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1.
沉积物中有机质的环境行为研究进展 总被引：57，自引：5，他引：52
水体沉积物是重金属,有毒有机化合物等环境污染物及C,N,P等营养元素的汇和释放源,而有机质对灾些污染物和营养元素在沉积物中的迁移,转化等地球化学行为中起着至关重要的作用,本文就近期有关沉积物中有机质的环境地球化学行为为方面的研究进行了综述,重点评述了有关沉积物中有机质本身的来源,性质,迁移和矿化及其环境效应等方面的研究进展。 相似文献
2.
Meng-Tan Gao 《地震学报(英文版)》1993,6(3):713-719
The models currently used in the seismic evaluation of important projects, microzoning and seismic zonation are all for site.
Although seismic hazard analysis have been done for many sites in seismic zonation and microzoning, relationship among sites
is not considered in the final results. Studies show that it is impossible to get total hazard for specific area from the
results of the hazard analysis of sites. So, when we consider the total seismic hazard of a specific spatial distributed system,
methods for site are not enough. Author discussed the relation and the difference between system hazard and segments hazard
which form the system and proposed a seismic hazard analysis model taking spatial linear distributed series and parallel system
as an example. In aseismic design and earthquake disaster prevention decision, not only the seismic hazard of segments of
the system but also the total seismic hazard of the system should be considered.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 347–352, 1993. 相似文献
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Organotin contamination in seafood and its implication for human health risk in Hong Kong 总被引：1，自引：0，他引：1
Organotins (OTs) have caused widespread adverse effects on marine organisms, while they can also induce health problems to humans via consumption of contaminated seafood. This study aimed to quantify the tissue concentrations of OTs in 11 seafood species in Hong Kong, and assess the human health risk for consuming these species. The tongue sole Paraplagusia blochii had the highest concentration of total OTs. Triphenyltin (TPT) accounted for 56–97% of total OTs. The highest hazard quotient (HQ) for TPT was 1.41 in P. blochii, while the HQs for butyltins were much less than 1. The results indicated that it is likely to have certain health risks for consuming P. blochii due to its high TPT contamination. Therefore, TPT should be a priority pollutant of concern. Appropriate management actions should be taken to control its use and release in the region in order to safeguard the marine ecosystem and human health. 相似文献
5.
Participatory methods of incorporating scientific with traditional knowledge for volcanic hazard management on Ambae Island,Vanuatu 总被引：6，自引：1，他引：5
Ambae Island is the largest of Vanuatus active volcanoes. It is also one of the nations potentially most dangerous, with 60 million m3 of lake-water perched at over 1340 m in the summit caldera and over the active vent. In 1995, small phreatic explosions, earthquake swarms and heightened gas release led to calls for evacuation preparation and community volcanic hazard awareness programs for the ~9500 inhabitants. Differences in perspective or world-view between the island dwellers adhering to traditional beliefs (Kastom) and external scientists and emergency managers led to a climate of distrust following this crisis. In an attempt to address these issues, rebuild dialogue and respect between communities, outside scientists and administrators, and move forward in volcanic hazard education and planning for Ambae, we adapted and applied Participatory Rural Appraisal (PRA) approaches. Initial gender-segregated PRA exercises from two representative communities provided a mechanism for cataloguing local traditional viewpoints and hazard perceptions. Ultimately, by combining elements of these viewpoints and perceptions with science-based management structures, we derived volcanic hazard management guidelines, supported by an alert system and map that were more readily accepted by the test communities than the earlier top-down plans imposed by outside governmental and scientific agencies. The strength of PRA approaches is that they permit scientists to understand important local perspective issues, including visualisations of volcanic hazards, weaknesses in internal and external communication systems, and gender and hierarchy conflicts, all of which can hinder community emergency management. The approach we describe has much to offer both developing and industrialised communities that wish to improve their awareness programs and mitigative planning. This approach should also enhance communication and understanding between volcanologists and the communities they serve. 相似文献
6.
