白兰高速公路沿线黄土场地震陷区判定与评价

采用DSD-160型电磁式振动三轴试验系统,通过对甘肃白银-兰州高速公路(国道109线)沿线黄土的震陷试验,探讨了该场地黄土在动荷载作用下的震陷特性.利用黄土震陷灾害预测方法和该地区黄土场地地震危险性分析结果,对该公路沿线黄土场地的震陷区进行了判定和评价.这些研究结果可作为该高速公路工程进行抗震设计和地震变形分析的基本依据,对黄土地区其它工程也有一定的参考价值.     

Web上的GIS资源分析与典型网站介绍

Web上蕴藏着巨大的资源，有效地利用这些资源将会给我们的学习和工作带来很大的帮助。文中分析了目前Web上的GIS资源，介绍了典型的GIS网站及如何在网上搜寻GIS资源。     

Spectral sensitivity of ALOS,ASTER, IKONOS,LANDSAT and SPOT satellite imagery intended for the detection of archaeological crop marks

This study compares the spectral sensitivity of remotely sensed satellite images, used for the detection of archaeological remains. This comparison was based on the relative spectral response (RSR) Filters of each sensor. Spectral signatures profiles were obtained using the GER-1500 field spectroradiometer under clear sky conditions for eight different targets. These field spectral signature curves were simulated to ALOS, ASTER, IKONOS, Landsat 7-ETM+, Landsat 4-TM, Landsat 5-TM and SPOT 5. Red and near infrared (NIR) bandwidth reflectance were re-calculated to each one of these sensors using appropriate RSR Filters. Moreover, the normalised difference vegetation index (NDVI) and simple ratio (SR) vegetation profiles were analysed in order to evaluate their sensitivity to sensors spectral filters. The results have shown that IKONOS RSR filters can better distinguish buried archaeological remains as a result of difference in healthy and stress vegetation (approximately 1–8% difference in reflectance of the red and NIR band and nearly 0.07 to the NDVI profile). In comparison, all the other sensors showed similar results and sensitivities. This difference of IKONOS sensor might be a result of its spectral characteristics (bandwidths and RSR filters) since they are different from the rest of sensors compared in this study.     

基于自动搜索和光谱匹配技术的训练样本纯化算法

提出了一种基于局部自动搜索和光谱匹配技术的监督分类训练样本的纯化方法。该方法首先利用遥感影像中像元的灰度信息在图像上局部范围内自动搜索和选择最佳样区位置,然后利用光谱匹配的思想对寻找到的最佳样区在光谱空间上进一步纯化。实验结果证明,通过手工选择样区的辅助,该算法能够自动有效地搜寻到最佳样区的位置,并对最佳样区进行纯化处理。原始遥感图像经过本文的样区纯化算法处理后,无论是目视判读效果,还是分类后混淆矩阵的统计及分类精度,均优于纯化处理前的分类结果,具有一定的实用价值。     

硬场地实测记录下几种土层地震反应分析程序可靠性对比

以日本KiK-net强震观测台网中硬场地井下记录为样本,对传统等效线性化方法LSSRLI-1（频域）、SHAKE2000,时域非线性方法DEEPSOIL和频域一致等效线性化方法SOILQUAKE等几种计算程序在硬土场地地震反应分析中的可靠性进行对比检验。检验工况包括KiK-net井下台网中地表峰值加速度不小于0.05g的水平硬场地的总计344台次的加速度记录,涉及5个台站,土层厚度6~50m,地表峰值加速度范围0.050~0.805g。结果表明:认为硬土场地以往计算方法能够体现土层放大的认识是片面的,在中强地震动情况下,现有流行方法计算出的地表响应会偏小,强地震动下会严重偏小,会给工程抗震设计提供偏于危险的输入;硬场地中烈度8度以下（地表PGA在0.19g以下）,SHAKE2000和DEEPSOIL、LSSRLI-1（频域）计算结果与实际记录差距可以接受,但烈度8度以上,计算出地表响应均较实际记录明显偏小,且随地震动强度增加差距急剧增大;硬场地中,无论何种烈度,SOILQUAKE16计算的地表加速度响应与实测相当,可体现出土层放大作用。     

Evaluation of seismic displacement demands from the September 19, 2017 Puebla‐Morelos (Mw = 7.1) earthquake in Mexico City

This short communication presents the assessment of seismic inelastic and elastic displacement demands computed from earthquake ground motions (EQGMs) recorded in Mexico City during the intermediate‐depth intraslab Puebla‐Morelos earthquake on 19 September 2017 (Mw = 7.1). Evaluation is conducted by means of peak elastic and inelastic displacement demand spectra, inelastic displacement ratio, C_R, spectra, and generalized interstory drift spectra computed for selected recording stations located in different soil sites of Mexico City, including those located in areas of reported collapsed buildings. Results of this study confirm previous observations made from interplate (subduction) EQGMs that peak inelastic displacement demands are greater than corresponding elastic counterparts for short‐to‐medium period structures, while the opposite is true for medium‐to‐long period structures. Possible basin site effects were identified from generalized interstory drift spectra. It is also shown that an equation introduced in the literature to obtain estimates of C_R developed from interplate EQGMs provides also a good estimate for mean C_R computed from the intermediate‐depth intraslab EQGMs.     

山西襄汾大柴更新统剖面划分的新观点

对山西襄汾丁村文化遗址群内大柴剖面进行的磁性地层学研究表明,松山与布容的极性界线（M/B）出现在距剖面顶部45 m处;磁化率对比结果显示,此位置正好与S8上部对应.由这种极性和磁化率的对应结果可推断,下、中更新统（Q1/Q2）的地层分界也应在距剖面顶部45 m处的S8上部,而不是传统上认为的Q1/Q2的地层分界,在距剖面顶部80 m处.这种以古地磁学为基础的新的划分方案,对丁村遗址群的对比以及丁村遗址年代的最终确定都有重要的指示意义.根据其沉积环境和地层特征推断,采样部位下部的磁化率低值带应为水成黄土.而岩石磁学研究结果显示,磁铁矿、赤铁矿和热不稳定性磁赤铁矿是大柴剖面沉积物中主要的磁性矿物;磁铁矿和赤铁矿同为高温稳定性磁性载体.     

Preserving our in situ archaeological heritage: a challenge to the geochemical engineer

Empirical evidence has shown that industrialization and changes in agricultural practices have caused worldwide dramatic changes in the burial conditions of the archaeological remains. The current understanding of the problem, however, is not sufficiently advanced, which hinders adequate measures to prevent a tremendous loss of archaeological information. In the beginning of the nineties, research programmes were started to gain insight into the deterioration of different kinds of organic and inorganic components, representing a great variety of archaeomaterials. Knowledge of the present-day preservation condition of the remains will create the scientific basis for an environmental risk assessment of archaeological sites. It also will be the basis for developing strategies for the monitoring of a well-defined number of endangered sites. Such a monitoring system particularly is needed at places where geotechnical measures, like the local up-levelling of the soil and the creation of an artificially high ground water table, have been carried out to protect the archaeological heritage.     

匼河旧石器遗址6054和6056地点地层的再研究

发现于 195 7年的河遗址群的年代一直存在较大的争议。对河遗址群中两个代表性的遗址的地层进行了再研究 ,认为 60 5 4地点文化层位于黄土—古土壤序列中 S2 以下 ,而 60 5 6地点位于马兰黄土之下 ,二者的时代有较大的差别 ,60 5 4地点可能比 60 5 6地点时代要早。