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591.
走滑拉分作用与相山产铀火山盆地的就位   总被引:1,自引:1,他引:1  
相山火山盆地是我国著名的产铀火山盆地。本文依据相山盆地深部地质研究成果以及大陆动力学理论,探讨了相山产铀火山盆地的就位机制。研究表明,相山火山盆地火山活动划分为两个旋回,其就位受制于区域深断裂的走滑拉分作用。即第一旋回的火山机构就位于NE向深断裂右旋走滑复活产生的EW向拉分构造,形成了东西向展布的裂隙式火山喷溢带;第二旋回的火山机构就位于NE向深断裂左旋走滑复活产生的SN向拉分构造与EW向基底断裂的结点,产生了中心式火山岩浆喷溢侵出。此外,还探讨了富大铀矿的形成机制。  相似文献   
592.
Abstract Drilling was carried out to penetrate the Nojima Fault where the surface rupture occurred associated with the 1995 Hyogo-ken Nanbu earthquake. Two 500 m boreholes were successfully drilled through the fault zone at a depth of 389.4 m. The drilling data show that the relative uplift of the south-east side of the Nojima Fault (south-west segment) was approximately 230 m. The Nojima branch fault, which branches from the Nojima Fault, is inferred to extend to the Asano Fault. From the structural contour map of basal unconformity of the Kobe Group, the vertical component of displacement of the Nojima branch–Asano Fault is estimated to be 260–310 m. Because the vertical component of displacement on the Nojima Fault of the north-east segment is a total of those of the Nojima Fault of the south-west segment and of the Nojima branch–Asano Fault, it is estimated to total to 490–540 m. From this, the average vertical component of the slip rate on the Nojima Fault is estimated to be 0.4–0.45 m/103 years for the past 1.2 million years.  相似文献   
593.
Abstract Crack-filling clays and weathered cracks were observed in the Disaster Prevention Research Institute, Kyoto University (DPRI) 1800 m cores drilled from the Nojima Fault Zone, which was activated during the 1995 Hyogo-ken Nanbu earthquake (Kobe earthquake). The crack-filling clays consist mainly of unconsolidated fine-grained materials that fill opening cracks with no shear textures. Most of the cracks observed in the DPRI 1800 m cores are yellow-brown to brown in color due to weathering. Powder X-ray diffraction analyses show that the crack-filling clays are composed mainly of clay minerals and carbonates such as siderite and calcite. Given that the top of the borehole is approximately 45 m above sea level, most of the core is far below the stable groundwater table. Hence, it is suggested that the crack-filling clays and weathered cracks in the cores taken at depths of 1800 m were formed by the flow of surface water down to the deep fractured zone of the Nojima Fault Zone during seismic faulting.  相似文献   
594.
INTRODUCTIONLaserablationinductivelycoupledplasmamassspectrome tryisanincreasinglydevelopedanalyticaltechniqueforsolidsampleanalysis.LA ICP MSoffersattractivecharacteristicsofhighsensitivity ,lowdetectionlimits,minimalsampleprepara tion ,lessoxidesinterfe…  相似文献   
595.
青藏高原地表反照率计算研究   总被引:13,自引:1,他引:13  
根据改进的甚高分辨率扫描辐射仪(AVHRR)5个观测波段的光谱特征,经多次试验,设计了一组从卫星观测的地-气系统的辐射测值中提取晴空资料的多通道门槛值判识法和提取月平均反照率的合成法;并对1992年NOAA-12卫星获取的AVHRR资料进行计算处理,分析提取晴空数据,在此基础上按卫星轨道覆盖周期合成计算得到的晴空行星反照率和地表反照率,并且计算了逐月的地表反照率。对计算结果做了初步分析和认真比较。  相似文献   
596.
THE FOUNDATION AND MOVEMENT OF TROPICAL SEMI-GEOSTROPHIC ADAPTATION   总被引:4,自引:0,他引:4       下载免费PDF全文
The breakdown and foundation of geostrophic balance is one of the important movements inthe mid-and high-latitude atmosphere and oceans.In the tropical area,the value of Coriolis pa-rameter is so small that it is difficult to satisfy the bi-geostrophic equilibrium between the pressureand velocity fields.However,in the tropical area,the zonal velocity of some motions in the atmo-sphere and oceans is large,so the Coriolis force is not small,geostrophic balance can exist in zonaldirection,i.e.semi-geostrophic balance.Furthermore,in the dominant area of Hadley circulationin the atmosphere or the area near the ocean meridional boundary,the meridional velocity is large,so geostrophic balance can also exist in meridional direction.In this paper,the process of the dis-persion of inertial gravity wave and the foundation of semi-geostrophic balance are first discussed.Second,the adjustment process between the velocity and pressure fields after adaptation is alsoviewed,and the scale criterion of the semi-geostrophic adaptation is discussed,i.e.for the motionwith meridional scale greater than the equatorial Rossby radius of deformation,the velocity andpressure fields after adaptation change to fit the initial pressure field;on the contrary,the fieldschange to fit the initial zonal velocity field,and the strength of the fields after adaptation dependson the zonal scale.  相似文献   
597.
东南沿海地震形势分析   总被引:2,自引:0,他引:2  
彭美凤  林世敏 《地震》1996,16(2):197-201
研究1900年以来东南沿海地震活动序特征,并进行了地震活动分幕,结果表明,1986年开始进入了本世纪以来的第V地震活跃幕,本活跃幕将延至2000年左右,期间有发生6级左右地震的危险,最大可能的发震区是闽粤交界及其沿海地区。  相似文献   
598.
立体影像匹配是自动提取SPOT影像高程信息的关键技术。本文根据SPOT影像在几何构像关系和影像质量上的特点,提出了多级匹配的结构策略。实际像对匹配实验表明,多级匹配法具有较好的可靠性和精度水平,而且运算速度快,在快速生成DEM数据辅助遥感信息分析方面,有重要的应用价值。  相似文献   
599.
We compute the interannual fluctuations of the surface heat budget of the North Atlantic using the trimmed monthly summaries of the Comprehensive Ocean-Atmosphere DataSet (COADS) for the period 1950–1979. The presence of long-period trends in the heat budget imply large variations of the northward cross-equatorial heat transport over the years. To assess the reliability of these variations, we compare the COADS climate signal to that derived from the ocean weather stations (OWSs) of the North Atlantic. The sea surface temperature, air temperature and sea level pressure show good correlation between the anomaly time series derived from the merchant ship monthly summaries of COADS, and those derived from OWS monthly summaries, except for northernmost locations during winter. In contrast, the sensible and latent heat parameters, which require simultaneous measurements of various variables, have merchant ships and ocean weather stations anomaly time series that are poorly correlated. Only in heavily travelled latitudes and during winter, when the air-sea heat exchange anomalies are large, are the merchant ship measurements able to reproduce the interannual fluctuations of the heat fluxes. The long-period trends in the surface heat budget of North Atlantic equatorward of 40° N implied by COADS thus appear unrepresentative of true climate trends. The COADS trends result from a gradual increase in the magnitude of the reported winds over the years due probably to variations in the ratio of measured to estimated winds, as well as from long period fluctuations in the near surface vertical temperature and humidity gradients. Offprint requests to: R Michaud  相似文献   
600.
青海可可西里无人区夏季温度分布特征   总被引:1,自引:0,他引:1  
张琳 《高原气象》1992,11(2):203-207
  相似文献   
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