祁连山西段测震指标异常综合应用

通过对1980年以来至今14个指标的全时间扫描,并使用祁连山西段地区Ms5．0地震进行对应。结果表明,选取A值、AC值、A（b）值、b值、Mf值和地震活动度S值进行同步异常分析,能显著提高祁连山西段地区的有震报震率,但有漏报。对目前地区异常集中区进行时间扫描,结果显示,祁连山西段地区出现同步异常,认为2012年或稍长时期有发生Ms≥5．0中强震的可能。     

云南水氡群体异常特征

采用非均匀度方法,分别提取滇西北、滇中北、滇西南、滇东南和滇东北地区水氡观测资料的地震前兆群体异常。结果表明,该方法能满足水氡观测点所在地区成组中强地震的中、短临预报要求;且该方法能自动识别异常,排除人为主观影响,便于在其他震区进行预报效能检验。     

太原地震台水位异常分析

针对太原地震台晋7-1井近年来水位大幅上升情况,进行资料收集和干扰因素分析,结果发现：2009年7月以来的井水位回升,与关闭小煤窑、汾河清水复流工程、关井压采、大量引用黄河水有直接关系。     

Applying Iterative Method to Solving High-Order Terms of Seafloor Topography

Abstract

We introduce an iterative inversion method to address the problems in high-order seafloor topography inversion using gravity data (gravity anomaly and vertical gravity gradient anomaly), such as the difficulty in computing the equation and the uniqueness of the calculation results. A part of the South China Sea is selected as the experimental area. Considering the coherence and admittance function of gravity topography and vertical gravity gradient topography, the inversion band of the gravity anomaly and vertical gravity gradient anomaly in the study area is 30?km–120?km. Seafloor topography models of different orders are constructed using an iterative method, and the performance of each seafloor topography model is analyzed against ETOPO1 and other seafloor topography models. The experimental results show that as the inversion order increases, the clarity and richness of seafloor topographic expression continuously improve. However, the accuracy of seafloor topography inversion does not improve significantly when the inversion order exceeds a certain value, which is related to the contribution of high-order seafloor topography to gravity information. The results show that the accuracy of BGT4 (inversion model constructed by the gravity anomaly) is slightly poorer than that of BVGGT4 (inversion model constructed by the vertical gravity gradient anomaly) in areas with complex topography, such as multi-seamounts and trenches, and the results are generally better in areas with flat seafloor topography.     

Substrate control on formation and maturation of glauconites in the Middle Eocene Harudi Formation, western Kutch, India

Formation and maturation of glauconites within the early Middle Eocene Harudi Formation, built up in a lagoon to shelf transition in western Kutch, India is addressed taking recourse to a combined sedimentological, micropalaeontological and mineralogical investigation. The glauconite is authigenic and its occurrence coincides with maximum flooding. The glauconite is more matured within the fecal pellets and is less matured within the intra-particle pores of bioclasts namely, foraminifera, ostracoda, gastropoda and bryozoa. SEM-EDS, XRD and geochemical studies clearly document that the infilling within the intra-particle pores of bioclasts belong to nascent to slightly evolved glauconite (<5 wt% K₂O), while the pellet belongs to slightly evolved to evolved glauconite (5-7 wt% K₂O). Based on chemical characteristics and SEM investigations the glauconitization process can be best explained by the ‘verdissement theory’. The glauconite possibly formed as initial authigenic glauconitic smectite precipitates; while the pellet matured subsequently by addition of K, the process was hindered in case of infillings. The maturation process also involved addition of Si and release of Al, with or without release of Mg. The glauconite maturation was facilitated in case of fecal pellets because of higher porosity, inter-granular nature of pores and availability of necessary elements in semi-confined micro-environments. In contrast, the maturation was aborted at an early stage in case of infillings because of the minute, closed nature of the pores and prevalent alkaline conditions not allowing dissolution of calcitic tests. A low negative cerium anomaly suggests glauconite formation in sub-oxic micro-environments, created by decay of organic matters within the fecal pellets and bioclasts. A clear case of substratum control on glauconitization becomes apparent.     

����ƫ��С���˻ع�ij�������쳣����ֵTECԤ��

????IGS????120??E???1999??2009??IONEX?????????????????????TEC?????????????С?????鷽??????????????????????????????????????TEC?????????????2009???TEC?????????????顣????????????????????????????????????TEC??仯?????????????????????Ч?????????????????????????????TEC?????????????????4.441 0??2.915 1 TECU??????????????23.26%??10.78%????????????????????????0.712 2??0.785 9??     

南昌地震台钻孔应变同震响应分析

通过总结2007年5月以来南昌地震台TJ-2钻孔应变仪的同震效应,并与同期中国地震台网(CSN)提供的全球大震目录中的数据进行对比分析,绘出了震级与震中距的对数关系图,得出南昌地震台体应变仪的映震能力的表达式近似为Ms=1.381gD+ 1.1.     

华北地区定点台站形变资料分析

对华北地区定点台站形变观测资料,采用傅立叶去年周期和线性拟合的方法进行处理.结果表明,华北地区现阶段的变化未形成主体异常时段,反映出断层未进入强烈活动阶段;首都圈地区跨断层资料异常数量不多,没有形成同步异常,异常变化幅值也不是很大,中短临地震异常不明显.     

北京五里营水温干扰分析及解决

北京五里营井水温每天都有24次锯齿状畸变,有很好的规律性,经分析认为是气氡观测对水温造成影响.将气氡和水温供电分离,并在水温地线和地网之间增加一个电感,以阻挡其他干扰信号由地线反馈到观测仪器,改造后水温脉冲干扰彻底消除,观测质量明显提高.     

MODIS干旱指数对华北干旱的敏感性分析

针对近年来干旱发生频繁的华北地区,通过利用2000-2009年MODIS数据和气象观测站降水资料,建立草地和农田距平植被指数(AVI)与不同时间尺度标准化降水指数(SPI)之间的相关统计模型,比较AVI和距平水分指数(AWI)对干旱响应的敏感性。结果表明：(1)植被生长季AVI与不同时间尺度SPI的相关关系不同。草地AVI与1个月尺度的SPI(即1-SPI)相关系数较低,而与3-SPI相关最显著;而农田区AVI与SPI的相关性较低,总体上农田AVI与3-SPI的相关性较高;(2) AWI与AVI类似,也对SPI存在时滞响应,均与3-SPI有着极显著的相关关系,并且在干旱发生较严重的6~8月份AWI与3-SPI的相关性好于AVI与3-SPI的相关性;(3)运用AWI反演的华北地区2009年夏季干旱分布图较好地反映了旱情的时空分布,与相关气象资料结果相符合。