江西省夏季干旱特征分析

根据1951～2000年江西省降雨量、降雨日数、降雨变率等资料,统计和分析江西省夏季干旱期间降雨量、降雨日数、降雨变率等变化与地理分布客观特征.文章还对江西干旱标准、干旱指数与伏、秋干旱时空分布客观特征等进行分析.分析结果为江西人工增雨抗旱作业提供依据.     

藏东花岗岩类的时空分布、成因类型及构造环境

藏东花岗岩类的时空分布、成因类型及构造环境王增，申屠保涌，姚鹏（地矿部成都地质矿产研究所）一、藏东地区主要构造单元（自东至西）１．金沙江结合带北起玉树经埃拉山、巴塘、得荣，进入云南奔子栏，与哀牢山连接。本结合带内，金沙江沿岸一带，蛇绿混杂岩极为发育，...     

果梅北缘地区花期授粉、坐果与气象因素的关系

一、引言 太湖地区是我国果梅的主要产区之一,也是我国目前果梅分布的北缘地区。近年来随着我省丘陵山区综合开发的不断深入,以及国内外市场对果梅需求量的骤增,果梅栽培面积不断扩大,已由原来的太湖流域老产     

深地震反射剖面揭示的天津地区张渤带地壳精细结构

穿过天津地区张渤带的长86 km、NE向深地震反射剖面揭示了该区清晰的地壳精细结构图像和断裂的深浅构造特征,为研究张渤地震构造带的深部孕震环境和构造模式提供了地震学证据,对探讨晚中生代以来华北裂陷盆地的深部动力学过程及演化具有重要意义.结果表明,天津地区张渤带地壳以结晶基底反射T_G为界,分为上下两部分;上地壳反射波组丰富,分层特征明显,界面起伏形态清楚,清晰地刻画出冀中坳陷新生代沉积分层、箕状沉积凹陷的底界、潮白河断裂、蓟运河断裂及丰台—野鸡坨断裂的几何结构;地壳内部结晶基底（T_G）至Moho之间,显示出近于"反射透明"的地震波场特征,无明显震相,这与华北其他地区的深地震反射剖面结果明显不同;地壳厚度为30.0~34.5 km,总体变化趋势为中段地壳厚而南北端相对较薄,Moho在横向上显示出明显的不均匀和横向间断特征,在Moho被错断处存在两个明显的反射事件R_A和R_C,R_A可能是软流圈热物质上涌的侧向残留物,叠层状反射震相R_C则表现出壳幔过渡带特征;剖面揭示了2条错断Moho的超壳深大断裂（F_D1和F_D2）和9条上地壳断裂,深大断裂应是软流圈热物质上涌,造成上地幔隆起而形成的,上地壳断裂与地壳垂直运动及侧向引张力有关;超壳深断裂（F_D1和F_D2）为本区深部热物质的上涌与能量交换提供了通道,而与之对应的地壳浅部断裂（F₃和F₉）,则为能量调整提供了可能的条件,断裂邻近区域可能是未来发生强震的地区,值得注意.     

伽师强震群区震源细结构的深地震反射探测研究

穿过伽师强震群的深地震反射剖面提供了研究区从地表直至莫霍界面的地壳细结构图像.探测结果表明：研究区上、下地壳分界面埋深约20～30 km，莫霍界面埋深约52～58 km.上地壳内部存在着两种截然不同的反射图像.上地壳上部为沉积盖层，厚度约8～9 km，盖层内部反射成层分布，显示了稳定而连续的沉积特点；上地壳下部则为“反射透明”背景下存在的叠层状反射带.下地壳内部呈现明显的反射性质，具体体现在上、下地壳分界面和莫霍间断面都表现为具有一定持续时间的多循环反射叠层结构特征.时间剖面上所有反射事件由北东向南西下倾的整体图像直观地反映了塔里木盆地地壳变形而向西昆仑下插入的事实.剖面47km桩号附近，上地壳下部至壳幔过渡带以上地壳范围内存在一条高倾角的深断裂，具有走滑性质，本研究认为该深断裂与1997年伽师强震群的发生密切相关，推断它为伽师强震群的发震构造.而时间剖面上壳幔过渡带反射的连续性则说明该断裂没有向下穿过莫霍面.存在于上地壳上部的两条高倾角的浅部断层可能对应于地质推测的麦盖提—下苏洪断裂带，它们与位于其下方的地壳深断裂构成了伽师强震群可能的深、浅构造关系.     

