爆破地震波在砼重力坝中的特性反应

根据某大坝右岸围堰爆破，对爆破地震波三维空间的频谱、加速度、速度、动力放大倍数进行了研究，得到爆破地震波在砼重力坝的不同高度、不同方向、不同介质中的反应特性。     

Changes in glacial lakes and glaciers of post-1986 in the Poiqu River basin, Nyalam, Xizang (Tibet)

Glacial lakes and glaciers are sensitive indicators of recent climate change. In the Poiqu River basin of southern Tibet, 60–100 km NW of Mt. Everest, Landsat imagery defines post-1986 changes in the size and distribution of both glacial lakes and glaciers. Total area of glaciers in the 229-km² drainage area has decreased by 20%. The number of glacial lakes with areas in excess of 0.020 km² has increased by 11%, and the total area of glacial lakes has increased by 47%. The areas of typical large glacial lakes of the area (Galongco, Gangxico, and Cirenmaco) have increased by 104, 118, and 156%, respectively, and these increases are confirmed by field investigations.Comparing the 1986 data, the area of glaciers in the basin headwaters has decreased by 46.18 km² to a present total area of 183.12 km², an annual rate of change of 3.30 km²/year. Trends indicate that the total area of glaciers will continue to decrease and that both the numbers and areas of glacial lakes will continue to increase. Accompanying these trends will be an increased risk of debris flows, formed by entrainment of sediment in glacial-outburst floods and in surges from both failure and avalanche- and landslide-induced overtopping of moraine dams. Based on both the local and world-wide history of catastrophes from flows of these origins, disaster mitigation must be planned and appropriate engineering countermeasures put in place as soon as possible.     

Multi-interferogram method for measuring interseismic deformation: Denali Fault, Alaska

Studies of interseismic strain accumulation are crucial to our understanding of continental deformation, the earthquake cycle and seismic hazard. By mapping small amounts of ground deformation over large spatial areas, InSAR has the potential to produce continental-scale maps of strain accumulation on active faults. However, most InSAR studies to date have focused on areas where the coherence is relatively good (e.g. California, Tibet and Turkey) and most analysis techniques (stacking, small baseline subset algorithm, permanent scatterers, etc.) only include information from pixels which are coherent throughout the time-span of the study. In some areas, such as Alaska, where the deformation rate is small and coherence very variable, it is necessary to include information from pixels which are coherent in some but not all interferograms. We use a three-stage iterative algorithm based on distributed scatterer interferometry. We validate our method using synthetic data created using realistic parameters from a test site on the Denali Fault, Alaska, and present a preliminary result of  10.5 ± 5.0  mm yr⁻¹ for the slip rate on the Denali Fault based on a single track of radar data from ERS1/2.     

Polyphase Deformation of the Weihai-Rongcheng UHP Unit Rocks, NE Sulu： Insights into the Tectonic Evolution of the Dabie-Sulu UHP and HP Belts, China

Different scales of structural data reveal a complex deformation history of ultrahigh- pressure （UHP） rocks exposed in the Weihai-Rongcbeng area, NE Sulu （northern Jiangsu-eastern Shandong）, eastern China. Excluding pre-UHP deformations, at least five major sequential deformational stages （D1-Ds） are recognized. The first deformation （DO produced a weak foliation and lineation in massive eclogites. The foliated eclogite with a dominant foliation containing a stretching and mineral lineation was developed during the I）2 deformation. Both the D1 and D2 deformations occurred under UHP metamorphic conditions, and are well preserved in the eclogite bodies. D3 structures which developed shortly after the formation of granulite/amphibolite facies symplectites are characterized by imbricated associations marked by a regional, steeply dipping foliation, compositional layering, eclogite boudinage, isoclinal folds and reverse ductile shear zones. The D3 deformation was accompanied by decompressional partial melting. A regional, gently dipping amphibolite facies foliation and stretching lineation, low-angle detachments, and dome- and arc-shaped structures formed during the D4 deformation stage dominate to some degree the map pattern of the Weihai-Rongcbeng UHP domain. The last stage of deformation （Ds） gave rise to the final exhumation of the UHP rocks. Ds is characterized by development of brittle-dominated high-angle faulting associated with emplacement of large volmnes of undeformed granite plutons and dykes dated at 134-100 Ma. The deformational and metamorphic sequence followed by the UHP rocks in the Weihai-Rongcheng area is similar to that studied in the entire Dabie-Sulu UHP and HP metamorphic belts from microscopic to mapping scale. Based on structural data, combined with available petrographic, metamorphic and geochronological data, a speculative tectonic evolutionary model for the Dabie-Sulu UHP and IIP belts is proposed, involving continental subduction/collision between the Sino-Korean and Yangtze cratons and subsequent polyphase exhumation histories of the UHP and IIP metamorphic rocks.     

