吉林省南部下元古界集安群地质特征与沉积期古环境分析

根据集安群地质特征,岩石化学,稳定同位素特征分析认为:蚂蚁河组沉积期古环境为强氧化泻湖相;荒岔沟组沉积期为强还原的泻湖相、大东岔组沉积期为开阔正常浅海潮坪相。集安群从发生发展到结束古环境演化规律是:构造上,由优地槽向冒地槽演化,气候上由炎热向温湿演化;古地理环境从有障壁的局限海变为无障壁的开阔海;从咸化海向正常海,从泻湖相向潮坪相转化。     

滇西试验场重力潮汐观测及其地震响应特征的研究

本文使用Ｎａｋａｉ预处理、Ｖｅｎｅｄｉｋｏｖ调和分析和滑动滤波等方法，对滇西地震实验场下关台ＧＳ１５－２２７重力仪１９８７－１９９２年 观测资料进行了系统分析，，确定了该地区最佳重力潮汐参数及潮汐和非潮汐动态变化背景，并对观察期间的６个震例进行清理，分析了重力异常变化与地震的关系，获得了该地区重力潮汐和非潮汐信息的地震响应特征。     

印尼8.7级地震前银川台形变数字化观测资料短临异常特征分析

采用形变观测资料分析方法中比较常用的形态法、差分法、消除潮汐改正和零漂法，处理了银川台形变数字化观测资料，发现在印尼8．7级地震前出现了一些短临异常情况，并对异常的变化特征做了相应的分析。     

Statistical analysis of the temporal and spatial controls on tidal signal preservation in late-Holocene tidal rhythmites, Romney Marsh, Southeast England

A hierarchical series of tidal periodicities are preserved within laminated tidal flat deposits at the barrier/back-barrier interface of Romney Marsh and the Dungeness Foreland in southeast England. The sedimentary record of the tidal signature, extracted from variations in sand layer thickness, was found to be severely truncated with neap-spring periods typically represented by five or less sand layers and possibly only alternate neap-spring periods present. Despite the low number of sand layers deposited in these higher frequency tidal cycles, semi-annual periods are clearly preserved but tend to contain less than the expected 6 months of sedimentation. Annual accumulation rates of around 0.2–0.3 m/year are indicated. Local emplacement of storm beaches is considered to have created the protected conditions suitable for tidal rhythmite preservation. Ongoing foreland progradation and infilling eventually restricted tidal inundation to the point where distinct sand laminae were no longer deposited. Here, in contrast with other systems, accommodation space was not limiting and tidal flat elevation is reflected as a more subtle control on spatial changes in the resolution of the tidal signal.     

Surface current variability in the Keum River Estuary (South Korea) during summer 2002 as observed by high-frequency radar and coastal monitoring buoy

High-frequency (HF) radar observations of surface currents were conducted for 3 months during summer 2002 in the Keum River estuary. A comparison between HF radar-derived currents and directly measured ones form a buoy showed that the regression slope is close to 1 and the correlation coefficient greater than 0.86, with an RMS difference less than 13 cm/s which is less than 17% of the tidal current. This fairly good agreement allows us to use HF radar observation in investigating the surface flow and circulation in this tidal-current-dominant coastal-plume area. To examine the spatial variation in tidal current characteristics, as well as currents associated with non-tidal forcing, the HF radar-derived currents were separated into tidal and sub-tidal frequency currents. The overall pattern of M₂-current ellipse distribution in the study area showed a counterclockwise rotation, with the offshore maximum current direction to the northeast. Eccentricity, the direction of maximum current, and the phase of net motion of the ellipse changed near the estuary mouth and near the gap of the Saemangeum reclamation tide dyke due to the complex coastal geometry and the out-flowing jet during the ebb period.     

