湖北省巴东县桐木园山坡型泥石流的形成机理及预警指标——以2003—03—31强降雨过程为例   总被引：4，自引：0，他引：4  

张永双  吴树仁赵越 何锋石菊松  罗菊英 《地质通报》2003,22(10):833-838

2003年3月31日，巴东县在连续强降雨作用下出现多处山体斜坡地质灾害，造成大量房屋破坏和人员伤亡。通过现场综合调查，笔者认为灾害比较严重的桐木园斜坡灾害体发球典型的山坡型泥石流，着重剖析了该山坡型泥石流的变形特征及其成灾机理，并探讨了斜坡浅表层松散岩土体快速变形的临界降雨阀值和预指标。  相似文献   

SrTiO3基钙钛矿结构X射线衍射谱特征     

刘粤惠  陈旭明 《矿物岩石》2003,23(4):58-62

通过对常规电子陶瓷工艺合成的Sr1-xCaxTiO3和Sr1-xPbxTiO3钙钛矿结构陶瓷进行研究X射线衍射谱特征、晶体结构和衍射强度I100/I110进行研究,并根据原子散射因子与衍射强度关系,提出用衍射强度I100/I110变化规律预测ABO3钙钛矿结构中置换A位离子种类的方法.  相似文献   

A media-based assessment of damage and ground motions from the january 26th, 2001<Emphasis Type="Italic">M</Emphasis> 7.6 Bhuj,India earthquake     

Susan E Hough  Stacey Martin  Roger Bilham  Gail M Atkinson 《Journal of Earth System Science》2003,112(3):353-373

We compiled available news and internet accounts of damage and other effects from the 26th January, 2001, Bhuj earthquake, and interpreted them to obtain modified Mercalli intensities at over 200 locations throughout the Indian subcontinent. These values are used to map the intensity distribution using a simple mathematical interpolation method. The maps reveal several interesting features. Within the Kachchh region, the most heavily damaged villages are concentrated towards the western edge of the inferred fault, consistent with western directivity. Significant sedimentinduced amplification is also suggested at a number of locations around the Gulf of Kachchh to the south of the epicenter. Away from the Kachchh region intensities were clearly amplified significantly in areas that are along rivers, within deltas, or on coastal alluvium such as mud flats and salt pans. In addition we use fault rupture parameters inferred from teleseismic data to predict shaking intensity at distances of 0–1000 km. We then convert the predicted hard rock ground motion parameters to MMI using a relationship (derived from internet-based intensity surveys) that assigns MMI based on the average effects in a region. The predicted MMIs are typically lower by 1–2 units than those estimated from news accounts. This discrepancy is generally consistent with the expected effect of sediment response, but it could also reflect other factors such as a tendency for media accounts to focus on the most dramatic damage, rather than the average effects. Our modeling results also suggest, however, that the Bhuj earthquake generated more high-frequency shaking than is expected for earthquakes of similar magnitude in California, and may therefore have been especially damaging.  相似文献   

无单元法在三维断裂力学中的应用   总被引：5，自引：1，他引：5  

胡云进  周维垣  林鹏 《岩土力学》2003,(Z2)

介绍了无单元法在三维断裂力学问题中的应用。无单元法基于滑动最小二乘拟合,只需结点信息就可建立离散模型。采用罚函数法来满足无单元法的本征边界条件。用可视准则来处理裂纹面对高斯点影响域的隔离作用,推导了裂纹两表面的相互作用对整体平衡方程组的贡献方程。利用单点位移公式来计算三维裂纹前缘点的应力强度因子。通过算例验证了应用该法确定三维裂纹前缘应力强度因子的有效性。  相似文献   

芙蓉矿田锡矿化强度垂直分布特征及其找矿意义   总被引：3，自引：0，他引：3  

刘东宏  田旭峰  陈民苏  许以明 《湖南地质》2002,21(2):115-118

引入矿化度的概念,=(矿体长度)·(平均厚度)·(平均品位),计(A)ALMC算并介绍了芙蓉矿田锡矿化强度的垂直分布特征,指出锡矿化集中分布在上、中、下个平台3(～、～、-～标高段),并对其在矿产资源量预测中的应用作了7001 300 m350700 m20350 m探讨,预测该矿田锡资源总量达×n102万t。  相似文献   