本文从场地地震危险性评价,地震危险性概率分析、场地地震工程地质单元划分、地震反应分析、活断层工程分类等五个方面、论述场地地震效应及其预测中基本原理和方法。根据工程地震危险性评价和分析、地震小区划等地震工程实践,对场地地震效应及其预测提供一些基本考虑和经验 相似文献
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简要介绍了“海西州震害信息管理系统”的研建原理和功能,2003年4月17日德令哈6．6级地震时,“系统”在地方政府应急救灾决策方面发挥了显功效。 相似文献
10.
To investigate the characteristics of earthquake hazard parameters as a means of identifying different zones of seismicity, we have compiled a catalogue of about 1850 moderate to large-sized earthquakes with magnitudes m4.0 or greater in southern Turkey for the time period from 1900 to 1990. Several methods have been applied to the earthquake catalogue to assess seismic hazard. The study area is divided into 77 overlapping cells of 2° size. Theoretical calculations were made for the prediction of maximum magnitude, intensity, b-values, strain energy release and corresponding m3 and peak ground acceleration levels for a given period of time. The resultant seismic hazard for each parameter is depicted as a contour map to indicate lateral variations in areas of seismic source. A combination and evaluation of various hazard parameters resulted in more reasonable estimates of hazard. It is found that the most hazardous seismic zones are the Rhodes and Burdur zones where the level of peak ground acceleration reaches up to 280 cm s-2 for an average return period of 100 years. 相似文献
11.
Georgios N. Stavrakakis 《Pure and Applied Geophysics》1988,127(1):21-31
Seismic hazard analysis requires the estimation of the probabilities that earthquakes will take place within a region of interest, and the expected level of ground motion which will be received at a site during the nextt years. The earthquake magnitude has been used as a basic parameter, because it is available, under the assumption that the earthquake occurrence is a compound Poisson process with exponential or multinomial distribution of magnitude.For improving the hazard prediction, we used the seismic moment as a basic parameter to estimate the mean rate, , of occurrence of earthquakes in a function of seismic moment rate and slip rate released in a seismogenic region.As an illustration of the model, the seismic hazard analysis at different sites in and around the Gulf of Corinth, central Greece, is presented on the basis of the earthquake magnitude and the seismic moment. Comparison of the results shows that determination of the mean rate of earthquake occurrence, using the conventional Gutenberg-Richter recurrence model, underestimates the seismic hazard at a site. 相似文献
12.
根据华北地区的地震目录,建立了4个空间光滑的地震活动性模型,并以这些模型为空间分布函数,将华北地震区每个地震带的地震年发生率分配到空间格点中,计算这一地区的地震危险性．结果表明,采用仪器记录地震计算得到的地震活动性模型和地震危险性结果能够反映华北地区现今的地震活动水平和地震危险性水平,符合人们对现今华北地区地震危险性的认识;采用历史破坏性地震（Mge;4.7）计算的地震活动性模型和地震危险性结果,较好地反映了华北地区中强地震活动区的地震危险性水平;以地震应变计算地震活动率,并根据点椭圆模型和线椭圆模型计算得到的地震活动性模型,能够较好地反映大地震的活动水平和空间构造特征．将根据4个模型计算得到的50年超越概率10%峰值加速度（PGA）分布加权平均,得到综合的华北地区PGA分布,并将该PGA分布与根据《中国地震动参数区划图》中综合潜源方案计算得到的50年超越概率10%的PGA分布做了比较,发现二者无本质差别,均能反映华北地震区的地震危险性水平．当然,二者也具有一定的差异:前者计算得到的符合PGAge;100 cm/s2条件的区域面积明显要比后者的大,而符合PGAge;250 cm/s2条件的区域面积则比后者的要小. 这主要是由于潜在震源区类型和空间分布函数不同造成的． 相似文献
13.
