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1.
作者在滇西红河断裂带北段布设了5个泉点,开展了砷含量变化的观测研究。通过近三年的观测,发现泉水中砷含量的变化能较好地反映该地区的中强地震活动,地震前泉水中砷含量明显增高。以澜沧7.6级地震为例,讨论了地震前后地下水中砷含量的异常特征及异常机理,并对其在地震预报中应用的可行性进行了论证。  相似文献   

2.
作者在滇西红河断裂带北段布设了5个泉点,开展了砷含量变化的观测研究。通过近三年的观测,发现泉水中砷含量的变化能较好地反映该地区的中强地震活动,地震前泉水中砷含量明显增高。以澜沧7.6级地震为例,讨论了地震前后地下水中砷含量的异常特征及异常机理,并对其在地震预报中应用的可行性进行了论证。  相似文献   

3.
渤海唐山地区的地下热结构及地表热流分布的数值模拟   总被引:1,自引:0,他引:1  
魏东平  周下兰 《地震地质》1991,13(3):283-288
本文采用空间有限元和时间有限差分法模拟了渤中盆地区域的演化历史和地下热结构,并分别计算了渤中上地幔的热隆起与浅部的沉积层对渤中盆地内部温度场的影响。文中得到的计算结果较好地解释了渤中盆地地区热流正异常的观测事实,据此,对渤中盆地在形成过程中产生的热应力与地震孕震力源的关系也进行了一些探讨  相似文献   

4.
薛兵 《地震》2021,41(1):40-50
用于定点连续观测的地震观测仪器, 产出的观测数据是一个时间序列, 反映了被观测量随时间的变化。 本文将地震观测系统中任何与频率特性有关的信号处理过程均视为滤波器, 如传感器的频率特性、 数据采集过程中的抗混叠滤波等, 对地震观测系统中的滤波器进行了深入讨论。 实际工作中往往认为慢变量信号中不存在高频分量, 使得在数据采集过程中忽视了抗混叠滤波器的应用, 从而在实际观测中导致频率混叠干扰时有发生。 针对这一问题, 本文通过模拟计算的示例, 显示了频率混叠干扰对观测数据质量的影响, 解释了分量应变分钟值观测数据中同震响应波形的不合理现象, 进一步阐明了数据采集过程中抗混叠滤波器的重要作用。  相似文献   

5.
在“十五”测震项目中,上海地震台网共建立了11个台站。在运行过程中,曾出现数采异常、通讯设备堵包死机和通信链路异常等问题。我们在反复调试中,解决了一部分问题,积累了一些经验。  相似文献   

6.
青海省流动测震台网观测系统的建设,在历次中强地震的现场测震流动观测中发挥了十分重要的作用。为了能够提供更好的数据服务,仪器设备近两年也进行了更新升级,并且在历年的西北应急演练中取得了较好的成绩,既检验了设备,又锻炼了队伍。  相似文献   

7.
本文运用社会学、社会心理学的有关基本理论。提出了震灾中情感互动、邻里互动、团体互动和社会互动的基本概念;分析了震灾中由上述互动方式构成的社会救灾体系或网络,探讨了震灾中超常行为和从众行为的二重性及其扬抑对策。  相似文献   

8.
综述了工程场地地震安全性评价中活动断裂评价和场地评价的方法和步骤,指出了评价方法中存在的问题,并提出了解决方案。  相似文献   

9.
本文利用重力资料对兰州—天水地区的深部构造进行了研究。在计算中,采用Parker-Oldenbarg三维位场反演方法,反演前对重力资料进行了地形改正和中新生代沉积层校正。根据反演结果,综合分析了有关资料,认为该区为青藏块体过渡带,并且提出了陇中盆地为断块型构造盆地的新认识。  相似文献   

10.
引用自助统计分析,对华北地区17次中强地震前地震活动震级分布的离散度自助统计方差σBM值与地震活动的关系进行了分析和研究,总结出了中强地震前地震活动离散度自助统计方差σBM值的异常特征。同时,把该方法应用到了河南及邻区中等地震预报研究中,制定了预报规则,进行了预测内符检验和预报评分。结果表明,该方法是一种有效的中短期地震预报方法,具有推广应用价值。  相似文献   

11.
淮河流域焦岗湖水质参数时空变化及影响因素   总被引:3,自引:1,他引:2  
焦岗湖是淮河左岸一个天然湖泊,集防洪、灌溉、养殖、旅游等多种功能于一体.利用焦岗湖4个季节水质监测数据,运用Kriging方法,分析焦岗湖水质参数的时空变化及影响因素.结果表明:由于受水文季节变化过程及人类活动等综合影响,焦岗湖水质参数在时间及空间上均存在一定差异.从时间变化来看,夏季透明度较低、秋季较高;溶解氧浓度在春、冬季显著高于夏、秋季;总氮、总磷浓度与高锰酸盐指数均表现为夏季最高、秋季最低.从空间变化来看,4个季节的透明度空间差异较为显著;溶解氧浓度在春、冬季空间分布较为均匀,夏季呈现中心高周围低的变化趋势,秋季则表现为西高东低;总磷浓度春季分布较为均匀,夏、秋及冬季则呈西高东低之势;高锰酸盐指数在春、秋季节呈现东高西低之势,夏季高浓度主要集中在湖区北部,冬季浓度变化不大.  相似文献   

