A geography of natural perils

Earthquakes, tropical cyclones and floods are the most important natural perils in terms of human deaths on a global basis. In Australia, at least 4300 deaths in the last 200 years have been produced by heatwaves; about 2000–2200 each by tropical cyclones and floods; and bushfires and lightning strikes have each killed at least 650 people. On a global basis it appears that floods, tropical storms, droughts and earthquakes are the most damaging natural perils. In Australia, in terms of median damage per event, hailstorms are the most expensive insured natural peril, while three events—the 1989 Newcastle earthquake, 1974's Cyclone Tracy, and the 1990 Sydney hailstorm—produced 36 per cent of the total insured damage in the period since 1967. The Newcastle earthquake and the Sydney hailstorm have provided opportunities for new understandings of these perils and their consequences. While much has been learnt from the devastation of Rabaul town by the 1994 eruption, a rare opportunity for a detailed study of building damage has been lost. Without detailed studies, risk rating, where Risk = Hazard (or peril) × Vulnerability, is difficult.     

中越边境分水岭自然保护区之土壤

中越边境分水岭自然保护区有五个土类,即:砖红壤性红壤、红壤、黄壤、黄棕壤、棕壤。它们按海拔由低到高,依次更替,山体的西南坡为迎风坡,东北坡为背风坡,各土类的界线前者比后者稍高。     

川藏公路通麦天险段山地灾害及其防治

本段是川藏公路有名的严重山地灾害段。近半个世纪来,十几年一遇的特大崩塌、泥石流、雪崩造成的生命、财产损失惨重,该段在雅鲁藏布江大拐弯峡谷顶端范围内,以上升为主的强烈构造活动,以大峡谷水汽通道进入水分、热量,是发生高频率高强度特大山地灾害的基础。结合当地实情,加强调查研究,划分各类灾害危险区段,提出防治措施。     

南沙群岛景观的类型和演化

南沙群岛景观分５种类型：礁丘热带海洋生物繁生景观，环礁带海洋生物繁生景观，灰沙岛热带常绿刮灌林磷积石灰土景观，大陆架热带海海海洋生物繁生景观，深海热带大洋性和深海性海洋生物景观，这５种景观归纳为两类，一类为热带海洋景观，包括浅海和深海；另一类为热带珊瑚礁景观，下分礁丘，环礁和灰沙岛３种，南沙群岛景观类型分布和演化与古地理和现代化环境条件有关。     

PGE和金的热液共生富集机制初探

本文初步探讨了热液条件下铂族元素和金共生富集的控制因素,包括配合物迁移形式和沉淀物理化学条件的相似性;此外,铂族元素和金的固溶作用、相对溶解度、源区特征、热液性质和活动历史也有不可忽视的影响。有关结论在一定程度上丰富和深化了对铂族元素热液成矿规律的认识。     

陕西地质自然历史遗迹及其特殊保护意义

在地球演化的漫长地质历史长河中，留下的珍贵的不可再生的地质自然遗产，是人类的宝贵财富，具有很高的科学研究价值。陕西地质遗迹丰富多样，应珍惜保护和进一步发掘、研究。     

The representation of geoscience information for data integration

In mineral exploration, resource assessment, or natural hazard assessment, many layers of geoscience maps such as lithology, structure, geophysics, geochemistry, hydrology, slope stability, mineral deposits, and preprocessed remotely sensed data can be used as evidence to delineate potential areas for further investigation. Today's PC-based data base management systems, statistical packages, spreadsheets, image processing systems, and geographical information systems provide almost unlimited capabilities of manipulating data. Generally such manipulations make a strategic separation of spatial and nonspatial attributes, which are conveniently linked in relational data bases. The first step in integration procedures usually consists of studying the individual charateristics of map features and interrelationships, and then representing them in numerical form (statistics) for finding the areas of high potential (or impact).Data representation is a transformation of our experience of the real world into a computational domain. As such, it must comply with models and rules to provide us with useful information. Quantitative representation of spatially distributed map patterns or phenomena plays a pivotal role in integration because it also determines the types of combination rules applied to them.Three representation methods—probability measures, Dempster-Shafer belief functions, and membership functions in fuzzy sets—and their corresponding estimation procedures are presented here with analyses of the implications and of the assumptions that are required in each approach to thematic mapping. Difficulties associated with the construction of probability measures, belief functions, and membership functions are also discussed; alternative procedures to overcome these difficulties are proposed. These proposed techniques are illustrated by using a simple, artificially constructed data set.     

苏州高岭土矿成矿期后的矿物演化及其与矿体改造的关系

苏州高岭土矿主要由高岭石、7埃洛石、10埃洛石及少量绢云母、蒙脱石、明矾石、三水铝石组成。高岭土矿物形成后因外界地化条件改变发生了以下转变:(1)埃洛石脱水向高岭石转化;(2)次生淋滤埃洛石形成;(3)埃洛石和三水铝石之间的互相转化;(4)Ca型蒙脱石形成;(5)高岭土的磷酸盐化作用;(6)次生淋滤明矾石的形成。矿物生成的先后顺序和共生关系可将矿物形成分为主要成矿期和成矿期后演化两个阶段。矿物的后期演化使优质高岭土进一步富集,改造,形成量大质优的高岭土矿。同时,非高岭土矿物的生成又使部分矿石质量变差,降低了矿石的工业价值。     

吉林省潜水地球化学分区及背景特征

本文以气候、地形地貌、含水介质等自然环境因素为分区原则,对吉林省潜水进行了水文地球化学分区,共划分4个区和13个亚区,并论述了各区的分布特点、水文地球化学及环境背景特征。