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1303年9月17日山西省洪赵县地震考察报告 总被引：1，自引：1，他引：1
为弄清元大德七年癸卯八月六日(公元1303年9月17日)山西洪赵县大地震的情况，于1967年7月至1967年11月作了2次野外调查，根据调查的结果，叙述了此次地震的概况，分别对Ⅹ度、Ⅸ度、Ⅷ度、Ⅶ度烈度区的范围、自然概况、人员伤亡情况等进行了描述，对此次地震的震中、烈度等问题进行了讨论，在此基础上绘出了此次地震的等震线示意图。认为该次地震的震中应在山西洪洞—赵城一带，震中烈度为Ⅹ度，震源深度为8km。 相似文献
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本文讨论了公元512年山西北部7.5级地震的震中、震级、震中烈度等问题,根据我们在大同盆地所发现的该地震的发震断层和许多地震遗迹,认为该地震的震中应在大同盆地,震级和烈度也应适当提高。 相似文献
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根据历史文献记载 ,我国历次正式出版的地震目录 ,皆将此次地震审定为M5 ,宏观震中为41 8°N ,1 2 3 4°E ,震中烈度为Ⅶ度。为进一步核实此次地震的参数 ,笔者查阅了已发表的有关资料 ,调阅了辽宁省档案馆 3 0卷历史档案 ,以确定文献中提供的破坏点的具体位置 ,统计了近、现代中强地震的烈度分布和人员伤亡情况 ,咨询了有关专家。经进一步研究认为 ,历次出版物对这次地震宏观震中位置和震中烈度的认定是合适的 ,但Ⅶ度区范围较笼统。我们依据历史地震烈度评定原则 ,确定了各破坏点的烈度 ,圈定了Ⅶ度区的范围 ,宏观震中在Ⅶ度区内 ,地震发生在当时的沈阳市区 ;根据极震区建筑物破坏程度和极震区长轴尺度、现代中强地震的震中烈度和人员伤亡情况 ,并考虑到确定历史地震的误差 ,震级取M5 较为合理。 相似文献
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根据近年来作者参与的重庆地区中强地震灾害损失评估工作,整理了重庆地区地震灾害损失情况,拟合了重庆地区震害经验回归曲线,包含地震震级与震中烈度关系、震级与受灾面积关系、震级(震中烈度)与死亡人数关系、震级(震中烈度)与受伤人数关系、震级(震中烈度)与倒塌房屋数量关系、震级(震中烈度)与直接经济损失关系,详细分析了重庆地区历史地震和现代地震的灾害特点、人员伤亡情况、建筑受损情况等。实际发生地震时,可以结合重庆地区震害经验回归曲线和社服系统软件计算得到的预评估结果进行综合考虑。重庆地区以北东向的断裂构造为主导,断裂分为基底断裂、基底断裂相关联的地表断裂和发育在背斜核部的盖层断裂,重庆地区地震绝大部分受这三类构造控制。 相似文献
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提出了一个根据有不确定影响的烈度资料来决定场地地震危险分析的方法。这种方法考虑了烈度的顺序和互不关联的特征，试图避免由于假定强度可以被处理作一个实数（连续分布估计量、衰减关系式等）而导出的错误结果。所提出的公式基于采用一个分布函数，它对每一个地震描述了场地受每一个烈度值影响的可以性。为了得到缺少当地地震资料地区的场地危险的评价，检验了这个分布函数随着到宏观地震震中的距离和震中烈度的变化情况。为了结 相似文献
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合理地确定场地的历史地震影响烈度，是工程场地震安全性评价工作中的重要一环。本文以广东南澳跨海大桥场址为例。论述了历史地震影响烈度分析的要点。首先对南澳附近１９１８年７．３级地震的震中位置及对桥址的影响烈度进行了确认。 相似文献
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1977年5月12日宁河6.6级地震的震中烈度较之震级相当的其他地震的震中烈度明显地偏低。为了阐明这种现象,由P波初动半周期及振幅求得了该区不同时期内的品质因数（Q值）及小震震源参数,并重新校对了这次地震以及1976年11月15日宁河6.9级地震的宏观及微观参数。分析结果表明:这次地震震中烈度异常低是因为1976年11月15日6.9级地震后,该区介质的品质因数大幅度下降,同时这个地震的震源深度比6.9级地震的震源深度约深5公里。品质因数和震源深度的综合效应可导致震中烈度降低近一度。 相似文献
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1590年7月7日甘肃永靖东南地震考证 总被引：1，自引：0，他引：1
公元1590年7月,在甘肃临洮附近有破坏性历史地震记载"……坏城廓庐舍,压死人畜无算"。同月,青海东部的冰沟城(今乐都县东北)也因地震而城崩。在过去出版的地震目录中,均按两次地震列出,分别称为甘肃临洮51/2级地震,震中烈度Ⅶ度;青海乐都5级地震,震中烈度Ⅵ度。根据史料考证和现场调查结果,综合分析认为,上述两次地震很有可能为同一次地震,其震中位于甘肃永靖东南的马衔山区,震中烈度达Ⅷ—Ⅸ度,震级61/2级左右,其发震构造很可能为兰州马衔山北缘断裂带的中西段。 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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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. 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
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