利用GDI 增强地图的显示效果

随着地图制图数字化的发展,计算机中地图的美学艺术性越来越受到重视。分析了GDI 及其新特性,提出了采用GDI 技术开发GIS地图可视化组件,从5个方面举例说明和实现了利用GDI 增强地图显示效果的方法,并通过比较和实验得出了美观的效果图。     

大跨度钢桁架转换结构振动台试验研究

以某带高位大跨钢桁架转换结构高层建筑为工程背景,进行了1/25缩尺比例的模型振动台试验,通过粘贴在钢桁架杆件上的应变片,测试了输入不同加速度峰值地震波作用下钢桁架的地震响应。在加速度峰值0.9g地震波作用下,两端支承钢桁架筒体剪力墙才出现裂缝,表明连接部位剪力墙受力性能较好;人工波作用下结构的地震响应最大,层地震作用力在钢桁架转换结构层有突变;试验中随模型结构裂缝发展和抗侧刚度衰减,层地震作用力分布发生变化,其中钢桁架转换结构层承担地震力相对减小,钢桁架应变反应也相对趋缓;钢桁架两端杆件受力较大,表明支承剪力墙对钢桁架的约束作用较大。     

Intercalibration of international and domestic ~(40)Ar/~(39)Ar dating standards

40Ar/39Ar method is a high precision dating means, of which the age is obtained by contrasting the un- known sample with those of standards. Usually the age of standard is determined by K-Ar method in which the 38Ar spike should be added for measurement. However, the absolute concentration of 38Ar spike is measured through the calibrated standards in turn, al- though occasionally the concentration of 38Ar spike is determined by other dating methods, such as Rb-Sr, U-Pb methods, which is kn…     

Variations of <Emphasis Type="Italic">δ</Emphasis><Superscript>18</Superscript>O in precipitation from the Muztagata Glacier,East Pamirs

Expeditions to Muztagata (in the eastern Pamirs) during the summer seasons of 2002 and 2003 collected precipitation samples and measured their oxygen isotopes. The δ ¹⁸O in precipitation displays a wide range, varying from −17.40‰ to +1.33‰ in June-September 2002 and from −22.31‰ to +4.59‰ in May-August 2003. The δ ¹⁸O in precipitation correlates with the initial temperature of precipitation during the observing periods. The positive correlation between δ ¹⁸O and temperature suggests that δ ¹⁸O can be used as an indicator of temperature in this region. The δ ¹⁸O values in fresh-snow samples collected from two snow events at different elevations on the Muztagata Glacier show a strong “altitude effect”, with a ratio of nearly −0.40% per 100 m from 5500 m to 7450 m.     

Variations of near-surface atmospheric CO2 and H2O concentrations during summer on Muztagata

Expeditions during the summers of 2002 and 2003 implemented continuous monitoring of near-surface (2 m height) atmospheric CO₂ and H₂O concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO₂ concentrations (of about 5 μmol·mol^-1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO₂ concentrations occur between 02:30-05:30 AM (local time) and the minimum levels occur between 12:00-15:30 PM. The atmospheric CO₂ concentrations in the summer of 2002 were around 5 μmol·mol^-1 lower than those during the same period of 2003, whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H₂O content in 2003 was much lower than that in 2002 and there exists a striking negative correlation between CO₂ and H₂O concentrations. We therefore suggest that the near-surface atmospheric CO₂ concentration is affected not only by photosynthesis and respiration, but also by the air H₂O content in the glaciated region around Muztagata.     

Relationships between δ18O in summer precipitation and temperature and moisture trajectories at Muztagata, western China

Based on summer observations of stable isotope of precipitation at Muztagata, western China, during 2002―2003, this paper presents the relationship between δ18O in precipitation and air temperature, and discusses the effect of moisture transport on δ18O in precipitation. Results show that air temperature correlates positively with δ18O in precipitation, and the temperature effect controls the δ18O of precipitation in this area. The Muztagata region exhibits high δ18O values in summer precipitation, similar to those shown at stations in adjacent regions. According to the results of our model set up to trace the moisture trajectories, the westerlies and local moisture circulation contribute to variations of oxygen isotopes in precipitation. In addition, the impacts of the moisture transport distance, the moisture transport level, and the incursion of the polar air mass also influence the variations of δ18O in precipitation. The moisture origins and transport mechanisms also contribute to the variation of δ18O in precipitation at Muztagata.     

山西洪洞ML5.0地震前后临潼台流体异常特征

采用滤波、拟合、去周期、五日均值等方法,对临潼台水氡、水温、水溶气资料进行了分析处理,得到以下认识:用提取异常方法对原始曲线进行处理后,地震前兆异常更加明显与突出,这些异常均属于短期和临震前兆异常;临潼台流体对2003年山西洪洞ML5.0地震有明显反映,其原因一方面由于此次地震距临潼台较近,另一方面也反映了临潼台所处构造位置比较特殊,位于映震的灵敏位置。     

利用多元地震属性预测测井特性

通过寻找井旁地震数据与测井曲线的关系,将这一关系应用到远离井的区域(只有地质数据,但无测井)来预测测井的有关特性,其方法有单属性分析和多属性分析[1]。本文通过实例描述了多属性分析的特点及预测结果。从单属性回归到多属性预测、再到神经网络预测过渡时,预测能力持续提高。同时对地震属性的选择和有效性进行了讨论,将结果应用到整个二维地震剖面上,能更好地确定井以外区域的测井特性。     

浅谈地震科技档案的归档管理

叙述了地震科技档案的重要性,针对当前地震科技档案归档工作中存在的制度不健全、档案原始件归档难等问题,提出了全面提高档案意识、领导重视、全员参与、及时归档等几点建议,以避免档案流失,做到资源共享,使科技档案更好地服务于防震减灾事业。     

鲜水河断裂带北西段不同破裂源强震震级（M≥67）及复发间隔研究

鲜水河断裂带是四川西部一条晚第四纪强烈左旋走滑活动的构造带，历史上发生多次强震. 它与西北侧的甘孜—玉树断裂带一起，构成青藏高原东部的侧向滑移构造系统中的川滇活动地块的北边界——羌塘地块的东北边界. 鲜水河断裂带北西段可以分成4个段落，每一段落均可作为一个独立的基本破裂单元而发生地震破裂，亦有可能发生不同尺度的多段联合瞧裂. 对鲜水河断裂带北西段不同尺度破裂的震级及复发间隔进行研究. 根据该地区的地质、地球物理、测量及地震等方面的资料，结合我国强震复发的特点，分析了拉分盆地内部的滑动速率分布，以确定各段落的等效长度和倾向宽度，从而建立适合我国大陆走滑断裂的面波震级与断裂发震面积的关系式；进而运用地震矩方法，考虑断层之间的相互作用，结合专家意见建立了该段的矩平衡断裂破裂模型；最后，给出了鲜水河断裂带北西段各破裂源特征化地震的复发间隔、震级大小和不确定性，以及他与中小地震的联合震级分布. 结果表明，鲜水河断裂带北西段较易发生单段破裂，复发间隔在100～150年左右.