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791.
792.
山东省防震减灾"十一五"监测台网建设是"十一五"监测类项目,包含区域数字地震台网扩建、地震监测预报试验场建设、地震烈度速报系统及信息服务系统完善。该项目由山东省人民政府和各市、县政府共同投资,为进一步提高山东省防震减灾综合能力,各级政府高度重视,加大支持力度,增加投入。与"十五"期间的监测系统相比,建成后的监测台网提高了观测动态范围,扩大了观测频带,丰富了记录信息量。台站数量与密度的增加,使台网监测能力得到了大幅提高。  相似文献   
793.
朱宝霞  申文庄  马明 《中国地震》2014,30(3):373-381
公众是实现地震重点监视防御区(以下简称地震重防区)防震减灾工作目标、提升社会防震减灾能力的主力军,而公众对地震重防区的认知与防震减灾宣传密不可分.本文通过问卷调查,发现许多公众对地震重防区和相关知识的认知程度低、公众的防震减灾素质有待提高、防震减灾宣传针对地震重防区的内容不够全面、宣传方式和手段不够多样化等问题.据此,提出建议:强化地震重防区宣传,丰富防震减灾宣传内容;防震减灾宣传方式和途径多样化;完善防震减灾宣传教育制度等.  相似文献   
794.
For the first time, we documented regional differences in amounts and long-term trends of marine debris along the US Atlantic coast. The Southeast Atlantic had low land-based and general-source debris loads as well as no increases despite a 19% increase in coastal population. The Northeast (8% population increase) also had low land-based and general-source debris loads and no increases. The Mid-Atlantic (10% population increase) fared the worst, with heavy land-based and general-source debris loads that increased over time. Ocean-based debris did not change in the Northeast where the fishery is relatively stable; it declined over the Mid-Atlantic and Southeast and was correlated with declining regional fisheries. Drivers, including human population, land use status, fishing activity, and oceanic current systems, had complex relationships with debris loads at local and regional scales. Management challenges remain undeniably large but solid information from long-term programs is one key to addressing this pressing pollution issue.  相似文献   
795.
The Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD) are the European umbrella regulations for water systems. It is a challenge for the scientific community to translate the principles of these directives into realistic and accurate approaches. The aim of this paper, conducted by the Benthos Ecology Working Group of ICES, is to describe how the principles have been translated, which were the challenges and best way forward. We have tackled the following principles: the ecosystem-based approach, the development of benthic indicators, the definition of ‘pristine’ or sustainable conditions, the detection of pressures and the development of monitoring programs. We concluded that testing and integrating the different approaches was facilitated during the WFD process, which led to further insights and improvements, which the MSFD can rely upon. Expert involvement in the entire implementation process proved to be of vital importance.  相似文献   
796.
Although research on a field investigation about quantification drawdown of ground water wells has hitherto been conducted with emphasis on Sanaa basin which is 3 200 km2 in area characterized by general hazard in quantity and quality of water,there exist uncertainties about the size of the hazardous annual decline in the level of underground water.So the authors are trying to assess reliable hazard data on the depth of ground-water which were obtained by measuring static water level.The data set are twenty six wells from 9 regions which were selected to represent Sanaa basin and collected during the course of the 20 months groundwater monitoring survey from January 2008 to January 2009.The results show that the average drawdown during 20 months to be 3.22 m with an average 0.16 m per month and 2 m per year.  相似文献   
797.
为研究联合法开采天然气水合物,在水合物三维实验开采模拟平台中利用双水平井进行降压联合注温水开采水合物实验,得到温度和压力分布、产气、产水、三相饱和度变化与开采方法的传热特性。整个开采过程可以分为自由气释放阶段、静置阶段、降压开采阶段和注热开采阶段。研究结果表明在自由气释放阶段和静置阶段有二次水合物生成。在注热阶段,水合物在降压和注热的协同作用下进行分解。反应釜中的水合物最终被完全分解,并且本研究的能效比高于前人利用垂直井进行降压联合热吞吐分解水合物的能效比,表明利用双水平井进行降压联合注温水是一种有效的分解水合物的方法。  相似文献   
798.
煤矿井下微震震源高精度定位研究   总被引:3,自引:0,他引:3       下载免费PDF全文
煤矿井下微震震源准确定位,对于动力灾害监测预警具有重要意义.由于微震震源需要通过井下传感器接收信息反演确定,传感器的安装位置限制于煤矿井下巷道周围,传感器沿巷道近平面的不合理布置将大大降低震源定位精度.针对由传感器信息反演震源位置引起的病态问题,本文提出了基于微震监测测点优化布置的震源高精度定位算法.首先通过计算系数矩阵条件数,判定病态问题;然后利用中心化法和行平衡法联合进行病态矩阵预处理.对预处理后的矩阵A、b利用L曲线法计算正则参数,结合Tikhonov正则化算法计算得到震源坐标正则解.研究结果表明,中心化法有效降低了矩阵数量级,行平衡预处理降低了病态条件数,预处理后Tikhonov正则解的震源坐标误差最小可以达到3.09m,与预处理前的高斯消去解相比误差大大降低.通过上述优化处理,实现了井下受限空间微震监测震源高精度定位.  相似文献   
799.
根据有关的国家与地震行业技术标准,结合建井的实践经验,本文论述了地震地下水观测井的定位、观测井结构设计与钻井施工的技术要求。  相似文献   
800.
In summer 1997, an intensive survey on the hard bottoms of the 'Abra de Bilbao' (N. Iberian Peninsula) was carried out in the context of the macrozoobenthic monitoring programmes developed to assess the biological recovery of the area. Three types of measurements (abundance, biomass and cover) were used to describe and compare the structure and composition of the communities at three littoral zones: subtidal, lower intertidal and upper intertidal. In addition, several taxonomic aggregation levels of data were successfully applied. The main objective of this paper is to explore the relative effect caused on the results of such programmes by earlier decisions concerning the type of measurement and the taxonomic resolution level to be applied. A 'second stage' multivariate procedure of analysis has been perforrmed based on the previously obtained sampling site ordinations. The measurement type chosen has been found to have a greater effect on the results than the taxonomic resolution used. Moreover, it is suggested that analyses based on abundance data usually lose more information when taxonomic resolution decreases than those based on biomass or cover estimates. The highest concordance among the different analyses has been found in the subtidal zone, which is considered the most appropriate habitat for the development of benthic monitoring programmes.  相似文献   
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