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1.
采用灰色系统理论的关联度分析方法,研究了涪江上游骨滑坡的主要形成条件及触发因素。结果显示,相对主同差是滑坡的主要形成条件,地震是滑坡的主要触发因素,此外,还对滑坡相关因素进行了相关显著性比较,评价了每项相关因素的其中所起的作用,最后讨论了灰色系统理论的关联度分析方法在滑坡研究中的利弊。  相似文献   

2.
贵州喀斯特山地的“石漠化”及防治对策   总被引:65,自引:3,他引:62  
贵州是一个碳酸盐岩分布广泛,生态环境脆弱、“石漠化”严重的山区省份,本文在综合大量实地考虑资料的基础上着重阐述了贵州喀斯特地区的山地“石漠化”现状及危害,探讨了“石漠化”过程的成因,指出不合理的人类活动是近期贵州喀斯特山地“石漠化”过程加快的主导因素,并据此提出了相应的防治对策。  相似文献   

3.
三峡库区武隆县滑坡灾害特点及成因机制   总被引:1,自引:1,他引:0  
在大量实地调查和资料分析的基础上,主要研究了武隆县滑坡灾害的特点和成因机制。全县共有233处滑坡,滑坡体体积达1.36×108 m3,在重庆市和三峡库区都是属于滑坡灾害的重灾区。滑坡厚度分类以浅层滑坡和表层滑坡为主,物质组成分类以坡积层滑坡为主,滑坡体体积分类则以中型和小型滑坡为主。全县46个乡镇中41个有滑坡分布,总体分布不均。滑坡发育的基岩地层以页岩和泥岩最多,绝大多数滑坡发育在10°~30°的斜坡上。滑坡的成因机制主要表现在3个方面。易滑地层的广泛分布,即全县分布大量的泥岩、页岩等软弱岩层;地质构造及河流下切造成坡体结构的不稳定;暴雨和人为活动的诱发。  相似文献   

4.
拉萨至尼木段位于西藏境内"一江两河"流域,地质条件复杂,气候恶劣,昼夜温差大,物理风化强烈,植被稀疏,地质灾害发育。"一江两河"地区是自治区政治、经济与文化中心,是近期重点开发区,随着地区的经济发展,其城镇建设与地质灾害之间的矛盾日益突出。文章总结了拉萨至尼木段滑坡、崩塌和泥石流灾害的发育分布特征,地质灾害成因,结合调查分析,提出了拉萨至尼木主要地质灾害的防治措施。  相似文献   

5.
基于GIS的凉山州德昌县滑坡危险性评价   总被引:1,自引:0,他引:1  
滑坡会对人民生命财产和社会经济发展造成严重威胁。以滑坡发育密集的凉山州德昌县为研究区域,分析了该区滑坡的发育环境和分布特征,选取9类影响因素,运用信息量模型对德昌县滑坡地质灾害进行危险性评价,并以此为基础将研究区划分5个不同等级:极高度、高度、中度、轻度和极轻度危险区。结果表明:(1)滑坡危险性较大的区域主要分布在坡度8°~25°、高差50~100 m以及岩浆岩、变质岩和碎屑岩的区域,断层、水系、道路建设和人类活动均会很大程度的诱发滑坡,且随着降水量的增大滑坡发生的概率也增大;(2)滑坡主要沿河流两岸及外围密集发育,93.95%的滑坡集中在中度及中度以上危险区;极高和高危险区主要集中在安宁河流域、茨达河流域和雅砻江左岸的中高山峡谷地区,县域东部地区危险性较低,受滑坡灾害影响较小;(3)运用ROC曲线验证得到AUC值为0.843,评价结果较合理,可为德昌县的防灾减灾及后续规划工作提供基础的理论支撑。  相似文献   

6.
冷渍沟是安宁河上游左岸的一级支沟,沟内发育了一大型滑坡 碎屑流,为后续泥石流活动提供充足的松散物质来源。为了研究冷渍沟泥石流的危害特征,在野外调查和实地勘测的基础上,分析了泥石流的形成背景条件及其特征,探讨了泥石流的发展趋势,提出了相应的泥石流防治对策。研究表明,冷渍沟泥石流属于过渡性(亚粘性)高频大规模泥石流,泥石流成灾速度快,危害严重;百年一遇的泥石流容重为21 t/m3,五十年一遇的泥石流容重为20 t/m3,二十年一遇害泥石流容重为19 t/m3,相应的峰值流量分别为12768、8171和3818 m3/s。在常态下,冷渍沟泥石流的发生频率和规模会逐渐减小;但如果近期遭遇强震或者暴雨,一旦滑坡失稳堵塞沟道,将会暴发大规模泥石流,很容易堵断安宁河,对上下游造成严重危害。因此,建议在该流域布设必要的泥石流防治工程;同时加强对沟道两岸和滑坡稳定性监测,做好泥石流发生的监测预警工作  相似文献   