Tidal effects on estuarine circulation and outflow plume in the Chesapeake Bay

The response of the Chesapeake Bay to river discharge under the influence and absence of tide is simulated with a numerical model. Four numerical experiments are examined: (1) response to river discharge only; (2) response to river discharge plus an ambient coastal current along the shelf outside the bay; (3) response to river discharge and tidal forcing; and (4) response to river discharge, tidal forcing, and ambient coastal current. The general salinity distribution in the four cases is similar to observations inside the bay. Observed features, such as low salinity in the western side of the bay, are consistent in model results. Also, a typical estuarine circulation with seaward current in the upper layer and landward current in the lower layer is obtained in the four cases. The two cases without tide produce stronger subtidal currents than the cases with tide owing to greater frictional effects in the cases with tide. Differences in salinity distributions among the four cases appear mostly outside the bay in terms of the outflow plume structure. The two cases without tide produce an upstream (as in a Kelvin wave sense) or northward branch of the outflow plume, while the cases with tide produce an expected downstream or southward plume. Increased friction in the cases with tide changes the vertical structure of outflow at the entrance to the bay and induces large horizontal variations in the exchange flow. Consequently, the outflow from the bay is more influenced by the bottom than in the cases without tide. Therefore, a tendency for a bottom-advected plume appears in the cases with tide, rather than a surface-advected plume, which develops in the cases without tide. Further analysis shows that the tidal current favors a salt balance between the horizontal and vertical advection of salinity around the plume and hinders the upstream expansion of the plume outside the bay.     

强震成组活动与潮汐力调制触发

本文应用构造场体成组震模型的研究结果，探讨了中国大陆Ms≥7．0地震的成组活动的引潮力的调制触发关系。研究表明：我国陆区7级以上强震明显受潮汐力的调制触发，且主要表现为对活跃期内（即成组发生的）7级强震的调制触发。平静期内的7级以上地震基本不受潮汐力触发，而活跃期内82．4％的7级强震发生在受潮汐力触发的月相期，比本底概率高出36．4％。因此，潮汐力的调制触发对于强震活跃期的判断和活跃期内强震的临震（时间）预测有实际意义。文章还分析了潮汐力触发与强震活动的区域动力学环境之间的关系，并用构造场体成组孕震模型讨论了潮汐力对强震活动触发作用的力学机制。     

SEDIMENT TRANSPORT IN THE YANGTZE RIVER ESTUARY

SEDIMENT TRANSPORT IN TIIE YANGTZE RIVER ESTUARYSHEN Zhigang'ANSTa^CTThe hy~ntalc and the sedimen tranSport Patter'nS within the estUaIy of the YangtZe mver arecomPlex because of intemehon of fluvial and the hdal forCes, depending on freshwate discharge andhdal range. Based on the data measuIed in meent years, thes papo discusses the characterishcs of flowand sNnt movemen in the tw forer EstUaIy and their iIifluences on the evolution of theestuaryKey W: YangtZe mver…     

Group Strong Earthquakes and Triggering by Tidal Stress

The results obtained using the group model of earthquakes generated in tectonic blocks are fur ther used in this paper to analyze the relationship between the Ms ≥ 7.0 events in Chinese ma inland and the modulation and triggering from the earth tides. The research shows that the Ms 7.0 events in Chinese mainland have been significantly triggered by the tidal stress, especially within the active period with group strong earthquakes. In the quiescence period of strong earthquakes, no Ms7.0 events were triggered, while within the active period, over 82.4% of strong earthquakes took place within a special moon phase, which is 36.4 % higher than the average. Therefore, the modulation and triggering of tidal stress can be used to distinguish the active periods and to forecast the time of the strong earthquakes within the active period. The relationship between the tidal triggering and the tectonic dynamic condition is investigated and the mechanism of the modulation is simulated with the group model of earthquakes generated in tectonic blocks.     

高村井水位潮汐参数的动态特征及其对大同地震的前兆响应

介绍了高村（京１４）井１９８３－１９９０年的观测结果，分析该井水位及潮汐参数的动态特征、气压对观测结果的影响，讨论了Ｍ２波潮汐因子对１９８９年大同地震的前兆响应。