云南省2001年上半年地震活动综述

据云南数字地震台网测定 ,2 0 0 1年上半年云南省共记录到 3级以上地震 5 5次 (不含余震 ) :其中 3～ 3 9级地震 44次、 4～ 4 9级 5次、 5～ 5 9级 5次。 2 0 0 1年上半年云南地区地震活动最显著的特点是历史上少见的中强震连发 (表 1 )。表 1　云南地区 2 0 0 1年上半年 5级地震目录编号发震时间震中位置年月日农历时分秒北纬东经地名 震源深度震级ＭＬ ＭＳ精度12 0 0 1 2 19廿七 2 3-5 1-362 1°2 6′ 10 2°5 0′老挝 10ｋｍ 5 2 42 2 0 0 1 2 2 0廿八 0 3-0 2 -5 12 1°2 2′ 10 2°5 4′老挝 8ｋｍ 5 432 0 0 1 3 12十八 16-5 7…     

2000年震情述评

1　全球地震活动概况据我国台网测定 ,2 0 0 0年全球共发生 7级以上强震 2 0次 (表 1 ) ,最高震级为 7 8,即 6月 5日印度尼西亚苏门达腊岛南部、6月 1 8日印度洋和 1 1月 1 6日所罗门群岛共 3次 7 8级地震 (图 1 )。　　表 1　 2 0 0 0年全球 7级以上地震目录序号月日时 分 秒纬度经度　地点震级震源深度0 1 0 1 0 90 0 4 7 0 3 0 1 5 1°Ｓ 1 73 7°Ｗ汤加 7 00 2 0 1 2 82 2 2 1 0 1 94 3 1°Ｎ 1 4 6 7°Ｅ千岛群岛 7 00 3 0 2 2 50 9 4 3 54 0 1 9 0°Ｓ 1 74 5°Ｅ斐济 7 00 4 0 3 2 81 9 0 0 2 1 0 2 2 3°Ｎ 1 4 3 5°…     

1999年9月14日四川省绵竹清平5.0级地震前区域地震活动

1　空间分布我们采用四川省地震台网目录资料 ,选取发生在北纬 3 0°3 0′～ 3 0°5 0′,东经 1 0 3°5 0′～1 0 5°1 0′德阳及邻区内的地震 ,对 1 970年以来的资料进行了分析。据统计 ,1 970年至 1 999年1 0月 ,该区发生 3 .0级以上地震共 85次 (图1 )。 1 999年 9月 1 4日绵竹清平 5 .0级地震为图 1　德阳地区 M≥ 3.0地震分布图近 3 0年来的最大地震 ,其次是 1 970年 3月 2 2日什邡、绵竹九顶山间 4.9级地震。历史上最大的地震为 1 95 8年 2月 8日绵竹 (微观震中 )6.2级地震 ,宏观震中为北川 ,震害较为严重。2　频次异常从 M-t、 N -…     

永胜6.0级地震灾害调查及分析

20 0 1年 1 0月 2 7日 1 3时 3 5分 ,云南省永胜县发生 6.0级地震。据昆明数字地震台网测定 ,截止 2 0 0 1年 1 0月 3 1日 1 9时震区共发生Ｍ≥ 1 0的地震 1 3 6次 ,其中 6 0级 1次 ;4 0～4 9级 1次 ;3 0～ 3 9级 3次 ;2 0～ 2 9级 3 1次 ;1 0～ 1 9级地震 1 0 0次。微观震中位于1 0 0°3 4′Ｅ ,2 6°1 4′Ｎ ,震源深度 1 5ｋｍ ,微观震中位于永胜县涛沅乡东龙潭村附近 ,宏观震中位于微观震中西南约 4ｋｍ ,即涛沅乡下坪村至金江街一带 ,震中烈度Ⅶ度 ,灾区主要涉及丽江地区永胜县、大理州的宾川县、鹤庆县 ;灾区总面积约…     

