1850年西昌地震地表破裂带

着重从1850年西昌地震的地表破裂带调查入手,通过对地表破裂的分布特征、几何特征以及与各次级断层的关系的研究,对这次地震的震级、震中位置和震源深度进行讨论。     

西藏申扎南发现地震地表破裂

1990年作者在申扎地区进行地震地质调查时,在申扎县城南约15公里的甲岗(山峰名)雪山东麓发现了一条北起果地南西,向南延伸至巴荣沟北侧、走向NNE、长约10公里、宽十几米至数十米的地震地表破裂带。其中,枪嘎下—日阿—扎嘎鄂玛一段(长约5公里)破裂最为发育(破裂规模大,种类齐全)。破裂带沿甲岗雪山东麓的基岩(花岗岩)与松散堆积物(冰碛、冰水积和洪积物)的界线明显,偏向松散堆积物一侧。构造上,破裂沿甲岗东麓右旋走滑正断层发育(图     

昆仑山口西8.1级地震地表破裂带西段考察

20 0 1年 1 1月 1 4日 1 7时 2 6分 (北京时间 ) ,在我国昆仑山口西新疆维吾尔自治区与青海省交界处发生了 8.1级地震。震区为海拔 4 90 0 m以上的高原和山地。这是新世纪发生在中国境内的第一个 8级大地震。地震发生后 ,中国地震局组织了综合考察队对此次地震进行了全面考察。     

1850年西昌地震地表破裂带

着重从1850年西昌地震的地表破裂带调查入手,通过对地表破裂的分布特征、几何特征以及与各次级断层的关系的研究,对这次地震的震级、震中位置和震源深度进行讨论.     

1850年西昌地震地表破裂带

着重从 1850年西昌地震的地表破裂带调查入手 ,通过对地表破裂的分布特征、几何特征以及与各次级断层的关系的研究 ,对这次地震的震级、震中位置和震源深度进行讨论。     

甘肃高台合黎山南缘发现地震地表破裂带

据最新野外考察发现,位于河西走廊中段北部的合黎山南缘断裂东段有2条较新的地震地表破裂带遗迹,破裂带长度分别为7km和10km,保存较为完整,认为其为较近的一次地震活动所致。根据该地区历史地震资料和目前该地区的研究程度,该地震地表破裂带可能与2次历史地震(公元180年表氏8级地震、公元756年张掖-酒泉7级地震)中的其中之一或与一次漏记的历史强地震有关     

玉树7.1级地震断层地表破裂带应急科考

玉树7.1级地震断层同震地表破裂带由3条主破裂左阶组成,总体走向300°～320°,隆宝镇上见有约2km长的雁列式张裂缝,北侧主破裂长约16km,中间主破裂长约9km,南侧主破裂长约7km,总长约34km。各主破裂均由一系列支破裂雁列组成,支破裂表现为一系列挤压鼓包与张裂缝相间排列或雁列式张裂缝,最南端禅古寺表现为垂直位错。破裂为左旋走滑性质,最大走滑位移量位于北侧主破裂上,约1.8m。     

1303年山西洪洞8级地震地表破裂带di

综合20世纪90年代初在霍山山前断裂和近年在绵山西侧断裂和太谷断裂获取的最新调查资料，讨论了1303年山西洪洞8级地震地表破裂带的展布和位移特征. 如果太谷断裂、绵山西侧断裂与霍山山前断裂在1303年洪洞地震中同时活动，则该次地震的地表破裂带长163 km，分为3段，即霍山山前断裂段、绵山西侧断裂段和太谷断裂段. 各段长度分别为50，35和70 km，3段之间存在4和8 km的阶区. 该地震地表破裂带具右旋走滑特征，北段和中段右旋走滑位移量6～7 m，南段最大为10 m. 在山西断陷带盆地边界的单条断裂一般只对应7级地震，而该次8级特大地震则突破两个盆地之间的障碍体，显示了强震地表破裂尺度的可变特征.      

