Hazard mapping based on macroseismic data considering the influence of geological conditions

The object of this study is to consider directly the influence of regional geological conditions on the assessment of seismic hazard. It is assumed that macroseismic data at individual locations contain, in an average way, the influence of geological conditions.A Data Base referring to 199 historical (5) and instrumental (194, in the 1947–1993 period) events with macroseismic information in 1195 locations of Portugal was built. For any given seismic event, whenever macroseismic information was available at a location (town, village, etc.), an EMS-92 intensity value was estimated. To each one of those locations a geological unit, representing the most common type of soil, was assigned, based on the Geological Portuguese Map at a scale 1:500 000; the geological units were grouped into three categories: soft, intermediate and hard soils.The Data Base was used to determine the attenuation laws in terms of macroseismic intensity for the three different geological site conditions, using multiple linear regression analysis. The reasonability of the laws was tested by (i) checking residual distributions and (ii) comparing the map of isoseismals of important earthquakes with the isoseismals generated by the attenuation curves derived for each one of the three different soil classes, taking into consideration the soil class of each site. The main results of attenuation modeling are: high dispersion on macroseismic intensity data; all the models predict intensity values, for short hypocentral distances, lower than the ones observed; and for some important analyzed earthquakes and for the observed range of distances, the models confirm the expectancy that macroseismic intensity increases from hard to soft soil.The approach to obtain the hazard assessment at each location consisted in the use of the attenuation law specifically derived for the class of soil of that particular location. This method, which considers the influence of the regional geology, was illustrated with the mapping of hazard for the country for several return periods. Comparison with previous maps not taking into consideration the regional geological conditions emphasizes the importance of this new parameter. It can be concluded that (i) soil segmentation is clearly the cause for hazard increase in the region to the north of Lisbon, especially at sites with soft and intermediate soils as the ones in lower Tagus valley; the maximum increase on hazard is, in any case, less than one degree; (ii) when geological conditions are disregarded in the attenuation regression analysis, hazard pattern is similar to the one obtained for the case of hard soil everywhere.     

弹性波CT技术及应用

弹性波ＣＴ技术是一种新的物探方法。本文简单地介绍了该技术的方法原理及影响图像重建的因素，并以实例说明了弹性波ＣＴ技术在煤矿井下的应用效果     

煤矿采空区场地建筑适宜性工程地质研究方法

简述了煤矿采空区场地存在的工程地质问题；提出了查明采空区场地工程地质条件的现场勘察和室内模拟研究方法。并结合采空区活化特点，对采空区场地建筑适宜性作了分析；提出了地基处理和建筑物防护措施     

新疆布尔克斯岱金矿床含金矿物标型特征及其地质意义

对布尔克斯岱金矿床的主要含金矿物采用多种测试手段进行研究：如重砂、化学分析、Ｘ射线衍射分析、电子探针、ＥＰＲ谱、数学地质和包裹体分析等。对矿物特征及其与金矿化的关系作了较详细的研究。对确定矿床成因、找矿标志和成矿预测有一定意义。为矿床外围和深部找矿提供了依据。     

赣西北地区修水县联测图组1：5万区调主要进展与体会

本文重点总结赣西北地区修水县联测图１∶５万区调取得的主要进展与区调方法上的创新。其中，在中元古界双桥山群浅变质岩系中所识别、填绘出的近东西向紧闭同斜倒转褶皱，叠加近南北向开阔圆滑褶皱，在中小型陆相红盆中探索出的运用数理统计与沉积学研究相结合确定冲积扇体，并用扇体与岩性段双重方法予以图面表达以及第四纪研究成果等取得的重要进展。此外，就有关提高区调质量等问题浅谈其体会。     

贵州三都早奥陶世同高组下燕高页岩段的生物标志化合物

本文着重报道了贵州三都早奥陶世同高组下燕高页岩段生物标志化合物特征，首次在采自该层位的样品中检出丰富的正烷烃、链状类异戊二烯烷烃、萜类化合物及甾类化合物。测试结果显示:正烷烃图谱呈双驼峰形，碳数分布为ｎＣ_１５～ｎＣ_３５，以ｎＣ_１８为主峰碳，ｎＣ_２９为次主峰碳，Ｃ－_２１/Ｃ＋_２２为０.７７～１.０２，ＯＥＰ为０.９４～１.０４；植烷占优势，Ｐｒ/Ｐｈ为０.４０～０.４６；藿烷碳数为Ｃ_２７～Ｃ_３５，以Ｃ_３０占优势，Ｃ_２７＋Ｃ_２９＜Ｃ＋_３１；仅见碳数分布为Ｃ_２０～Ｃ_２９的长链三环二萜烷，以Ｃ_２８为主峰碳；甾烷丰度顺序为Ｃ_２９甾烷＞Ｃ_２７甾烷＞Ｃ_２８甾烷，同时检出了孕甾烷和４－甲基甾烷。生物标志化合物显示出还原环境特点，且可能主要来自藻类。     

Effects of geology and human activity on the dynamics of salt-water intrusion in three coastal aquifers in southern Spain

 Mathematical modelling of salt-water intrusion processes in three aquifers on the southern coast of Spain (Río Verde, Río Vélez and Castell de Ferro) reveals that, although all three systems are subject to the same climate and seasonal over-exploitation, geological and human factors have very different effects on the dynamics of contamination. In the Río Verde aquifer, the most important influence is the high volume of extractions occurring during the dry season; in Río Vélez, the intrusion is strongly controlled by infiltration of water from the river to the aquifer, and, in the Castell de Ferro system, an intensely karstified carbonate massif lying in contact with both the sea water and the detrital aquifer represents the main entrance point for influx of sea water and subsequent washing of the aquifer. We have undertaken a mathematical simulation of various possible measures to counteract intrusion, according to the specific characteristics of the process in each aquifer. These measures include artificial recharge, use of natural recharge from the river as a hydraulic barrier, and the construction of a low-permeability barrier. Received: 5 December 1995 · Accepted: 12 April 1996     

冀西北麻粒岩区早前寒武纪主要地质事件的年代格架

本文通过年代学资料和其它地质依据建立了冀西北及邻区麻粒岩地体早前寒武纪主要地质事件的年代格架。早期的基性火山喷发事件发生在2868—2932Ma期间,形成本区的早期地壳。在2761Ma左右发生了大规模的TTG岩浆侵位事件,在2650Ma时发生了基性岩浆侵位,使地壳加厚。在2561—2503Ma期间,花岗闪长质岩浆在本区广泛侵入,使地壳进一步加厚。2477—2461Ma期间,紫苏花岗岩以岩株形式侵入,同时发生区域麻粒岩相变质,早期地壳受到改造。大约在2300Ma时发生第二阶段的麻粒岩相变质。此后,在2144—2087Ma期间红色花岗岩侵位,形成花岗岩带。     

地史转折期的生态系

生态系的演变是地球各圈层系统耦合关系变化的直接标志。地史转折期的生态系具有复杂的生物内涵，在绝灭—残存—复苏过程中，各生物类别的演替遵循着一定的生存型式。大绝灭后生态系复苏的原动力是绝灭后迁入避难所的复活类型和大绝灭末期高压环境中产生的祖先类型的新生和辐射发展。全面了解绝灭后生态系的组成和结构，对于正确认识地史转折期，即圈层耦合结点处的地质作用型式和过程具有重要作用。     

胶东涧里金矿床地质特征及找矿方向

论述了涧里金矿区地质概况及矿床地质特征，对矿床成因进行了探讨，并在此基础一进行了臧放预测，提出了今后找矿方向