粉质黏土重塑试样在小应变条件下变形特征的试验   总被引：1，自引：0，他引：1  

张培森郭进军  陈绍杰 《岩矿测试》2007,26(3):248-250

采用具有高精密局部位移传感器的三轴测试系统，对粉质黏土重塑试样在小应变条件下应力应变关系和剪切模量的变化规律及其影响因素进行了试验，结果表明：即使在极小应变条件下（0.0008％≤｜εs｜≤0．0021％），应力应变关系也一直保持高度非线性；在小应变条件下粉质黏土具有很高的剪切模量，且在一个很小的应变范围内迅速衰减，最后趋于一定值；剪切模量与应力状态、应力历史以及当前的加卸载方向有关，当应力方向与历史应力方向一致时，其衰减速率较快。  相似文献   

ldquo;区域-时间-长度rdquo;算法中特征参数的估计及应用   总被引：2，自引：0，他引：2       下载免费PDF全文

荣代潞  李亚荣 《地震学报》2007,29(3):250-257

根据地震前震源及周围地区出现的空区的时空特征， 提出了一种估计ldquo;区域-时间-长度rdquo;算法中特征参数（特征距离和特征时间）的方法， 并介绍了2006年一些学者提出的用相关系数估计特征参数的方法. 用这两种方法研究了近年来发生在中国大陆西北和西南地区的4次中强地震前的地震活动异常特征. 结果表明， 本文提出的估计特征参数的方法是一种具有物理意义、 使用简单的方法， 对中国大陆西北和西南地区的4次中强震的应用都有较好的效果.   相似文献   

地图可视化系统中交互功能的图标设计     

张涛  游雄  徐云 《测绘学院学报》2007,(1)

图标是地图可视化系统中交互功能符号化的主要形式,图标设计是地图可视化系统符号设计的重要内容。通过对普通软件界面中图标类型的总结和常见问题的分析,认为能否最大限度地缩短认知距离是图标设计成败的关键。最后,提出了在地图可视化系统中进行图标设计时应采取的一些策略和方法,并给出了图标设计实现的一个实例。  相似文献   

Study on Inelastic Attenuation and Source Parameters of the Shidian Swarm in 2001     

Liu Lifang 《中国地震研究》2007,21(1):62-73

Based on horizontal-component digital seismograms recorded on 6 stations of the Yunnan Regional Digital Network, we inversed the inelastic attenuation in the source region of the Shidian swarm using the Atkinson method and the site responses of the 6 stations 200km around the Shidian epicenters using the Moya method. The observational seismic waveform data were corrected by removing the propagation, instrument and site effects before the source parameters of the Shidian swarm in 2001 were determined using genetic algorithms. The results are as follows: (1) There is a linear relation between seismic moment and local magnitude. The seismic moment is between 1×10~ 12 and 10~ 14 N·m. The rupture radius of the seismic focus varies from 157m to 973m. The seismic moment and the rupture radius maintain a linear correlation. (2) The corner frequency increases as the seismic moment decreases. Based on the expression between corner frequency and seismic moment using least squares fitting, we can obtain the estimated value of the corner frequency. The time-varying value of the calculated corner frequency minus the estimated corner frequency shows that there were continuous high and low anomalies before the strong aftershocks. (3) The seismic stress drop is in the range of 0.07～1.55MPa. The stress drop seems independent of the local magnitude. The variation of stress drops is high before the occurrence of the strong aftershocks. (4) The depth of aftershocks is mostly in a range from 5km to 10km, which means that energy release of aftershocks is mainly concentrated in this range of depth.  相似文献   

Estimation of characteristic parameters m region-time-length algorithm and its application     

荣代潞  李亚荣 《地震学报(英文版)》2007,20(3):265-272

On the basis of gap＇s temporal-spatial characteristics in and around source area before an earthquake, we propose a method to estimate characteristic parameters （characteristic distance and time） in the region-time-length （RTL） algorithm and introduce the method of correlation coefficient developed by some authors in 2006 to determine the characteristic parameters. The anomalous seismic activities before four moderately strong earthquakes occurred in the northwestern and southwestern China in recent years are studied by the two methods. The results show that the method to estimate characteristic parameters advanced in this paper is a simple one, which possesses a physical meaning and is well applicable to the four moderately strong earthquakes studied.  相似文献   

An inversion of site response and Lg attenuation using Lg waveform   总被引：1，自引：0，他引：1  