We develop a probabilistic model for estimating the tsunami hazard along the coast of New Zealand due to plate-interface earthquakes
along the South American subduction zone. To do this we develop statistical and physical models for several stages in the
process of tsunami generation and propagation, and develop a method for combining these models to produce hazard estimates
using a Monte-Carlo technique. This process is largely analogous to that used for seismic hazard modelling, but is distinguished
from it by the use of a physical model to represent the tsunami propagation, as opposed to the use of empirical attenuation
models for probabilistic seismic hazard analysis. 相似文献
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归纳总结2017年度全球81座活火山的活动情况,共计活动1058座次,平均每周记录20座活火山的活动信息。根据火山潜在喷发的危险性和火山活动的强弱程度对上述火山进行分级描述,火山活动主要反映了地球表层的构造活动,其中大角度俯冲带的弧后火山最为强烈,小角度的俯冲带、拉张裂谷和走滑为主的板块边界火山活动较为平静,火山活动频繁的印度尼西亚岛链是受灾最为严重的区域。预计全球火山活动将进一步加剧,印尼岛链受火山灾害威胁的程度依然较大。位于印尼岛链巴厘岛上的阿贡火山自2017年9月开始活动以来,整个喷发过程极具代表性,监测阿贡火山喷发过程可为全球典型火山喷发事件研究提供参考。 相似文献
15.
Devlin MJ McKinna LW Alvarez-Romero JG Petus C Abott B Harkness P Brodie J 《Marine pollution bulletin》2012,65(4-9):224-235
The extent of flood plume water over a 10 year period was mapped using quasi-true colour imagery and used to calculate long-term frequency of occurrence of the plumes. The proportional contribution of riverine loads of dissolved inorganic nitrogen, total suspended sediments and Photosystem-II herbicides from each catchment was used to scale the surface exposure maps for each pollutant. A classification procedure was also applied to satellite imagery (only Wet Tropics region) during 11 flood events (2000-2010) through processing of level-2 ocean colour products to discriminate the changing characteristics across three water types: "primary plume water", characterised by high TSS values; "secondary plume water", characterised by high phytoplankton production as measured by elevated chlorophyll-a (chl-a), and "tertiary plume water", characterised by elevated coloured dissolved and detrital matter (CDOM+D). This classification is a first step to characterise flood plumes. 相似文献
16.
基于熵值环境基尼系数法的平原河网区污染物总量分配 总被引：1，自引：0，他引：1
为制定科学合理的水污染物总量控制方案,以典型平原河网地区——张家港市为例,构建与人口、资源、经济和水污染物承受能力相协调的单因子环境基尼系数模型,并通过贡献系数判断引起不公平的主要污染物分配单元.利用熵值—环境基尼系数最小化模型,确定张家港市各乡镇基于多元公平性原则的氨氮总量分配方案.结果表明:在水污染物总量分配过程中,污染物削减比例的大小和污染物现状排放量之间并不具有一致性,最终的分配方案要综合考虑多方因素确定.本研究构建的熵值—环境基尼系数最小化模型综合考虑了研究区域社会、经济、资源等多种客观因素,对于平原河网地区,由于其特殊的地理位置和自然条件,人口、资源等分布相对比较均匀,故基于该模型所得到的分配方案充分表现了多元公平性原则,更公平合理. 相似文献
17.
I.Tumwikirize 《中国地震研究》1999,(1)
For earthquake-prone countries of the world, it is crucial to develop countermeasures and to share experiences in seismic hazard mitigation. The measures for seismic hazard mitigation are related to many factors, e.g., social, economic, and political. Research focused on modern science and technology paves the way for a better understanding of the earthquake phenomenon and helps to plan against its effects in seismically active areas.In this paper, we consider some of the events that occurred in earthquake-prone countries, both developing and developed, which caused devastation to the society and economy. These are mainly major events that have affected a considerable portion of the gross domestic product of these economies.Measures to mitigate seismic hazard are stressed and suggested. In addition, experiences in seismic hazard mitigation in Uganda and the rest of the world are discussed in general terms. Attention is given to geotectonic settings as well as the work of seismic hazard and disaster mana 相似文献
18.
