Evidence of NW extension of the North Anatolian Fault Zone in the Marmara Sea: a new interpretation of the Marmara Sea (Izmit) earthquake on 17 August 1999

Active faults aligning in NW–SE direction and forming flower structures of strike-slip faults were observed in shallow seismic data from the shelf offshore of Avcılar in the northern Marmara Sea. By following the parallel drainage pattern and scarps, these faults were traced as NW–SE-directed lineaments in the morphology of the northern onshore sector of the Marmara Sea (eastern Thrace Peninsula). Right-lateral displacements in two watersheds of drainage and on the coast of the Marmara Sea and Black Sea are associated with these lineaments. This right-lateral displacement along the course of these faults suggests a new, active strike-slip fault zone located at the NW extension of the northern boundary fault of the ?ınarcık Basin in the Marmara Sea. This new fault zone is interpreted as the NW extension of the northern branch of the North Anatolian Fault Zone (NAFZ), extending from the ?ınarcık Basin of the Marmara Sea to the Black Sea coast of the Thrace Peninsula, and passing through B üy ük ?ekmece and K ü ? ük ?ekmece lagoons. These data suggest that the rupture of the 17 August 1999 earthquake in the NAFZ may have extended through Avcılar. Indeed, Avcılar and İzmit, both located on the Marmara Sea coast along the rupture route, were strongly struck by the earthquake whereas the settlements between Avcılar and İzmit were much less affected. Therefore, this interpretation can explain the extraordinary damage in Avcılar, based on the newly discovered rupture of the NAFZ in the Marmara Sea. However, this suggestion needs to be confirmed by further seismological studies.     

Fractal Determination of Coastal Types Based on GIS--A Case Study of China

The probability of fractal determination of coastal types based on GIS is preliminarily discussed with China as an example. Finally, some significant conclusions are drawn: (1) The fractal dimension of coastline of the bedrock coast is larger than that of the plain coast on the same scale map; (2) As far as the bedrock coast is concerned, the larger fractal dimension of coastline of the bedrock coast on the same scale map indicates that the bedrock coast is probably not typical; (3) As far as the plain coast is concerned, the smaller fractal dimension of coastline of the plain coast on the same scale map indicates that it is probably the silt plain coast; (4) The different substantial compositions affect the fractal dimensions of coastlines of different coastal types. In general, the coast which lies in the north of the Hangzhou Bay consists of sand mainly, its surface is flat, and it is connected with the coastal plain, its landform is broad shoal, its total change is comparatively homogenous in the tidal dynamic process, and thus, the relatively smaller fractal dimension of coastline results from this. For the bedrock coast, there is more bedrock, the coastline is comparatively smooth and straight, being affected by the faults and ocean dynamic process, which result in the larger fractal dimension.     

冲绳海槽中段沉积岩芯碳酸盐和烧失量的古环境意义

对冲绳海槽中段 3个沉积岩芯碳酸盐和烧失量的系统分析得知 ,岩芯沉积物的CaCO3含量一般 >1 0 % ,最高含量接近 30 % ,烧失量大都在 1 0 %～ 30 %之间变化 ,反映了该海区处于溶跃面之上钙质生物极为发育的生物地球化学环境。结合δ1 8O曲线所反映的气候环境变化 ,探讨了 1 2 0kaB .P .以来碳酸盐旋回的“大西洋型”演变特点 ,同时对该区沉积地层中的火山热液活动印记作了一定的探讨。     

地形坡度对多金属结核分布的控制作用

选取我国东太平洋多金属结核开辟区内的一个区域作为研究区,利用人工神经网络中应用最为广泛的BP网络,建立控制多金属结核分布的地质因素与多金属结核分布之间的映射关系,探讨地形坡度对多金属结核分布的控制作用.结果表明,在经度、纬度、水深、坡度四个因素中,坡度对结核分布影响程度最大;多金属结核主要分布于坡度小于5°的地方;当坡度小于5°时,丰度与地形坡度呈正相关,品位与地形坡度呈负相关,丰度与品位呈负相关;品位与坡度似呈指数关系,坡度增大,品位降低.     

