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1505年10月9日6(3/4)级地震震中原订在黄海(32.8°N,122.7°E)。1983年以后,因苏南、泰山核电站选址和上海地震烈度复核需要,有人对原定震中提出怀疑,并进行部分修正。我们对1505年地震震中做了考证研究,主要根据地震史料,同时也考虑同期历史地震分布、现代微小地震条带、构造地貌、活动构造和深部构造,建议将1505年6(3/4)级地震震中南移到长江口(30.9°N,122.7°E),并称为1505年长江口6(3/4)级地震。 相似文献
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金宣宗兴定三年(公元1219年),在今宁夏回族自治区南部发生强烈地震,现有文献给出的地震次数、地震时间、震中位置差异很大.本文根据我国地震史料和近年固原发现的碑文和地方志记载,考证该强震时间在六月十八日巳时(公历格列历8月6日10时前后);震中在固原南(35.6°N,106.2°E);震级为61/2级;震中烈度为Ⅷ至Ⅸ度. 相似文献
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地震目录给出的 1067年广东潮汕地震的参数不能合理解释历史记载中该地震的震害分布。文中将这次地震与 1918年南澳大地震在相同地点的震害记载进行了对比,发现几乎相同,进而论证了这两次地震属发生在同一震源的特征地震事件的可能性,认为 1067年地震的震中很可能位于南澎列岛西侧,其震级可达 71 /4。鉴于目前对 1574年福建东北沿海 53 /4级地震事件有不同的认识,文中重新分析了该地震的破坏区与有感区的分布,并与 1906年厦门海外地震进行了比较。结果认为, 1574年地震的震中更有可能位于福州—莆田以东的海域,且震级可能达到 61 /4。文中还认为:史料中有关 1574年浙江庆元地震的记述所指的可能不是发生在当地的破坏性地震,而更可能就是同年发生在福州—莆田以东海域的那次地震。1067年和 1574年地震可能都发生在NE向的滨海断裂带上 相似文献
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收集了元代至正七年(1347)三月东平路发生的一次较强有感地震的史料,通过地震历史资料记载情况的比较,元、明、清的行政区划演变分析,判定和厘清了东平路地震可靠的史料.这次地震目录校订为1347年4月山东省东阿县(36.3°N、116.2°E)M4?级地震. 相似文献
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随着应用、研究的广泛和深入,对历史地震参数精度有了更高的要求.因此,有必要探讨历史地震参数校订的新思路和新方法.公元294年(晋惠帝元康四年)记载了北京延庆的一次强震事件.由于年代久远,史料简略,对史料的理解及对此次地震的参数存在分歧.通过系统收集、整理原有研究成果,详细分析其异同,并通过细读原始资料,实地考察以及定量分析1970年以来的中小地震时空分布特征与强震的关系等多个方面,对此次地震参数进行了校订.校订后的结果是:地震名称应为北京延庆海坨山地震,发震时间为公元294年9月,震级为6级,震中位置为115.85°E、40.59°N,震中误差为Ⅱ类.并以此为例,探讨了历史地震参数校订的一般原则和方法. 相似文献
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通过对1944年初青海乐都瞿昙寺地震史料的搜集和现场考察、采访,获得了此次地震更加丰富的资料,进而核定了此次地震的基本参数。研究结果表明：此次地震的震中位于青海省乐都县以南的瞿昙寺附近,震中位置大致为36.3°N、102.2°E,精度2类,误差小于等于25 km,震级约5.5级,震中烈度可达VII度。此次地震位于拉脊山北麓与西宁—民和盆地的交界部位,靠近拉脊山北缘断裂带附近,地震等震线长轴方向呈近东西向,与拉脊山北缘断裂走向大体一致,综合分析认为,拉脊山北缘断裂的最新构造活动可能导致了此次地震的发生。 相似文献
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In this paper, the changes in sediment transport over 51 years from 1955 to 2006 in the Kuye River in the Loess Plateau in China are assessed. Key factors affecting sediment yield and sediment transport, such as precipitation depth, discharge, and human activities are studied. To investigate the changes in sediment yield in this watershed, a trend analysis on sediment concentration, precipitation depth, and discharge is conducted. Precipitation depths at 2 Climate Stations （CSs）, as well as discharge and sediment transport at 3 Gauging Stations （GSs） are used to assess the features of sediment transport in the Kuye River. The rtmoff modulus （defined as the annual average discharge per unit area, L/（s·km^2）） and the sediment transport modulus （defined as the annual suspended sediment transport per unit area, t/（yr km^2）） are introduced in this study to assess the changes in runoff and sediment yield for this watershed. The results show that the highest average monthly discharge during the study period in the Kuye River is 66.23 m^3/s in August with an average monthly sediment concentration of 88.9 kg/m^3. However, the highest average monthly sediment concentration during the study period in the Kuye River is 125.34 kg/m^3 and occurs in July, which has an average discharge of 42.6 m^3/s that is much less than the average monthly discharge in August. It is found that both the runoff modulus and sediment transport modulus at Wenjiachuan GS on the Kuye River has a clear downward trend. During the summer season from July to August, the sediment transport modulus at Wenjiachuan GS is much higher than those at Toudaoguai and Longmen GSs on the Yellow River. The easily erodible loess in the Kuye River watershed and the sparse vegetation are responsible for the extremely high sediment yield from the Kuye River watershed. The analyses of the grain size distribution of suspended load in the Kuye River are presented. The average monthly median grain size of suspended load in the Kuye River is largest in February and then decreases until June. In July, the average monthly median grain size of suspended load approaches another peak and decreases until September. Then, the median grain size of suspended load starts to increase until February of the following year. However, the average monthly median grain size of suspended load in the Yellow River at Toudaoguai and Longmen GSs is the smallest between early summer and late fall The median grain size in the Yellow River starts to increase in November and approaches the largest size in January. 相似文献
