Cesium-137 in Crimean Salt Waters

Water Resources - The concentration of the technogenic radionuclide 137Cs was studied in different groups of salt lakes of Crimean Peninsula. It was established that one of the major sources of...     

Assessing the Local Renewable Water Resources in the Crimean Peninsula

Water Resources - Data on annual runoff at 15 gages, reflecting the relatively natural conditions of runoff formation were used to reveal the present-day features of its space and time variations....     

The Main Problems of Karst Hydrogeology in the Crimean Peninsula

Water Resources - The Crimean Peninsula, with 84% of its territory composed of soluble rocks, is a region of wide occurrence and diverse manifestations of karst. Practically all groundwater of...     

古今气候略论

自2009年入冬以来北半球经受了创记录的严寒侵袭,联合国IPCC报告的权威性受到质疑。地球气候变化趋向陷入纷争的境地。从地质学和考古学的视角,以更长的时间周期去认识和了解气候变化规律和成因机制,或许对将来气候的长期预报有所启示。地球在漫长的演化史中经历了以千万年计的＂地质气候旋回＂、千百年计的＂史前气候周期＂及近现代以百年计的＂世纪气候波动＂。不同级次的周期均为内在自然因素所制约,CO2含量在地球演化史中趋于波动下降过程,当代的CO2浓度和气温均处于地质史的低点。人类活动可能在百年尺度内存在对气候和生态环境的影响。自20世纪初开始至今近百年升温趋向中,令人关注的是在中国曾有1941年、1969年、2009~2010年之交极度低温的出现,＂低温节点＂时距约为30~40年,似与海洋存在数十年为变化周期之说相近。由此引发对人为因素导致持续增温的质疑。2009年入冬以来的严寒是否为近百年升温波动周期的终结抑或只是次级的突变因素所致,尚有待观察。但自然因素主导的周期波动规律不可逆转,不能被未经实证而被夸大了的＂人为因素＂所左右。     

晋阳古城遗址考古地球物理特征

晋阳古城遗址历史悠久、面积开阔、文化层叠压错综复杂,地下蕴含丰富,埋藏形式特殊,是一处重要的古文化埋藏区,其考古调查是一项巨大的、长期的系统工程,需要采用传统的考古调查手段与其他先进的科学技术相结合的方法,才能尽快掌握古城遗址分布特点,使古城遗址面貌逐渐清晰起来.由于晋阳古城目标层和目标体尺度范围较宽,从十几厘米到十几米,分辨率也有不同的要求,本文借助先进的地球物理方法,采用高密度电阻率法与探地雷达结合的手段对晋阳古城多处古文化层、古遗迹靶区进行地球物理试验性探测,取得了非常丰富的地球物理特征认识,为传统方法考古提供了大量的有效信息,同时也为今后在晋阳古城遗址应用地球物理探测技术考古研究打下了坚实的基础.     

古建筑木结构构架加固试验研究

通过对未加固构架和加同构架低周反复荷载试验,研究碳纤维布加固效果和构架的抗震性能.试验得出构架水平力和水平位移的滞同曲线及骨架曲线,根据滞回曲线和骨架曲线的特征,得出了水平力和位移的关系方程和构架恢复力模型,从强度、刚度、变形能力几个方面说明加固效果较好.研究结果为古建筑的抗震性能研究和修缮加周提供了有用的参考.     

古建木构枓栱侧向刚度的试验研究

通过对典型枓栱的模型的低周反复荷载试验,研究了枓栱侧向刚度的退化规律.试验得出枓栱的力 - 位移滞回曲线及骨架曲线,并拟合出了力 - 位移的关系方程和枓栱恢复力模型,由实验结果给出枓栱侧向刚度的线性强化性能.研究结果为古建筑的抗震性能研究和修缮加固提供了理论基础.     

