Origin and tectonic significance of a Mesozoic multi-layer over-thrust system within the Yangtze Block (South China)

In the Yangtze Block (South China), a well-developed Mesozoic thrust system extends through the Xuefeng and Wuling mountains in the southeast to the Sichuan basin in the northwest. The system comprises both thin- and thick-skinned thrust units separated by a boundary detachment fault, the Dayin fault. To the northwest, the thin-skinned belt is characterized by either chevron anticlines and box synclines to the northwest or chevron synclines to the southeast. The former structural style displays narrow exposures for the cores of anticlines and wider exposures for the cores of synclines. Thrust detachments occur along Silurian (Fs) and Lower Cambrian (Fc) strata and are dominantly associated with the anticlines. To the southeast, this style of deformation passes gradually into one characterized by chevron synclines with associated principal detachment faults along Silurian (Fs), Cambrian (Fc) and Lower Sinian (Fz) strata. There are, however, numerous secondary back thrusts. Therefore, the thin-skinned belt is like the Valley and Ridge Province of the North American Applachian Mountains. The thick-skinned belt structurally overlies the thin-skinned belt and is characterized by a number of klippen including the Xuefeng and Wuling nappes. It is thus comparable to the Blue Ridge Province of Appalachia.The structural pattern of this thrust system in South China can be explained by a model involving detachment faulting along various stratigraphic layers at different stages of its evolution. The system was developed through a northwest stepwise progression of deformation with the earliest delamination along Lower Sinian strata (Fz). Analyses of balanced geological cross-sections yield about 18.1–21% (total 88 km) shortening for the thin-skinned unit and at least this amount of shortening for the thick-skinned unit. The compressional deformation from southeast to northwest during Late Jurassic to Cretaceous time occurred after the westward progressive collision of the Yangtze Block with the North China Block and suggests that the orogenic event was intracontinental in nature.     

饱水黄土隧道变形规律研究

新松树湾隧道位于饱和的砂粘土中,土体的稳定性极差,施工难度较大。为此,在隧道施工期间,通过土工试验、隧道收敛和围岩内部位移的现场监测、隧道变形的三维有限元仿真计算等手段,对该隧道的变形规律进行了系统研究,获得了大量试验数据。研究成果对隧道的施工组织和支护参数的确定起到了重要作用,为此类隧道的施工积累了经验。     

Empirical correlations of soil parameters based on Cone Penetration Tests (CPT) for Greek soils

This study presents the results of Cone Penetration Tests (CPT) and estimated correlations with the results of other in-situ tests (standard penetration test, cross-hole, seismocone) and laboratory tests (classification and undrained shear strength tests). These tests cover nearly all types of penetrable soils in Greece and, together with the formulation of empirical correlations, complement and improve on previous studies due to the significant number of CPT measurements.     

场地条件对地震动相干函数的影响

本通过弹性半空间内位错源的数值解法研究了曲岩地震动相干函数，采用有限元方法分析了一些典型场地的地表地震动相干函数，两的对比结果表明：复杂场地对地震动相干函数的影响强烈。     

团树断层场地地震反应的数值模拟

团树断层场地在多次地震中出现了烈度异常。为了弄清烈度异常的原因，应用显式有限元方法，数值模拟了在脉冲地震波斜入射情形下断层场地的地震反应。结果表明：在基岩山脚附近土层场地地震动放大比基岩山区平均高4倍、比远离基岩山脚土层场地平均高2倍，与历史震害分布有较好的对应。     

北京正负电子对撞机注入器复测分析

介绍北京正负电子对撞机注和器复测的精度要求，阐述采用波带板激光准直系统与精密水准测量相结合的方法，进行注入器复测的观测、数据处理与调整。根据复测数据分析了隧道地基变形与加速管位置变形及其规律，提出了一些有益的结论与建议。     

Looting, collecting, and the destruction of archaeological resources

Archaeological sites, the material remnants of our human past, are finite and nonrenewable cultural resources that are under constant threat from environmental forces, development activities, warfare, vandalism, and looting. Site looting is the destructive removal of archaeological objects to supply the art market. Looting is part of an economic system, the antiquities market, that works to supply the demand of collectors for archaeological objects. The destruction of archaeological resources by looters is an international crisis and threatens to obliterate the world’s cultural heritage and our ability to understand past cultures. The scale and intensity of the looting problem can be estimated by studying the extent of site destruction in countries of origin and by investigating the sources of antiquities held by collectors. Finding a solution to the problem of looting will require a focus on the demand side of the market (i.e., collectors) instead of the traditional focus on the supply side (looters, dealers)     

A methodology for drought preparedness

Drought is a normal, recurrent feature of climate that affects virtually all countries to some degree. The number of drought-induced natural disasters has grown significantly since the 1960s, largely as a result of increasing vulnerability to extended periods of precipitation deficiency rather than because of an increase in the frequency of meteorological droughts. This increase in drought-induced natural disasters has resulted in a considerable growth of interest in drought mitigation and preparedness worldwide. The purpose of a national preparedness plan is to reduce societal vulnerability to drought through the adoption of preventive, anticipatory policies and programs. This paper describes a ten-step planning process that nations can follow to develop a drought preparedness plan. This process, originally developed in 1987, has been the basis of discussions at training seminars on drought preparedness for developing nations in Africa, Asia, and Latin America. It has also been adopted, with appropriate modifications, by state or provincial governments and by municipalities. The process is intended to be flexible so that governments can add, delete, or modify the suggested steps, as necessary.Published as Paper No. 10946, Journal Series, Nebraska Agricultural Research Division. The work reported here was conducted under Nebraska Agricultural Research Division Project 27-007. This material is based in part upon work supported by the National Science Foundation under Grant ATM-8704050.     

Seismic hazard assessment in the Ionian Islands based on observed macroseismic intensities

Catalogues of actual observed intensities are constructed for three towns in the Ionian Islands. They are used for seismic hazard assessment and the results are compared with those obtained by standard approaches; that is, by statistics applied to the data computed from epicentral parameters. The results show that seismic hazard is better assessed using observed rather than computed data, but preparation of the local catalogue presents non-trivial difficulties.