兴海6．6级地震前后地震波的变化

2000年9月12日在青海省海南州兴海县西南发生了6．6级地震。震后发现，青海省6个专业台站的地震波速比在震前出现了下降－低值－发震的过程。波速比空间分布在兴海地震前形成了一个椭圆形的异常分布区，异常波速比的地震占总地震的73％。另外，在武台的尾波持续时间在兴海地震前显示出了较为完整的异常过程。     

兴海6．6级地震的科学问题及反思

在综合分析兴海6．6级地震前震（前）兆异常及其时空演化特征的基础上，探讨预报过程中存在的科学问题。     

兴海6．6级地震前地震活动异常图像与序列主要特征

兴海6．6级地震异常特征典型，从背景空区、孕震空区、大面积震群活动到地震条带、前震序列，长、中、短期地震活动性异常配套。该地震序列无论从其能量释放比、震级差，还是序列参数计算均符合主震－余震型判断指标，根据全序列特征，该地震为前震－主震－余震型序列。     

青海省兴海6．6级地震形变和深井地温前兆异常

对青海省现有的形变和深井地温资料进行了分析处理，发现在2000年9月12日兴海6．6级地震前，德令哈地应力、乐都倾斜、祁连深井地温、平安深井地温均有前兆异常存在，在此基础上对于出现的异常现象给出了初步的解释。     

兴海6．6级地震前海东地区前兆资料异常特征

20 0 0年 9月 1 2日在青海省海南州兴海县以北 ( 3 5°1 5′N ,99°3 0′E)发生了Ms6 6级地震 ,随后又发生多次余震 ,其中 5级以上强余震 5次。兴海地震前青海省海东地区所属台站的一些前兆观测项目均出现了不同程度的异常 ,分析与研究这些异常特征对于及早发现地震异常信息、预报地震以及减轻地震灾害有着重要的意义     

兴海6．6级地震前宏观异常调查

0　前　言2 0 0 0年 9月 1 2日 0 8时 2 8分 ,在海南藏族自治州兴海县发生了 6 6级强烈地震。这次地震波及范围较广 ,距震中约 1 3 0ｋｍ的州府所在地共和县恰卜恰镇震感强烈。此次地震是继 1 990年共和 7 0级地震之后又一次发生在海南州境内的强烈地震。震前 2周内出现的动物异常与 1 990年地震前极为相似。本文将介绍观测和调查了解到的动物和地下水前兆异常。1　动物习性异常地震前 1周至临震前 1 0多分钟 ,震中区和邻近地区均出现了较为明显的动物异常。动物种类有狗、猪、兔、鼠、羊、蚂蚁等。现分述如下 :( 1 )狗 :在震中区的兴海温泉…     

兴海6．6级地震前地震活动的演化过程及地下流体异常的分析

应用“全时空、有限时空扫描及时空强三维轴向稳定性检验”等“九五”研究最新技术途径，深入分析和研究了兴海6．6级地震前，2年时间尺度内小震活动的发展及强震的孕育过程，并提取了较为稳定、清晰的小震活动演化图像。其演化过程为：中短期空区（2年尺度）→短期空区（1年尺度）→中小震条块（1－0．5年尺度）→显地震事件（1－0．5年尺度）→副近地震（≤0．3个月）→主震发生。同时，对青海省东北部出现的大面积地下流体异常也进行了系统地分析。     

青藏高原北部地震活动形势及其与中国大陆地区地震活动的关系研究

简要回顾了中国学者对地震大形势的主要研究结果 .指出地震活动时空强分布的不均匀性是地震活跃期和平静期的外在表现 .系统地分析了青藏高原北部地区的地震活动形势 ,指出 2 0世纪以来 ,该区MS ≥ 6 .0地震经历了 6个活跃期和 6个平静期 ,与中国大陆地区的地震活动不同步 .2 0 0 0年 6月甘肃景泰 5.9级地震和同年 9月青海兴海 6 .6级地震的发生意味着该区进入了一个新的地震活跃期     

青海省兴海7.0级地震前兆

介绍了青海省兴海７．０级地震前水氡，地下水位，地表形变，地震活动性，气象及动物等出现的异常，并对震前的预报作了简介。     

2008年西藏当雄6．6级地震浅析

介绍了2008年10月6日西藏当雄6．6级地震的基本情况,认为当雄6．6级地震势必对西藏的中部及东南部地区的地震活动产生一定的影响,对此次地震提出一些相关问题并进行了分析。     

Anomalous strontium and lead isotope signatures in the off-rift Öræfajökull central volcano in south-east Iceland: Evidence for enriched endmember(s) of the Iceland mantle plume?

