Cold-water coral banks and submarine landslides: a review

This paper aims to review the relation between cold-water coral bank development and submarine landslides. Both are common features on continental margins, but so far it has not been reviewed which effect—if at all—they may have upon each other. Indirect and direct relations between coral banks and landslides are evaluated here, based on four case studies: the Magellan Mound Province in the Porcupine Seabight, where fossil coral banks appear partly on top of a buried slide deposit; the Sula Ridge Reef Complex and the Storegga landslide both off mid-Norway; and the Mauritania coral bank province, associated with the Mauritanian Slide Complex. For each of these locations, positive and negative relationships between both features are discussed, based on available datasets. Locally submarine landslides might directly favour coral bank development by creating substratum where corals can settle on, enhancing turbulence due to abrupt seabed morphological variations and, in some cases, causing fluid seepage. In turn, some of these processes may contribute to increased food availability and lower sedimentation rates. Landslides can also affect coral bank development by direct erosion of the coral banks, and by the instantaneous increase of turbidity, which may smother the corals. On the other hand, coral banks might have a stabilising function and delay or stop the headwall retrogradation of submarine landslides. Although local relationships can be deduced from these case studies, no general and direct relationship exists between submarine landslides and cold-water coral banks.     

浙江地区引发滑坡的降雨强度-历时关系

由于独特的地理位置,复杂的地质、地形和气候背景,浙江成为中国降雨型滑坡（土体和岩体滑动,也包括泥石流和崩塌等）最频发的地区之一。为评价浙江地区的滑坡灾害,本文对该地区1990年至2003年雨量站记录的降雨数据进行了详细分析,确定了引发土体滑坡-泥石流的降雨强度―历时下限。     

Some catastrophic landslides since the twentieth century in the southwest of China

Landslides occur frequently in China. Especially, in the western part of China, large-scale landslides are notable for their scale, complex formation mechanism, and serious destruction. This paper presents some typical large-scale landslides that occurred in the southwest of China since the beginning of the twentieth century but were rarely reported worldwide. These cases represent different geological conditions and different triggering factors and mechanisms. The analysis shows that about 80% of large-scale landslides occurred in the first slope-descending zone along the eastern margin of Tibet Plateau, which is tectonically very active. The intensive interactions between the endogenic and epigenetic geological process cause serious dynamic change on the high steep slope and then result in the development of large-scale landslides. Strong earthquakes are also common in this area, and repetitive seismic activities make the slopes unstable and more vulnerable to failures. Besides earthquake, the area also experiences high rainfall, which is also responsible for triggering some of the large landslides.     

中国滑坡降雨试验的研究现状与发展趋势

滑坡降雨试验是降雨型滑坡形成机理研究的重要方法之一。20世纪90年代以来,我国的工程地质学家对降雨型滑坡的关注与研究日益深入,更加注重通过试验的方法研究降雨型滑坡。本文对我国的降雨型滑坡的研究现状与发展趋势进行了评述。     

Landslide risk evaluation and hazard zoning for rapid and long-travel landslides in urban development areas

Risk evaluation for earthquake-induced rapid and long-travel landslides in densely populated urban areas is currently the most important disaster mitigation task in landslide-threatened areas throughout the world. The research achievements of the IPL M-101 APERITIF project were applied to two urban areas in megacities of Japan. One site is in the upper slope of the Nikawa landslide site where previous movements were triggered by the 1995 Hyogoken-Nambu earthquake. During detailed investigation, the slope was found to be at risk from a rapid and long-travel landslide induced by sliding surface liquefaction by earthquakes similar in scale to the 1995 event. A new plan to prevent the occurrence of this phenomenon was proposed and the plan was implemented. Another area is the Tama residential area near Tokyo. A set of field and laboratory investigations including laser scanner, geological drilling and ring-shear tests showed that there was a risk of sliding surface liquefaction for both sites. A geotechnical computer simulation (Rapid/LS) using the quantitative data obtained in the study allowed urban landslide hazard zoning to be made at individual street level.     

