首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
研究了蒙古发震块体地震活动特征。综合有关资料从全球地震活动特征、喜马拉雅山地区地震活动以及地震活动是大尺度、大面积、甚至全球性相关的观点,论述了我国大陆的地震形势。初步认为中国大陆目前处于地震能量积累阶段,估计正在孕育着较大地震。这与全球性地震活动增强,蒙古发震块体,特别是蒙古西部、喜马拉雅山地区可能存在着8级地震危险相呼应。指出了应当引起注意的地区。  相似文献   

2.
张雅玲 《地震》1994,(5):59-64
本文从背景性地震活动、地震活动的时空分布以及前兆震群活动等基本特征出发,分析了共和地震前地震活动的异常特征。结果说明,共和地震是发生在青藏高原北部地震区地震活动增强的背景中。震前20年存在着中强地震空区。震前2-3年几乎同步出现了多种测震学异常。但无短临信息的前震活动。  相似文献   

3.
清江隔河岩水库诱发地震的条件与地震活动特征   总被引:4,自引:0,他引:4  
分析了清江隔河岩水库区诱发地地震的形成条件、地震时空分布特征以及库水位与地震活动的相关性,结果表明:该水库的地震活动类型属典型的震群水库地震,其成因主要为岩溶陷落。  相似文献   

4.
临汾盆地地震危险性浅析   总被引:1,自引:0,他引:1  
本文通过强震地震穴的地震序列分析,华北地震迁移、汾渭地震带地震丛式分布,和地震丛的强度分析以及汾渭地震带分段及强弱段相间分布特征,与本活动期地震丛活动空间分布等论述了临汾地震的危险性。  相似文献   

5.
前兆性地震平静在中期预报中的定量研究   总被引:6,自引:4,他引:6       下载免费PDF全文
对中国东部14次中强地震前地震活动的中期平静特征进行了深入研究.使用了归一化的NT和LT图及地震活动统计量βn.βn等值线分布中的每一点给出了地震活动程度及其相应的持续时间和结束时间,由此可以定量确定中期平静时间段.还总结了中强地震前几种不同的地震活动方式.总的特征是主震前地震活动的速率增强,然后转为低活动速率,NT与LT曲线呈现非规则的正弦波形变化.  相似文献   

6.
阴山地震带中强地震的活动特征   总被引:2,自引:1,他引:2  
阴山地震带是中国内蒙古自治区的一条主要地震带,根据多年从事地震预报的工作经验,对阴山地震带与鄂尔多斯其他3个边缘的地震活动特征进行了对比分析,研究了阴山地震带自身地震活动演化、周期性、月分布地震及包头西震情窗口等方面的特征,并对阴山地震带的地震危险性作了预测。  相似文献   

7.
2005年前山西地震危险性预测   总被引:2,自引:0,他引:2  
以一系列断裂盆地为主体的断裂盆地带是山西的地震构造带和未来地震的主要危险区,叙述地的新生性,第四纪活动度,盆地和剪切运动和拉张运动特征及盆地的现代地壳运动特征和现代地壳应力场特征,分析了盆地的特征,地震震级一频度模式,古地震复发间隔和地震活动周期,山西历史强震前的地震活动图像及盆地的各项特征和地震活动的关系,在此基础得到,2005年山西基本上不具备发生M≥7地震的危险性,其发震概率在0.05~0.  相似文献   

8.
总结了1993年1月27日普洱6.3级地震前的地震活动特征和余震序列特征。发再震前一年,震中区及其所在的思茅、普洱地震带地震活动平衡,而与其相邻的耿马、澜沧震带地震活动增强,表现出与该地区往中强震之前不同的地震活动特点。余震序列各项参数则表现主余震型的典型特征。  相似文献   

9.
印度板块北边界地震活动和中国大陆地震   总被引:17,自引:8,他引:17  
本文研究了印度板块北边界地震活动与我国大陆地震活动的关系,给出了两者在时间起伏上的一致性,以及印度板块北边界兴都库会和缅甸两端点附近中深地震对中国大际强震活动所具有的前兆性和相关性。这些特点,对于中国大陆强震活动的预测,尤其是地震大形势预测是十分有意义的。文中还应用了中国大陆强震孕育发生的计算机模型的研究结果,讨论了强震活动的时空分布特征,对于理解中国大陆作为一个孕震系统在周围地质构造块体动力作用  相似文献   

10.
姚清林  马宗晋 《地震》1995,(2):117-124
为了探讨小区域内地震活动的时间规律。本文在中国大陆选择了11个地点分析其从远古至公元1990年间的破坏性地震(M≥4 3/4)的活动性。因而发现小区的地震活动规律主要表现于以大震为代表的地震活动分期上,破坏性地震的频率、集中程度与阶段性变化上,以及与所在地震区地震活动期的关系上,不同小区的地震活动特征有共性,有类型区别,更有各自的特殊性。  相似文献   

11.
12.
13.
《国际泥沙研究》2014,(4):F0003-F0003
  相似文献   

14.
《国际泥沙研究》2014,(2):F0003-F0003
  相似文献   

15.
《国际泥沙研究》2014,(3):F0003-F0003
  相似文献   

16.
17.
The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi‐strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open‐area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for palmito, respectively, 0·5% in the cupuaçu monoculture and 3·1% in the fallow. With more than 20% of the open‐area rainfall, the highest stemflow contributions to the water input into the soil were measured in the palm monocultures and in the fallow. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

18.
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.  相似文献   

19.
Red tide, a recurrent phenomenon has become conspicuous in several Kashmir lake ecosystems since 1991. The responsible organism (Euglena pedunculata), a rare flagellate rediscovered in the Kashmir Himalaya (Khan 1993) caused first and unprecedented red tide outbreak, constituting a maximum of 96% of resident numerical phytoplankton density in Dal Lake. At present, conflicting hypotheses exist on the generation of causal assemblage(s) imparting redness to waters: Jeeji Bai (1991) linked its origin to acid precipitation – a fallout of burning oil‐fields during the Gulf War – whilst Khan (1993) holds local factor(s) responsible. Field/experimental studies support the latter contention that the influx of untreated sewage, in unison with warm temperatures, high levels of PhAR, iron and interruption to hydrological flow‐pattern together with absence/or reduction in grazing activity created conducive environmental milieu for red tide outbreak. Dal Lake “red tide” drifted the bloom‐inoculum to other waters, including Lake Wular, where additional ecological niches were carved out, threatening the aesthetic value and biological diversity of Kashmir lakes. Ecological monitoring indicates frequent seasonal red tide occurrence in Dal Lake (including summer‐autumn event of 1998) which testifies its unabated eutrophication status. Further studies are needed on ecological adaptability and biogeographic distribution of this rare and unique red tide‐causing flagellate.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号