基于ArcGIS的洪水淹没分析与三维模拟     

孙君  奚赛英  尤迪  郑付涛 《城市地质》2012,7(3):31-33,37

洪水淹没范围的确定是洪灾损失评估和防洪决策的核心环节。基于TIN数据,运用ArcMap,采用＂无源淹没分析＂方法对区域天然防洪能力进行划分;实现了在给定水位条件下,对洪水淹没范围提取与统计计算,建立了洪水水位高程和淹没面积关系公式,并用于洪水淹没快速预测;运用ArcScene,对水位抬升的＂无源渐进淹没＂情况进行了三维模拟。  相似文献   

独山子背斜的几何学运动学数字模拟          下载免费PDF全文

陈伟  郝晋进  李世琴  彭文利  鲜地  陈丽花  李志刚 《地质科学》2012,47(1):37-50

独山子背斜位于准噶尔盆地南缘西段,是北天山逆冲推覆带在前陆盆地山前形成的断层相关褶皱。本文以横跨背斜的过井地震剖面为蓝本,用钻井数据、相邻地震剖面和地表形态为约束,运用断层相关褶皱模型对独山子背斜进行几何学定量分析,以建立合理的与实际接近的构造模型; 提取构造特征参数进行基于Trishear模型的运动学定量模拟,选取与实际数据吻合度最高的构造形态为独山子背斜的最佳几何模型。模拟数据表明:独山子背斜为前翼呈三角剪切的断层传播褶皱; 背斜变形从喜马拉雅山晚期更新统(Q_1-3)沉积期间开始形成并生长,平均推覆速率为0.18 mm/a; 全新统沉积期间(Q₄)推覆活动强度达到最大值,平均推覆速率为 4.64 mm/a。形成独山子背斜所需的总推覆位移量为5 600 m左右,第四纪期间的平均推覆速率约为0.19 mm/a。  相似文献   

塔里木盆地孔雀河斜坡尉犁断鼻构造的构造特征与形成演化          下载免费PDF全文

刘阵  何登发  李涤  张宁宁 《地质科学》2012,(3):588-606

孔雀河斜坡位于塔里木盆地的东北部,其成因与南天山和阿尔金山的地质作用密切相关。尉犁断鼻构造位于孔雀河斜坡西北部,完整地记录了孔雀河斜坡的构造演化历史,该断鼻构造特征的解析对揭示塔里木盆地东北缘早古生代以来的地球动力学背景具有重要的意义。本文利用断层相关褶皱理论,通过对过孔雀河斜坡尉犁断鼻构造带地震剖面的精细解释,分析了该断鼻构造的构造特征与形成演化,并讨论了其成因机制。尉犁断鼻构造在北西-南东向上为一古生界背斜,北西翼较陡,南东翼稍缓,背斜核部上古生界被剥蚀,并被后期由北向南的冲断层所切割。该构造主要反映了3期构造事件的叠加:中奥陶世-晚奥陶世,受北西-南东向挤压应力的影响,形成了北东-南西向展布的背斜; 志留纪-二叠纪,受南天山洋消减、闭合向南产生的挤压应力的影响,尉犁背斜北部持续地抬升剥蚀,形成鼻状构造; 侏罗纪,燕山早期运动影响了古生界和中生界,并使得北西西走向的南冲断层重新活动,错断了先存的鼻状构造。研究认为,尉犁断鼻构造北东-南西向展布的背斜在中奥陶世就开始形成,其主应力可能来自盆地东南的阿尔金山方向,与北阿尔金洋在加里东期运动时的俯冲与碰撞造山对该区域的远程挤压作用有关; 伴随着基底叠瓦构造往北西方向前展,背斜向北西移动了104 km,基底缩短率为48.4％。  相似文献   

论西藏扎达上白垩统波林夏拉组     

李国彪  潘懋  万晓樵  谢丹  修迪  李兴鹏  高茂龙  耿彦杰 《地层学杂志》2012,(1):37-48

上白垩统波林夏拉组的命名地点位于西藏西南部扎达波林,是一套以泥灰岩及灰岩为主的地层,底部以含海绿石灰岩与下伏下白垩统嘎姐组含海绿石石英砂岩整合接触,未见顶。波林夏拉组的时代据其所含丰富浮游有孔虫可被确定为晚白垩世Albian晚期至Maastrichtian晚期,其所含化石组合可以与晚白垩世特提斯喜马拉雅从台地到盆地的同...  相似文献   

Volume estimate of flow-type landslides along carbonatic and volcanic slopes in Campania (Southern Italy)   总被引：1，自引：0，他引：1  

M. De Falco  G. Di Crescenzo  A. Santo 《Natural Hazards》2012,61(1):51-63

Recent studies on flow-type landslides in pyroclastic deposits have been performed to identify potential source areas and the main depositional mechanisms. Interesting methods for mapping landslide susceptibility have also been proposed. Since the potential volume of flow-type landslides is a measure of event magnitude, hence of considerable use in hazard assessment, we propose a method to estimate the potential volume for the morphometric analysis of 213 flow-like landslides occurred in Campania in recent centuries. First, our data show that the height, H, of the detachment and erosion-transport zones (i.e. the difference in height between the top of source area and a point, the first break at the foot of the slope, where the deposition stars to take place and the landslide loses velocity) and the area, A _f, of the same zones are linked by a mathematical function. Secondly, only part of the entire thickness of the pyroclastic material on the slope is involved. To define the potential volumes of the flow-type landslides, we analysed slopes, both in volcanic and carbonatic contexts, considering both channelled and unchannelled flow-type landslides. The most susceptible areas are identified by using a landslide-triggering susceptibility map, and then in each case the height H was estimated. This height is the difference in level between the point on the slope with highest susceptibility and the first break at the foot of the slope. Using the statistical correlation between H and A _f, both calculated for historical landslides, we evaluate the area of a potential landslide on a slope. Finally, potential volumes are calculated by using A _f and a constant thickness of the pyroclastic cover for the whole slope. This method could represent a useful tool to detect the main areas where risk mitigation works are required.  相似文献   