12.
This study investigated the subcellular distribution of Cu, Zn, Cd and Ag in liver of mallard (Anas platyrhynchos), spot-billed duck (A. poecilorhyncha) and great cormorant (Phalacrocorax carbo) to better understand metal fractionation and dynamics in avian liver. Most of the total Cu, Zn, Cd and Ag were present in hepatocytosol, and their concentrations increased with total hepatic levels in all the three avian species. Copper, Zn and Cd in hepatocytosol were present mostly in metallothionein fractions (MTs), and Cu and Cd contents in this fraction were positively correlated with hepatocytosol levels in all the species. Silver was observed mostly in both high-molecular weight and MT fractions in hepatocytosol in mallard and great cormorant, whereas it was present in both low-molecular weight and MT fractions in spot-billed duck, suggesting that distribution of Ag in the hepatocytosol was species-specific. The elution profile of metals in MT fractions revealed six metallic peaks in mallard and spot-billed duck, and three peaks in great cormorant, implying the presence of multiple MT isoforms in the liver of these avian species. The present study demonstrated that MTs are closely associated with metal regulation, especially Cu and Cd, in these three aquatic birds.  相似文献   

13.
滇西怒江断裂带新构造特征   总被引:9,自引:0,他引:9       下载免费PDF全文
李京昌 《地震地质》1998,20(4):25-320
怒江断裂带从走向上可以分为南北走向段和北东走向段,其喜马拉雅期的构造变形以右行剪切为主导。右行剪切的变形历史可以分为早期压剪变形和晚期张剪变形两个大的阶段。这两期变形各自在南北走向段和北东走向段表现出不同的特点。总之,怒江断裂带喜马拉雅期构造变形具有时空不均一性的特点  相似文献   

14.
1951~2002年中国东、西部地区地面气温变化对比   总被引:27,自引:1,他引:26       下载免费PDF全文
利用1951~2002年全国733个测站经过非均一性检验的月平均气温资料,在剔除50万以上人口大城市测站后,分析了52年来中国东、西部及青藏高原地区的气温变化趋势的一致性和差异性,并讨论了其可能原因.结果表明我国东、西部地区年、季平均气温变化有着较好的一致性;近52年来,我国东、西部和青藏高原地区年平均气温均呈升温趋势,年平均气温的增温速率东部为026℃/10a,西部018℃/10a,东部比西部高008℃/10a;季平均气温东部地区冬、春季的增暖趋势大于西部和青藏高原,而其夏、秋季的增暖趋势小于西部和青藏高原.我国东、西部地区年、季平均气温变化关系密切,说明其主要是受全球气候变化的影响而变化,但东部年平均气温的增暖总趋势大于西部,又说明地域差异在气温变化中也有重要作用.  相似文献   

15.
张贵刚  韩博平 《湖泊科学》2010,22(3):445-450
舌状叶镖水蚤(Phyllodiaptomus tunguidus)是我国特有的大型哲水蚤,主要分布在我国华南地区.根据2000年对广东省19座典型大中型水库的2次采样和2002年对流溪河水库和新丰江水库的5次采样,重点测定了流溪河水库、新丰江水库和鹤地水库等3座大型水库中舌状叶镖水蚤个体体长及形态参数,分析了广东省大中型水库中舌状叶镖水蚤的种群与个体大小的分布特征.在对19座水库的2次采样中,11座水库发现该种成体,其中5座水库在丰水期没有出现该种的成体,6座水库在丰水期和枯水期都有该种类成体的出现.丰水期与枯水期舌状叶镖水蚤的平均丰度分别为0.465ind./L和0.996ind./L.舌状叶镖水蚤主要出现在大型水库中,特别是贫营养的大型水库,其丰度主要由食物数量、质量与捕食压力所决定.2002年,流溪河水库丰度和新丰江水库舌状叶镖水蚤全年的平均值为1.308ind./L和0.294ind./L,丰水期高于枯水期.在个体大小和形态特征上,2座贫营养水体——流溪河水库、新丰江水库的舌状叶镖水蚤的体长与第一触角长度均大于中营养水体——鹤地水库,这种形态上的差异是由鱼类捕食方式(滤食或选择性捕食)所决定.  相似文献   