鲁皖豫交界地区地震活动特点及趋势分析

引言本文所述的鲁皖豫交界地区是指 3 1 .5°～ 3 6°N,1 1 3 .5°～ 1 1 7°E的范围。据历史地震记载 ,1 40 0年以来该区共发生 M≥ 6的地震 1 0次 ,最大地震为 1 93 7年荷泽 7.0级。近期地震活动实况表明 ,1 983年荷泽 5.9级地震后 ,研究区中等地震活动出现约 8年的平静 ( 1 984～ 1 991 )后 ,于 1 992年开始活动 ,特别是近两年来 ,连续发生 5次中等地震( 1 998年 1月 2 6日濮阳 4 .0 ;1 999年 5月 2 0日濮阳 4 .0 ,1 2月 3 0日阜阳 4 .6;2 0 0 0年 1月 2 8日随州 4 .1级及 4月 2 6日成安 4 .1级地震 )。这种由平静转为活跃的特点是否预…     

2002年10～11月首都圈地区ML≥2.0地震动态

根据中国地震局分析预报中心提供的资料 ,2 0 0 2年 1 0月首都圈地区 ( 3 8 0°～ 41 0°Ｎ ,1 1 3 0°～ 1 2 0 0°Ｅ)共发生ＭＬ≥ 2 0地震 1 5次 (见表 1 ) ,其中ＭＬ≥ 3 0地震有 3次。 1 2日 0 0时 55分大同ＭＬ4 0地震是本月最显著的事件。首都圈本月地震活动频次远高于上月 ,能量释放处于中等水平 ,震中主要分布在大同及唐山地区。1 1月共发生ＭＬ≥ 2 0地震 1 4次 (见表 1 ) ,无ＭＬ≥ 3 0地震。首都圈本月地震活动频次与上月基本相当 ,能量释放低于上月 ,震中主要分布在京西北及唐山地区。表 1　 2 0 0 2年 1 0～ 1 1月首都…     

2004年7月首都圈地区ML≥2.0地震动态

根据中国地震局地震预测研究所提供的资料 ,2 0 0 4年 7月华北地区 ( 33 0°～ 4 2 0°N ,1 1 1 0°～ 1 2 5 0°E)共发生ML≥ 3 0地震 4次 (见表 1 ) ,2 3日 0 9时 1 7分河北宁晋ML3 6地震是本月显著的事件。本月地震频次略低于上月 ,参考 1 992年以来的月平均地震频次 ,7月处于中等偏低水平 ,地震活动月能量释放处于中等偏低状态。震中分布在新河断裂带、大青山山前断裂带以南及该断裂带向东北的延长线上。表 1　 2 0 0 4年 7月华北地区ML≥ 3 0地震序号发　震　时　刻　　年月日时分秒震中位置φN/°　　　　λE/°震级ML震　中0 …     

2000年6月6日甘肃景泰5.9级地震震源机制解

20 0 0年 6月 6日 1 8时 59分 ,甘肃省景泰发生了ＭＳ5.9地震 .经甘肃省监测台网测定 ,该次地震震中位于 3 7. 0°Ｎ ,1 0 3 . 9°Ｅ ,震源深度 1 5ｋｍ .作者收集了甘肃及青海地区共 2 5个地震台站的Ｐ波初动符号 ,求出了该次地震的震源机制解 .见表 1和图 1 .矛盾比为 0 .2 8. 表 1　震源参数节面Ａ节面Ｂ节面应力轴Ｐ轴Ｂ轴Ｔ轴倾向 2 72° 1 88°方位角 2 3 5° 1 71° 1 3 4°倾角 82° 56°仰角 1 8° 54° 3 0°图 1　震源机制解Ｆｉｇ. 1　ＴｈｅｆｏｃａｌｍｅｃｈａｎｉｓｍｏｆＪｉｎｇｔａｉ 　　　 ＭＳ5. 9ｅａｒｔｈｑ…     

