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１９９３年９月份首都圈地区Ｍ＿Ｌ≥２．０级地震１９９３年９月份在首都圈（３８．０°—４１．０°Ｎ，１１３．０°—１２０．０°Ｅ）范围内，共发生１７次Ｍ＿Ｌ≥２．０地震，其中１２次２—２．９级地震，５次Ｍ＿Ｌ＞３的地震。震级最大的一次为９月２７日发生在... 相似文献
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１９９６年５月首都圈地区Ｍ_Ｌ≥２．０地震动态根据国家地震局地球物理研究所四室提供的资料，本月在首都圈（３８．０°～４１．０°Ｎ，１１３．０°～１２０．０°Ｅ）范围内，共发生ＭＬ≥２．０地震１４次，其中震级最大的为５月４日河北大城ＭＬ３．９地震。唐山?.. 相似文献
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１９９４年９月首都圈Ｍ＿Ｌ≥２．０地震动态１９９４年９月份在首都圈（３８．０°─４１．０°Ｎ，１１３．０°─１２０．０°Ｅ）范围内，共发生Ｍ＿Ｌ≥２．０以上地震１１次，其中最为显著的是９月９日发生在河北卢龙Ｍ＿Ｌ≥３．２地震（见下表）。本月发生的２级... 相似文献
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本月在首都圈（38．0°－41．0°N，113．0°—120．0°E）范围内，共发生ML≥2．0地震20次，其中2至2．9的18次，震级最大为5月24日河北安平ML3．5地震（见下表人本月地震活动频度较上月有所增强，首都圈东西两区2级以上地震活动呈北东东向分布，北京及其邻近地区无2级以上地震发生。1994年5月份首都圈地区M_L≥2.0地震@王琳瑛$国家地震局地球物理研究所@舒曦$国家地震局地球物理研究所 相似文献
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１９９６年９月首都圈地区Ｍ_Ｌ≥２．０地震动态根据国家地震局分析预报中心提供的资料，１９９６年９月份在首都圈（３８．０°～４１．０°Ｎ，１１３．０°～１２０．０°Ｅ）范围内，共发生ＭＬ≥２．０地震１２次，其中震级最大的为９月２４日河北卢龙ＭＬ３．１地?.. 相似文献
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根据中国地震局地球物理研究所四室提供的资料,１９９９年５月首都圈地区（３８０°～４１０°Ｎ,１１３０°～１２００°Ｅ）共发生ＭＬ≥２０地震３３次,其中ＭＬ≥３０地震５次,（见表１）。５月１５日１１时应县发生一震群,５月１５日１６时１１分和１８时３４分应县ＭＬ４６地震是本月最显著的事件。本月地震频度与上月相比,明显升高（包括应县地震１９次）,首都圈西部地震较为活跃,中部相对较为平静,东部保持原有的活动水平。表１ １９９９年５月份首都圈地区ＭＬ≥２０地震序号发 震 时 刻 年月日时… 相似文献
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１９９６年６月首都圈地区Ｍ＿Ｌ≥２．０地震动态根据国家地震局地球物理研究所北京遥测地震台网（ＢＳＴＮ）提供的资料，本月在首都圈（３８．０°～４１．０°Ｎ，１１３．０°～１２０．０°Ｅ）范围内，共发生ＭＬ≥２．０地震１５次（见附表），其中最显著的事件是... 相似文献
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中国西南和印缅地区8级地震活动特征及趋势 总被引：1，自引：0，他引：1
本分析了１９００年以来北纬１５°－３２°,东红８５°－１０５°,中国西南及印缅地区７级以上地震的时空特征,得出Ｍ≥７．５级地震有密集－平静现中活跃期持续时间长、短交替、印缅地区７级地震启动是８级地震的重要标志,８级地震发生在７级地震密集区附近。 相似文献
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台湾海峡发生7．3级地震 总被引：4，自引：0，他引：4
台湾海峡发生７．３级地震１９９４年９月１６日，台湾海峡发生７．３级地震。据我国地震台网测定，这次地震发生于１４时２０分，震中位置：２３．°Ｎ，１１８．５°Ｅ。至１１月１０日１５时０７分止，共发生３．０级以上余震２１４次，其中３．０～３．９级１７３次；... 相似文献
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Gtz Schroth Luciana Ferreira Da Silva Marc‐Andree Wolf Wenceslau Geraldes Teixeira Wolfgang Zech 《水文研究》1999,13(10):1423-1436
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
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
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
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M. A. Kahn 《洁净——土壤、空气、水》2000,28(2):95-101
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