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Observations of trace gases (SO2, NH3, NO2 and O3) were made during the period 1981 to 1984 at 6 different locations representative of urban industrial, urban, nonurban, thermal power plant and marine environment. Diurnal variations of the trace gases were studied in an urban environment. Except in the urban industrial environment, the concentration of NH3 was found in the range of background values. Also, the average concentrations of NO2 and O3 at the different environments were in the order of background values. However, the concentrations of SO2 were substantially higher by about 7 times, in urban industrial and thermal power plant environments. The diurnal variations of SO2, NH3 and NO2 showed anitphase relationship with surface temperature at the urban environment station which is relatively free of industrial pollution. Discussion is centred on trace gas variations in different environments in India together with the values reported for various countries in the world. 相似文献
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Ingvar B. Fridleifsson 《Pure and Applied Geophysics》1978,117(1-2):242-252
In an active spreading area like Iceland, where the regional geothermal gradient is in the range 50–150°C/km, it is normally not a problem to find high enough temperature with deep drilling, but the difficulties arise with finding permeable layers at depth within the strata. Various volcanological methods can be applied in the search for aquifers and geothermal reservoir rocks. The flow pattern (as deduced from deuterium studies) indicates that the thermal water flows preferentially along high porosity stratiform horizons and dyke swarms from the recharge areas in the highlands to the hot spring areas in the lowlands. The primary porosity of the volcanic strata is dependent on the chemical composition and the mode of eruption of the volcanic units. Both the reservoir rocks and the flow channels forming the geothermal plumbing system are thought to vary from the Tertiary to the Quaternary provinces due to environmental conditions at the eruptive sites. 相似文献
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3He/4He ratios up to 3.5 times the ratio of atmospheric He were found in groundwater samples. The3He enrichment can be attributed to radiogenic3He produced by in-situ beta-decay of3H. This shows that tritiogenic3He is accumulating in confined waters. From tritiogenic3He and3H concentrations, ages of groundwaters can be calculated. Detection of tritiogenic3He gives a tool to trace a tritium contamination which occurred in the past and cannot be assessed only by the3H counting method. 相似文献
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The aim of this study is to estimate likely changes in flood indices under a future climate and to assess the uncertainty in these estimates for selected catchments in Poland. Precipitation and temperature time series from climate simulations from the EURO-CORDEX initiative for the periods 1971–2000, 2021–2050 and 2071–2100 following the RCP4.5 and RCP8.5 emission scenarios have been used to produce hydrological simulations based on the HBV hydrological model. As the climate model outputs for Poland are highly biased, post processing in the form of bias correction was first performed so that the climate time series could be applied in hydrological simulations at a catchment-scale. The results indicate that bias correction significantly improves flow simulations and estimated flood indices based on comparisons with simulations from observed climate data for the control period. The estimated changes in the mean annual flood and in flood quantiles under a future climate indicate a large spread in the estimates both within and between the catchments. An ANOVA analysis was used to assess the relative contributions of the 2 emission scenarios, the 7 climate models and the 4 bias correction methods to the total spread in the projected changes in extreme river flow indices for each catchment. The analysis indicates that the differences between climate models generally make the largest contribution to the spread in the ensemble of the three factors considered. The results for bias corrected data show small differences between the four bias correction methods considered, and, in contrast with the results for uncorrected simulations, project increases in flood indices for most catchments under a future climate. 相似文献
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This paper briefly summarizes the works in the processing of strong ground motion data, the factors affecting strong ground motion, the modeling of strong ground motion and the calculating of broad-band response spectrum which have been done recent years by engineering seismologists and seismologists of China. In addition, we think back to the international cooperation in strong ground motion of the recent years and make some expectations for the future. 相似文献