Landslide susceptibility analysis using GIS and artificial neural network     

Saro Lee  Joo‐Hyung Ryu  Kyungduck Min  Joong‐Sun Won 《地球表面变化过程与地形》2003,28(12):1361-1376

The purpose of this study is to develop landslide susceptibility analysis techniques using an arti?cial neural network and to apply the newly developed techniques to the study area of Yongin in Korea. Landslide locations were identi?ed in the study area from interpretation of aerial photographs, ?eld survey data, and a spatial database of the topography, soil type and timber cover. The landslide‐related factors (slope, curvature, soil texture, soil drainage, soil effective thickness, timber age, and timber diameter) were extracted from the spatial database. Using those factors, landslide susceptibility was analysed by arti?cial neural network methods. The landslide susceptibility index was calculated by the back‐propagation method, which is a type of arti?cial neural network method, and the susceptibility map was made with a geographic information system (GIS) program. The results of the landslide susceptibility analysis were veri?ed using landslide location data. The validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide location. A GIS was used to ef?ciently analyse the vast amount of data, and an arti?cial neural network to be an effective tool to maintain precision and accuracy. The results can be used to reduce hazards associated with landslides and to plan land use and construction. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

A procedure for evaluating seismic energy demand of framed structures     

Chung‐Che Chou  Chia‐Ming Uang 《地震工程与结构动力学》2003,32(2):229-244

Energy serves as an alternative index to response quantities like force or displacement to include the duration‐related seismic damage effect. A procedure to evaluate the absorbed energy in a multistorey frame from energy spectra was developed. For low‐ to medium‐rise frames, it required a static pushover analysis of the structure to determine the modal yield force and ductility factor of an equivalent single‐degree‐of‐freedom system for the first two modes. The energy spectra were then used to determine the energy contribution of each mode. A procedure was also developed to distribute the energy along the frame height based on energy shapes. This study showed that the second‐mode response in some cases needs to be considered to reflect the energy (or damage) concentration in the upper floors. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

System identification of the Vincent Thomas suspension bridge using earthquake records     

Andrew W. Smyth  Jin‐Song Pei  Sami F. Masri 《地震工程与结构动力学》2003,32(3):339-367

The Vincent Thomas Bridge in the Los Angeles metropolitan area, is a critical artery for commercial traffic flow in and out of the Los Angeles Harbor, and is at risk in the seismically active Southern California region, particularly because it straddles the Palos Verdes fault zone. A combination of linear and non‐linear system identification techniques is employed to obtain a complete reduced‐order, multi‐input–multi‐output (MIMO) dynamic model of the Vincent Thomas Bridge based on the dynamic response of the structure to the 1987 Whittier and 1994 Northridge earthquakes. Starting with the available acceleration measurements (which consists of 15 accelerometers on the bridge structure and 10 accelerometers at various locations on its base), an efficient least‐squares‐based time‐domain identification procedure is applied to the data set to develop a reduced‐order, equivalent linear, multi‐degree‐of‐freedom model. Although not the main focus of this study, the linear system identification method is also combined with a non‐parametric identification technique, to generate a reduced‐order non‐linear mathematical model suitable for use in subsequent studies to predict, with good fidelity, the total response of the bridge under arbitrary dynamic environments. Results of this study yield measurements of the equivalent linear modal properties (frequencies, mode shapes and non‐proportional damping) as well as quantitative measures of the extent and nature of non‐linear interaction forces arising from strong ground shaking. It is shown that, for the particular subset of observations used in the identification procedure, the apparent non‐linearities in the system restoring forces are quite significant, and they contribute substantially to the improved fidelity of the model. Also shown is the potential of the identification technique under discussion to detect slight changes in the structure's influence coefficients, which may be indicators of damage and degradation in the structure being monitored. Difficulties associated with accurately estimating damping for lightly damped long‐span structures from their earthquake response are discussed. The technical issues raised in this paper indicate the need for added spatial resolution in sensor instrumentation to obtain identified mathematical models of structural systems with the broadest range of validity. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

全站仪机载导线测量程序开发研究   总被引：2，自引：0，他引：2  

许承权  邹进贵  倪涵  王永弟  陈伟 《测绘信息与工程》2003,28(6):11-13

介绍了全站仪机载程序开发的重要性和必要性，基于Leica公司TPS1000／1100系列全站仪机载程序开发工具——GeoBASIC，阐述了机载导线测量程序开发的技术关键，所开发的程序达到了预期的效果，满足了用户的需求。  相似文献   

