惠民凹陷大芦家地区馆陶组三段沉积微相类型及空间展布     

国景星  郭卫萍  刘斌楠  曹铮 《地球科学与环境学报》2015,(1)

针对惠民凹陷大芦家地区各断块地层单元划分不一致,沉积相认识存在分歧等问题,依据旋回级次、旋回性质等,将馆陶组三段划分出2个四级旋回、4个五级旋回、16个六级旋回;并以岩芯及室内分析资料、测井资料等为主要依据,综合分析岩石类型、粒度及结构特征、垂向粒序变化、层理构造类型及自然电位曲线形态等。结果表明:惠民凹陷大芦家地区馆陶组三段主要发育冲积扇及辫状河;冲积扇主要发育辫流砂岛、辫流沟道、辫流带、漫流席状砂、远端砂丘等微相;辫状河主要发育心滩,辫状河道充填,天然堤、漫滩和道间洼地沉积,泛滥平原沉积,废弃河道等微相;2个四级旋回的沉积相类型及空间展布特征相似;第Ⅰ五级旋回在研究区中偏西部属冲积扇沉积,主要发育辫流砂岛、辫流沟道、辫流带微相,在东部属扇前平原沉积;第Ⅱ五级旋回早期以辫状河沉积为主,河道规模较大,仅在第Ⅱ1六级旋回的东北部位见冲积扇的辫流砂岛及辫流沟道微相;第Ⅱ五级旋回中期属辫状河沉积,河道规模减小,2个河道群自NW向SE方向流动;第Ⅱ五级旋回晚期河道规模更小,逐渐向曲流河沉积过渡。  相似文献   

吉林省三所城市电磁辐射监测结果统计分析与评价   总被引：1，自引：0，他引：1  

高彦伟  王笑晗  张静 《世界地质》2011,30(3):435-438

以城市环境电磁污染为研究对象,根据吉林省长春、延吉、四平环境综合电场强度监测数据．利用统计学方法和指数评价法进行统计分析和评价,计算了三所城市的电磁污染评价指数和污染风险概率,并对环境电磁辐射容量进行了估算。结果表明：目前三所城市环境电磁辐射电场强度监测值具有不同的概率分布,辐射强度低于中国电磁辐射安全标准,污染风险概率为0。如果电磁辐射能量以年均14％的速度递增,长春、延吉、四平将分别在19年、16年和18年后电磁辐射水平超过电磁环境保护限值,因此应该加强城市环境电磁辐射的管理和防控。  相似文献   

Evaluation of wave impact loads on caisson breakwaters based on joint probability of impact maxima and rise times     

Giovanni Cuomo  Rodolfo Piscopia  William Allsop 《Coastal Engineering》2011

When waves break against seawalls, vertical breakwaters, piers or jetties, they abruptly transfer their momentum into the structure. This energy transfer is always spectacular and perpetually unrepeatable but can also be very violent and affect the stability and the integrity of coastal structures. Over the last 15 years, increasing awareness of wave-impact induced structural failures of maritime structures has emphasised the need for a more complete approach to dynamic responses, including effects of impulsive loads. At the same time, movement of design standards toward probabilistic approaches requires new statistical tools able to account for uncertainties in the variability of wave loading processes. This paper presents a new approach to the definition of loads for use in performance design of vertical coastal structures subject to breaking wave impacts.  相似文献   

消频散变换反演海底地声参数     

姚玉玲  高大治  任新敏 《中国海洋大学学报(自然科学版)》2011,(Z1):433-435

提出1种将消频散变换应用到海底地声参数反演的方法。对单一水听器接收声压信号进行消频散处理后,根据群延时差建立代价函数,反演得到主要海底参数,最后根据贝叶斯统计理论给出了待反演地声参数的边缘后验概率密度。对单层波导进行仿真证明这种新方法的有效性。  相似文献   

密云水库周边山区滑坡泥石流易发区预估   总被引：4，自引：1，他引：3  

宋杨  程维明  柏延臣  万丛  申元村  蒋艳  刘海江 《地理科学进展》2011,30(3):343-351

滑坡、泥石流等地质灾害的易发度主要是地质灾害自然属性特征的体现,它与孕灾环境的各项因子密切相关。这些因子包括地形地貌、流域水文、构造等内部条件因子以及地震、降雨等外部触发因子。为突出反映滑坡及泥石流主导因子的作用,本文参考了许多研究所采用的评价方法和因子选择,重点选取对该地区滑坡及泥石流发生区域分析评价起一定主导作用的、便于研究区域数据资料与空间资料匹配、关系密切的几个指标,包括地形地貌要素(坡度、坡向、坡形、相对高差、地貌类型)、环境要素(植被指数、河网密度、洪水淹没范围)、构造要素(距断层的距离、断层密度、地质岩性),通过对这些因子的敏感性进行分析,采用专家打分方法确定每种要素及因子的权重,借助因子加权叠加办法得出研究区地质灾害易发程度空间分布,用于表示其可能发生的统计意义上的可能性(概率),该研究对于区域地质灾害预防具有一定的适用价值。  相似文献   

