地下水位下降对井壁破坏的影响分析

在用“２Ｄ σ”软件对所建模型进行数值计算的基础上, 分析了因采煤引起淮北矿区下部含水层水位下降而对井壁产生的影响。其表现为： 下部含水层水位下降将引起地层压缩沉降; 地层与井壁间产生附加应力, 并在基岩下部产生应力为零的中性点; 轴向应力由小变大; 当第一含水层和下部含水层同时有水位下降时, 也有类似的规律。计算结果与淮北诸矿井壁变形位置及变化状况基本相符, 因此在此基础上进行的井筒优化设计具有实际指导意义     

SOFTWARE REVIEWS

software reviews are in this article MACATLAS . Number Cruncher Statistical System (NCSS) TRANSPRO FIRE-ROUTER     

平行走滑断层相互作用的粘弹模型和减震作用

研究了二维粘弹性介质中平行走滑断层的相互力学作用及其地震活动性的影响。当一条断层发生滑动,将导致平行断层面上剪切应力减小,因此,可能推迟平行断层发生滑动,推迟时间在几年至几百年的范围内,这取决于发生滑动的断层与平行断层之间的距离,以及平行断层自身应力积累孕育地震过程经历的时间。     

Estimation of quantiles and confidence intervals for the log-Gumbel distribution

The log-Gumbel distribution is one of the extreme value distributions which has been widely used in flood frequency analysis. This distribution has been examined in this paper regarding quantile estimation and confidence intervals of quantiles. Specific estimation algorithms based on the methods of moments (MOM), probability weighted moments (PWM) and maximum likelihood (ML) are presented. The applicability of the estimation procedures and comparison among the methods have been illustrated based on an application example considering the flood data of the St. Mary's River.     

安宁河-则木河断裂带地震视应力研究

利用四川和云南数字遥测地震台网的数字地震记录资料。研究了包括地震视应力在内的震源参数。首先对资料进行预处理,然后计算地动位移和速度的功率谱积分,再计算地震辐射能量和视应力等震源参数。根据计算结果分震级区间研究了视应力值沿安宁河-则木河断裂带的分布情况,及该断裂带上中等地震的震源谱及参数差异,认为安宁河断裂带视应力相对更高。     

庐山地区地表温度反演分析

研究庐山地区的地表温度,对于本地区的生态保护和开发具有重要意义。本文使用了目标区域内Landsat TM/ETM+从2000~2010年间共8幅影像数据,利用单通道算法和NDVI地表辐射率估算方法反演了区域内的温度场,并生成了历年温度对比效果图。分析推断目标区域内的温度场可能存在一个短年限的温度变化起伏规律,对庐山周边山区的影响有待进一步研究。     

Parameter estimation for basin-scale ecosystem-linked population models of large pelagic predators: Application to skipjack tuna

A Spatial Ecosystem and Population Dynamic Model (SEAPODYM) is used in a data assimilation study aiming to estimate model parameters that describe dynamics of Pacific skipjack tuna population on ocean-based scale. The model based on advection–diffusion–reaction equations explicitly predicts spatial dynamics of large pelagic predators, while taking into account data on several mid-trophic level components, oceanic primary productivity and physical environment. In order to improve its quantitative ability, the model was parameterized through assimilation with commercial fisheries data, and optimization was carried out using maximum likelihood estimation approach. To address the optimization task we implemented an adjoint technique to obtain an exact, analytical evaluation of the likelihood gradient. We conducted a series of computer experiments in order to (i) determine model sensitivity with respect to variable parameters and, hence, investigate their observability; (ii) estimate observable parameters and their errors; and (iii) justify the reliability of the computed solution. Parameters describing recruitment, movement, habitat preferences, natural and fishing mortality of skipjack population were analysed and estimated. Results of the study suggest that SEAPODYM with achieved parameterization scheme can help to investigate the impact of fishing under various management scenarios, and also conduct forecasts of a given species stock and spatial dynamics in a context of environmental and climate changes.     

Income distribution dynamics and cross-region convergence in Europe

This paper presents a continuous version of the model of distribution dynamics to analyse the transition dynamics and implied long-run behaviour of the EU-27 NUTS-2 regions over the period 1995–2003. It departs from previous research in two respects: first, by introducing kernel estimation and three-dimensional stacked conditional density plots as well as highest density regions plots for the visualisation of the transition function, based on Hyndman et al. (J Comput Graph Stat 5(4):315–336, 1996), and second, by combining Getis’ spatial filtering view with kernel estimation to explicitly account for the spatial dimension of the growth process. The results of the analysis indicate a very slow catching-up of the poorest regions with the richer ones, a process of shifting away of a small group of very rich regions, and highlight the importance of geography in understanding regional income distribution dynamics.

Modelling peak accelerations from earthquakes

This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.