The relationship between seismic velocity and radioactive heat production in crustal rocks: An exponential law

In crystalline rocks seismic velocityV _p and densityp increase, whereas radioactive heat productionA decreases from acidic to basic compositions. From the velocity-density systematics for crustal rocks at different pressures an empiricalA(V _p) relationship has been derived for the range 5.0–8.0 km/sec which follows the exponential law:A(V _p )=a exp (-bV _p ), where the numerical factorsa andb depend onin situ pressure. A graph is given by means of which the heat production distributionA(z) can be obtained for any givenV _p (z) structure.Contribution No. 207, Institute of Geophysics, ETH Zurich.     

Effects of basement topography on subsidence history analysis

Tectonic subsidence history analyses performed without consideration of fault-controlled or other basement topography and interpreted using the depth-dependent extension model may yield very inaccurate estimates of crustal and subcrustal extension for sedimentary basins. Analyses of data from wells over local basement highs can lead to predictions of incorrectly low crustal extension and high subcrustal extension. Predictions based on data from wells over basement lows may be incorrect in the opposite sense. Calculating the sediment unloading correction assuming local-isostatic compensation, rather than flexural compensation, reduces this problem. This is not meant to indicate that depth-dependent extension does not occur, but that it should not be invoked simply to explain variations in basement depth due to rough topography.     

Effects of fault movement and material properties on deformation and stress fields of Tibetan Plateau

We compare the factors which affect the movement of Tibetan Plateau by building three types of finite element models: an elastic materials (M-EC), a continuous model composed by non-linear materials (M-PC), and an elastic model with discontinuous fault movements (M-ET). Both in M-ET and M-EC, the materials in Qiangtang and Lhasa block are elastic, and in M-ET, discontinuous movement of faults is considered for evaluating the effects of strike-slip faults. In model M-PC Druker-Prager plastic materials are us...     

Subsidence history and forming mechanism of anomalous tectonic subsidence in the Bozhong depression, Bohaiwan basin

The Bozhong depression of the Bohaiwan basin belongs to a family of extensional basins in East China, but is quite different from other parts of the basin. The Cenozoic subsidence of the depression is controlled by a combination of lithospheric thinning and polycyclic strike-slip movements. Three episodic rifts have been identified, i.e. Paleocence-early Eocene, middle-late Eocene and Oligocene age. The depression underwent syn-rift and post-rift stages, but two episodic dextral movement events of the strike-slip faults modify the subsidence of the Bozhong depression since the Oligocene. The early dextral movement of the Tan-Lu fault associated with crustal extension resulted in accelerated subsidence during the time of deposition of the Dongying Formation with a maximum thickness of 4000 m. A late reactivation of dextral movement of the Tan-Lu fault began in late Miocene (about 12 Ma), which resulted in the intense subsidence of Minghuazhen Formation and Quaternary. In addition, dynamic mantle convection-driven topography also accelerated the post-rift anomalous subsidence since the Miocene (24.6 Ma). Our results indicate that the primary control on rapid subsidence both during the rift and post-rift stages in the Bozhong depression originates from a combination of multiple episodic crustal extension and polycyclic dextral movements of strike-slip faults, and dynamic topography.     

混凝土材料动力本构模型研究进展

综述了近20年来国内外混凝土材料动力本构模型的研究状况。对国内外最新的几种混凝土动力本构模型进行了述评，指出了各种模型的适用条件及其优缺点。最后，根据现有的研究成果及混凝土材料的动力试验研究结果，得出了建立混凝土动力本构模型中应考虑的主要因素。     

Evaluating the impacts of climate change and switchgrass production on a semiarid basin