“This is a Montreal Issue”: Negotiating responsibility in global production and investment networks     

Noah Quastel 《Geoforum》2011,42(4):451-461

While geographers have increasingly focused on how global commodity and production networks create new ‘geographies of responsibility’ there has been little empirical work considering how responsibility is worked into management systems and social activism in such networks. Drawing on literature from global production networks, geographies of responsibility and other literatures, this paper explores the dynamic and contested ways in which concepts of responsibility can play a role in network regulation. Both foreign direct investment and commodity networks (here referred to as ‘global production and investment networks’) are subject to complex negotiations and compromises involving corporate social responsibility and sustainability initiatives as well as shareholder activist, human rights, labor, and environmental activism. This is illustrated by reference to conflicts in Canada over Alcan, Inc.’s investments from 1993 to 2007 in the Utkal Alumina Project in Orissa, India. The project involved significant socio-environmental conflict. In Canada, Alcan’s investment was met by civil society campaigns that tested the company’s commitments to sustainability and corporate social responsibility. The case study suggests revising theories of geographies of responsibility. While foreign direct investment can create new relationships between distant others, these are fluid and contingent and not necessarily desirable. Rather than see networks as a source of responsibility we should work to ensure that the relationships that networks foster be structured to ensure our deeper values are respected.  相似文献   

青藏高原沱沱河地区冻土融化深度预测的概率分析   总被引：2，自引：2，他引：0  

石云静  马巍 《冰川冻土》2011,33(1):126-131

多年冻土空间异质性和边界条件及土性参数的可变性,往往会导致了冻土变化预测的不确定性,全球气候变暖更加剧这一过程.以青藏高原沱沱河地区试验段冻土融化深度预测为例,提出了在全球气候变暖条件下,基于参数服从某一概率分布的确定性模型的概率分析方法,基于此方法进行了融化深度的概率预测.由含水量、干容重的概率分布和20组ATI(空...  相似文献   

Archimedean族Copulas函数在多变量干旱特征分析中的应用     

于艺  宋松柏  马明卫 《水文》2011,31(2):6-10

以甘肃省陇西站月降水资料为例,应用9种3维Archimedean Copulas函数构造了干旱历时、干旱烈度和烈度峰值的联合概率分布,并进行了多变量的拟合优度评价,利用优选出的3维非对称型M12 Copula函数,计算联合分布的重现期以及不同组合下的条件概率与条件重现期。结果表明,M12Copula函数可以描述干旱历时、干旱烈度和烈度峰值间的联合分布。由于Copula函数能够用来构建不同边缘分布的联合分布,可以获得变量间不同组合下的重现期,因而能够更全面客观地反映干旱的特征,是描述干旱多变量分布的一种有效途径。  相似文献   

FOSM在水平场地液化概率评价中的应用          下载免费PDF全文

潘建平 《水文地质工程地质》2011,38(4):117-120

为了更好地进行场地液化评价,将可靠度理论引入水平场地液化概率评价中。以标准贯入试验(SPT)实测数据的统计分析结果为基础,用一次二阶矩法(FOSM)建立水平场地液化概率评价模型,分析了测试数据变异系数对抗液化安全系数与液化概率的影响,并建议了水平场地液化概率评价标准。实例分析表明,新建水平场地液化概率评价模型各参数的物理意义与统计指标明确,相比传统的确定性分析方法,不仅能判定液化的发生与否,还能给出液化发生的概率,这为进行基于风险分析的抗震设计提供了可能。  相似文献   

Study on Probability Distributions of Multi-Timescale Aerosol Optical Depth Using AERONET Data          下载免费PDF全文

WU Lin  ZENG Qing-Cun 《大气和海洋科学快报》2011,4(4):216-222

The probability distribution analysis is per-formed for multi-timescale aerosol optical depth (AOD) using AErosol RObotic NETwork (AERONET) level 2.0 data.The maximum likelihood estimation is employed to determine the best-fit probability density function (PDF),and the statement that the fitting Weibull distribution will be light-tailed is proved true for these AOD samples.The best-fit PDF results for multi-site data show that the PDF of AOD samples with longer timescale in most sites tends to be stably represented by lognormal distribution,while Weibull distribution is a better fit for AOD samples with short timescales.The reason for this difference is ana-lyzed through tail characteristics of the two distributions,and an indicator for the selection between Weibull and lognormal distributions is suggested and validated.The result of this research is helpful for determining the most accurate AOD statistics for a given site and a given time-scale and for validating the retrieved AOD through its PDF.  相似文献