西昌市泸山地区典型火后泥石流特征与成因机制研究——以响水沟左岸3^#支沟为例     

铁永波  徐如阁  刘洪  王家柱  巴仁基  向安平  杨剑  欧阳渊  张玙  王宏 《中国地质调查》2020,7(3):82-88

2020年3月30日,四川省凉山州西昌市经久乡发生森林大火,山火燃烧后形成的山火灰和烧焦土体在强降雨作用下极易启动形成泥石流,给西昌市泸山、琼海景区生态环境及当地百姓生命财产安全带来潜在地质灾害风险。以西昌市安哈镇响水沟左岸3^#支沟为例,采用野外调查、无人机航拍、地球物理探测、现场及室内实验等手段,对2020年5月1日该沟发生的火后泥石流流体特征、动力学参数及成因机制等开展研究,系统分析了山火及降雨过程对该次火后泥石流形成的影响机制。该成果可为系统认识西昌泸山“3·30”山火地区火后泥石流的运动特征、物源规模、激发雨量及其发展趋势研判提供科学参考。  相似文献   

Main active faults and seismic activity along the Yangtze River Economic Belt: Based on remote sensing geological survey     

《China Geology》2020,3(2):314-338

The Yangtze River Economic Belt (YREB) spans three terrain steps in China and features diverse topography that is characterized by significant differences in geological structure and present-day crustal deformation. Active faults and seismic activity are important geological factors for the planning and development of the YREB. In this paper, the spatial distribution and activity of 165 active faults that exist along the YREB have been compiled from previous findings, using both remote-sensing data and geological survey results. The crustal stability of seven particularly noteworthy typical active fault zones and their potential effects on the crustal stability of the urban agglomerations are analyzed. The main active fault zones in the western YREB, together with the neighboring regional active faults, make up an arc fault block region comprising primarily of Sichuan-Yunnan and a “Sichuan-Yunnan arc rotational-shear active tectonic system” strong deformation region that features rotation, shear and extensional deformation. The active faults in the central-eastern YREB, with seven NE-NNE and seven NW-NWW active faults (the “7-longitudinal, 7-horizontal” pattern), macroscopically make up a “chessboard tectonic system” medium-weak deformation region in the geomechanical tectonic system. They are also the main geological constraints for the crustal stability of the YREB.  相似文献   

中国-丝路国家基础设施连通性评估方法与格局     

王成金  陈沛然  王姣娥  李娜 《地理研究》2020,39(12):2685-2704

基础设施互联互通是不同区域之间空间网络形成的支撑,对区际生产要素流动、市场融合和资源配置具有重要作用,也是“一带一路”建设的重点内容和前提条件。立足于综合基础设施网络,以“一带一路”沿线国家/地区为分析地域,设计数理模型,评价了中国与沿线国家的基础设施网络连通性,考察其基本特征与空间格局,然后分别从铁路、公路、航运、通讯、能源等各种基础设施方式的视角,分析了不同基础设施网络的互联互通水平,探讨了基础设施连通的类型分异及其主导因素,凝练基础设施连通的空间模式。主要结论如下：① 从海陆属性来看,岛屿型国家与中国设施连通性最高,其次为综合型国家,内陆型国家最低。对国际区域而言,俄蒙和东南亚地区与中国的设施连通性最高,中东欧地区连通性最低。从国家尺度来看,俄罗斯和越南是与中国设施连通水平最高的国家,巴勒斯坦、东帝汶等5个国家与中国尚未形成设施连通性。从连通方式的构成来看,航运网络的连通性最高,其次为航空和光缆。② 空间距离、连通方式和重大交通走廊共同主导了设施连通性的类型分异。③ “一带一路”沿线国家/地区与中国的设施连通形成了四种典型模式,包括海陆融合型外缘连通模式、陆路通道直接连通模式、陆心内生性低水平连通模式、远距离不均衡连通模式。  相似文献   