2002年10～11月华北地区ML≥3.0地震动态

根据中国地震局分析预报中心提供的资料 ,2 0 0 2年 1 0月华北地区 ( 3 3 0°～ 42 0°Ｎ ,1 1 1 0°～ 1 2 5 0°Ｅ)共发生ＭＬ≥ 3 0地震 8次 (见表 1 ) ,其中 1 2日 0 0时 55分大同ＭＬ4 0地震是本月最显著的事件。本月地震频度略低于上月 ,参考 1 992年以来的月平均地震频次 ,1 0月处于中等偏低水平 ,地震活动月能量释放处于中等状态 ,震中主要分布在山西带和东部沿海及海域。1 1月共发生ＭＬ≥ 3 0地震 6次 (见表 1 ) ,其中 7日 1 4时 3 4分郑州ＭＬ4 5地震是本月最显著的事件。本月地震频度与上月相比又略有下降 ,仍处于中等偏低…     

2003年5月华北地区ML≥3.0地震动态

根据中国地震局分析预报中心提供的资料 ,2 0 0 3年 5月华北地区 ( 33 0°～ 4 2 0°N ,1 1 1 0°～ 1 2 5 0°E)共发生ML≥ 3 0地震 9次 (见表 1 ) ,其中 2 2日 1 6时 4 8分唐山ML4 1地震是本月最显著的事件。本月地震频次低于上月。参考 1 992年以来的月平均地震频次 ,5月处于中等偏高水平 ,地震活动月能量释放处于中等状态。表 1　 2 0 0 3年 5月华北地区ML≥ 3 0地震序号发　震　时　刻年月日时分秒震中位置φN/°　　　　λE/°震级ML震　中0 12 0 0 3 0 5 0 1T2 3 12 2 2 34 4 115 13 4睢县0 2 2 0 0 3 0 5 0 7T19 34 11…     

Changes in sediment transport in the Kuye River in the Loess Plateau in China

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.     

Variations in trace gas concentrations in different environments in India

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.     

TritiogenicHe in groundwater in Takaoka

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.     

Projected changes in flood indices in selected catchments in Poland in the 21st century

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.     

Changes in thermal extremes in Poland

Changes in thermal extremes of the climate of Poland in 1951–2010 are examined. Warm extremes have become more frequent, while cold extremes have become less frequent. In the warming climate of Poland, the increase in the number of extremely warm days in a year and the decrease in the number of extremely cold days in a year have been observed. Also the increase of the maximum number of consecutive hot days in a year and the decrease of the maximum number of consecutive very cold and extremely cold days in a year have been observed. However, the trends are not of ubiquitous statistic significance, as the natural variability is strong.     

Copper in natural waters in Transbaikalia

Cu concentrations in surface (river and lake) and subsurface waters are determined. The geographic pattern of Cu distribution in natural water is identified. This pattern is controlled by the difference between its concentrations in drained rocks and soils and the geochemical redox conditions of its migration. Territories with low, medium, and elevated Cu concentrations in natural waters are identified. The concentrations of Cu in natural waters of the region are found to be generally lower than the Clarke values.     

Hydrological changes in the Ganges system in Bangladesh in the post-Farakka period

Abstract

The basin area of the Ganges River in Bangladesh is extremely dependent on a regular water supply from upstream to meet requirements for agriculture, fisheries, navigation, salinity control, and domestic and industrial sectors. In 1975, India commissioned a barrage on the Ganges River at Farakka to divert a significant portion of the dry season flow in order to make the Calcutta Port navigable. Statistical analyses of discharge and water level data have been carried out to determine if significant changes have occurred in the hydrology of the Ganges system in Bangladesh in the post-Farakka period. Siltation of the Gorai River (an offtake of the Ganges River) has also been examined using the stage-discharge relationship and regression analysis. The analyses show that the diversion has caused considerable hydrological changes in the Ganges system in Bangladesh. The water supply in the dry season has been reduced substantially, while siltation of the Gorai River has increased significantly.