Climate and land use changes greatly modify hydrologic regimes. In this paper, we modelled the impacts of biofuel cultivation in the US Great Plains on a 1061‐km² watershed using the Soil and Water Assessment Tool (SWAT) hydrologic model. The model was calibrated to monthly discharges spanning 2002–2010 and for the winter, spring, and summer seasons. SWAT was then run for a climate‐change‐only scenario using downscaled precipitation and a projected temperature for 16 general circulation model (GCM) runs associated with the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios A2 scenario spanning 2040–2050. SWAT was also run on a climate change plus land use change scenario in which Alamo switchgrass (Panicum virgatum L.) replaced native range grasses, winter wheat, and rye (89% of the basin). For the climate‐change‐only scenario, the GCMs agreed on a monthly temperature increase of 1–2 °C by the 2042–2050 period, but they disagreed on the direction of change in precipitation. For this scenario, decreases in surface runoff during all three seasons and increases in spring and summer evapotranspiration (eT) were driven predominantly by precipitation. Increased summer temperatures also significantly contributed to changes in eT. With the addition of switchgrass, changes in surface runoff are amplified during the winter and summer, and changes in eT are amplified during all three seasons. Depending on the GCM utilized, either climate change or land use change (switchgrass cultivation) was the dominant driver of change in surface runoff while switchgrass cultivation was the major driver of changes in eT. Copyright © 2014 John Wiley & Sons, Ltd.     

Effects of water and heat on seedling emergence

The effects of soil temperature and soil moisture content on germination and seedling emergence as known from literature are reviewed.     

Convection with heat flux prescribed on the boundaries of the system. I. The effect of temperature dependence of material properties

Abstract

We study the bifurcation to steady two-dimensional convection with the heat flux prescribed on the fluid boundaries. The fluid is weakly non-Boussinesq on account of a slight temperature dependence of its material properties. Using expansions in the spirit of shallow water theory based on the preference for large horizontal scales in fixed flux convection, we derive an evolution equation for the horizontal structure of convective cells. In the steady state, this reduces to a simple nonlinear ordinary differential equation. When the horizontal scales of the cells exceed a certain critical size, the bifurcation to steady convection is subcritical and the degree of subcriticality increases with increasing cell size.     

Tracer properties of eroded sediment and source material

This paper examines the conservativeness of tracers through the sediment generation process. This is done by comparing a selection of tracer properties of sediment eroded from large plots by simulated rainfall, with the corresponding properties of the source materials within the plots. Sediment was generated using three simulated rainfall events for each of five selected erosion source types in the Tarago catchment, Victoria, Australia. As there were particle size and organic content differences between the source material and the generated sediment, the measured tracer properties of the source material were corrected for these differences. The possible role of analytical errors in this investigation was also addressed. The geochemical property, concentration of Fe₂O₃, was not conservative for any of the process sources investigated. Concentration of Al₂O₃ was not conservative for three of the four process sources investigated, and the sum of molecular proportions of CaO**, Na₂O, K₂O and Al₂O₃ was not conservative for two of the four process sources investigated. Mineral magnetic properties, IRM₈₅₀ and χ were also found to be not conservative, although this may be the result of the complex relationship between particle size and mineral magnetic properties not being adequately accommodated in this analysis. The radionuclide tracers, ¹³⁷Cs and ²¹⁰Pb_ex, were found to be conservative through the sediment generation process. Copyright © 2002 John Wiley & Sons, Ltd.     

A geothermal study of the Jharia Gondwana basin (India): Heat flow results from several holes and heat production of basement rocks

Temperatures have been measured in nine boreholes (ranging from 400 to 900 m in depth) in the Jharia Gondwana sedimentary basin of the Indian shield. About two hundred thermal conductivity determinations have been made on core samples from these holes. Temperature profiles, Bullard plots and heat flow profiles of these holes indicate different types of disturbances in the shallow geothermal regime, attributable principally to groundwater movement. Heat flow in the region of the “anticlinal high” is about 0.4 HFU higher than the heat flow in the main synclinal region of the basin. The possible sources for this variation are regional groundwater movement and upwelling of thermal waters through a deep-seated fault/fracture system. The heat flow of 1.9 HFU characterizing the main synclinal region, taken as the regional value for the basin as a whole, has been related to the heat generation of the Precambrian basement rocks. A plot of heat flow vs. heat generation falls in line with three plots for the Precambrian complexes of the Indian shield, indicating the absence of a thermal anomaly due to deeper crustal conditions underneath this basin.     