堆积阶地古老滑坡识别方法及其在线状工程地质勘察中的应用     

安玉科  樊江  马胜午  马建全  高娟  毛立军 《吉林大学学报(地球科学版)》2020,50(6):1787-1794

阶地型古老滑坡体形成后，长期受各种营力影响，导致古老滑坡地貌形态破坏严重甚至消失。目前遥感技术和普通工程地质调绘很难发现这些滑坡的存在，给工程建设和后期运营造成较大安全隐患。为准确识别形态特征不明显的古老滑坡体，从阶地物质结构特征演变入手，找到阶地受剪切破坏产生的典型物质结构特征，将地层结构错断、卵砾石异常定向排列、摩擦镜面和泥包粒的眼球构造等作为滑坡准确识别依据。首先采用沿沟谷进行工程地质测绘的纵横交错追踪法确定滑坡体纵向范围和滑面形状，再结合地貌特征推测各级、块滑坡平面范围和分布，最后用点状勘探工程验证和校正推测结论。可将其总结为由"地貌异常、沿沟追踪、面上推断、点状校验"组成的阶地型滑坡识别方法，即物质结构异常推断法。结合线状工程勘察设计各阶段工作特点，提出线状工程前期工作中阶地型滑坡识别步骤，并在临渭高速公路工程建设项目中取得成功应用。  相似文献   

Land Resource Carrying Capacity in Xilin Gol Grassland Transects: A Perspective on Food Nutritional Demand     

YANG Wanni  ZHEN Lin  LUO Qi 《资源与生态学报(英文版)》2019,10(6):614-620

Food safety is an important issue for the development of the national economy and society. Studying regional food supply and demand from the perspective of land resource carrying capacity can provide new references for regional resource sustainability. This study uses the data from farmer and herdsmen household questionnaires, statistical data, land use data, and other sources to construct a land resource carrying capacity (LCC) assessment framework, targeting the food supply and demand of residents in representative areas, specifically the typical grassland pastoral areas, sandy pastoral areas and agro-pastoral areas on the Xilin Gol grassland transects. The three food nutritional indicators of calories, protein and fat were selected for analyzing the balance of land resource carrying capacity. We found that: 1) Along the Xilin Gol grassland, the main local food supply showed a shift from meat and milk to grains, vegetables and fruits. 2) From north to south along the grassland transects, the calorie intake increased gradually, while the intake of protein and fat was highest in pastoral areas and lowest in agricultural areas. 3) The overall land resource carrying capacity of the Xilin Gol grassland transects was in a surplus state, but the land carrying capacity of typical grassland pastoral area was higher than the two other types of areas. This study provides an empirical reference for the sustainable development of regional food nutrition.  相似文献   

中国市域居民住房支付能力时空演变及影响因素          下载免费PDF全文

康珈瑜  索志辉  梁留科  买哲  方明 《干旱区地理》2019,42(5):1153-1165

利用泰尔指数、σ系数、莫兰指数和空间回归模型等方法，对2012—2017年中国大陆346个市域单元收入房价比的时空演变规律进行分析，并探究其影响因素。结果表明：2012—2017年，中国市域单元收入房价比排名整体表现为东部>中部>东北>西部，其相对差异和绝对差异均随时间呈现增大趋势，居民住房支付能力稳步增强。2012—2017年，中国市域单元收入房价比的空间集聚性显著增强，空间分布不均衡性有逐渐增强的趋势。经济水平、城镇化水平、房地产投资水平、城市规模是影响中国市域住房支付能力的主要影响因素，其中，经济水平和城镇化水平对居民住房支付能力具有较大的正向影响，而房地产投资水平和城市规模为负向影响；2012—2017年我国东北和东中西部则不同程度上受不同影响因素的影响。  相似文献   