16.
Spatial and temporal distributions of the trends of extreme precipitation indices were analysed between 1986 and 2005, over the Iberian Peninsula (IP). The knowledge of the patterns of extreme precipitation is important for impacts assessment, development of adaptation and mitigation strategies. As such, there is a growing need for a more detailed knowledge of precipitation climate change.This analysis was performed for Portuguese and Spanish observational datasets and results performed by the Weather Research and Forecast (WRF) model forced by the ERA-Interim reanalysis. Extreme precipitation indices recommended by the Expert Team for Climate Change Detection Monitoring and Indices were computed, by year and season. Then, annual and seasonal trends of the indices were estimated by Theil-Sen method and their significance was tested by the Mann-Kendal test. Additionally, a second simulation forced by the Max Planck Institute Earth System Model (MPI-ESM), was considered. This second modelling configuration was created in order to assess its performance when simulating extremes of precipitation.The annual trends estimated for the 1986–2005, from the observational datasets and from the ERA-driven simulation reveal: 1) negative statistically significant trends of the CWD index in the Galicia and in the centre of the IP; 2) positive statistically significant trends of the CDD index over the south of the IP and negative statistically significant trends in Galicia, north and centre of Portugal; 3) positive statistically significant trends of the R75p index in some regions of the north of the IP; 4) positive statistically significant trends in the R95pTOT index in the Central Mountains Chain, Leon Mountains and in the north of Portugal.Seasonally, negative statistically significant trends of the CWD index were found in Galicia, in winter and in the south of the IP, in summer. Positive statistically significant trends of the CWD index were identified in the Leon Mountains, in spring, and in Galicia, in autumn. For the CDD index, negative statistically significant trends were seen in Valencia, in the spring, and, in Galicia and Portugal (north and centre), in summer. Positive statistically significant trends of the CDD index were found: in the east of the IP, in the winter; in the Cantabrian Mountain, in the spring; and, in the south of the IP, in summer. Regarding to the R75p index, negative statistically significant trends were found in Galicia, in winter and positive statistically significant trends in the north of Portugal, in spring and in the Central Mountains Chain and north of Portugal, in autumn. For the R95pTOT index, negative statistically significant trends were found over the Sierra Cuenca and Sierra Cazorla, in winter and positive statistically significant trends were found over the Sierra Cebollera, in winter and in Castile-la Mancha region, in spring.The results of the annual and seasonal trends of the extreme precipitation indices performed for observational datasets and the simulation forced by ERA-Interim, are similar. The results obtained for the simulation forced by MPI-ESM are not satisfactory, and can be a source of criticism for the use of simulation forced by MPI-ESM in this type of climate change studies. Even for the relatively short period used, the WRF model, when properly forced is a useful tool due to the similar results of Portuguese and Spanish observational datasets and the simulation forced by ERA-Interim.  相似文献   

17.
大通湖及东洞庭湖区生物体重金属的水平及其生态评价   总被引:4,自引:0,他引:4  
于2005年11月采集了大通湖及东洞庭湖区湖水和水生生物样品,并测定了水和水生生物样品中重金属(Cd、Pb、Hg、As)的含量,并对湖区生物体重金属进行了污染评价.研究结果表明,大通湖及东洞庭湖区湖水中重金属含量较小,绝大部分采样点水质都属于国家Ⅰ类水标准;水生生物体内CD、Pb含量为虾>螺>鱼,Hg的含量为鱼>螺>虾,As的含量为螺>虾>鱼;而鱼类重金属含量则为底栖鱼类>中上层鱼类,肉食性鱼类>植食性鱼类.大通湖及东洞庭湖区生物体中CD、Pb的污染指数为虾>螺>鱼,Hg的污染指数则为鱼>螺>虾,As的污染指数则为螺>虾>鱼.  相似文献   

18.
Changes in potential evapotranspiration and surface runoff can have profound implications for hydrological processes in arid and semiarid regions. In this study, we investigated the response of hydrological processes to climate change in Upper Heihe River Basin in Northwest China for the period from 1981 to 2010. We used agronomic, climatic and hydrological data to drive the Soil and Water Assessment Tool model for changes in potential evapotranspiration (ET0) and surface runoff and the driving factors in the study area. The results showed that increasing autumn temperature increased snow melt, resulting in increased surface runoff, especially in September and October. The spatial distribution of annual runoff was different from that of seasonal runoff, with the highest runoff in Yeniugou River, followed by Babaohe River and then the tributaries in the northern of the basin. There was no evaporation paradox at annual and seasonal time scales, and annual ET0 was driven mainly by wind speed. ET0 was driven by relative humidity in spring, sunshine hour duration in autumn and both sunshine hour duration and relative humility in summer. Surface runoff was controlled by temperature in spring and winter and by precipitation in summer (flood season). Although surface runoff increased in autumn with increasing temperature, it depended on rainfall in September and on temperature in October and November. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

19.
20.
Spatial and seasonal patterns of flood change across Brazil   总被引:1,自引:1,他引:0  
Brazil has some of the largest rivers in the world and has the second greatest flood loss potential among the emergent countries. Despite that, flood studies in this area are still scarce. In this paper, we used flood seasonality and trend analysis at the annual and seasonal scales in order to describe flood regimes and changes across the whole of Brazil in the period 1976–2015. We identified a strong seasonality of floods and a well-defined spatio-temporal pattern for flood occurrence. There are positive trends in the frequency and magnitude of floods in the North, South and parts of Southeast Brazil; and negative trends in the North-east and the remainder of Southeast Brazil. Trends in the magnitude (frequency) were predominant in the winter (summer). Overall, floods are becoming more frequent and intense in Brazilian regions characterized by wet conditions, and less frequent and intense in drier regions.  相似文献   

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