朱新运  陈运泰 《地震学报(英文版)》2007,20(6):605-616

Based on spectral ratio method, a joint inversion method was used to obtain parameters of Lg wave attenuation and site response. The inversion method allows simple and direct (two-parameter) determination of Lg wave attenua- tion and site response from sparse spectral data, which are not affected by radiation pattern factor and different response of same instrument after geometrical spreading. The method was used successfully for estimating site re- sponse of stations of Zhejiang Seismic Network and measuring Lg wave attenuation. The study is based on 20 earth- quakes occurred in northeast of Taiwan with magnitude MS5.0~6.7 and 960 seismic wave records from 16 stations in Zhejiang area from 2002 to 2005. The parameters of site response and Lg attenuation were calculated with a fre- quency interval of 0.2 Hz in the range of 0.5 Hz to 10 Hz. Lg wave attenuation coefficient corresponding to U-D, E-W and N-S components are γ ( f )=0.00175 f 0.43485, γ ( f )=0.00145f 0.48467 and γ ( f )=0.0021f 0.41241, respectively. It is found that the site response is component-independent. It is also found that the site response of QIY station is significant above the frequency of 1.5 Hz, and that the site response of NIB station is low for most frequency  相似文献   

祁连山中东段地区非弹性衰减系数、震源参数和场地响应研究          下载免费PDF全文

郭晓  张元生  莘海亮  张辉 《地震工程学报》2007,29(4):319-325

利用甘肃数字地震台网的波形记录,基于遗传算法,首先用Atkinson方法计算非弹性衰减系数,在此基础上用Moya方法同时反演震源参数和场地响应。反演结果表明,祁连山中东段地区非弹性衰减Q值与频率的关系为:Q(f)=687.9f0.460;除了湟源台(HYQ)外,其余台站的场地响应均有不同程度的放大效应;研究区地震的应力降范围为2~40 bar,优势分布在2~20 bar;震源参数拐角频率与地震矩、地震矩与震级之间存在依赖关系。  相似文献   

伽师-巴楚地区中强地震加速度衰减关系研究   总被引：2，自引：0，他引：2       下载免费PDF全文

唐丽华  李锰  王海涛 《地震工程学报》2007,29(4):377-379,384

采用直接估计经验方法对巴楚-伽师地区1996-2003年126条M≥4地震的加速度记录进行回归分析,得到中强地震在土层场地上的水平向和垂直向加速度衰减规律。其中水平向加速度衰减关系适用的震级范围为4.0≤M≤6.9,垂直向为4.0≤M≤5.9。  相似文献   

利用M_L振幅研究地壳横波Q值I: 不同构造区的衰减特征   总被引：3，自引：2，他引：3       下载免费PDF全文

汪素云  裴顺平  许忠淮  张国民  俞言祥  潘华 《地球物理学报》2007,50(6):1740-1747

本文利用《中国地震年报》中测定震级M_L时所用的区域地震图中水平向的最大振幅及周期资料，研究了地壳内横波的衰减及介质品质因子Q₀特征. 结果表明，中国整个区域平均的Q₀值为367，以华南地台最高，为460，塔里木盆地为442，鄂尔多斯高原为419，华北地区最低，为294，其次是川滇地区为295. 由这个结果可知，Q₀与地质构造之间存在明显的相关特征，在构造上稳定的克拉通地台，如塔里木盆地、鄂尔多斯高原、华南地台等具有较高的Q₀值；而构造上活动的强烈剪切变形带和新生代扩张盆地，如川滇地区和华北断陷盆地往往是Q₀值低的地区，这和Pn速度分布特征也很相似，在Pn速度高的地区地壳Q₀值亦高，在Pn速度低的地区Q₀值亦低.  相似文献   

冰雹云提前识别及预警的研究   总被引：14，自引：2，他引：14  

李金辉  樊鹏 《南京气象学院学报》2007,30(1):114-119

利用雷达强回波45 dBZ高度和降雹日08时月平均零度层高度,对1991-2003年宝鸡雷达站观测的165 d 231块对流云数值拟合,得出了识别冰雹云的指标:处于发展中的对流云,雷达强回波45 dBZ高度大于或等于多年降雹日08时零度层月平均值的2.9 km,将有冰雹酝酿形成.对降雹造成灾害的雷达回波分析表明:雷达强回波的45 dBZ平均底部越高、提前识别的时间越长,顶部越高距离降雹时间越短,冰雹的形成是雷达强回波从云体的中部开始向上下扩展而成.该识别冰雹云方法对单体降雹平均提前识别12 min,而对超级单体平均提前识别18 min,对多单体、飑线中超级单体的降雹具有提前预警的作用,平均提前预警时间22 min.  相似文献