多维多点激励下考虑支座摩擦滑移及结构碰撞的非规则桥梁抗震性能研究          下载免费PDF全文

闫磊  李青宁  岳克锋  李鲁平  付亚男  蓝仕成  喻国根 《世界地震工程》2019,35(2):068-77

以一座典型山区非规则梁桥为研究对象，建立了该桥梁多维多点激励下的多自由度动力计算模型，研究了该桥梁在多维多点激励下考虑支座摩擦滑移及结构碰撞等非线性因素时的抗震性能。研究结果表明:相比一维地震输入，多维地震可使结构的动力响应增加，桥墩底部弯矩需求增大；相比一致激励，多点激励可使得支座的位移需求增大，且地震波最后到达的桥墩上方支座位移最大；同时考虑多点激励和碰撞效应可使桥墩的弯矩需求增加；水平地震作用下，矮墩上部的支座容易滑动，且双向地震较单向地震更明显，三向地震输入较双向有所增强。因此，对山区非规则梁桥进行抗震设计时应有针对性地进行多维多点地震输入计算，找出结构的最大地震需求，以期指导设计。  相似文献   

Nishinoshima volcano in the Ogasawara Arc: New continent from the ocean?     

Yoshihiko Tamura  Osamu Ishizuka  Tomoki Sato  Alexander R. L. Nichols 《Island Arc》2019,28(1)

Nishinoshima, a submarine volcano in the Ogasawara Arc, approximately 1 000 km south of Tokyo, Japan, suddenly erupted in November 2013, after 40 years of dormancy. Olivine‐bearing phenocryst‐poor andesites found in older submarine lavas from the flanks of the volcano have been used to develop a model for the genesis of andesitic lavas from Nishinoshima. In this model, primary andesite magmas originate directly from the mantle as a result of shallow and hydrous melting of plagioclase peridotites. Thus, it only operates beneath Nishinoshima and submarine volcanoes in the Ogasawara Arc and other oceanic arcs, where the crust is thin. The primary magma compositions have changed from basalt, produced at considerable depth, to andesite, produced beneath the existing thinner crust at this location in the arc. This reflects the thermal and mechanical evolution of the mantle wedge and the overlying lithosphere. It is suggested that continental crust‐like andesitic magma builds up beneath submarine volcanoes on thin arc lithosphere today, and has built up beneath such volcanoes in the past. Andesites produced by this shallow and hydrous melting of the mantle could accumulate through collisions of plates to generate continental crust.  相似文献   

中国城市抗御地震灾害研究的发展与实践   总被引：1，自引：1，他引：0  

薄景山  李平  孙有为  蔡晓光  焦淙湃  张莹允 《震灾防御技术》2019,14(2):259-268

城市是社会发展的产物，它具有人口密集、经济发达、基础设施集中等特点。城市安全一直是人们普遍关心的问题，城市地震安全受到政府和社会的广泛关注，并且是学术界研究的热点问题之一。唐山大地震后，在反思惨痛震害教训的同时，中国政府和学术界开始了长达40余年的城市抗御地震灾害的研究与实践，形成了有中国特色的城市抗震防灾技术和方法。本文简要地归纳了破坏性地震对城市的影响，从我国先后开展的城市抗震防灾规划、防震减灾规划和韧性城市3个方面系统地总结了中国城市抗御地震灾害研究和实践的发展历程，讨论和评述了在这一研究领域存在的问题。本文对韧性城市的定义、研究内容、特征、评价指标和方法进行了较为详细的介绍，在此基础上，提出了在城市抗震中应重点加强研究的5个方面的问题和今后的研究方向。  相似文献   

Analog simulation of urban construction land supply and demand in Chang-Zhu-Tan Urban Agglomeration based on land intensive use     

Xiong  Ying  Chen  Yun  Peng  Fen  Li  Jingzhi  Yan  Xiaojing 《地理学报(英文版)》2019,29(8):1346-1362

Journal of Geographical Sciences - Urban land intensive use is an important indicator in harmonizing the relationship between land supply and demand. The system dynamics (SD) can be used to...  相似文献