共和盆地干热岩地热资源的成因机制:来自岩石放射性生热率的约束

共和盆地位于青藏高原东北缘,是我国重要的干热岩地热资源赋存区之一.成因机制研究是干热岩地热资源研究中最为基础与核心的工作之一,也是干热岩地热资源潜力精细评价和合理开发利用的重要依据.本文基于98块采自共和—贵德盆地岩石样品的放射性生热率数据,分析了盆地主要岩性岩石的放射性生热率分布特征,讨论了共和盆地干热岩地热资源的成因机制,并初步建立了干热岩地热资源的成因模式.研究表明,共和盆地恰卜恰地热区沉积岩（以泥岩和粉砂质泥岩为主）放射性生热率为1.21~2.02 μW·m^-3,平均值为1.67±0.29 μW·m^-3;以花岗岩和花岗岩闪长岩等为主的基底岩石的放射性生热率介于1.17~5.81 μW·m^-3之间,平均值为3.20±1.07 μW·m^-3.贵德盆地扎仓寺地热区沉积岩（以砂岩和泥质砂岩为主）放射性生热率为1.83~2.40 μW·m^-3,平均值为2.13±0.23 μW·m^-3;基底花岗质岩石的放射性生热率介于0.92~6.49 μW·m^-3之间,平均值为2.81±1.40 μW·m^-3.测试数据显示共和—贵德盆地基底花岗岩不存在高放射性生热率异常.但是,新生代以来印度—欧亚板块持续性陆-陆碰撞作用造成的壳内放射性生热元素富集层增厚,导致了花岗岩放射性生热率的热贡献量同步增大（30.3~40.5 mW·m^-2）,因此,花岗岩放射性生热可为共和盆地干热岩地热资源提供稳定的壳内热源基础.基于放射性生热率数据和热流配分研究,结合研究区已有地质-地球物理研究资料,本文认为壳内部分熔融层作为附加热源为共和盆地干热岩地热资源提供了重要的附加热流贡献.在此基础上,本文初步构建了共和盆地干热岩地热资源成因模式：加厚地壳花岗岩放射性生热与壳内部分熔融层供热.

     

Some aspects of testing small-scale masonry building models on simple earthquake simulators

The basic aspects of testing small-scale masonry building models on simple earthquake simulators are discussed. Since the scale effects represent a difficult problem to solve, the overall seismic behaviour of structural systems, and not the behaviour of structulal details, has been studied by testing the reduced-sized models on a simple earthquake simulator. Accurate results regarding the dynamic behaviour and failure mechanism of the tested structures have been obtained by means of testing the relatively simple, adequately designed small-scale masonry building models. A simple earthquake simulator capable of simulating the uni-directional earthquake ground motion has been developed to study the seismic behaviour of masonry building models. Although a multipurpose programmable actuator was used to drive the shaking table, the comparison of the dynamic characteristics of the generated shaking-table motion and the earthquake acceleration records used for the simulation of seismic loads showed an acceptable degree of correlation between the input and output seismic motion.     

Impacts of changing climate on the hydrology and hydropower production of the Tagus River basin

The Tagus River basin is an ultimately important water source for hydropower production, urban and agricultural water supply in Spain and Portugal. Growing electricity and water supply demands, over‐regulation of the river and construction of new dams, as well as large inter‐basin and intra‐basin water transfers aggravated by strong natural variability of climate in the catchment, have already imposed significant pressures on the river. The substantial reduction of discharge is observed already now, and projected climatic change is expected to alter the water budget of the catchment further.In this study, we address the effects of projected climate change on the water resources availability in the Tagus River basin and influence of potential changes on hydropower generation of the three important reservoirs in the basin. The catchment‐scale, process‐based eco‐hydrological model soil and water integrated model was set up, calibrated and validated for the entire Tagus River basin, taking into account 15 large reservoirs in the catchment. The future climate projections were selected from those generated within the Inter‐Sectoral Impact Model Intercomparison Project. They include five bias‐corrected climatic datasets for the region, obtained from global circulation model runs under two emissions scenario – moderate and extreme ones – and covered the whole century. The results show a strong agreement among model runs in projecting substantial decrease of discharge of the Tagus River discharge and, consequently, a strong decrease in hydropower production under both future climate scenarios. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of long-term wastewater irrigation on soil physical properties and performance of selected infiltration models in a semi-arid region