Public perception of climate change and disaster preparedness: Evidence from the Philippines     

Vincenzo Bollettino  Tilly Alcayna-Stevens  Manasi Sharma  Philip Dy  Phuong Pham  Patrick Vinck 《Chemie der Erde / Geochemistry》2012

The Philippines is highly susceptible to both geophysical and climate-related disasters. This article explores Filipinos knowledge and perception of climate change and their association with what action Filipinos take to prepare for rapid onset natural hazards such as typhoons. Data for this study were collected from a nationally representative random survey of 5,184 adults conducted between March and April of 2017. Filipinos self-report relatively low levels of knowledge of climate change and cited increased temperatures, shifts in seasons, and heavier rains as the most likely consequences. Levels of disaster preparedness in the Philippines differ widely by region. Although most Filipinos perceive that natural hazards are a risk to them, only a third of Filipinos undertake measures to prepare for disasters. Filipinos who perceive climate-related changes directly impacting their households report taking greater action to prepare for disasters. Filipinos who believe they have been directly impacted by climate-related changes are also more likely to prepare for disasters, take planning actions, and undertake material actions to prepare, such as dwelling improvements. Other factors associated with disaster preparedness include gender, membership in an association, wealth, risk perception, and prior exposure to and losses due to disasters. The findings imply that, while posing different challenges and requiring different responses, adaptation to climate change and disaster preparedness are inherently associated and potentially mutually reinforcing. Policies and programs would arguably benefit from a more unified intervention framework that links climate change adaptation and disaster preparedness.  相似文献   

雪峰山西侧重点白云岩储层成岩、储集特征及质量影响因素     

李嵘  张娣  赵瞻  朱丽霞 《中国区域地质》2012,(11):1852-1861

雪峰山西侧地区下古生界中-上寒武统和震旦系灯影组白云岩是潜在的重要油气储集层。作为主要目的层段．本区的白云岩类型主要包括结晶白云岩、残余颗粒白云岩、灰质白云岩和藻白云岩四大类。白云岩储层总体上均属于低-特低孔、低-特低渗储层。影响储层发育的成岩事件包括重结晶作用、白云岩化作用、溶蚀作用、破裂作用等。研究表明,白云岩结晶程度可以影响其初始孔隙的发育程度,具粉晶一细晶结晶程度的白云岩具有最好的孔渗性。白云岩化作用的强弱对储层物性具有较为直接的影响。最佳白云岩储层中主要储集空间包括晶间孔隙（包括剩余晶间孔和晶间溶蚀孔）、次生溶孔、洞和裂缝。总体上,较强的白云岩化作用、一定程度的重结晶、较发育的微裂缝、较好的区域渗透性、晚期压溶缝合线发育和晚期较大构造缝不发育等因素有利于白云岩储层的发育。  相似文献   

基于区域气候模式的流域农业干旱成因分析          下载免费PDF全文

吴迪  裴源生  赵勇  严登华 《水科学进展》2012,23(5):599-608

以湄公河流域为研究区,采用区域气候模式RegCM3为模拟工具,以根系层土壤含水量为代表性指标,对A1B情景下未来研究区月尺度农业干旱进行了预估。基于地表能量平衡原理,系统分析了降水、蒸发、地表温度和根系层土壤含水量等农业干旱主要影响因素与区域气候模式模拟的大气环流、地表感热通量、地表潜热通量、地表净通量之间的联系和变化规律,从气陆间能量和水汽通量平衡角度,对农业干旱发生机理进行了识别。预估结果表明:从年内各月地表净通量和地表温度变化来看,未来春末(6月)和秋末(10月)湄公河流域温度增加明显,且土壤含水量减少也较为明显;同时,这两个时段蒸发旺盛和降水减少的趋势,有可能导致流域局部地区(尤其是非灌溉农业区)农业干旱的发生。  相似文献   

苏门答腊岛西北海域中尺度涡源区特征与形成机制          下载免费PDF全文

张家赢  周锋  田娣  黄挺 《海洋学研究》2021,39(3):1-11

孟加拉湾内和湾口附近有丰富的中尺度现象,本文利用2.0版可分辨低纬地区中尺度涡的Chelton数据集,通过溯源的方法得到中尺度涡的源地分布。苏门答腊岛西北海域(以5°N,94°E为核心的区域)是中尺度涡重要源区之一。通过拉格朗日方法的涡旋追踪表明,1993—2017年该海域(3°N—6°N、92°E—95°E),分别有57个气旋式和40个反气旋式中尺度涡。频谱分析显示海表面高度异常存在180 d和360 d两个显著周期。地形和风场的共同作用是该海域产生中尺度涡的动力机制：沿5°N西传的罗斯贝波在海岭地形的作用下触发了中尺度涡的生成;赤道风场是源区重要的能量来源,局地风场能诱发中尺度涡的极性。本研究也揭示了以往文献虽刻画了苏门答腊岛西北部海域为高涡动能区,却没有识别出较多中尺度涡的原因。  相似文献   

CO2 Geological Storage Capacity of the Qiongdongnan Basin in Offshore Hainan,China     

ZHANG Cuimei  LI Pengchun  ZHOU Di  SUN Zhen  ZHANG Yunfan  LI Fucheng  ZHAO Zhongxian 《《地质学报》英文版》2013,87(Z1):982-982

  相似文献