中国数字地震台网(CDSN)的近期发展

中国数字地震台网（CDSN）自20世纪80年代建成并投入运行以来,有力地促进了我国的数字地震学研究,扩大并加深了我们对地壳、地球内部构造和地震震源过程的认识,从而有助于地震预报和减轻地震灾害的研究工作．本文阐述了基于CDSN二期技术改造建立的CDSN数据通信系统,研发CDSN数字地震实时分析系统的进展．     

中国数字地震台网(CDSN)技术系统

中国数字地震台网(CDSN)经过第3期升级改造后,硬件系统性能有了质的飞跃,设备的可维护性及数据稳定性全面提升,系统的复杂程度也逐渐攀升。本文详细介绍CDSN技术系统的构成及升级过程,阐述技术规范和实施细节及对CDSN技术改造发挥的作用。     

中国数字地震台网(CDSN)的现状和进展

1　中国数字地震台网概况中国大陆邻接印度、欧亚和太平洋板块的边缘 ,其特点在于具有复杂的地壳构造和高地震活动性。中美合建的中国数字地震台网 ( CDSN)运行 1 5年来 ,在中国地震学研究中发挥了重要的作用。CDSN作为美国地震学联合研究协会 ( IRIS)部署的全球地震台网 ( GSN)的参与伙伴 ,为全球地震学研究做出了贡献。CDSN系中美地震研究科技合作议定书中的项目 ,也是两国政府间的科技合作项目之一。台网的建设始于 1 983年 5月 ,历经 3年的场地准备和技术实施 ,于 1 986年 7月建成。1 986年 1 0月 1日起 ,CDSN数据管理中心以…     

中国数字地震台网地震事件数据库系统

中国数字地震台网 (CDSN)地震事件数据库系统是一个数据服务软件系统。它以国际著名的 ORACLE数据库为开发环境 ,以 CDSN数字地震事件数据为基础 ,借鉴 IRIS等国际地震学机构优秀的数据服务方式 ,利用 rdseed、 SAC等地震学领域流行的数字软件 ,为网上用户共享 CDSN数字地震数据提供了一个全新的服务窗口。本文对该数据服务软件系统及分布数据库系统作相关的介绍。     

中国数字地震台网(CDSN)的现状

介绍了中国数字地震台网数据处理中心计算机系统的硬件软件配置和台网的数据处理及生成的地震数据。     

国家数字地震台网中心的技术系统

详细阐述了国家数字地震台网中心技术系统的组成部分与地震数据流程。计算机网络系统和地震数据硬件系统是整个台网中心技术系统的基础;地震数据接收与自动定位系统、人机交互系统、半自动CM T系统、地震数据格式转换系统和地震数据管理与服务系统这5个地震专业应用系统实现了台网中心的二个基本任务: 防震减灾和为地震基础研究服务。     

中国数字地震台网的建设与发展

ldquo;十五rdquo;（2001——2005年）期间,中国地震观测系统得到了迅速的发展,中国地震局完成了ldquo;中国数字地震观测网络rdquo;项目建设,将所有模拟地震观测系统全部进行了数字化改造,并新建了一些数字化地震台站,标志着中国的地震观测已进入数字时代. 本文介绍了新一代国家数字地震台网、区域数字地震台网、火山数字地震台网和流动数字地震台网的规模、布局原则和主要功能.      

中国数字地震台网的建设与发展

地震台站作为地震系统基础单元,是设置地震监测设施并开展地震监测的基层机构,完备的地震监测设施和良好的地震观测环境是地震观测的基础。掌握完整、准确的地震台站基础信息是做好地震台站管理的关键。由于观测手段更新、观测环境变迁和建设条件差异的原因,投入运行后的地震台站基础信息与规划设计有偏差,一定程度上影响地震观测数据的准确性和有效性。本文论述了地震台站基础信息完善的意义,通过实例说明准确、有效的地震台站基础信息,在地震观测干扰排查、观测环境保护和台站升级改造方面的应用,旨在引起行业重视地震台站基础信息的收集、管理和应用,进而确保地震观测数据科学有效。     

