岫岩-海城5.4级地震前小震震源机制解与记录特征分析

采用Pn、Pg初始波初动符号，利用乌尔夫网上半球投影，用作图方法求解了岫岩－海城震区（1999年1月－1999年11月29日）主震前辽宁数字地震台网记录（ML≥2.5)的41个小震的震源机制参数。结合前震记录的某些特征，对主震前应力方向的时空变化，震源错动性质进行分析和讨论。     

Study of crustal structure with S—wave data from Maqen—Jingbian profile

2-D crustal velocity structure and vp/vs are obtained by processing and interpretation of S-wave data from Maqen-Jingbian deep seismic sounding(DSS)profile.The result shows that there exist obvious differences in 2-D S-wave velocity structure and vp/vs ratio structure along the profile.The S-wave velocities are low and vp/vs ration is high for the westem section of the profile and Haiyuan region,while they are normal for the middle and eastern sections.The changes in lithologic characters of two major anomalous zones are discussed according to lateral variation of S-wave velocity structure and vp/vs ratio structure.It is concluded that the development and occurrence of the Haiyuan strong earthquake is not only related to tectonic activities,but also to lithologic characters of the region.     

略阳煎茶岭铜镍硫化物矿床Re—Os同位素年龄及其地质意义

采用矿石Re-Os同位素方法对陕西省煎茶岭硫化镍矿床矿石进行了成矿年代学研究,获得了878士27 Ma(1σ)的等时线年龄,首次厘定了该矿床成矿时代为新元古代,成岩成矿基本同时.通过对878 Ma硫化镍矿石初始Re-Os同位素体系的γOs计算和Re/Os值分析表明,其yOs和Re/Os值变化范围大,深部条带状矿石的Re/Os值仅为0.05,yOs为-6.70;块状矿石的Re/Os值范围为4.24～24.43,γOs为-15.37～+280.65,说明成矿过程中有壳源物质的混染;两件样品的γOs为负值(-15.37,-6.70),可能指示其超镁铁质岩浆来源于Re亏损地幔.煎茶岭超基性岩体年龄及其镍矿石的Re-Os等时线年龄与扬子克拉通北缘火山岩浆活动时间相对应,它们是扬子克拉通西北缘晋宁期构造岩浆成矿作用的产物.     

GPS RTK测量技术的应用与体会

GPS RTK测量技术以快捷、精准的特点广泛地被测量人员所接受，但是在到量中仍存在一些问题需要研究。本文介绍了几种经常遇到的棘手问题及其解决方法。     

Geological outline of the Alps

The Alps were developed from the Cretaceous onwards by subduction of a Mesozoic ocean and collision between the Adriatic (Austroalpine-Southalpine) and European (Penninic-Helvetic) continental margins.The Austroalpine-Penninic wedge is the core of the collisional belt, a fossil subduction complex which floats on the European lower plate. It consists of continental and minor oceanic nappes and is marked by a blueschist-to-eclogite-facies imprint of Cretaceous-Eocene age, followed by a Barrovian overprint. The collisional wedge was later accreted by the Helvetic basement and cover units and indented by the Southalpine lithosphere, which in turn was deformed as an antithetic fold-and-thrust belt.     

对几种1980系简捷坐标换带程序计算结果的分析

对几种计算简捷而精度又较高的1980系坐标换带计算程序分别进行一定数量的试算，现将试算、分析、比较情况介绍给同行们，供工作中参考。     

影响惠州的一次寒露风过程

1992年9－10月，由于冷空气不断爆发南下，致使各地先后出现降温。10月4日和11日冷空气两次南侵本省，副高明显减弱，加上空气干燥并伴有3级以上的偏北风，我市从12日开始出现了长达9天的干冷型寒露风天气过程，对晚稻的抽穗扬花有严重影响。本文对这次寒露风天气过程进行分析。1寒露风过程的冷空气活动1992年10月份内，共有3次冷空气活动，分别出现在上旬中期、中旬前期和下旬前期。就强度而言，除上旬中期的冷空气活动达到了中等强度以外，其余2次均为弱冷空气。1．1上旬中期的冷空气过程上旬中期的冷空气活动主要影响我国北部和东部地区…     

甘孜州早晚霜冻的分析与预报

8、9月的早霜冻和5、6月的晚霜冻是高原主要气象灾害之一，常造成大面积粮食减产。它们的形成形成要经过降水降温、平流降温和辐射降温三过程，以辐射降温为主。青藏高压是高原霜冻形成的主要天气系统，其次是强西北气流。白天温度较低、湿度小和晴朗的夜间最容易出现霜冻，应用这三要素建立了预报方法。