闽台铲状活动断裂

福建台湾大型铲状活动断裂系在深部(深5—100km)构成一系列向东倾斜、倾角为4°—10°的滑脱面,在近地表利用老断层的重新活动,形成NNE与NW向网格交叉的高角度断层。活动断裂系的地震能量释放主要集中在台湾东部。推断现代构造应力场的最大主压应力方向是NW—SE向,缓倾斜、向西撒开呈扇状特征。断裂系中各断裂的滑动速率不同,东大西小。     

区域航空γ能谱场地球化学解释及预测方法的探讨

本文以“铀矿区域评价准则”为依据,试用因子分析主成分比值法,铀对钍(钾)的区域相对场法和铀成矿有利指数法,对我国YW-10和YW-10B两个测区的区域航空γ能谱场进行了地球化学解释及预测方法的研究,与已知矿区660测区从宏观上做了对比分析,并研究了γ能谱参数在走向长270km,宽50—70km空间上的分布变化规律。研究结果表明,这些方法对了解成岩时原始铀的分布及后期铀的地球化学活动规律,估计成岩、成矿阶段铀源岩可能提供的生铀量,识别铀成矿有利地区是有用的。     

A steady state model of the Somali current

A steady state model of the Somali current including forcing by both the curl and the divergence of the wind stress is discussed. The model equations are linear, but the results presented are for the one nonlinear case. The grid resolution was 12 km in the zonal and 24 km in the meridional direction. The streamfunction and velocity potential of the current are presented for forcing by divergence and compared with a situation when only the curl is present. The results indicate that a two-gyre system appears in July, a representative month for the summer monsoon, only when divergence is included. Computations with available data indicate that the divergence is comparable in magnitude to the curl near the location of the Somali current. The model produces three other important features: (i) strong upwelling off the east coast of Africa, (ii) downwelling over central Arabian sea and (iii) a strong eastward current in the upper layer towards the interior of the Arabian sea near 12°N.     

Direct Measurement Of Shear Stress During Snow Saltation

Wind-tunnel experiments were carried out to measure the shear stressduring snow saltation. Shear stress acting on the snow surface, measured directly with a newly developed drag meter system, revealedthat the shear stress increased with the development ofsaltation. This result supports Owen's hypothesis that the saltationlayer acts as an increased roughness to the flow above the saltationlayer, leading to an increase in surface shear stress. To investigate the contribution of the grain borne shear stress_g and the fluid shear stress _f to the increment of the total shear stress _total, _g was calculated from the loss of horizontal momentum of saltating snowparticles. Since _g is the largest contribution to theincrement of _total, the collision of thesaltating particles is dominant for the shear stressmodification. The results qualitatively support the numericalsimulation reported by McEwan and Willetts.     

论中国含油气区的构造环境性质、分区及其成油气专属性

在前中生代,形成了华北、扬子和塔里木等较大的海相及海陆交互相含油气区（盆地）,构造格架呈南北分异。经海西-印支运动,形成统一的中国大陆板块,且整体构造格架演变为东西分异。根据盆地结构、构造变形样式、岩浆活动、地温场、壳幔结构及壳幔连通程度等方面的特征,论述了中、新生代中国含油气区的大地构造环境性质与含油气特征。据此划分出 4个具有不同构造环境性质的含油气区：①东部裂谷伸展区,其西带为华夏裂谷系,以产下第三系和白垩系原油为主,东带为大陆架裂谷系,以产下第三系煤型气为主;②中部克拉通构造稳定区,以产古生界天然气为主;③西北构造反转区,含油气层系较多,油气成因类型也多样;④特提斯碰撞-走滑区,构造变形复杂,部分地区具有较好的油气资源前景。进一步讨论了油气形成的"构造环境专属性"问题。     

Rupture zones in the area of the 17.08.99 Izmit (NW Turkey) large earthquake (Mw 7.4) and stress changes caused by its generation

The M_w 7.4 Izmit earthquake of 17 August 1999 struck a part ofthe North Anatolian fault in the area of Izmit Bay (NW Turkey). Historicalinformation shows that the fault which moved during the generation of thisearthquake consists of two fault segments moved during the generation oflarge (M 7) earthquakes in 1719 and 1754, respectively. Since then onlythe central part (between Izmit and Lake Sapanca) of this fault ruptured bythe generation of a smaller shock (M = 6.6) in 1878.The spatial stress variations based on the calculation of changes in theCoulomb Failure Function (CFF) associated with this earthquake aresupported by the distribution of strong aftershock foci. Large positive valuesof CFF to the east and west of the mainshock epicenter are inagreement with the notion that secondary faults were triggered there by thegeneration of the main event. Large positive values of CFF are alsoobserved in the adjacent western fault segment where the 1766 event wasgenerated, evidencing the occurrence of the next strong earthquake in thissegment.     

璜山金矿找矿模式及应用

诸暨璜山金矿是除治岭头以外浙江省第二金矿,它的找矿模式为"三高两低一复合"的找矿模式,即高金晕、高极化率、高磁场跳跃、低电阻率、低电位和北东断裂与北东东断裂复合处是成矿最有利部位.在其附近仍有类似成矿部位,有望扩大远景.     

漫湾水库蓄水前后库区地震活动性与构造应力场分析

对漫湾水库蓄水诱发地震作了分析，结果表明，蓄水后库区小震频次明显增加，近距离地震明显增多，在蓄水首次达到高水位和由高水位突降至低水位时，诱发了最强地震。表明蓄水对库区构造应力场产生了影响，使得局部应力场较区域构造应力场作用方向出现明显偏转，作用方式发生改变，呈现较大的垂直作用效应，节面错动出现较大正倾滑动分量。     

双节点有限元模拟直立走滑断裂地震位移场

结合位错理论和有限单元法，对介质横向不均匀性引起的直立走滑断裂地震水平位移场不对称性进行了数值模拟研究。结果表明，断层两侧介质泊松比和弹性模量的横向不均匀性，均可以引起直立走滑断层同震破裂及地震位移场的不对称性，其中，断层两侧介质的剪切模量比(刚度比)对直立走滑断裂地震位移场不对称性起主要作用。     

Inverted-polarity electrical structures in thunderstorms in the Severe Thunderstorm Electrification and Precipitation Study (STEPS)

Balloon-borne electric field soundings and lightning mapping data have been analyzed for three of the storms that occurred in the Severe Thunderstorm Electrification and Precipitation Study field program in 2000 to determine if the storms had inverted-polarity electrical structures. The polarities of all or some of the vertically stacked charge regions in such storms are opposite to the polarities observed at comparable heights in normal storms. Analyses compared the charge structures inferred from electric field soundings in the storms with charges inferred from three-dimensional lightning mapping data. Charge structures were inferred from electric field profiles by combining the one-dimensional approximation of Gauss's law with additional information from three-dimensional patterns in the electric field vectors. The three different ways of inferring the charge structure in the storms were found to complement each other and to be consistent overall. Charge deposition by lightning possibly occurred and increased the charge complexity of one of the storms.Many of the cloud flashes in each case were inverted-polarity flashes. Two storms produced ground flash activity comprised predominantly of positive ground flashes. One storm, which was an isolated thunderstorm, produced inverted-polarity cloud flashes, but no flashes to ground. The positive and negative thunderstorm charge regions were found at altitudes where, respectively, negative and positive charge would be found in normal-polarity storms. Thus, we conclude that these storms had anomalous and inverted-polarity electrical structures. Collectively, these three cases (along with the limited cases in the refereed literature) provide additional evidence that thunderstorms can have inverted-polarity electrical structures.