Petrogenesis of the Pt–Pd mineralized Jinbaoshan ultramafic intrusion in the Permian Emeishan Large Igneous Province,SW China

The Jinbaoshan ultramafic intrusion is a sheet-like body with a thick wehrlite unit in the center and thin pyroxenite units at the margins. PGE are enriched in several disseminated sulfide zones in the intrusion. Olivine from the intrusion has low Fo and depleted Ni contents compared to olivine from coeval Emeishan picrites. Whole rock major and trace element concentrations suggest that the Jinbaoshan wehrlites originally contained <30% trapped liquid. The total amount of sulfide in the rocks exceeds that which could have been dissolved in the trapped liquid. The Jinbaoshan wehrlites are interpreted to represent residual assemblages formed by dissolution of plagioclase by passing magma. No clear evidence of crustal contamination is indicated by S, Nd and Os isotopes. We envision that sulfide saturation occurred at depth due to olivine and chromite crystallization. Immiscible sulfide droplets were transported to the Jinbaoshan conduit where they accumulated and reacted with magma successively passing through the conduit to achieve high PGE concentrations.     

广东省典型地形土地整理项目中土方量的计算

土方量计算是土地整理规划的重要内容,计算法的科学选取对工程预算和项目实施的准确性具有重要意义。文中在分析比较当前主要土方量计算法的基础上,以国土资源部广东省佛冈县龙山镇土地整理项目和广东省云安县前锋镇土地整理项目为例,分别利用方格网法和梯形断面法对广东省两种典型地形的土方量进行了计算。结果表明,这两种方法在各自适用范围内计算土方量是可行的。     

Vertical Crustal Displacements Due to Surface Fluid Changes

Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the ...     

多星拼图的再处理技术

由于不同静止气象卫星的观测时间、分辨率及红外通道的红外扫描辐射计的光谱响应函数和空间响应函数都不尽相同,因此,将两颗静止气象卫星的红外云图融合在一起而形成的多星拼图,就会在交界处呈现不连续性,图像上表现为一条明显的拼缝且拼缝的两边亮度不一致。本文利用“直方图匹配方法”对多星拼图进行处理,消除了亮度不均匀现象,提高了图像的整体视觉效果。     

利用微波成像仪资料反演台风Aere(2004)降水水平结构

利用热带降雨测量卫星（TRMM）的微波成像仪（TMI）和星载测雨雷达（PR）资料，从台风Acre（2004）接近台湾岛的观测资料中选取3个时次的数据，采用4种不同方法进行TMI反演降水试验。结果表明，常用的仅用高频通道反演降水方法的效果并不理想，多通道直接组合法的反演结果虽然稳定性很好，但始终无法达到最佳，多通道直接对数组合法的反演结果虽然有时较好，但反演结果不稳定，而多通道间接对数组合法既可以较好地表征弱降水区的范围和强度分布，又能描绘强降水区的位置，且反演效果稳定，是由微波亮温资料反演洋面降水的一种较为理想的方法。结果对于利用我国自行发射的气象卫星遥感资料反演降水具有一定的参考价值。     

黄淮麦区小麦拔节后霜害的风险评估

小麦拔节后抗寒力迅速减弱, 遇强冷空气侵入会发生霜害。该文首先分析了黄淮麦区小麦拔节期的变化规律和霜害温度出现的规律。结果表明:逐日进入拔节期的概率随日序的变化可以用正态分布函数来表示; 霜害温度出现的累积概率随日序的变化可以用指数方程表示。根据拔节期和霜害温度出现的规律, 建立了霜害的风险评估模式。给出了霜害风险度的地区分布, 并指出利用模式中的参数值可以判断几种防御措施的有效性。