宁夏数字地震台网观测技术系统

宁夏数字地震台网观测技术系统是国家重点建设的防震减灾基础设施项目之一,系统架构的技术特点是:台网数据处理技术先进,子台布局合理,采用光纤传输方式,实现了网络到台站、IP到仪器。台网中心采用JOPENS地震处理软件包,可支持台网数据的实时监控和汇集,结合自动和人机交互方式实现地震事件处理,数据平台初具规模。新的台网观测技术系统使测震台网的监测能力得到明显提高,由原来的银川市区M_L≥1.5,宁夏大部分地区M_L≥2.0,宁夏境内M≥2.5,提高到宁夏大部分地区能控制在M_L1.5、边缘能控制在M_L 2.0。提高了台网的地震速报能力,这些改进将在防震减灾和地震分析预报工作中发挥重要作用。     

百色水利枢纽数字遥测地震台网技术系统

介绍了百色水利枢纽遥测地震台网工程技术方案,主要仪器设备选型,并通过不断优化技术方案,确保台网的实际监测能力达到设计要求。通过实际震例检验了台网的监测能力及定位误差。从台网的运行情况表明,台网技术系统先进,设备运行稳定可靠,对监测百色水利枢纽库区及附近地区地震发挥重要作用。     

CDSN: Present status and future development

Introduction At present, China Earthquake Administration (CEA), National Nature Science Foundation(NNSF) of China, Geological Survey (USGS), National Science Foundation (NSF) of UnitedStates and Incorporated Research Institutions for Seismology (IRIS) all support Sino-Americatechnical cooperation project— China Digital Seismograph Network (CDSN). Institute of Geo-physics, China Earthquake Administration (IGCEA) and Albuquerque Seismological Laboratory,Geological S…     

日地系统研究的现状和趋势

日地系统研究的发展趋势是将日地系统各圈层作为一个整体来开展三维的定量研究,发展各国之间和各学科之间科学家的广泛合作,加强空间探测和地面综合监测网的建设,密切观测分析、理论研究、数值模拟和环境预报之间的联系,直接为生存和生产服务．     

日地系统研究的现状和趋势

日地系统研究的发展趋势是将日地系统各圈层作为一个整体来开展三维的定量研究，发展各国之间和各学科之间科学家的广泛合作，加强空间探测和地面综合监测网的建设，密切观测分析、理论研究、数值模拟和环境预报之间的联系，直接为生存和生产服务．     

新疆天山地区地下流体地震前兆研究的现状与发展前景

系统地介绍了新疆天山重点震监视区下流体观测网，及其地质构造环境和地下水的成因类型，总结了２０年来地下流体地震前兆探索与地震前兆探索与地震预报研究的基本经验和成果。     

甘肃省地应力资料分析及近期地震趋势判断

甘肃省地应力资料分析及近期地震趋势判断张国英杨国栋（中国地震局兰州地震研究所,兰州７３００００）主题词应力分析异常特征甘肃地震趋势判断１资料甘肃省现有５个地应力观测站,分布在其东部和南部．近５年来,在全国资料评比中,这５个站的资料均被评为优秀,其中刘...     

R.C.框架结构的振动台试验和面向设计的时程分析方法

钢筋混凝土框架结构的弹塑性时程反应分析是抗震设计规范所要求的一项重要内容,但目前还滑有比较简单实用肯计算可靠的方法。本文进行了两个六层钢筋混凝土框架结构模型的地震模拟震动台试验,通过分析试验模型的自振特性、变形形式、加速度反应、位移反应和破坏开矿以及钢筋混凝土框架结构的实际震害,建立了面向设计的钢筋混凝土框架结构弹塑性里程反应分析的计算方法。在这一方法中,对钢筋混凝土框架整体结构采用层间剪切模型,     

Continuous real‐time analysis of the isotopic composition of precipitation during tropical rain events: Insights into tropical convection

