Morpho-tectonic evolution of the Marmara Sea inferred from multi-beam bathymetric and seismic data

In an initial stage, the Sea of Marmara developed as a graben and, in due course, considerable volumes of sediments were deposited in this basin. Before 200 ka, a new fault (New Marmara Fault) cutting through the whole basin developed, which postdated large sub-marine land sliding in the western part of the basin. This mass movement created the Western Ridge. The initiation of this strike-slip fault indicates that the extensional stress regime was replaced by a new, shearing stress field. In the eastern part of the Marmara Basin, the New Marmara Fault consists of two branches. The northern one replaces the normal faulting at the bottom of the northeastern slope of the basin. As a result, this slope has been rejuvenated. The southern branch is located along the central axis of the basin, forming the major extension of the North Anatolian Fault Zone within the region. Two restraining bends were formed because of the counterclockwise rotation of that part of the Anatolian Block. This resulted the uplifting of the Eastern Ridge and the formation of the positive flower structure within the Tekirdag Basin. The establishment of the compressional regime around the Sea of Marmara also resulted in the northwest–southeast shortening of the initial Marmara Basin.     

我国海水养殖业发展现状与可持续发展问题

简要分析、总结了我国近 1 0 a来的主要海水鱼、虾、贝、藻等的增养殖现状和存在的问题 ,并对今后可持续发展问题进行了探讨     

The Geoelectrical Structure of Northwestern Anatolia,Turkey

The magnetotelluric method has been employed to generate a geoelectrical model that will reveal the rich geological pattern and dynamic character of western and northwestern Anatolia, Turkey. Magnetotelluric data were collected from 53 sites along a profile of 290 km from the Dardanelles to the Ala?ehir Graben. Magnetotelluric data were in the range of 0.00055 Hz to 320 Hz. The models were obtained through 2-D joint inversion of transverse electric and transverse magnetic modes. Lateral changes in geoelectrical models are verified by using gravity and magnetic data. In addition, some of the seismological data presented here agree with proposed models that suggest a brittle-ductile structure boundary at a depth of 20 km. Generally speaking, a regional extensional regime caused reduction in the thickness of the crust and consequent uplift towards the south. The constructed model delineates the western part of the North Anatolian Fault Zone along the Biga Peninsula. The current patterns of volcanic activity on the Biga Peninsula and at Kula are related to conductive spots presented in the models. The border of the Gördes Basin, located between the Izmir - Ankara suture zone and the Menderes Massif, is also well delineated. The North Anatolian Fault Zone presents a pattern in which density and susceptibility anomalies attain relatively high values. Fillings covering most of the surface have lower density and susceptibility values than those of underlying structures.     

易县地震台地形变模拟和数字化记录资料对比分析

用形变前兆台网及台站数据处理系统软件对易县地震台2002年度自记水管仪和伸缩仪的模拟记录和数字化记录资料进行处理,求得噪声水平、潮汐因子和误差,再计算出内在精度,从而在噪声水平和内在精度两个方面对模拟和数字化记录资料进行对比分析,从中发现数字化记录资料在内在精度和噪声水平两个方面均优于模拟记录资料.     

Seismic energy dissipation in deteriorating systems through low‐cycle fatigue

Energy dissipation characteristics of structural members which exhibit both strength and stiffness deterioration under imposed displacement reversals are investigated. In the experimental part, 17 reinforced concrete beam specimens were tested under constant and variable amplitude inelastic displacement cycles. The constant‐amplitude tests were employed to determine the low‐cycle fatigue behaviour of specimens where the imposed displacement amplitude was the major variable. A two‐parameter fatigue model was developed in order to express the variation of dissipated energy with the number of displacement cycles. This model was then used to predict the energy dissipation of test specimens subjected to variable‐amplitude displacement cycles simulating severe seismic excitations. It has been demonstrated that the remaining energy dissipation capacity in a forthcoming displacement cycle is dependent on the energy dissipated along the completed displacement path. Moreover, it is observed that total energy dissipation is dependent on the length of the displacement path. Copyright © 2003 John Wiley & Sons, Ltd.     

Energy‐based hysteresis and damage models for deteriorating systems

The low‐cycle fatigue model presented in the companion paper is employed for developing hysteresis and damage models for deteriorating systems. The hysteresis model performs strength reduction at a current displacement cycle by evaluating the loss in the energy dissipation capacity along the completed displacement path. Hence it is completely memory dependent. Pinching is accounted for implicitly by a reduced energy dissipation capacity in a displacement cycle. The model predicts the experimental results obtained from variable‐amplitude tests reasonably well. Response analysis under earthquake excitations reveals that both the maximum displacements and the number of large‐amplitude displacement response cycles increase significantly with the reduction in energy dissipation capacity, resulting in higher damage. Damage is defined as the deterioration in the effective stiffness of a displacement cycle, which is in turn related to the reduction in the energy dissipation capacity. A simple damage function is developed accordingly, consisting of displacement and fatigue components. It is observed that the fatigue component of damage is more significant than the displacement component for deteriorating systems under ground motions with significant effective durations. Copyright © 2003 John Wiley & Sons, Ltd.     

资源环境一体化对西部大开发的重要意义——参考广东区域可持续发展研究

资源和环境是一个自然体的两种功能，应当将资源和环境问题置于一个系统中来研究，在资源开发的始端到资源利用的全过程，统筹兼顾环境保护，逐步转变先污染后治理的被动局面。一个区域的现代化水平和可持续发展能力直接受当前科技条件下资源环境一体化开发程度的影响。因此，认真研究我国东、西部地区资源环境系统的特色是地球科学的当务之急；其中，不仅需要加强对矿产资源和能源的环境效应研究，而且特别应重视对土地资源、水资源等可再生资源的优化配置和合理利用研究，以保护好生态环境。在这方面，先发展的广东省提供了一些经验教训。     

Engineering characteristics of the near-field strong motions from the 1999 Kocaeli and Düzce Earthquakes in Turkey

The purpose of this paper is to summarize the strong motion data from thenearest stations to the fault ruptures of the August 17, 1999 Kocaeli andNovember 12, 1999 Düzce earthquakes and to document informationthat will be significant for its interpretation. Significant engineeringcharacteristics of the near-field strong motions are discussed, with particularemphasis on the site conditions, rupture directivity effects and transversecomponent orientations relative to the fault. In the course of this study,the most significant strong motion stations and adjacent parts of the faultare visited. All locations are verified using a hand-held GPS receiver. Thusinstrument housing characteristics, preliminary impression on siteconditions, and relatively precise relationship of the stations to the nearestfaulting can be reported.     

A New Approach to Optimize Ultimate Geometry of Open Pit Mines with Variable Overall Slope Angles

Natural Resources Research - The optimization method for determining open pit limit is important, as it is crucial to achieve the most profitable outcome from the limited amount of reserves...