贵州省三都县滑坡特征及分布规律研究

为提高贵州省三都县地质灾害的防灾减灾能力,通过资料收集、地质灾害调查、数理统计、GIS空间分析等手段,查明了研究区滑坡数量及特征,研究了滑坡与地质构造、工程地质岩组、斜坡结构、坡度、坡形和人类工程活动等孕灾因子的关系,总结该县滑坡发育特征与分布规律。结果表明：研究区共发育滑坡57处,多发育在坡度20°~30°范围内,相对高差主要在20~40 m之间,坡形以凸形坡为主。在地质构造方面,丰乐断层、大河断层、烂土断层影响较大,该区域发育地质灾害共35处。软质岩组、顺向坡结构的斜坡区与河流两侧地质灾害数量也较多。按照地质环境差异和滑坡分布规律进行孕灾地质条件复杂、中等和一般分区,研究成果可为地质环境条件相似的地区在风险防控方面提供参考。     

复杂巨型滑坡形成机制三维离散元模拟分析

滑坡位于金沙江下游某拟建的大型水电站库区左岸,距坝址较近,总体积约为2 560万m3,属特大型滑坡,其稳定与否将直接威胁到大坝安全和水库正常运营。由于滑坡成因复杂,对其进行合理评价和科学预测尚有困难。为此,结合野外详细勘查资料的分析,对其形成机制进行了定性分析,认为主要以滑移-弯曲型为主,局部可能存在滑移-拉裂或蠕滑-拉裂变形。在此基础上,运用三维离散元数值模拟分析方法,再现了其变形破坏演化过程,进一步证实了其滑移-弯曲型变形破坏机制,很好地解释了主滑带低于现今河床、主滑体南侧边界比较模糊等原因,从而为其发展演化趋势、稳定性和危害性评价提供了有力依据。     

Modelling of submarine landslides of rock and soil

Landslides and their hydraulic effects are studied by numerical and experimental means. A two-dimensional model based on Navier–Stokes equations has been developed considering the sediments and water as a mixture. A Bingham law written in effective stress and an erosion–diffusion law at the water–sediment interface have been introduced into the model. Laboratory experiments consisting in the sliding of a block, a coarse gravel and a fine sand have been carried out. The results are compared with the numerical model. These experiments show the importance of sediment rheology and interstitial pressure in slide velocity and water wave generation. Copyright © 1999 John Wiley & Sons, Ltd.     

灾难性地震和降雨滑坡的体积与运动距离研究

为预测和评价灾难性滑坡的致灾机制,基于国内近年来地震和降雨诱发的灾难性滑坡资料,对地震和降雨滑坡的等价摩擦系数H/L、最大水平运动距离L、最大垂直运动距离H与滑坡体积V的关系进行分析。研究灾难性地震和降雨滑坡的远程运动特征以及不同规模滑坡最大水平运动和垂直运动的优势距离。研究结果表明,滑坡的H/L、L、H与V具有幂律关系,其中H/L与V具有负幂律关系,L、H与V具有正幂律关系。同一规模等级的地震和降雨诱发灾难性滑坡的水平和垂直运动距离不同。以H/L＝0.42作为滑坡远程运动的标准,地震诱发的灾难性滑坡与滑坡远程运动的关系较小,而降雨诱发灾难性滑坡与滑坡的远程运动的关系较大。根据滑坡运动距离的累积分布表,以80%滑坡的运动距离所分布的范围,建立了滑坡不同规模等级的优势运动距离区间,同规模等级的地震滑坡和降雨滑坡在水平和垂直运动的优势距离区间上存在差异。灾难性滑坡的运程不仅受滑坡体积的控制还与其诱发机制相关,其研究成果可为由地震和降雨诱发的灾难性滑坡的致灾区域和致灾强度的预测和评价提供参考依据。     

四川金川-小金公路沿线滑坡、崩塌影响因素分析

高原山区地质灾害是交通线路最大的危害,而有效避险的关键是掌握沿途地质灾害发生的工程地质条件内因及诱导因素。本文以川西阿坝州高原山区金小公路沿线带状区域内的滑坡、崩塌为研究对象,以地理、地质、气象、遥感资料和实地调查为基础,运用空间分析和数理统计方法,对其形成的影响因素进行了系统研究。结果表明：（1）金汤弧形褶皱形成的同时,区内软硬互层的炭质泥岩、粉砂质泥岩、粉砂岩的地层发生劈理化,喜山期构造运动及频繁的地震活动,加剧了岩石的破碎程度,为区内滑坡、崩塌提供了物源,并为高山峡谷地形地貌的塑造创造了有利条件;（2）区内6–9月份的集中降雨是诱发滑坡、崩塌的主要因素;（3）高山、峡谷、高角度斜坡等地形地貌以及公路建设中坡脚开挖为崩塌、滑坡等埋下了隐患;（4）季节性冻融作用加速了基岩风化破坏,对滑坡、崩塌的形成具有促进作用。     