中国古代大木作结构斗栱竖向承载力的试验研究

为探讨中国古代大木作结构斗栱在竖向地震作用下隔震、减震机理以及相应的竖向极限承载能力,对三个缩尺比为l／3．52的二等材计心造两跳五铺作斗栱进行了竖向荷载作用下的试验研究,得出了相应的P-△曲线。结果表明,在竖向荷载作用下：(1)斗栱结构特性可视为变刚度线弹性变化,可用单自由度的质量-弹簧-阻尼器模型来说明;(2)斗拱的破坏始于华栱中部的塑性变形和劈裂;(3)在地震动过程中,其运动的竖向传递率大约为0．019,说明斗栱在减小结构地震响应方面发挥了重要作用;(4)在正常使用阶段,斗拱的内力与变形不超过其极限承载力的l／7左右,强度裕度很大。这保证了很多中国古代木结构能够抵御许多强烈地震作用并且矗立千年而不倒。     

Experimental study of human-induced effects on floor slab of an ancient Tibetan structure

With the opening of ancient Tibetan structures to visitors worldwide, human load has become the principal live load on these structures. This project studies the properties of the floor structure of an ancient Tibetan building and its behavior under human-induced load effects. Tests were conducted with static and dynamic crowd load, including stepping and jogging by people at a fixed position. The tests show that the floor structure does not behave as a continuous slab. It takes the load from local areas with minimal load transference properties. The acceleration response shows significant peaks when the footstep frequency is close to the natural frequency of the structure, but the human jogging excitation frequency does not have any obvious effect on the structural response. The elastic modulus of the Agatu material is estimated to be close to zero from the measured natural frequency of the slab. The Agatu material is concluded to be a discrete compacted material with insignificant contribution to the structural rigidity of the floor slab.     

Traces of strong earthquakes of the 9th century in the ruins of Dvin,ancient Armenian Capital

The results of an archeoseismological investigation of the Dvin (ancient Armenian capital) ruins are presented. Multiple occasions of seismogenic damage and destructions have been revealed in the remains of walls, including places where they are tilted or pushed out, or fragments and particular stone blocks are rotated. The extensive cracks that run through several blocks have also been found. The identified systematics in how deformations occurred suggests that the epicenter of the ancient earthquake that struck Dvin in the late 9th century was located close to the city. Most likely, the western termination of an unnamed east-tonortheast trending fault (situated north of the city) was ruptured.     

Frequency-Magnitude Relationships for seismic areas around the capital cities of Solomon, Vanuatu, Tonga and Fiji Islands

We studied the relationships between the frequency ofoccurrence and the magnitudes in seismogenic areasthat will affect four capital cities in the SouthPacific, namely: Honiara in Solomon Islands, Port Vilain Vanuatu, Suva in Fiji and Nuku'alofa in Tonga. Weused the NEIS catalogues for the period 1973–1997, formagnitudes greater than about 5, in the proximity tothe city under investigation. The definitions of thegeographic boundaries of the seismogenic zones arebased on the classical concepts of the distribution ofthe tectonic plates, the overwhelming number ofstudies that describe the seismotectonics in thoseactive regions and on the observed seismicity andstudies of the local people. Completeness of thecatalogue is assumed because of the high seismicity inthese areas, despite the relatively short time span.We have used a hybrid process combining least squaresfitting and Newtonian search process to find the bestfit of the statistical parameters. The characteristicb value is 1.27, and seems to be irrespective of thedepth and/or region.     

Spatial and temporal variation of gravity field in the capital region

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Investigating the ancient Martian magnetic field using microwaves

The new microwave palaeointensity technique has been used to investigate samples from the Martian meteorite Nakhla. This technique is a promising new way to obtain absolute palaeointensity information regarding the ancient Martian magnetic field as recorded by the Martian meteorites. Assuming that a part of the magnetic remanence is of thermal origin and originating on Mars the two samples studied yield estimates of 4 μT for the Martian magnetic field at 1.35 Ga.     

Deep solar activity minima, sharp climate changes, and their impact on ancient civilizations

It is shown that, over the past ～10000 years (the Holocene), deep Maunder type solar minima have been accompanied by sharp climate changes. These minima occurred every 2300–2400 years. It has been established experimentally that, at ca 4.0 ka BP, there occurred a global change in the structure of atmospheric circulation, which coincided in time with the discharge of glacial masses from Greenland to North Atlantic and a solar activity minimum. The climate changes that took place at ca 4.0 ka BP and the deep solar activity minimum that occurred at ca 2.5 ka BP affected the development of human society, leading to the degradation and destruction of a number of ancient civilizations.     

