活动特征与古地震事件

南定河断裂带是滇西南地区一条重要的北东向断裂构造，它由东、西两分支断裂组成。本文根据沿断裂带发育的串珠状盆地展布、沉积物的分布以及第四纪地层的变动情况，分析了该断裂带的活动特征，西支断裂第四以来活动强烈且明显的差异性，东支断裂从晚第三纪末起已停止活动，对于这条缺少地震历史载和仪器记录的活动断层，古地地震研究也是一个进一步认识其活动强度的行之有效的方法。     

On the faults of western Hexi Corridor and its nearby regions, northwestern China:Thrust faults and strike-slip faults of Late Cenozoic

Introduction Hexi Corridor, a corridor extended over 1 000 km and with a strike of WNW-ESE, is locatedbetween Alxa uplift and northern Qilianshan Caledonian folding belt of northern Qinghai-Xizang(Tibet) Plateau (Figure 1). In the paper, we will discuss the regions between Altun fault and Yu-mushan of the western Hexi Corridor, where the climate is arid, which results in sparse vegetation,but abundant oil and gas resource, and being one of the most important petroleum industry base…     

A PRELIMINARY RESEARCH ON THE RIGHT-LATERAL STRIKE-SLIP CHARACTERISTICS AND THE STRUCTURAL SIGNIFICANCE OF THE NORTHERN KUANTANSHAN FAULTS,HEXI CORRIDER,BASED ON HIGH-RESOLUTION IMAGERY

The sinistral strike-slip characteristic of the Altyn Tagh Fault gradually disappears near the Jiuxi Basin at the west end of Hexi Corridor, and the Kuantanshan Fault and the northern marginal fault of Heishan on its east are thrust structures. There are two faults distributed in the north of Kuantanshan, namely, the Taerwan-Chijiaciwo Fault and the Ganxiashan Fault, both are featured with obvious activity. Predecessors thought that the Taerwan-Chijiaciwo Fault is a thrust fault with low movement rate, but there is few detailed study on its horizontal motion. Is there horizontal strike-slip movement in the northern marginal fault of Kuantanshan? This issue has an important significance to further explore the structural transformation mode between the Altyn Tagh strike-slip faults and the northern thrust faults in the north margin of Qilianshan. Using high resolution remote sensing images and field work, such as combining with UAV SfM photogrammetry, the paper studies the strike-slip characteristics of the Taerwan-Chijiaciwo Fault and Ganxiashan Fault on the northern margin of Kuantanshan, and get two preliminary understandings:(1) The northern marginal fault of Kuantanshan is an active right-lateral strike-slip fault with thrust component, the horizontal to vertical dislocation ratio is about 3-4 times. Based on the statistics of dislocation amount of the gullies and terraces along the north marginal Kuantanshan fault, it is preliminarily estimated that the late Pleistocene right-lateral strike-slip rate is about 0.2-0.25 mm/a and the Holocene right-lateral strike-slip rate is about 0.5-1.5 mm/a. (2) The main driving force to the tectonics at the western end of Hexi Corridor, where the northern marginal fault of Kuantanshan locates, comes from the northward extrusion of the Qilian Mountains, which results in the right-lateral strike-slip of the northern marginal fault of Kuananshan and the thrust movement of several faults inside the Jiuxi Basin. The effect of the Altyn Tagh Fault on other tectonic structures is not obvious in this region.     

酒西盆地断层活动特征及古地震研究

通过室内航片判读和野外调查 ,在酒西盆地发现 3条全新世活动逆掩断层 ,它们全新世以来的垂直活动速率都很接近 ,为 0 18～ 0 2 5mm/a。通过探槽揭露出的 3条断层全新世以来各发生两次古地震事件。根据探槽揭露的古地震年代及断层活动所形成的微地貌特征分析 ,阴洼山断层是独立活动的 ;北大河断层和新民堡断层上的古地震事件在时间上可能非常接近 ,具有丛集特征 ,或者是一次地震事件分别破裂这两条断层 ,但目前的测年手段还无法区别它们是一次破裂事件形成还是时间上非常接近的两次事件所形成的     

祁连山北缘断裂带的现代构造运动

本文依据现今区域水准测量资料及跨断层位移测量资料阐明祁连山北缘断裂带现今活动特点是以近南北—北东向的挤压并兼有右旋走滑的水平活动方式为主,在玉门一张掖段并伴有近似反对称的升降运动,最大垂直形变梯度R为0.2毫米/公里·年左右,跨断层基线测量的缩短速率为0.2—0.5毫米/年。在河西走廊内部,受次级构造运动的影响也存在有局部的隆起、拗陷的升降运动及断裂活动     