台风最大风速增强的数值研究   总被引：7，自引：3，他引：7  

周嘉陵  罗哲贤 《南京气象学院学报》2002,25(2):199-206

用一个高分辨率的正压模式，实施了8组时间积分为36h的试验，分析了中尺度涡旋和台风涡旋的相互作用及其对台风强度变化的影响，讨论了初始中尺度涡旋空间尺度大小与台风强度变化之间的联系。结果表明：在一定的合理的参数条件下，这种相互作用可以使台风切向风速量大值增加，显示出台风增强的现象。  相似文献   

The Arequipa (Peru) earthquake of June 23, 2001   总被引：1，自引：0，他引：1  

H. Tavera  E. Buforn  I. Bernal  Y. Antayhua  L. Vilacapoma 《Journal of Seismology》2002,6(2):279-283

The Arequipa earthquake of 23 June 2001 hasbeen the largest earthquake (Mw = 8.3)occurredin the last century in southern Peru with amaximum intensity of VIII (MM scale). Focalmechanisms of main shock and three largeraftershocks have been studied, showingthrusting solutions for main shock and twoaftershocks and normal motion for the eventof July, 5. The rupture area has beenobtained from distribution of aftershocks.The occurrence of the Arequipa earthquakeis related with the convergence processbetween the Nazca and South Americaplates.  相似文献   

Environmental hazards in Xinjiang Line of New Eurasian Continental Bridge     

陈亚宁  李卫红  杨思全  徐海量 《中国科学D辑(英文版)》2002,45(Z1)

Xinjiang Line of New Eurasian Continental Bridge is the important lifeline project inwestern China. Various disasters, such as flood, strong wind, sandstorm, and roadbed disasters,have been seriously affecting the railway transportation. The field investigation and analysis on thedata collected since 1959 show that: serious floods often occurred when the rain intensity reached25 mm/h or 30 mm/d; the critical wind speed for turning over a train is between 35 m/s and 67 m/s,and such cases happened in draught places of mountain opening and trunk valley; the angle be-tween wind direction and railway is closely related to the thickness of accumulative sand along thelines; roadbed disasters taking the form of side-slope sliding, roadbed sinking and silt turning uptook place in spring when the temperature rapidly rose to 10-15℃ from zero and precipitationcame forth or when the thickness of snow cover on shade slope reached above 20 cm in winter;the disasters taking place in the 1990s were far stronger than those of the 1980s and the order ofhazard intensity along the Xinjiang Line is Urumqi＞Shihezi＞Kuitun＞Liuyuan＞Shanhan＞Hami.  相似文献   

Measurements Of Thermal Updraft Intensity Over Complex Terrain Using American White Pelicans And A Simple Boundary-Layer Forecast Model     

Harlan D. Shannon  George S. Young  Michael A. Yates  Mark R. Fuller  William S. Seegar 《Boundary-Layer Meteorology》2002,104(2):167-199

An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of soaring American white pelicans and from diagnostic boundary-layer model-produced estimates of the boundary-layer depth z_i and the convective velocity scale w_*. Comparison of the flatland data with the profiles of normalized updraft velocity obtained from previous studies reveals that the pelican-derived measurements of thermal updraft intensity are in close agreement with those obtained using traditional research aircraft and large eddy simulation (LES) in the height range of 0.2 to 0.8 z_i. Given the success of this method, the profiles of thermal vertical velocity over the flatland and the nearby mountains are compared. This comparison shows that these profiles are statistically indistinguishable over this height range, indicating that the profile for thermal updraft intensity varies little over this sample of complex terrain. These observations support the findings of a recent LES study that explored the turbulent structure of the boundary layer using a range of terrain specifications. For terrain similar in scale to that encountered in this study, results of the LES suggest that the terrain caused less than an 11% variation in the standard deviation of vertical velocity.  相似文献   

地层水矿化度检测的地球物理测井方法   总被引：1，自引：1，他引：1  

赵发展  戚洪彬  王赟 《地球物理学进展》2002,17(3):551-558

传统的水文地质研究方法在进行地下水的矿化度评价时，是通过地层水的取样进行室内分析化验，确定含水岩组中地层水的矿化度，目前，在利用已有的地质、地球物理资料进行西部地下水资源评价的研究中，鉴于大多数石油井不含有浅层地层水的水样化验资料，因而本文介绍一种利用石油测井数据（主要为自然电位曲线）计算地层水矿化度的方法，并将之应用于鄂尔多斯白垩系自流水盆地地层水的矿化度估算，方法研究和应用实例证明这种方法是较为可靠的，虽然求取的地层水的矿化度的数值存在一定的误差，但完全可以满足地层水矿化度分级评价的需求，从而开发了石油测井数据在水文地质中的应用，也降低了单纯利用水文取样，由于样点少，矿化度预测精度低的缺点。  相似文献