汶川MS 8.0地震地表破裂带

2008年5月12日14时28分4秒,四川省汶川县发生MS8.0大地震。发震断裂为龙门山断裂带中的映秀-北川断裂。该次地震的地表破裂可分成2条,分别出现在龙门山断裂带中的映秀-北川断裂、彭县-灌县断裂上,前者破裂长度约200km,后者破裂长度约80km。本次地震的最大垂直和右旋水平同震位移出现在都江堰市虹口乡附近的映秀-北川断裂上,分别为(5±0.2)m和(4.8±0.2)m。破裂带南段出露的地表断层产状为N32°E/NW∠76°,其上的侧伏角为S75°～80°W,反映了该次地震在南段以逆冲运动为主,兼有少量的右旋走滑分量     

DISCOVERY OF SURFACE RUPTURE ZONE IN JIUXI BASIN,GANSU PROVINCE

Qilian Shan-Hexi Corridor is located at the northeastern margin of Tibetan plateau. Series of late Quaternary active faults are developed in this region. A number of strong earthquakes even large earthquakes occurred in history and present-day. In the past, the study of active faults in the area was mostly concentrated in the northern margin fault zone of the Qilian Shan on the south side of the corridor, while the research on the interior and the north side of the corridor basin was relatively rare. We found a new fault scarp in the northern part of the Baiyanghe anticline in Jiuxi Basin in 2010. It is an earthquake surface rupture zone which has never been reported before. In this paper, we carried out palaeoearthquake trench analysis on the newly found earthquake surface rupture zone and textual research of relevant historical earthquakes data. According to the interpretation of aerial photo and satellite image and field investigation, we found the surface rupture has the length of about 5km. The rupture shows as an arc-shaped line and is preserved intact comparably. The lower terrace and the latest flood alluvial fan are offset in addition to modern gullies. By differential GPS measurement, the height of the scarp is about 0.5~0.7m in the latest alluvial fan and about 1.5m in the T₁ terrace. From the residual ruins along the earthquake rupture zone, we believe the surface rupture might be produced by an earthquake event occurring not long ago. In addition, the rupture zone locates in the area where the climate is dry and rainless and there are no human activities induced damages. These all provide an objective condition for the preservation of the rupture zone. The trench along the fault reveals that the surface rupture was formed about 1500 years ago, and another earthquake event might have happened before it. Based on the textural research on the historical earthquake data and the research degree in the area at present, we believe that the surface rupture is related to the Yumen earthquake in 365, Yumen Huihuipu earthquake in 1785 or another unrecorded historical earthquake event.     

辽宁内蒙交界区地震危险性研究

对辽宁、内蒙交界区地震活动整体性和有序性研究的基础上,利用增能(S)、降维(b)、减熵(Q~T)空间扫描的方法,来划定孕震区域,并以(0—1)权重回归模型法,进行发震危险性判别。     

晋冀蒙交界地区中强地震危险性的灰色拓扑预测

应用灰色系统理论 ,建立了晋冀蒙交界地区的 5级和 6级以上地震的灰色预测模型 .利用上述模型对该地区未来几年内中强地震的活动趋势进行了预测     

龙陵-澜沧新生断裂带地震破裂分段与地震预测研究

龙陵 -澜沧新生断裂带的地震活动具频度高、强度大、周期短等特征 ,并以双震或震群型为主。断裂带由多条次级新生断层组成 ,呈斜列或共轭式展布 ,根据结构、规模、地震活动差异等因素把断裂带划分为 4个一级段、13个二级段 ,其中有 4个二级段又可划分出 8个三级段。历史上发生过大震、强震并有地震断层伴生的断层段为地震破裂单元 ;断裂带上晚第四纪有活动并有古地震事件 ,但无历史地震记载的地段为断层闭锁单元 ;次级断层之间的阶区或连接点为障碍体单元。从地震破裂特征分析 ,断裂带由破裂、闭锁、障碍体单元组成 ,根据地震、古地震、活断层、断层阶区的活动规律 ,断裂带可划分出 9个破裂单元、8个闭锁单元、10个障碍体单元。三者之间呈迁移、触发和转换能量的关系。根据这些关系和地震构造标志 ,对断裂带上未来可能发生大震、强震、中强震的地区分别作了预测。预测的危险区有 9个 ,其中大震区 1个 (永康 -永德地区 ) ,强震区 3个 (马站、石灰窑、酒房-勐混 ) ,中强震区 5个 (下顺江、里仁、大岗山、南明 -澜沧、勐遮     