阿尔金断裂东端的旋转构造及其动力学意义

在阿尔金主断裂与祁连山北缘断裂的交汇部位，发育一个反时针旋转构造——照壁山旋转构造，它是新构造运动期阿尔金断裂左行走滑运动的结果。结合前人资料，对照壁山旋转构造变形及其发育过程进行了初步分析，认为阿尔金断裂与祁连山北缘断裂的构造转换是通过旋转构造变形来实现的。沿阿尔金断裂一系列旋转构造的存在和青藏高原东北缘旋转构造的发育表明，伴随青藏高原北部物质绕喜马拉雅东构造结的顺时针旋转运动，使旋转构造成为高原北部边缘带转换、吸收构造变形的重要表现形式。     

关于阿尔金北缘活动断裂带运动方式的转变机制的讨论

通过对构造变形、构造空间展布关系、断面产状变化以及构造应力场等的综合分析研究认为,阿尔金北缘活动断裂带在第四纪内的运动方式经历了由挤压逆掩为主（早更新世—中更新世初期）到左旋走滑兼具挤压逆冲（中更新世中、晚期）直至纯左旋走滑运动（晚更新世—现今）的逐渐转变过程．作用于这种转变,研究区内区域构造应力场的演变大致可以划分为三期,其主压应力轴方向由老至新依次为近南北向、北北东向和北东向．构造应力场和断裂带运动方式的这些变化主要是由于印度板块持续向北推挤导致青藏高原内部次级块体向东滑动、岩石圈物质向东流展而造成的．     

阿尔金构造系晚更新世中晚期以来的逆冲活动

在阿尔金构造系中,阿尔金走滑断裂具有逆冲分量。文中将阿尔金构造系的逆冲活动分为西、中、东3段描述。西段从阿依耐克至车尔臣河河口,阿尔金南缘断裂具有逆冲活动迹象,在山前发育了规模较小的逆冲断层,有较新的地貌面被错动;中段从车尔臣河河口至拉配泉一带,在阿尔金山北缘发育大规模的逆冲断层,有较新的地貌面被错动;东段从拉配泉至宽滩山,逆冲断层有2种形式,此段阿尔金北缘断裂有逆冲分量,同时在阿尔金山北缘及山前冲洪积扇上发育逆冲断裂。自晚更新世中晚期以来,中段及东段逆冲速率<2mm/a。中段西部江尕拉萨依地区自16kaBP以来逆冲速率约为0.33mm/a,中部米兰桥一带自32kaBP以来的逆冲速率约为1.42mm/a。东段最大的逆冲速率在近中部的团结乡,自约5.31kaBP以来达到约1.81mm/a,向东西两端有减小的趋势,在西部柳城子自约72.36kaBP以来的逆冲速率为0.57mm/a,而东端的红柳沟自约8.99kaBP以来仅为0.05mm/a。团结乡地区约自19kaBP以来,逆冲活动有增强的趋势     

喀喇昆仑断层与塔什库尔干地震形变带

喀喇昆仑断层位于我国新疆、西藏和阿富汗、克什米尔之间,是亚洲大陆中部一条巨型的右旋走滑断裂带,长约1000km,呈北西向展布,十分醒目。喀喇昆仑断层和阿尔金断层形成一个巨大的挤出构造,使青藏高原向东运动,对东亚的新构造和地震活动具有重要的控制作用。木吉-塔什库尔干盆地是公格尔山和慕士塔格山西侧一条串珠状断陷盆地带,东西两侧发育系列山前活动断裂,主要表现为正断层。这里曾发生多次强震活动,3条地震形变带(地震断层)已被发现。塔什库尔干断裂带呈北北西走向,是喀喇昆仑断层北部的一条分支     

PRESENT KINEMATICS CHARACTERISTICS OF THE NORTHERN YUMUSHAN ACTIVE FAULT AND ITS RESPONSE TO THE NORTHEASTWARD GROWTH OF THE TIBETAN PLATEAU