The currently active off-rift central volcano Öræfajökull in south-east Iceland sits unconformably on much older (10–12 Ma) and eroded crust. The composition of recent volcanics ranges from basalt to rhyolite, but the series is more sodic alkaline than the common rift zone tholeiitic suites. In this study we present Sr, Nd, Pb and O isotopic data for a suite of Öræfajökull samples. The complete suite shows typical mantle values for oxygen isotopes. The ⁸⁷Sr/⁸⁶Sr ratios (average of 15 SAMPLES=0.703702) of the modern Öræfajökull rocks (basalts as well as rhyolites) are much higher than observed so far for any other Icelandic rocks. The ¹⁴³Nd/¹⁴⁴Nd ratios (average=0.512947; n=15) are lower than for rift rocks, but similar to rocks of the off-rift Snæfellsnes volcanic zone. Furthermore, the Öræfajökull rocks are enriched in the ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb isotope ratios compared to Icelandic rift basalts. The enriched nature of the suite indicates that Öræfajökull samples a source component that has characteristics common with EM2 type mantle. Furthermore, it is concluded that the silicic rocks of Öræfajökull formed by fractional crystallization from mafic melts rather than by partial melting of older crust.     

北部湾6.1,6.2级地震序列的环境应力场

应用Ｐ波初动半周期直接测定环境剪应力值的方法,测定了北部湾６．１,６．２级地震前后中小地震的环境剪应力值τ０,由此分析了北部湾地震过程的环境应力场特征。结果表明,北部湾６．１级地震后平均剪应力值较高,达１８ＭＰａ左右;６．２级地震及两次５级余震后剪应力值下降很快,降至目前的６ＭＰａ左右。在此基础上对北部湾地震活动趋势作了初步分析。     

Non-cosmogenic lithium-6 in iron meteorites

A neutron activation method is used to measure⁶Li via the reaction⁶Li(n, α)³H in iron meteorites. It is found that most⁶Li occurs in non-metallic inclusions which can be separated by dissolution of the metal in 4 M H₂SO₄. The non-magnetic portion of such a residue has as high as 0.9 ppm⁶Li, while in the bulk sample⁶Li ranges from 0.02 to 10 ppb. Average⁶Li contents (ppb) for various classes are IA, 1.8; IIAB, 1.6; and IIIA, 0.4. Cosmic-ray-produced⁶Li is generally much smaller than the native⁶Li.     

山西数字遥测地震台网监测能力评估

根据台网布局和实际获得的参数，运用反推方法，对山西数字遥测地震台网和模拟遥测地震动中网的监控能力进行了对比分析，粗定了数字遥测地震台网速报责任区的范围，并对数字遥测地震台网的大震响应能力进行了讨论，依据数字化台网的两期改造方案，估算了其监控能力，结果表明，目前山西数字遥测地震台网中部和南部的台站密度明显不够，北部监控能力为1.8级，中部监控能力为2.3级，南部监控能力为2.5级，山西数字遥测地震台网对网中大震参数的测定能力为6.6级。     

Seismically active fracture zones and distribution of thermal springs in Ecuador

Summary The analysis of the geometry of distribution of earthquake foci occurring in the continental South American plate above the subducted Nazca plate reveals that in the region of Ecuador these earthquakes accumulate in 8 well-separated fracture zones. These zones are interpreted as a system of deep seismically active fractures induced in the continental plate by the process of subduction. It is shown that the position of known thermal springs and of observed hydrothermal alterations in Ecuador correlates with the outcrops of the fracture zones.