ABSTRACT

In many arid and semi-arid countries, wastewater irrigation is becoming a common practice in agriculture. In this study, the effect of long-term (40 years) wastewater irrigation on selected physical and hydraulic properties of soil in different parts of a landscape was investigated. The performance of some infiltration models, including Philip (Ph), Kostiakov (Kos), Kostiakov-Lewis (Kos-L), Horton (Ho), Huggins and Monke (Hug-M), and linear and nonlinear Smith-Parlange (S-P(L) and S-P(NL)), was compared. This study was performed in the Urmia region, Iran, where flooding wastewater irrigation has been practised for at least 40 years. Five paired sites, each of which contained a measurement location at the wastewater-irrigated (WWI) and adjacent control area were studied. Accuracy of the infiltration models was evaluated using several statistical criteria, including root mean square error (RMSE) and Akaike information criterion (AIC). The models were classified into groups using cluster analysis based on level of similarity in their performance. The cumulative water infiltration into soils after 1 h (I_1h) was calculated using the selected most accurate models and introduced so as to use only one term to compare the infiltration behaviour of soils. Based on RMSE and AIC, the performance of the Ph, Ho, Kos and Kos-L models was considerably better than that of Hug-M, S-P(L) and S-P(NL). The ranking of the models in terms of their AIC values was: Kos-L > Ho > Kos > Ph > S-P(L) > Hug-M > S-P(NL). The models were classified into two distinct groups. The similarity among Ph, Ho, Kos and Kos-L models was more than 80% and for Hug-M, S-P(L), and S-P(NL) models, it was more than 79%. However, the similarity between these two groups of models was less than 58%.

Editor M.C. Acreman; Associate editor not assigned     

黄土震陷研究及相关问题探讨

回顾了30多年来关于黄土震陷的研究工作和成果.黄土震陷已为微结构特征、动三轴和现场爆破试验所证实,成为黄土地震工程研究领域的一项重要课题,但仍缺少典型震例,且停留在饱和土理论研究阶段.应用微结构形态学方法表征土体结构性变得困难,土力学方法将是微结构应用于震陷性研究的有效途径.震陷性判定仅是在多个参变量值区间内的确定性判定,概率性震陷预测应得到开展.震陷系数估算多是基于室内试验数据的经验公式或半经验半理论公式,并未完全解决其物理过程和力学机制问题,比如参变量多、计算繁琐和实用性差等,故应从黄土震陷的物理力学机制出发,厘清影响黄土震陷的主导因素及其表征参变量,建立具有物理力学意义的数学理论估算模型.抗震陷处理技术的关键是消除土体的震陷性,并减缓震陷时土与土工结构物的相互作用.     