Qilian Shan and Hexi Corridor, located in the north of Tibetan plateau, are the margin of Tibetan plateau's tectonic deformation and pushing. Its internal deformations and activities can greatly conserve the extension process and characteristics of the Plateau. The research of Qilian Shan and Hexi Corridor consequentially plays a significant role in understanding tectonic deformation mechanism of Tibetan plateau. The northern Yumushan Fault, located in the middle of the northern Qilian Shan thrust belt, is a significant component of Qilian Shan thrust belt which divides Yumushan and intramontane basins in Hexi Corridor. Carrying out the research of Yumushan Fault will help explain the kinematics characteristics of the northern Yumushan active fault and its response to the northeastward growth of the Tibetan plateau.Because of limited technology conditions of the time, different research emphases and some other reasons, previous research results differ dramatically. This paper summarizes the last 20 years researches from the perspectives of fault slip rates, paleao-earthquake characteristics and tectonic deformation. Using aerial-photo morphological analysis, field investigation, optical simulated luminescence(OSL)dating of alluvial surfaces and topographic profiles, we calculate the vertical slip rate and strike-slip rate at the typical site in the northern Yumushan Fault, which is(0.55±0.15)mm/a and(0.95±0.11), respectively. On the controversial problems, namely "the Luotuo(Camel)city scarp" and the 180 A.D. Biaoshi earthquake, we use aerial-photo analysis, particular field investigation and typical profile dating. We concluded that "Luotuo city scarp" is the ruin of ancient diversion works rather than the fault scarp of the 180 A.D. Biaoshi earthquake. Combining the topographic profiles of the mountain range with fault characteristics, we believe Yumu Shan is a part of Qilian Shan. The uplift of Yumu Shan is the result of Qilian Shan and Yumu Shan itself pushing northwards. Topographic profile along the crest of the Yumu Shan illustrates the decrease from its center to the tips, which is similar to the vertical slip rates and the height of fault scarp. These show that Yumu Shan is controlled by fault extension and grows laterally and vertically. At present, fault activities are still concentrated near the north foot of Yumu Shan, and the mountain ranges continue to rise since late Cenozoic.     

THE LATE QUATERNARY ACTIVITY AND FORMATION MECHANISM OF BAOERTU FAULT ZONE,EASTERN TIANSHAN SEGMENT

Influenced by the far-field effect of India-Eurasia collision, Tianshan Mountains is one of the most intensely deformed and seismically active intracontinental orogenic belts in Cenozoic. The deformation of Tianshan is not only concentrated on its south and north margins, but also on the interior of the orogen. The deformation of the interior of Tianshan is dominated by NW-trending right-lateral strike-slip faults and ENE-trending left-lateral strike-slip faults. Compared with numerous studies on the south and north margins of Tianshan, little work has been done to quantify the slip rates of faults within the Tianshan Mountains. Therefore, it is a significant approach for geologists to understand the current tectonic deformation style of Tianshan Mountains by studying the late Quaternary deformation characteristics of large fault and fold zones extending through the interior of Tianshan. In this paper, we focus on a large near EW trending fault, the Baoertu Fault (BETF) in the interior of Tianshan, which is a large fault in the eastern Tianshan area with apparent features of deformation, and a boundary fault between the central and southern Tianshan. An M_S5.0 earthquake event occurred on BETF, which indicates that this fault is still active. In order to understand the kinematics and obtain the late Quaternary slip rate of BETF, we made a detailed research on its late Quaternary kinematic features based on remote sensing interpretation, drone photography, and field geological and geomorphologic survey, the results show that the BETF is of left-lateral strike-slip with thrust component in late Quaternary. In the northwestern Kumishi basin, BETF sinistrally offsets the late Pleistocene piedmont alluvial fans, forming fault scarps and generating sinistral displacement of gullies and geomorphic surfaces. In the bedrock region west of Benbutu village, BETF cuts through the bedrock and forms the trough valley. Besides, a series of drainages or rivers which cross the fault zone and date from late Pleistocene have been left-laterally offset systematically, resulting in a sinistral displacement ranging 0.93~4.53km. By constructing the digital elevation model (DEM) for the three sites of typical deformed morphologic units, we measured the heights of fault scarps and left-lateral displacements of different gullies forming in different times, and the result shows that BEFT is dominated by left-lateral strike-slip with thrust component. We realign the bended channels across the fault at BET01 site and obtain the largest displacement of 67m. And we propose that the abandon age of the deformed fan is about 120ka according to the features of the fan. Based on the offsets of channels at BET01 and the abandon age of deformed fan, we estimate the slip rate of 0.56mm/a since late Quaternary. The Tianshan Mountains is divided into several sub-blocks by large faults within the orogen. The deformation in the interior of Tianshan can be accommodated or absorbed by relative movement or rotation. The relative movement of the two sub-blocks surrounded by Boa Fault, Kaiduhe Fault and BETF is the dominant cause for the left-lateral movement of BETF. The left-lateral strike-slip with reverse component of BETF in late Quaternary not only accommodates the horizontal stain within eastern Tianshan but also absorbs some SN shortening of the crust.