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11.
上海城市天际线与高层建筑发展之关系分析 总被引:4,自引:1,他引:3
以上海市2000年中心城区航空影像为基础,基于GIS技术分析城市高层建筑与天际线的分布特点及其影响机制。认为城市天际线与高层建筑相互制约,高层建筑的发展与布局必须考虑城市天际线的特色。 相似文献
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中国大陆科学钻探先导孔零偏VSP资料解释 总被引:3,自引:3,他引:0
用六级三分量检波器在中国大陆科学钻探先导孔中实施了零偏VSP测量.数据处理结果表明,中国大陆科学钻探孔区超高压变质岩石的地震波速度主要介于4500~7000m/s之间,显著高于一般的沉积岩地区,而且随深度变化不明显.声波测井速度系统地稍低于VSP层速度,可能是由于井壁处岩石的完整性受到破坏而造成的.地震波速度与岩石密度和岩性存在明确的对应关系,榴辉岩的密度和地震波速度均显著高于片麻岩类岩石;由榴辉岩退变生成的斜长角闪岩类岩石,其密度和地震波速度均呈现出较大的变化,主要与其退变质程度有关;超基性岩中的裂隙系统导致其密度和地震波速度大幅度下降.由于榴辉岩与其他岩石类型之间存在较大的波阻抗差异,因此用零偏VSP资料标定该区地震波的地质层位是有效的.关于地震波反射的原因,通过综合研究地震波(包括反射纵波、上行转换横波、井筒波)的特征、岩石速度和密度分布以及井径变化,认为主要是岩性分界面、韧性剪切带和断裂(带),但还有一些因素尚待进一步研究. 相似文献
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We analyzed thin sections from two palaeoseismic trenches across the low-slip-rate Geleen Fault in the Belgian Maas River valley to help identifying the most recent large palaeoearthquake on this fault segment. In the first trench we sampled silty sediment below and above a prehistoric stone pavement that was supposedly at or near the surface at the time of the event, and subsequently thrown down. The samples below show a well-developed in situ argillic Bt soil horizon in parent sediment containing remnants of stratification, whereas the sediment above is a structureless colluvium reworked at least partly from Bt-horizon material. Below the stone pavement, we also found evidence of contorted stratification, which is in agreement with macroscopic observations of both the sediment and the stone pavement itself, and which is attributed to co-seismic soft-sediment deformation. In the second trench, we sampled a sequence of vaguely discernible soil horizons in the hanging-wall, interpreted as a buried soil profile (Bt, E, and possibly A horizons), overlain by a featureless deposit. Thin-section analysis supports the colluvial nature of the latter, and also provides evidence that both the base of this layer and the top of the poorly developed A horizon below have occupied a shallow position in a soil profile. A sample from the same depth in the footwall is composed of very different material. Instead of colluvium, we find patches of Bt soil, most likely representing the same pedogenic level as the in situ Bt horizon at larger depth in the hanging-wall, but displaced and subsequently degraded. Furthermore, thin sections confirm that vertical structures cutting this Bt horizon are sand dykes. These dykes could be traced macroscopically upward to the base of the colluvium. In both trenches, we have thus identified a stratigraphic boundary in the hanging-wall, close to the surface, separating an in situ soil below from colluvium above. We interpret this limit and the overlying colluvium as the event horizon and the colluvial wedge, respectively, of a surface-rupturing palaeoearthquake. In addition, in both cases we found evidence of soft-sediment deformation (related to liquefaction) contemporaneous with the event within the stratigraphic resolution. 相似文献
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目前海面辐照度的测量,在消除天空光影响的同时,却引入了仪器接收面倾斜的误差。作者经过多年的实践,提出动态水平的理念和一整套技术方法,解决了这一问题。动态水平技术的应用,需应用最新技术的发展,而且必然引起海洋光学测量仪器、特别是海洋光学浮标的一系列变革,对海洋水色遥感具有重要的意义和影响。 相似文献
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Helen C. Bostock Bruce W. HaywardHelen L. Neil Kim I. CurrieGavin B. Dunbar 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(1):72-85
We have compiled carbonate chemistry and sedimentary CaCO3% data for the deep-waters (>1500 m water depth) of the southwest (SW) Pacific region. The complex topography in the SW Pacific influences the deep-water circulation and affects the carbonate ion concentration ([CO32−]), and the associated calcite saturation horizon (CSH, where ??calcite=1). The Tasman Basin and the southeast (SE) New Zealand region have the deepest CSH at ∼3100 m, primarily influenced by middle and lower Circumpolar Deep Waters (m or lCPDW), while to the northeast of New Zealand the CSH is ∼2800 m, due to the corrosive influence of the old North Pacific deep waters (NPDW) on the upper CPDW (uCPDW). The carbonate compensation depth (CCD; defined by a sedimentary CaCO3 content of <20%), also varies between the basins in the SW Pacific. The CCD is ∼4600 m to the SE New Zealand, but only ∼4000 m to the NE New Zealand. The CaCO3 content of the sediment, however, can be influenced by a number of different factors other than dissolution; therefore, we suggest using the water chemistry to estimate the CCD. The depth difference between the CSH and CCD (??ZCSH−CCD), however, varies considerably in this region and globally. The global ??ZCSH−CCD appears to expand with increase in age of the deep-water, resulting from a shoaling of the CSH. In contrast the depth of the chemical lysocline (??calcite=0.8) is less variable globally and is relatively similar, or close, to the CCD determined from the sedimentary CaCO3%. Geochemical definitions of the CCD, however, cannot be used to determine changes in the paleo-CCD. For the given range of factors that influence the sedimentary CaCO3%, an independent dissolution proxy, such as the foraminifera fragmentation % (>40%=foraminiferal lysocline) is required to define a depth where significant CaCO3 dissolution has occurred back through time. The current foraminiferal lysocline for the SW Pacific region ranges from 3100-3500 m, which is predictably just slightly deeper than the CSH. This compilation of sediment and water chemistry data provides a CaCO3 dataset for the present SW Pacific for comparison with glacial/interglacial CaCO3 variations in deep-water sediment cores, and to monitor future changes in [CO32−] and dissolution of sedimentary CaCO3 resulting from increasing anthropogenic CO2. 相似文献
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对相邻钻孔数据的类型进行了分析,对不同连续性和规则性的地层分界面进行了建模.考虑地层分界面的光滑性和整体控制性,运用边界表示法(B-Rep)和B样条曲面重构地层分界面,为地层建模提供了一种新的方法.建模研究表明:在钻孔数据前处理算法的基础上,B-Rep能够建立连续型、非连续型、空洞型等任意边域的地层分界面. 相似文献
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