黄河上游德恒隆-锁子滑坡堵塞黄河事件

黄河上游龙羊峡刘家峡河段两岸岸坡形成了众多残留体积超过10⁸ m³的古巨型滑坡,最大体积近30×10⁸ m³,且大部分堵塞过黄河。但部分巨型滑坡至今未有学者进行科学研究,其中包括德恒隆滑坡和锁子滑坡。结合区域地质环境条件,通过对德恒隆-锁子两个巨型滑坡基本特征和滑坡堵塞黄河的野外7个地质现象进行分析,并对德恒隆-锁子滑坡形成机制进行初步探讨,认为德恒隆-锁子滑坡为地震型滑坡,且形成原因与青藏高原8万 a的构造期有密切关系。通过分析黄河沿岸堰塞湖湖相沉积,认为堰塞湖形成时间为8万 a左右,这与德恒隆-锁子滑坡的形成年代一致。因此德恒隆-锁子滑坡在地震作用下触发并堵塞黄河。     

藏北羌塘中部冈塘错花岗岩体中环带条纹钾长石巨斑晶的特征

冈塘错花岗岩体是分布于西藏双湖角木日地区的一套晚三叠世酸性侵入岩。于2008年1∶5万区域地质调查填图中首次发现该岩体中的中粗粒巨斑状含黑云母二长花岗岩中的巨斑晶为环带条纹钾长石。主要描述了该岩体中环带条纹钾长石巨斑晶的矿物学、岩石学特征,利用电子探针详细分析了环带条纹钾长石巨斑晶从核部到边缘的成分变化特征,运用二长石温度计简单地计算了斑晶的结晶温度。根据斑晶的化学成分变化特征和结晶温度,结合岩体的岩石学、地质学特征,初步确定该岩体为岩浆混合作用的产物。     

藏北羌塘中部冈塘错花岗岩体中环带条纹钾长石巨斑晶的特征

冈塘错花岗岩体是分布于西藏双湖角木日地区的一套晚三叠世酸性侵入岩。于2008年1∶5万区域地质调查填图中首次发现该岩体中的中粗粒巨斑状含黑云母二长花岗岩中的巨斑晶为环带条纹钾长石。主要描述了该岩体中环带条纹钾长石巨斑晶的矿物学、岩石学特征,利用电子探针详细分析了环带条纹钾长石巨斑晶从核部到边缘的成分变化特征,运用二长石温度计简单地计算了斑晶的结晶温度。根据斑晶的化学成分变化特征和结晶温度,结合岩体的岩石学、地质学特征,初步确定该岩体为岩浆混合作用的产物。     

新疆伊犁皮里青河黄土滑坡类型及其发育特征

皮里青河流域地处新疆西北部黄土覆盖区,属于大陆性半干旱气候,春季降水与融冻作用引发大量黄土滑坡灾害,造成人员伤亡和财产损失。本文通过对该流域内黄土滑坡现场开展调查,在查明皮里青河基本环境地质条件的基础上,采用统计分析法和定性分析方法对滑坡进行分类和时空分区,将其滑坡分为黄土泥流、黄土层内滑坡、黄土基岩滑坡3类;分析滑坡分布与河流和地层的位置关系;分析滑坡发生时间规律。对滑坡的基本特征数据进行统计分析,得出区域滑坡形态、体积、主滑方向和滑坡坡度基本特征呈现出的规律。文章定性分析了滑坡的诱发因素,主要为降水作用、河流侵蚀和冻融作用。     

Dynamic propagation criteria for catastrophic failure in planar landslides

Quantitative assessment of the risk of submarine landslides is an essential part of the design process for offshore oil and gas developments in deep water, beyond the continental shelf. Landslides may be triggered by a reduction in shear strength of subsea sediments over a given zone, caused for example by seismic activity. Simple criteria are then needed to identify critical conditions whereby the zone of weakness could grow catastrophically to cause a landslide. A number of such criteria have been developed over the last decade, based either on ideas drawn from fracture mechanics, or considering the equilibrium of the initial weakened zone and adjacent process zones of gradually softening material. Accounting for the history of the weak zone initiation is critical for derivation of reliable propagation criteria, in particular considering dynamic effects arising from accumulating kinetic energy of the failing material, which will allow the failure to propagate from a smaller initial zone of weakened sediments. Criteria are developed here for planar conditions, taking full account of such dynamic effects, which are shown to be capable of reducing the critical length of the softened zone by 20% or more compared with criteria based on static conditions. A numerical approach is used to solve the governing dynamic equations for the sliding material, the results from which justify assumptions that allow analytical criteria to be developed for the case where the initial softening occurs instantaneously. The effect of more gradual softening is also explored. Copyright © 2016 John Wiley & Sons, Ltd.     