THE COSEISMIC VERTICAL DISPLACEMENTS OF SURFACE RUPTURE ZONE OF THE 1556 HUAXIAN EARTHQUAKE

Coseismic displacement plays a role in earthquake surface rupture, which not only reflects the magnitude scale but also has effect on estimates of fault slip rate and earthquake recurrence intervals. A great historical earthquake occurred in Huaxian County on the 23^rd January 1556, however, there was lack of surface rupture records and precise coseismic vertical displacements. It's known that the 1556 Huaxian earthquake was caused by Huashan front fault and Weinan plateau front fault, which are large normal faults in the east part of the southern boundary faults in Weihe Basin controlling the development of the basin in Quaternary. Here, we made a study on three drilling sites in order to unveil the coseismic vertical displacements. It is for the first time to get the accurate coseismic vertical displacements, which is 6m at Lijiapo site of Huashan front fault, 7m at Caiguocun site, and 6m at Guadicun site of Weinan plateau front fault. These coseismic displacements measured based on same layers of drilling profiles both at footwall and hanging wall are different from the results measured by former geomorphological fault scarps. It's estimated that some scarps are related with the nature reformation and the human beings' activities, for example, fluviation or terracing field, instead of earthquake acticity, which leads to some misjudgment on earthquake displacements. Moreover, the vertical displacements from the measurement of geomorphological scarps alone do not always agree with the virtual ones. Hence, we assume that the inconsistency between the results from drilling profiles and geomorphological scarps in this case demonstrates that the fault scarp surface may have been demolished and rebuilt by erosion or human activities.     

隐伏活断层未来地表破裂带宽度与位错量初步研究

采用Okada(1992 )有关地震断层地表位移的计算方法和程序 ,依据《建筑抗震设计规范》(GB 5 0 0 11- 2 0 0 1) ,推导了隐伏活断层突然错动产生地表破裂带的临界值 ,即在相隔 5m的水平上 ,位移差超过 0 1m。初步讨论了隐伏活断层地表破裂带随埋深、倾角、断裂力学性质和断面位错量的变化特点。结果表明 :对于隐伏正断层 ,地表破裂带宽度随覆盖层埋深的增加表现出非线性特点 ,具有从小到大 ,再变小的特点 ;地表破裂带位错量峰值随埋深线性递减。在其他参数不变的情况下 ,隐伏正断层倾角越小 ,地表破裂带越偏向下盘 ,并且 ,地表破裂带的宽度也变小。与隐伏正断层相比 ,隐伏走滑断层地表位移差随埋深衰减更快。随着隐伏活断层断面上位错量的增加 ,地表破裂带宽度会显著变宽 ,位错量也随之增大。这些认识和计算结果为城市规划、各种生命线工程和建 (构 )筑物的跨断层设防 ,提供了可以参考的依据     

汶川M_S 8.0地震地表破裂带北端位置的修订

对汶川MS8.0地震地表破裂石坎乡以北段的野外地质调查显示,这一段地表破裂仍然十分明显。地表破裂并未沿地质填图所标定的位置发育,而是在走向上稍有变化,但清楚的地貌显示它在此段并不是一条新生断裂。与前期工作相比,可观察到的地表破裂又往NE方向延长了约12km。该段破裂位于平武县石坎乡至青川县马公乡窝前村之间,走向为15°～45°,运动学性质主要为右旋走滑逆冲。地震地表破裂显示的同震垂直位移与石坎乡一带相近,为1～2m左右;右旋水平位移略有增加,为2.0～3.0m之间。地表调查的情况显示,地表破裂在北端可能消失在红光乡东河口一带。     

汶川Ms 8.0地震绵竹县汉旺镇周边地表破裂带展布方式及其震害意义

2008年5月12日汶川MS8.0地震的震中烈度为Ⅺ度,但位于地震烈度为Ⅹ度区边缘的绵竹县汉旺镇,无论是房屋毁坏情况还是遇难和失踪人员的数目,均高出周边地震烈度Ⅰ度,接近极震区的破坏程度。文中从汉旺镇周边地表地震破裂带展布方式的角度讨论了这种震害加重现象的原因,介绍了位于汉旺镇北面和南面出现的2条相距1.5km呈左阶斜列展布的地表破裂带。其中,位于汉旺镇北侧的地表破裂带,垂直位移1.4m,水平右旋位移0.44m;位于汉旺镇南侧的地表破裂带,垂直位移量由西向东递减,为3.0～0.2m。尽管这2条地表破裂带没有从汉旺镇中心通过,但汉旺镇正位于这2条地表破裂带夹持的左阶阶区,致使阶区内建筑物除遭受来自震源的振动外,又受到阶区内的挤压,由此加重了汉旺镇建筑物的破坏,也显示出地表破裂带对建筑物破坏形式的多样性。汉旺镇汶川MS8.0地震震害实例表明,地表破裂带的阶区,也是遭受地震时破坏加重的特殊构造部位