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一、预报情况的回顾四川是一个多震的地区,从1970年四川成立地震研究机构以来,在龙门山、鲜水河及安宁河等三个主要断裂带上先后布设了十七个地磁台站。这些地磁台大多数使用磁秤观测地磁垂直分量ΔZ的相对变化。1975年以后郫县走石山台装置了三分量磁变仪。根据上述台站资料的情况,我省以磁报震工作主要利用日变曲线,根据相对变化寻找震磁 相似文献
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本文根据1976年8月16日松潘、平武7.2级地震前所形成的档案文件、技术材料、地震简报和工作报告等资料,介绍了松潘、平武7.2级地震预测、预报和预防过程,预报的技术思路、方法和依据,并初步总结了这次地震预报的经验教训。 相似文献
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在1976年8月16日、22日松潘发生的两次7.2级地震前,静宁地应力电感曲线显示了明显的异常,并据此在震前提出了预报意见。本文对该异常形态特征进行了分析研究。1.观测条件静宁地应力站建于1975年上半年,从1976年元月1日起正式观测。观测孔深34.6m,其 相似文献
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本文扼要记述了１９７６年松潘－平武７．２级地震预报过程，并对震前观测预报各个阶段的对策和震后的应急措施等作了详细的回忆和归纳，对本次地震的预报效益和工作体会进行了简要的介绍。 相似文献
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震情变化是对 1976年松潘-平武7.2级地震提出预报意见的主要依据之一,震后曾对此作过多次总结。随着时间的推移,资料的积累,特别是经过与其它震例的对比,我们认为,有必要更系统地整理震前较长时间和不同范围的资料,全面地分析震前地震活动图象随时间的变化,进而讨论松潘-平武7.2级地震的孕育过程。 相似文献
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本文对松潘7.2级地震前后四川省水氡点的测值进行了较系统的分析研究,发现震前距该地震震中110公里范围以内的松潘川主寺和茂汶吉鱼寨两泉点的测值具有短期和临震异常,距该地震震中300公里以外的姑咱泉点测值具有区域性的临震突跳异常,康定泉点的测值具有区域性异常变化,并提出了松潘7.2级地震的水氡异常模型。文中还对上述四个泉点的地质构造背景和水文地质条件也作了简要介绍。 相似文献
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在重新全面深入收集整理历史档案和资料的基础上,回顾性研究总结了1976年8月16-23日松潘、平武两次7.2级地震的监测预报和防震抗震工作。研究表明,对于该次地震甘肃省和四川省地震工作者从中期预测开始,到短期、临震阶段,从地震预测到强震观测,组织开展了诸多有成效的工作。使松潘地震这个称之为重要的成功预报的实例,在我国地震工作发展史的记载中有更加充实、完整和科学的记载。并根据修订过的中国地震台网中心国家科学数据共享中心数据库给出的地震系列参数,对该次地震命名提出商榷,认为这次地震应当称之为"松潘-文县地震",或"平武-文县地震"或"松潘-文县-平武地震"更为妥当。 相似文献
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1976年8月16日晚10时06分四川省松潘、平武地区发生了7.2级强烈地震。震中位于四川省松潘、平武、南坪与甘肃省文县四个县交界地区的四川省境内,其中文县的铁楼公社所在地距震中仅20千米。震前半年,这里曾被国家地震局确定为仝国四大危险区之一。震前二三个月成都和兰州地震大队的地震工作者为“捕捉”这次大地震进行过连续紧张的工作。成都地震大队为这次地震做了较为成功的预报,已有诸多文章、报道涉及。而当时,在震中北侧的情况却鲜为人知,实际上有地震前四十多天的时间里,根据全国趋势会商意见和后来前兆异 相似文献
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本文对鲜水河地震带和松潘、龙门山地震带未来半年内是否能发生5级以上的地震进行了多因子模糊聚类分析。介绍了应用系统模糊聚类分析方法的具体步骤。根据各单项预报手段预报效能的清理结果,选用了9项地震活动性及前兆手段为指标,分别建立了鲜水河地震带和松潘、龙门山地震带31个时段的半年预报样本。利用这些样本分别对两地震带半年内是否可能发生5级以上地震进行了模糊聚类分析判断,并对其预报效能作了评分。结果表明用模糊聚类分析方法进行综合预报的预报评分值明显高于各单项手段的预报评分值。 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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