Effects of large organic material on channel form and fluvial processes

Stream channel development in forested areas is profoundly influenced by large organic debris (logs, limbs and rootwads greater than 10 cm in diameter) in the channels. In low gradient meandering streams large organic debris enters the channel through bank erosion, mass wasting, blowdown, and collapse of trees due to ice loading. In small streams large organic debris may locally influence channel morphology and sediment transport processes because the stream may not have the competency to redistribute the debris. In larger streams flowing water may move large organic debris, concentrating it into distinct accumulations (debris jams). Organic debris may greatly affect channel form and process by: increasing or decreasing stability of stream banks; influencing development of midchannel bars and short braided reaches; and facilitating, with other favourable circumstances, development of meander cutoffs. In steep gradient mountain streams organic debris may enter the channel by all the processes mentioned for low gradient streams. In addition, considerable debris may also enter the channel by way of debris avalanches or debris torrents. In small to intermediate size mountain streams with steep valley walls and little or no floodplain or flat valley floor, the effects of large organic debris on the fluvial processes and channel form may be very significant. Debris jams may locally accelerate or retard channel bed and bank erosion and/or deposition; create sites for significant sediment storage; and produce a stepped channel profile, herein referred to as ‘organic stepping’, which provides for variable channel morphology and flow conditions. The effect of live or dead trees anchored by rootwads into the stream bank may not only greatly retard bank erosion but also influence channel width and the development of small scour holes along the channel beneath tree roots. Once trees fall into the stream, their influence on the channel form and process may be quite different than when they were defending the banks, and, depending on the size of the debris, size of the stream, and many other factors, their effects range from insignificant to very important.     

On simple models for simulation of nonlinear processes in convection and turbulence

The mechanism of nonlinear interaction in hydrodynamics is studied with dynamical systems having finite degrees of freedom. The equations are assumed to have the same integrals of motion and main features as those peculiar to hydrodynamical equations. The simplest system of this kind is a triplet (a system described by three parameters). Its equations of motion coincide with the Euler equations in the theory of the gyroscope. The forced motion of a triplet is treated theoretically. A real hydrodynamical system controlled by the equations of motion of a triplet was devised and verified in the laboratory.

The simplest theoretical model of baroclinic motion which provides a basis for studies of of forced heat convection in an ellipsoidal cavity was also constructed. Under certain conditions, the addition of rotation causes a regime of motion analogous to the Rossby regime in a rotating annulus.

More complicated models constructed from a large number of interacting triplets can simulate the cascade process of energy transformation in developed turbulence.     

Comparative analysis on macroscale material models for the prediction of masonry in-plane behavior

Bulletin of Earthquake Engineering - Simulating the mechanical behavior of masonry structures with reasonable approximation using numerical models is a complex issue, mainly due to the...     

柴达木盆地现今大地热流与晚古生代以来构造-热演化

依据钻孔系统稳态测温、静井温度资料与实测热导率数据分析了柴达木盆地地温场分布特征,建立了柴达木盆地热导率柱,新增了17个大地热流数据. 柴达木盆地现今地温梯度介于17.1~38.6 ℃·km-1,平均为28.6±4.6 ℃·km-1,大地热流介于32.9~70.4 mW·m-2,平均 55.1±7.9 mW·m-2. 盆地不同构造单元地温场存在差异,昆北逆冲带、一里坪坳陷属于"高温区",祁南逆冲带属于"中温区",三湖坳陷、德令哈坳陷及欧龙布鲁克隆起属于"低温区",盆地现今地温场分布特征受控于地壳深部结构、盆地构造等因素. 以现今地温场为基础,采用磷灰石、锆石裂变径迹年龄分布特征定性分析与径迹长度分布数据定量模拟相结合,研究了柴达木盆地晚古生代以来的沉积埋藏、抬升剥蚀和热演化史,并结合区域构造背景,对柴达木盆地构造演化过程进行了探讨,研究表明柴达木盆地晚古生代以来经历了六期(254.0—199 Ma,177—148.6 Ma,87—62 Ma,41.1—33.6 Ma,9.6—7.1 Ma,2.9—1.8 Ma)构造运动,六期构造事件与研究区构造演化的动力学背景相吻合. 其中白垩纪末期(87—62 Ma)的构造事件导致了柴达木盆地东部隆升并遭受剥蚀,欧龙布鲁克隆起形成雏形,柴达木盆地北缘在弱挤压环境下形成坳陷盆地; 中新世末的两期构造事件(9.6—7.1 Ma和2.9—1.8 Ma)使柴达木盆地遭受强烈挤压,盆地快速隆升,构造变形强烈,基本形成现今的构造面貌.