Quasi-waveform seismic tomography of crustal structures in the capital circle region of China

Seismic tomography is one of the main tools to explore the interior of the earth.In this study,the quasi-waveform seismic tomographic method is used for the first time to reveal the crustal structures in the capital region of China.3-D highresolution V_P,V_S and the Poisson’s ratio models are generated by inverting 29839 direct P-and 29972 direct S-wave traveltimes selected from 3231 local earthquakes.The results reveal strong crustal heterogeneities.The velocity anomalies at shallow depths are well consistent with surface geologic structures.The relatively low-velocity anomaly layer in the middle crust may be the result of multiple phases of tectonic activity.Earthquakes generally occurred on the boundaries of high-and low-velocity and Poisson’s ratio anomalies.There are obvious low-velocity anomalies below the hypocenters of the Tangshan earthquake and the historical Sanhe-Pinggu earthquake,implying the existence of fluids.The similar velocity structures around the hypocenters of the two earthquakes indicate that the occurrences of the two earthquakes may be related to the same mechanism.The highresolution velocity models provide important observational constraints on the small-scale heterogeneities and dynamic mechanism of the crust in the capital region of China.     

中国古代大木作结构抗震构造研究

通过对翔实历史与考古资料的调查,并结合于中国古建筑遗构的勘测,进行了许多有关这类结构的起源、发展和演变方面的研究工作,结果表明：(1)木构架具有相当好的抗(耐)震性能,由于这类木造结构的材料具有良好的弹塑性性能、以及榫卯节点的柔性连接,以致在地震过程中,大量的地震动能量被消耗掉。(2)在其结构构造方面,采用了许多诸如柱的生起、侧脚等木作工艺;柱顶、柱脚分别连以阑额、地袱以及其他的结构构件,使柱架层形成一个闭合的构架系统,并与重量很大的屋盖结合,俾使构架具有很大的稳定性和抗震性能。(3)通过阑额、由额与柱头方之间施以拱眼壁或蜀柱或人字拱;在节点部位施以绰幕方等的构造方式,显著增强了结构整体与其构件和节点的抗弯刚度。(4)对于单体建筑,通常情况下采用矩形或其他规则的几何图形作为其平面,在构架竖向上,通常为(下大上小的)棱台形,尤其对于多层建筑。实践证明这种构造方式具有较好的抗震性能。(5)通过抛光柱基础的顶面,显著地减少柱底与柱基础顶面之间的摩擦进而有效地产生隔震作用,使结构免于坍塌。总之,中国古建筑结构体系是高度有机的,对其科学的构造原理进行研究和探索,是一件有意义的事情,并且无疑地对我们现代的建筑活动以有益的启示。     

广东省地震局劳资现状、问题分析及对策

分析了广东省地震局劳资现状,针对在劳资方面可能或已经出现的一些具有共性的问题,结合广东省地震局机构改革实际,提出了几个解决问题的对策,并对其可行性进行了探讨。     

Evidence of geodynamical processes in the ancient crust from the seismoacoustic model of the kola superdeep borehole

The spectral-profile and wavelet analyses are applied for estimating the periodicity in the depth variations of the elastic wave velocities in the detailed seismoacoustic model of the Kola Superdeep Borehole. The geological confinement of the revealed multiscale periodicity and its relationship with the geodynamical processes in the Earth??s crust are considered. The hierarchical sequence of the sizes of the blocks identified in the section is determined; this hierarchy is consistent with the geophysical structure of the medium.     

An expert system for the tectonic characterization of ancient volcanic rocks

The expert system approach enables geochemical evidence to be integrated with geological, petrological and mineralogical evidence in identifying the eruptive setting of ancient volcanic rocks. This paper explains the development of ESCORT, an Expert System for Characterization of Rock Types. ESCORT uses as its knowledge base a set of dispersion matrices derived from a geochemical data bank of some 8000 immobile element analyses, together with tables of magma-type membership probabilities based on a-priori knowledge, the dominant flow type, the facies of intercalated sediment, the basement to the volcanic sequence, the presence or absence of an iron-enrichment trend and the phenocryst phase assemblage. Inferencing is based on the Bayes Decision Rule, adapted to take into account possible uncertainties in the geological evidence. Upper and lower probability thresholds are used to decide whether an interpretation is likely or unlikely. Evaluation of the system shows that it is able to overcome many of the well-publicized ambiquities attached to geochemical discrimination diagrams, as well as providing a unified method of decision making and a measure of the correctness of the interpretation.     

中国古建筑抗震性能分析

本文根据我国古建筑在历次地震作用下的结构破坏状况,总结了古建筑结构的震害特点,介绍了古建筑抗震性能分析方法,结合泰安市古建筑实例进行了抗震性能分析并给出了抗震性能分析结果。