To investigate stable isotopic variability of precipitation in Singapore, we continuously analysed the δ‐value of individual rain events from November 2014 to August 2017 using an online system composed of a diffusion sampler coupled to Cavity Ring‐Down Spectrometer. Over this period, the average value (δ¹⁸O_Avg), the lowest value (δ¹⁸O_Low), and the initial value (δ¹⁸O_Init) varied significantly, ranging from ?0.45 to ?15.54‰, ?0.9 to ?17.65‰, and 0 to ?13.13‰, respectively. All 3 values share similar variability, and events with low δ¹⁸O_Low and δ¹⁸O_Avg values have low δ¹⁸O_Init value. Individual events have limited intraevent variability in δ‐value (Δδ) with the majority having a Δδ below 4‰. Correlation of δ¹⁸O_Low and δ¹⁸O_Avg with δ¹⁸O_Init is much higher than that with Δδ, suggesting that convective activities prior to events have more control over δ‐value than on‐site convective activities. The d‐excess of events also varies considerably in response to the seasonal variation in moisture sources. A 2‐month running mean analysis of δ¹⁸O reveals clear seasonal and interannual variability. Seasonal variability is associated with the meridional movement of the Intertropical Convergence Zone and evolution of the Asian monsoon. El Niño–Southern Oscillation is a likely driver of interannual variability. During 2015–2016, the strongest El Niño year in recorded history, the majority of events have a δ¹⁸O value higher than the weighted average δ¹⁸O of daily precipitation. δ¹⁸O shows a positive correlation with outgoing longwave radiation in the western Pacific and the Asian monsoon region, and also with Oceanic Niño Index. During El Niño, the convection centre shifts eastward to the central/eastern Pacific, weakening convective activities in Southeast Asia. Our study shows that precipitation δ‐value contains information about El Niño–Southern Oscillation and the Intertropical Convergence Zone, which has a significant implication for the interpretation of water isotope data and understanding of hydrological processes in tropical regions.     

Real time hybrid simulation: from dynamic system,motion control to experimental error

Real‐time hybrid simulation (RTHS) has increasingly been recognized as a powerful methodology to evaluate structural components and systems under realistic operating conditions. It is a cost effective approach compared with large scale shake table testing. Furthermore, it can maximally preserve rate dependency and nonlinear characteristics of physically tested (non)structural components. Although conceptually very attractive, challenges do exist that require comprehensive validation before RTHS should be employed to assess complicated physical phenomena. One of the most important issues that governs the stability and accuracy of an RTHS is the ability to achieve synchronization of boundary conditions between the computational and physical substructures. The objective of this study is to propose and validate an H_∞ loop shaping design for actuator motion control in RTHS. Controller performance is evaluated in the laboratory using a worst‐case substructure proportioning scheme. A modular, one‐bay, one‐story steel moment resisting frame specimen is tested experimentally. Its deformation is kept within the linear range for ready comparison with the reference closed‐form solution. Both system analysis and experimental results show that the proposed H_∞ strategy can significantly improve both the stability limit and test accuracy compared with several existing strategies. Another key feature of the proposed strategy is its robust performance in terms of unmodeled dynamics and uncertainties, which inevitably exist in any physical system. This feature is essential to enhance test quality for specimens with nonlinear dynamic behavior, thus ensuring the validity of the proposed approach for more complex RTHS implementations. Copyright © 2012 John Wiley & Sons, Ltd.     

A new approach of selecting real input ground motions for seismic design: The most unfavourable real seismic design ground motions

This paper presents a new way of selecting real input ground motions for seismic design and analysis of structures based on a comprehensive method for estimating the damage potential of ground motions, which takes into consideration of various ground motion parameters and structural seismic damage criteria in terms of strength, deformation, hysteretic energy and dual damage of Park & Ang damage index. The proposed comprehensive method fully involves the effects of the intensity, frequency content and duration of ground motions and the dynamic characteristics of structures. Then, the concept of the most unfavourable real seismic design ground motion is introduced. Based on the concept, the most unfavourable real seismic design ground motions for rock, stiff soil, medium soil and soft soil site conditions are selected in terms of three typical period ranges of structures. The selected real strong motion records are suitable for seismic analysis of important structures whose failure or collapse will be avoided at a higher level of confidence during the strong earthquake, as they can cause the greatest damage to structures and thereby result in the highest damage potential from an extended real ground motion database for a given site. In addition, this paper also presents the real input design ground motions with medium damage potential, which can be used for the seismic analysis of structures located at the area with low and moderate seismicity. The most unfavourable real seismic design ground motions are verified by analysing the seismic response of structures. It is concluded that the most unfavourable real seismic design ground motion approach can select the real ground motions that can result in the highest damage potential for a given structure and site condition, and the real ground motions can be mainly used for structures whose failure or collapse will be avoided at a higher level of confidence during the strong earthquake. Copyright © 2007 John Wiley & Sons, Ltd.