7.
滑坡、崩塌和泥石流是三峡库区的三大主要地质灾害类型,其中滑坡所占比例最大。强降水、连阴雨等气象因素是诱发滑坡、泥石流等地质灾害的重要因子。利用三峡库区及其周边地区蓄水前常规气象站1971~2003年逐日降水资料和库区有完整记录的滑坡个例资料分析了滑坡灾害与发生前各个时段降雨的强度、持续时间、总量等之间的关系,初步确定不同保证率下诱发三峡库区滑坡灾害发生的临界降水量值,为开展三峡库区滑坡灾害气象监测预警提供科学依据  相似文献   

8.
我国西南山区滑坡灾害发生频繁且分布广泛,对耕地资源造成严重影响和危害,山区滑坡灾毁耕地的修复利用正引起广大技术人员的关注。运用Delphi法选取了耕地土壤条件、耕地环境条件、耕作灌溉条件和耕作便利性条件等4个方面8个因子,基于AHP法构建了西南山区滑坡灾毁耕地修复利用适宜性评价指标体系,应用综合指数模型基于地理信息系统空间分析功能实现适宜性评价。将该成果应用于实际案例,得到的评价结果符合案例区灾毁耕地修复利用适宜性情况,表明其具有一定的科学性和应用价值,对制定西南山区滑坡灾毁耕地修复利用的科学决策与工艺选择具有重要的参考价值。  相似文献   

9.
通过对岷江大咕噜沟1999-06-16泥石流的数次现场考察与观测,首先叙述了本次泥石流的活动及其危害情况,描述了泥石流的形成条件,指出了泥石流发生的原因,认为本次泥石流是由于大咕噜沟流域内物质的含水量较高,在连续暴雨的条件下其含水量超饱和,引起二岔沟以上南支右岸海拔3750m处的沟岸滑坡,进而产生泥石流的。然后对主沟沟床演变以及单侧支流入汇的影响进行了分析,认识大咕噜沟主沟呈串珠状沟道,平面上宽窄相间,纵剖面为深潭-跌水形式,跌坎的形成通常有以下三种情况:一种是沟床枯本身为岩石或含有岩石,一种是两岸崩塌或滑坡而残留的粗大堆积物形成,一种是支流的冲出物或堆积扇形成。另外,同岸支沟在存在使主河逼近对岸,在岩坡稳定性较差的条件下,使对岸产生相当规模的崩塌或滑坡。最后,提出防治泥石流灾害的建议。  相似文献   

10.
GIS技术在三峡库区滑坡灾害研究中的应用   总被引:5,自引:1,他引:4  
对三峡库区选定的研究区域,建立地质、地形等滑坡因子空间数据库和滑坡空间分布数据库(比例尺均为1:10 000),利用GIS技术对滑坡和各影响因子相关性进行了统计分析。计算得出滑坡发生的主要影响因子类属:Q\-4、J\-1x, J\-1z、S岩性岩组;90 m以下、90~135 m和135~175 m三个高程带;15~20m局部高差;10°~15°、15°~20°和20°~25°坡度;北向、南向和西北向方向和 1~1曲率范围。研究的结果是进行滑坡易发性评价的基础,可以帮助指导库区滑坡灾害管理、土地利用等。  相似文献   

11.
Integration of indigenous knowledge and ethnoscientific approaches into contemporary frameworks for conservation and sustainable management of natural resources will become increasingly important in policies on an international and national level, both in countries that are industrialised and those that have a developing status. We set the scene on how this can be done by exploring the key conditions and dimensions of a dialogue between ȁ8ontologiesȁ9 and the roles, which ethnosciences could play in this process. First, the roles of ethnosciences in the context of sustainable development were analysed, placing emphasis on the implications arising when western sciences aspire to relate to indigenous forms of␣knowledge. Secondly, the contributions of ethnosciences to such an ȁ8inter- ontological dialogueȁ9 were explored, based on an ethnoecological study of the encounter of sciences and indigenous knowledge in the Andes of Bolivia, and reviewed experiences from mangrove systems in Kenya, India and Sri Lanka, and from case-studies in other ecosystems world-wide, incl. Australia, Burkina Faso, Ecuador, Ethiopia, Guatemala, Indonesia, Nepal, Niger, Philippines, Senegal, South-Africa and Tanzania.  相似文献   