VLBI观测的电离层延迟改正模型研究   总被引：2，自引：1，他引：2  

张捍卫  盘关松等 《测绘学院学报》2003,20(1):14-17,21

电离层是大气层中的一个电离区域，高度范围大约在60－1000km。电磁波信号穿越电离层时其传播速度会发生变化，传播路径也会略微发生弯曲，从而使信号的传播时间乘以在真空中的光速不等于信号源至测站的几何距离。对VLBI观测来讲，电离层引起的差异可达近百米百米。文中从电磁波的传播原理出发，讨论了信号传播速度和传播路径变化引起的VLBI观测延迟；对目前采用的各种电离层延迟模型进行了分析总结；并指出单频率VLBI观测应顾及高阶项和路径弯曲的影响或使用区域性电离层延迟改正模型。  相似文献   

松潘-甘孜造山带地壳速度结构   总被引：64，自引：7，他引：64       下载免费PDF全文

王椿镛  韩渭宾  吴建平  楼海  白志明 《地震学报》2003,25(3):229-241

位于川西地区的奔子栏——唐克深地震测深剖面以NNE走向穿越松潘——甘孜造山带．根据人工地震记录分析得到的震相走时和相关的振幅信息，确定了该剖面二维P波地壳速度结构．剖面的地壳结构可分为5层，其中第1，2，3层为上地壳；第4，5层为下地壳．上地壳中部普遍存在低速异常带，但龙日坝以北，这一低速带与其上覆的低速基底合为一体．同时，沿剖面的地壳速度结构具有较强的横向变化．据此，可将剖面分为4段，即甘孜——理塘断裂以南、甘孜——理塘断裂至鲜水河断裂、鲜水河断裂至龙日坝断裂和龙日坝断裂以北. 这与区域构造划分基本一致． 地壳厚度沿测线从南西向北东逐渐减薄，即从金沙江畔的62 km减小到黄河附近的52 km． 根据PmP震相分析，莫霍界面深度在鲜水河断裂两侧没有明显变化．全剖面的地壳平均速度较低，为6.30 km/s．奔子栏——唐克剖面揭示了该地区的造山带型地壳上地幔结构特征．鲜水河断裂带位于剖面的中部，该地区的上地壳速度为正异常，而下地壳和上地幔顶部存在负异常．笔者认为，这是一类有利于强震孕育和发生的深部构造环境．   相似文献   

Vertical Ozone Profile over Tibet Using Sage I and II Data   总被引：8，自引：0，他引：8  

Zou Han  Gao Yongqi 《大气科学进展》1997,14(4):505-512

ＶｅｒｔｉｃａｌＯｚｏｎｅＰｒｏｆｉｌｅｏｖｅｒＴｉｂｅｔＵｓｉｎｇＳａｇｅＩａｎｄＩＤａｔａ①ＺｏｕＨａｎ（邹捍）ａｎｄＧａｏＹｏｎｇｑｉ（郜永祺）ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙｓｉｃｓ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅ...  相似文献   

用NOAA卫星监测甘肃森林草原火灾     

杨兰芳  韩涛 《干旱气象》1997,(2)

本文介绍利用ＮＯＡＡ极轨气象卫星ＡＶＨＲＲ资料监测森林草原火点的原理和方法。对甘肃省１９９２年１０月至１９９６年１２月监测到的火点进行时空统计，分析了火灾监测中可能产生的误差原因，并提出相应改进措施。  相似文献   

地震能量空间分布局域标度特性中短期预报方法及效能评价——实际震例的回顾性检验   总被引：1，自引：1，他引：1  

蒋海昆  王忠民  陶九庆  刁守中  韩加法 《地震研究》1997,(2)

利用中国大陆丰富的地震记录，对表征地震能量空间分布局域标度特性的各参量〔１〕及其组合进行系统研究，提炼具有可操作性、能够用于日常地震监测预报的实用方法，特别着重于“异常”划分方式及划分标准的研究。这一划分方式及划分标准对不同地区或不同时段均是“动态”可变的，对所研究的１０个区域内发生的中强地震进行回顾性的预报检验，发现对于较短时期（０．５－１．５年），其最大预报评分的平均值介于０．３—０．６之间，明显高于随机应答的概率评分，表明多参数综合使用具有相对强的预报能力  相似文献   

应用神经网络建立加速度峰值衰减规律   总被引：2，自引：0，他引：2  

崔建文  温瑞智 《地震研究》1997,20(3):278-285

在假定了加速度峰值衰减规律的形式后，本采用人工神经网络拟合实际加速度峰值观测资料来求取方程中的待定系数。为加速神经网络的训练，本设计了基于ＢＰ学习算法的目标分段网络训练法。  相似文献