水库大容量气枪震源激发条件优化实验研究

通过人工拾取震相,统计记录台站数、台站最远观测距离、接收能量等3个参数,自主研发了最优工况处理软件来研判工况激发效果,并确定棉花滩水库最优工况为水深25m,枪阵沉放深度9m,枪阵尺寸7m×7m。对定点300次激发的每10次累计叠加结果进行分析后发现,叠加1090次时激发效果快速增强,100150次时缓慢增强,160240次时快速增强,250300次时缓慢增强,即随着叠加次数的增加,激发效果增强,传播距离和记录台数也逐步增加。     

Analysis of the 2012–2013 Torreperogil-Sabiote seismic swarm

This study analyses the temporal clustering, spatial clustering, and statistics of the 2012–2013 Torreperogil-Sabiote (southern Spain) seismic swarm. During the swarm, more than 2200 events were located, mostly at depths of 2–5 km, with magnitude event up to m_bLg 3.9 (M_w 3.7). On the basis of daily activity rate, three main temporal phases are identified and analysed. The analysis combines different seismological relationships to improve our understanding of the physical processes related to the swarm's occurrence. Each temporal phase is characterized by its cumulative seismic moment. Using several different approaches, we estimate a catalog completeness magnitude of m_c≅ 1.5. The maximum likelihood b-value estimates for each swarm phase are 1.11 ± 0.09, 1.04 ± 0.04, and 0.90 ± 0.04, respectively. To test the hypothesis that a b-value decrease is a precursor to a large event, we study temporal variations in b-value using overlapping moving windows. A relationship can be inferred between change in b-value and the regime style of the rupture. b-values are indicators of the stress regime, and influence the size of ruptures. The fractal dimension D₂ is used to perform spatial analysis. Cumulative gamma and beta functions are used to analyse the behaviour of inter-event distances during the earthquake sequence.     

上派河大桥控制爆破拆除的施工实践

运用控制爆破技术,成功完成对悬臂钢筋混凝土斜拉桥爆破拆除,其布孔、装药、防护等方面为同类工程提供了参考作用。     

Point- and curve-based geometric conflation

Geometric conflation is the process undertaken to modify the coordinates of features in dataset A in order to match corresponding ones in dataset B. The overwhelming majority of the literature considers the use of points as features to define the transformation. In this article we present a procedure to consider one-dimensional curves also, which are commonly available as Global Navigation Satellite System (GNSS) tracks, routes, coastlines, and so on, in order to define the estimate of the displacements to be applied to each object in A. The procedure involves three steps, including the partial matching of corresponding curves, the computation of some analytical expression, and the addition of a correction term in order to satisfy basic cartographic rules. A numerical example is presented.     

甘肃地区近震震级的量规函数研究

采用甘肃测震台网“十五”宽频带数字地震记录资料,选取自2009 年1 月～ 2012 年12 月所记录的13086 次地震事件,通过震级残差统计方法计算了各台站单台震级与台网平均震级的偏差、平均偏差和标准偏差,分析了震级偏差频次分布和定量统计,修正了ML量规函数,得到了代表甘肃地区的地方性均匀震级量规函数。     

A probabilistic performance‐based approach for mitigating the seismic pounding risk between adjacent buildings

Existing design procedures for determining the separation distance between adjacent buildings subjected to seismic pounding risk are based on approximations of the buildings' peak relative displacement. These procedures are characterized by unknown safety levels and thus are not suitable for use within a performance‐based earthquake engineering framework. This paper introduces an innovative reliability‐based methodology for the design of the separation distance between adjacent buildings. The proposed methodology, which is naturally integrated into modern performance‐based design procedures, provides the value of the separation distance corresponding to a target probability of pounding during the design life of the buildings. It recasts the inverse reliability problem of the determination of the design separation distance as a zero‐finding problem and involves the use of analytical techniques in order to evaluate the statistics of the dynamic response of the buildings. Both uncertainty in the seismic intensity and record‐to‐record variability are taken into account. The proposed methodology is applied to several different buildings modeled as linear elastic single‐degree‐of‐freedom (SDOF) and multi‐degree‐of‐freedom (MDOF) systems, as well as SDOF nonlinear hysteretic systems. The design separation distances obtained are compared with the corresponding estimates that are based on several response combination rules suggested in the seismic design codes and in the literature. In contrast to current seismic code design procedures, the newly proposed methodology provides consistent safety levels for different building properties and different seismic hazard conditions. Copyright © 2012 John Wiley & Sons, Ltd.     

沈阳地震台大震速报震级差分析

利用沈阳台测算震级与国家台网速报标准震级进行比较,寻找存在震级差的原因,分析得出,台站测算震级存在误差的原因主要有震中距,方位角,地震震级等。     

GPS姿态测量中模糊度搜索方法的确定与比较

GPS载波相位观测值作为高精度观测量在姿态测量中得到广泛应用。姿态测量系统中,基线长度可以通过提前量测精确求得。作为约束条件,可以用于模糊度搜索,提高模糊度搜索效率和准确度。本文介绍了传统的LAMBDA方法,且在此基础上提出了附有基线长度约束的LAMBDA搜索方法,并比较了两者的搜索效率。     

建立大型线路工程独立坐标系的方法

本文结合大型线路工程控制测量实例,分别对根据E1、E2、E3椭球建立适合大型线路工程独立坐标系的GPS方法进行阐述。应用实测数据对采用不同椭球作为投影面得到的平面距离进行比较,结果表明,应用区域性椭球建立的GPS平面控制网的控制测量成果适合国家测量规范的要求。     

PATHCLUST在聚落遗址空间模式研究中的应用

本文主要讨论PATHCLUST算法的原理和方法,给出了聚类分析选择最优算法应注意的问题;以郑州地区仰韶文化聚落遗址空间模式研究为例,讨论了PATHCLUST算法在聚落遗址空间模式研究中的应用。结果表明,此算法可有效揭示聚落遗址的空间分布结构规律。