12.
We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.  相似文献   

13.
湘鄂赣地理位置优越,农业资源丰富,稻谷、茶叶、麻类、棉花、油料、柑桔和淡水产品、禽蛋、肉类等在我国居有重要的地位,因此,大力发展三省农业生产,对我国人民实现小康生活具有战略意义。今后,要加速专业化区域化进程。我们找出生产潜力所在:改造低产田、低产园、低产水面;开发“三高”技术;开垦荒地、荒山、荒水;适当提高复种指数。通过建设,三省主要农产品将自给有余,还可满足国内外市场的需要。努力方向:高效农业开发——综合农业开发,吨粮田开发,玉米带开发,饲料稻开发,山区开发;合理布局农业生产;深化农业商品基地建设,发展综合利用,搞活商品流通;全面提高农业现代化水平,加强农业社会服务体系。  相似文献   

14.
The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased  相似文献   

15.
Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999-2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.  相似文献   

16.
Variation in the reproduction of Varroa jacobsoni mite was studied in relation to the expansion of the range of its parasitism on the honeybee. Geographic differences in the seasonal dynamics of mite reproduction in the nests of bee families were revealed. Variation in the sex ratio of mites and the factors inhibiting their reproduction at the northern boundary of the honeybee range are considered. The forms of parthenogenetic reproduction in V. jacobsoni are discussed.  相似文献   

17.
The Eastern Mediterranean region is among the regions which were predicted to become drier under IPCC climate scenarios. Here, we document a gradual reduction of rainfall and tree growth and the loss of rural springs during the last decades of the twentieth century. Years with severe drought are associated with very low tree growth (dendrochronology) and dry falling of springs as evidenced by interviews with local stakeholders. The paper discusses the consequences of accelerating drought on natural vegetation and agriculture and points at the interaction with fire dynamics and economy, both likely to enhance the drought effect.  相似文献   

18.
The effect of long-term exposure to natural excretions of the European polecat on the morphological parameters and hormonal status of adult male Campbell hamsters (Phodopus campbelli) and dwarf hamsters (Ph. sungorus) was studied. Exposure to volatile components of natural excreta of a potential predator did not have any significant effect on hamsters. The combined influence of volatile and nonvolatile components of the polecat’s excretions caused physiological stress in Ph. campbelli, while in Ph. sungorus, on the contrary, an increase in thymus weight and the plasma testosterone level was recorded.  相似文献   

19.
The use of experimental settings to observe human behaviour in a controlled environment of incentives, rules and institutions, has been widely used by the behavioural sciences for sometime now, particularly by psychology and economics. In most cases the subjects are college students recruited for one to two hour decision making exercises in which, depending on their choices, they earn cash averaging US$ 20. In such exercises players face a set of feasible actions, rules and incentives (payoffs) involving different forms of social exchange with other people, and that in most cases involve some kind of externalities with incomplete contracts, such as in the case of common-pool resources situations. Depending on the ecological and institutional settings, the resource users face a set of feasible levels of extraction, a set of rules regarding the control or monitoring of individual use, and sometimes ways of imposing material or non-material costs or rewards to those breaking or following the rules. We brought the experimental lab to the field and invited about two hundred users of natural resources in three Colombian rural villages to participate in such decision making exercises and through these and other research instruments we learned about the ways they solve - or fail to - tragedies of the commons with different social institutions. Further, bringing the lab to the field allowed us to explore some of the limitations of existing models about human behaviour and its consequences for designing policies for conserving ecosystems and improving social welfare.  相似文献   

20.
The size of shells in some freshwater pulmonate mollusk species abundant in Western Siberia (Lymnaea fragilis, L. terebra, Planorbis planorbis, and Anisus leucostoma) is relatively large in the south and decreases in the north. It is supposed that this phenomenon is explained by the fact that the season with conditions allowing the growth of mollusks is shorter in the north than in the south of Western Siberia.  相似文献   

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