摄食水平和性别对稀有鮈鲫生长和能量收支的影响

于1995年10月采集本所自繁有ju鲫（约1.03g/ind)，在30℃水温下进行摄食－生长实验，研究了从饥饿到饱食5个摄食水平对不同性别稀有ju鲫的生长和能量收支的影响，结果表明，鱼体干物和能量含量不受摄食率和性别的影响，随着摄食率的增加，雌鱼的湿重，干重和能量特定生长率均呈双对数增加，雄鱼湿重特定生长率呈双对数增加，而干物质和能量特定生长率呈指增加，雄鱼生长速度及摄食率低于雌鱼，随着摄食率的增加，食物能损失于粪便中的比例均呈上升趋势，损失于排泄物中的比例变化不大，呈下降趋势，用于代谢的比例呈下降趋势，用于生长的比例呈上升趋势，除饥饿组外，在各个摄食水平，雌鱼食物能用于代谢的比例较雄鱼低，而用于生长的比例较雄鱼高。     

石斑鱼鱼虱病的研究──Ⅰ.南海鱼虱,新种Caligus nanhaiensis n.sp.

记述华南地区网箱养殖石斑鱼鱼虱病病原──南海鱼虱，新种Caligusnanhaiensisnsp．形态的光镜和电镜观察结果，并对南海鱼虱与相似种C．seriolaeYamaguti，1936和C.tanagoYamaguti，1939的形态特征进行详细比较。     

Numerical Study on Instantaneous Discharge of Unsorted Particle Cloud in Cross Flow

The mixing characteristics of particles such as dredged sediment of variable size discharged into cross flow are studied by a 3D numerical model, which is developed to model the particle-fluid two-phase flow. The Eulerian method with the modified k-ε parameterization of turbulence for the fluid phase is used to solve fluid phase, while a Lagrangian method for the solid phase (particles), both the processes are coupled through the momentum sources. In the model the wake turbulence induced by particles has been included as additional source term in the k-ε model; and the variable drift velocities of the particles are treated efficiently by the Lagrangian method in which the particles are tracked explicitly and the diffusion process is approximated by a random walk model. The hydrodynamic behavior of dumping a cloud of particles is governed by the total buoyancy of the cloud, the drag force on each particle and the velocity of cross-flow. The computed results show a roughly linear relationship between the displacement of the frontal position and the longitudinal width of the particle cloud. The particle size in the cloud and the velocity of cross flow dominate the flow behavior. The computed results are compared with the results of laboratory experiments and satisfactory agreement is obtained.     

福建漳浦前湖湾有孔虫群落及其沉积环境

对福建漳浦前湖湾潮间带两个钻孔岩心和表层沉积物中的有孔虫进行分析研究,有孔虫出现在钻孔最上部厚约2.46-2.96m的砂层中.根据群落优势种生态和非种特征判断,该段各样品有孔虫沉积环境均为近岸浅水环境,尽管其间海面有过3次上下波动变化.根据地层关系判断,其当为现代的产物.     

高纯河豚毒素对蛙坐骨神经动作电位的影响

用电生理学方法观察了4种不同浓度的高纯河豚毒素(tetrodotoxin,TTX)对蛙离体坐骨神经动作电位的影响.实验结果表明:1μmol/dm3TTX在给药后7 min能显著抑制动作电位的上相幅度(P<0.05),但在给药后10 min才显著抑制动作电位的下相幅度(P<0.01);20μmol/dm3TTX在给药后3 min内能完全抑制动作电位的形成.1μmol/dm3TTX在给药后1~5min对动作电位传导速度的影响没有统计学意义,5μmol/dm3TTX在5min时可显著抑制传导速度(P<0.05),而10μmol/dm3TTX在2min时便显著抑制传导速度(P<0.05).实验结果提示高纯河豚毒素对蛙离体坐骨神经动作电位的影响存在剂量效应关系.     

超短基线声学定位原理及其应用

声学定位系统（Acoustic Positioning System)的技术研究和应用开发在现代海洋科学调查中起着重要作用。以挪威Simrad公司的HPR410P超短基线定位系统为例，从几方面讨论了超短基线（Ultrashort Baseline)声学定位系统的原理、应用范围、定位误差来源及其相应的修正方法；通过最大程度地减少误差来提高系统的定位精度，从而获取高质量的海洋科研调查资料。