极盖等离子体云块是极区空间天气重要现象之一,其形成过程是当前重要研究课题.观测表明,日侧磁场重联对应的极区电离层高速流可能对舌状等离子体(TOI)形成"切割"作用,最终形成极盖等离子体云块.伴随磁场重联,同时存在极光粒子沉降,会引起F层等离子体密度的增大,阻碍"切割"效应.本文利用耦合极区电离层模型,模拟研究电场和软电子沉降共同作用下F层等离子体密度的演化.结果表明,在局部电离层电场大于一定数值(80 mV)的情况下,"切割"效应能有效发生.并详细分析了"切割"效应发生时等离子体各参量的演化过程,对"切割"效应的内在物理过程进行了探讨. 相似文献
19.
FEATURES OF EARTHQUAKE CLUSTERING FROM CALCULATION OF COULOMB STRESS AROUND THE BAYAN HAR BLOCK,TIBETAN PLATEAU 
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下载免费PDF全文 Since 1997, several major earthquakes occurred around the Bayan Har block in the Tibetan plateau, providing an opportunity to further understanding the mechanism of intraplate earthquakes. What is the effect of interactions among these events on the earthquake occurrence pattern is an issue to be addressed. In this article, we use the visco-elastic Coulomb stress changes model to calculate the stress interactions among the historical events close to or large than MS7.0 since 1893 in the Bayan Har block. We apply the relationships between the slip rate and stress accumulation rate to transform the Coulomb stress changes into the influenced time. Then we remove such influence time from the occurrence years, and analyze the effects of the earthquake interactions on the clustering patterns of the historical earthquakes in the Bayan Har block. The results show that the major earthquakes in the Bayan Har block are characterized by a quasi-period of about 16 years from 1893 to 1973 and a clustering occurrence time period from 1997 to present following a relatively long quiescence period. The Bayan Har block is still in the active period with high probabilities of major quakes. We calculate the conditional probabilities of the rupture segments that did not rupture since 1893 of the boundary faults of the Bayan Har block in the next 30 years. The following faults or fault sections seem to be of major risk:The Maqin segment and the Maqu fault of the East Kunlun fault zone, the Awanang fault, the Luocha segment of the Tazhong fault, the Moxi segment of the Xianshuihe fault, and the Dangjiang fault. Other Fault segments in the Bayan Har block without seismic events since 1893 probably also have hazard of MS7 earthquakes in the future. 相似文献
20.
V. V. Blinov N. G. Granin I. B. Mizandrontsev R. Yu. Gnatovskii A. A. Zhdanov 《Water Resources》2017,44(3):417-427
For the first time, T,S-analysis was used to determine the specifics of seasonal variations in the vertical structure of Lake Baikal active layer. In the under-ice period, the active layer includes the under-ice, top winter, and upper intermediate water masses. The under-ice water mass, unlike other masses, shows an increase in mineralization to 100.74 mg/kg, which corresponds to a release of 71.1 g salt under 1 m2 of water surface in a layer 0–40 m in the process of salt freezing out during ice cover formation and accretion. In the phases of mixing (homothermy), the water masses of the active layer transform into a surface homogeneous mass. In summer and autumn, surface and upper intermediate water masses, separated by a water mass of summer thermocline can be identified. A specific feature of the summer thermocline water mass is the increased sum of ions because of an increase in HCO 3 - concentration at the decay of organic matter accumulating in the bottom part of the thermocline. The existence of the under-ice water mass and the water mass of summer thermocline was established in Lake Baikal for the first time. In the deep-water zone (>250 m), except for the bottom parts, the lower water masses (the lower intermediate and the deep) are permanent, their characteristics remaining stable during the year. The changes in the bottom water mass are due to the character of the processes of bottom water renewal. 相似文献