Fine upper crustal structure of Jiashi strong earthquake swarm region in Xinjiang inferred from high resolution seismic refraction profile data

Introduction Jiashi-Artux area in southwest Xinjiang is one of the most active earthquake provinces at pre-sent in Chinese mainland. In the last century, about 3/4 strong earthquakes in Chinese mainland hit this area, and especially from January 21 to April 16 in 1997, 7 earthquakes with the magnituderanging from 6.0 to 6.9 occurred in a very small area of 9 km×18 km near Jiashi (ZHU et al, 1998). It has never taken place before in Chinese mainland that a series of strong earthquakes shoo…     

Joint processing and analysis of seismic gravity measurements in Capital Circle area

In Capital Circle area, there are three groups of repeated gravity measurements observed by different institutes using different instruments or methods. The simultaneous adjustment of absolute and relative measurements and the elimination of systematic error among the relative measurements have been carded out in this paper. Thus an unified temporal gravity change system with absolute reference has been established. On the basis of this, the crustal subsidence effect on gravity, which belongs to non-tectonic factor, is analyzed and the station displacement corrections are carried out, so that the long-wave disturbance is eliminated. So far our following aims are realized： the advantages of the absolute and relative measurement methods are complementary to each other; the contradiction and environment disturbance are eliminated; the amounts of information are enlarged; the sampling interval of time domain is compressed. In a word, the ability of identifying the tectonic activity process is enhanced. The results show that： there are systematic errors between the two groups of relative measurements and within the data of 10 campaigns ; the uneven local crustal subsidence in the southeast of the study area results in a linear rise of gravity value at 10 stations; they can be corrected by the regression analysis. The maps of revised temporal gravity change can obviously and integrally reflect the Ms=5.0 earthquake in Guye on October 6, 1995.     

俄罗斯海军重返大洋

在跨入2000年之际,俄罗斯海军总参谋长克拉夫琴科宣称,“海军是新世纪保障俄罗斯在世界大洋上民族利益的最重要工具之一,只有加强海军建设,才能提高在海洋方向的防御能力。俄罗斯海军不能老靠在岸边。”今年3月,俄罗斯军方正式宣布,俄罗斯海军将向地中海派遣一支舰队,这支由重型巡洋舰、核潜艇等组成的舰队将定期在地中海执行任务。尔后,俄罗斯海军总司令库罗耶多夫说,以“库兹涅佐夫”号航空母舰为首的航空母舰编队今年将定期     

GENETIC DIVERSITY OF THE WILD AND REARED PSEUDOSCIAENA CROCEA

The genetic diversity of both wild and reared Pseudosciaena crocea (Richardson) col-lected from Guan-Jing-Yang in Ningde, China in May 1999 was investigated by random amplified poly-morphic DNA (RAPD) in the present study. The polymorphism and mean difference of the wild popula-tion as revealed by RAPD were 18.9% and 0.0960 respectively, and those of the reared stocks were rel-atively lower, with 16.7% in polymorphism and 0.0747 in mean difference. The genetic distance be-tween the two stocks was 0.0041. From the comprehensive investigation, the main reasons for the loss of genetic diversity were probably overilshing, small number of parents as broodstocks and the debatable arti-ficial ranching. Results from this study also showed that the large yellow croaker populations distributed along Fujian coastal waters including Guan-Jing-Yang still potentially wide genetic variability. It is sug-gested that genetic management and prevention should be scientifically conducted in order to maintain and improve the genetic diversity of the P. crocea population.