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Spring drought prediction based on winter NAO and global SST in Portugal

The aim of this paper is to test the ability of neural network approaches to hindcast the spring standardized precipitation index on a 6‐month time scale (SPI6) in Portugal, based on winter large‐scale climatic indices. For this purpose, the linkage of the spring SPI time series with the winter North Atlantic Oscillation (NAO) and the sea surface temperature (SST) was investigated by means of maps of the correlation coefficient for the period from October 1910 to September 2004. The results indicate that the winter NAO is a good predictor for the SPI6 of the spring (SPI6 finishing in April, May and June, SPI6_April, SPI6_May and SPI6_June, respectively) for the northern, central and southern regions of Portugal. The winter SST1 (area of the Mediterranean Sea) must only be considered for the northern region, and the winter SST3 (area of the North Atlantic between Iberia and North America) only for the southern region. Spatial maps of predictive SPI6 for April, May and June were created and validated. The neural models explained more than 81% of the total variance for the SPI6_April and SPI6_May and more than 64% of the total variance for the SPI6_June. Probability maps were also developed considering the values predicted by the neural methods for the spring months and all drought categories (moderate, severe and extreme). These maps indicating the probability of droughts can provide valuable support for the integrated planning and management of water resources throughout Portugal. Copyright © 2012 John Wiley & Sons, Ltd.     

花岗岩铀地球化学特征新认识——以赣南富城产铀花岗岩体为例

对富城花岗岩U、Th含量分析结果进行的频数统计分析表明富城花岗岩U的均值为8．92×10＾－6、众数为8．0×10＾－6、中位数为7．03×10＾－6,其概率密度曲线偏向高端呈右偏非对称分布（偏度系数CSK＝1．10）。Th的均值、众数和中位数三者一致,分别为25．7×10＾－6,25．75×10＾－6,25．8×10＾－6,其概率密度曲线呈对称正态分布（偏度系数CsK＝0．11）。核诱发裂变径迹研究查明富城花岗岩中铀有4种存在形式：（1）显微粒状铀矿物（晶质铀矿）;（2）以类质同像形式存在于锆石、磷灰石等副矿物之中;（3）均匀分散赋存在造岩矿物晶格之中的结构铀;（4）沿造岩矿物（长石、石英）微裂隙及粒间分布的非结构铀。对富城花岗岩铀配分研究发现,赋存在造岩矿物中均匀分散状的结构铀含量与全岩铀不呈消长关系,而是存在一定的极限值：长石、石英〈3X10＾－6,白云母〈5×10＾－6,黑云母〈9×10＾－6。溶浸实验结果表明,富城花岗岩活动性铀浸出率很高（平均值52％）,为富城花岗岩具有较大铀成矿潜力提供了佐证。     

On the question of carbon dioxide heat radiation in the atmosphere

Summary The new, more reliable data on transmisson function of the atmosphere in the region of 12–18 carbon dioxide absorption band are obtained. The radiation chart for calculations of atmospheric heat radiation is built on the base of this data. The dependence of atmospheric heat radiation on CO₂ and H₂O contents and also on temperature vertical distribution is investigated with the help of the radiation chart. It is shown, that the heat radiation of the atmosphere almost doesn't depend on variations of carbon dioxide content in the atmosphere. The income of atmospheric heat radiation in the region of spectra from 12 to 18 in integrated atmospheric radiation is determined.

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, 12–18. . , . , . 12–18 .

     

Accuracy of integral migration transformation in dependence on space-time sampling

Summary The accuracy of wave field extrapolation is studied with respect to the discretization of field data and integral extrapolator. Assuming a far-field approximation of the Rayleigh-Sommerfeld solution for a two-dimensional scalar wave equation, the minimum and the maximum transmitted frequency are expressed as functions of the sampling intervals t, x, and the half-width x₀ and angle _a of the migration aperture. The theoretical limitation of the transmitted frequency band is tested on numerical examples.

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On the expanding earth hypothesis

Summary The hypothesis of an expanding Earth is discussed on the basis of lunar laser ranging It is provcd that the given data do not indicate a secular increase in the principal moment of the Earth's inertia which would have to occur if the Earth were really expanding.

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