西安市白鹿塬滑坡发生时间预测研究

笔者通过对白鹿塬区降水与滑坡发生时间之间的规律进行总结，认为本区滑坡发生与降水的丰年有着密切的关系，并应用卡尔曼滤波分析法对白鹿塬区滑坡发生时间进行了全区性预测，提出白鹿塬滑坡发生具有10年左右的中周期，20年左右的长周期，应及早作好防治工作。     

Structurally controlled landslides in saprolitic soils in Hong Kong

A number of large slope failures which have occurred in Hong Kong have highlighted the important influence that discontinuities in saprolitic soils can have on slope stability. Conventional stability analyses normally adopted for such soils, which assume failure through intact materials of uniform shear strength, are not appropriate if discontinuity-controlled failures can be postulated. Stress history and present-day weathering effects should also be taken into consideration in the assessment of the long-term stability of slopes in weathered rocks in tropical and subtropical regions. © Rapid Science Ltd. 1998     

基于CiteSpace的浅层滑坡文献计量分析

基于Web of Science数据库,以1999—2019年检索所得1240篇浅层滑坡期刊论文为样本,利用CiteSpace对该领域内国家/机构、学科/期刊和高频关键词进行文献计量和可视化分析,结果表明：浅层滑坡研究的国际合作非常普遍,意大利在浅层滑坡研究中占据核心地位,意大利国家研究委员和中国科学院两家机构在该领域发挥重要作用,GEOMORPHOLOGY和LANDSLIDES杂志为浅层滑坡研究代表性期刊。复合模型算法为浅层滑坡研究领域近期的热点主题。     

澜沧江昌都段滑坡发育特征及形成机制

中国的山区和高原发育的滑坡地质灾害最严重,青藏高原东部横断山区的大江大河沿岸发育一系列严重和频繁的地质灾害.基于前期InSAR遥感解译的工作,通过现场的野外详细调查,最终确定了澜沧江昌都段的75处滑坡地质灾害,详细分析了滑坡的发育特征和主要影响因素,总结了砂泥岩软弱地层区滑坡、断裂控制型滑坡、堆积层滑坡共6类典型滑坡的...     

滇西北兰坪盆地金顶超大型矿床有机岩相学和地球化学

云南兰坪金顶矿床是世界上形成时代最新且唯一陆相沉积岩容矿的超大型铅锌矿床,也是中国目前最大的铅锌矿床,有机物质在金属成矿中可能发挥重要作用,受人关注.矿石及矿化岩石中产有包括干酪根、轻油、烃类气、重油、沥青及方解石中石油、甲烷包裹体等多种形式、产状和成熟度的有机物质,油气显示突出,古油气藏遗迹明显,是金顶古油气藏在铅锌成矿过程中热成熟、裂解和被改造、破坏不同阶段的产物.有机物质的氯仿沥青"A"变化大(72×106～395415.42×106)."A"的族组分中,总烃(58.47%)大于"非烃 沥青烯"(41.53%),饱和烃/芳香烃比值大于1,具Ⅰ型有机母质特征.有机转化率(A/C=0.5%～7.2%)较矿床外围岩石低,有机热成熟度高.矿石及矿化岩石中有机质的饱和烃包括正构烷烃、Pr、Ph和iC18等化合物,碳数分布介于C10～C34之间,C21 22/C28 29=0.78～3.582,Pr/C17=0.25～0.646,Ph/C18=0.39～1.57,有机母质为海相菌藻类.有机质中检测出萘、菲、三芳甾烷、联苯、荧蒽等芳香烃类化合物,菲系列化合物最为明显,MPI1=0.215～0.434,MPI2=0.252～0.588,菌藻等有机母质发育在高盐度还原沉积环境,烃源岩主要是三叠系残留海相碳质泥岩和泥灰岩.伴随金顶局部穹隆过程,很可能在金顶穹隆中形成油气藏,它是矿区铅锌快速大规模集中成矿的重要还原剂之一.