宁夏测震台网使用振动持续时间测定震级M_D的公式

本文用149次地震资料拟合出宁夏所属台网各台由振动持续时间求算震级M_D的公式,给出了各台M_D公式中的系数α,β,并讨论了当震级M_L≥5.0时持续时间“短缺”或饱和的原因。经统计检验,由持续时间测算的震级M_D比用最大振幅测算的震级M_L的残差减小一倍多,即精度有明显提高。     

福建测震台网单台震级偏差与台站场地响应关系的初步分析

利用福建测震台网2008年10月~2015年12月记录的每个事件至少有6个台站测算震级的3069个区域地震事件,进行单台震级与台网平均震级的偏差统计,获得了各台站的总的震级平均偏差为-0.31~0.68,并统计各台站测算震级所量取最大记录振幅相应的周期,获得优势周期为0.06~0.38s;通过Moya方法反演各测震台站的场地响应,获得98个台站对1~20Hz频带的场地响应,结果显示场地对某些频带信息有放大或抑制作用;通过比较Wood-Anderson地震仪摆固有0.8s周期所对应的场地响应、各台样本优势周期所对应场地响应的震级偏差与各台总的震级平均偏差,发现台站测算震级相应优势周期的场地响应的震级偏差与台站震级平均偏差有较好的线性关系,表明单台震级的偏差与测算震级所量取最大记录振幅相应的周期的场地响应有较大关系。     

长春地震台大震速报震级偏差研究

本次研究选用了本台 2 0 0 0年全年的速报地震资料 ,重新测算了DK 1地震仪各分向记录的面波震级 ,并以《中国地震速报台网观测报告》给出的震级为标准震级 ,进行了震级偏差统计分析。研究结果表明 ,以长春台DK 1地震仪水平向高倍档记录测算的面波震级平均偏低 0 1 1 ,标准误差为± 0 2 1 ;以水平向低倍档记录测算的面波震级平均偏高 0 1 0 ,标准误差为± 0 2 0 ;以垂直向记录测算的面波震级平均偏低 0 2 4,标准误差为± 0 2 6。通过对统计结果的全面分析 ,分别给出了长春台DK 1地震仪水平向高低倍档和垂直向记录测算面波震级的台站校正值。     

两种震级标度讨论

分析论述了我国在测报近震震级和面波震级业务中存在的种种问题，用现行起算函数测算的ML随震中距存在系统偏差，近场偏低，远场偏高；此函数系统建立的方法有不合理之处，它不适于DD-1仪。用现行公式测算的MS与国际上震级水平不一致，总体趋势偏高；在90(距离上震级零点严重失控；用单一水平向记录计算MS是个原则性差误。需要用新的起算函数系统代替R1(()计算ML; 需要用新的公式取代现行公式计算MS。     

泉州数字地震台速报震级偏差分析与校正

选取2004-01～2007-11共180多个速报地震,经震中距校核后测算的MS震级与全国大震速报台网发布的MS震级比对,得出泉州台在震级测算方面的偏差情况。并根据不同地震的相应特征,确定相应的震级校正值,以此提高泉州台的地震速报精度及作为提供日常处理地震资料数据的技术依据。     

灌云地震台面波震级偏差分析

选取2019年1月—2021年12月灌云地震台远震事件记录,将灌云地震台测算的面波震级与中国地震台网中心统一正式报目录震级进行对比,计算二者面波震级偏差平均值,并分析震级偏差与震级、震中距、震中方位之间的关系。结果表明：灌云地震台面波震级与中国地震台网中心统一正式报目录震级平均偏差为-0.08,总体偏差较小,表明该台地震记录精度较高。     

攀枝花台近震震级测算研究

通过对攀枝花台近震震级测算和周边地震台网及台站的震级结果进行综合对比,包括对测算方法和地震波形传播方式进行探讨.试图研究台站近震震级测算差异并初步找出与地质构造的相关关系;以期提高台站近震震级测算能力,减小误差.     

宝昌地震台面波震级偏差分析

选取宝昌地震台2016年1月至2018年12月国内外M_S≥5.0地震震级资料,将其与中国地震台网中心（CENC）地震数据管理与服务网站公布的标准震级进行震级偏差统计分析,并从震级、震中距、震中方位、震源深度等方面讨论了宝昌地震台面波震级存在偏差的原因。     

地震震级的实用化

目前我国台网测定震级仍存在较大误差,中国大陆浅源地震Ms和国际ISC测定m_b的换算,在Ms4.5—6.0之间有较大的离散。国内Ms和M_L的换算关系式有几种,震级差△M_L最大可达1.2级。本文初步分析震级测定的误差和影响震级的几种可能原因,分析我国沿用震级公式的现状,提出一些意见和建义。     

中国地震观测台网速报震级的分析

本文介绍并分析了中国地震观测台网及各速报台站目前速报震级的现状,存在的问题及原因,并利用1984、1985两年速报震级资料,统计分析了中国地震观测台网确定震级的精度及各速报台相对全国地震台网测定震级的偏差,同时也统计分析了全国地震台网相对地球物理所临时报告和美国地质调查所震中初定报告(PDE)的震级的偏差。并对所得结果进行了初步的讨论。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

Dissolved Carbohydrate Concentration,Composition, and Bioavailability to Microbial Heterotrophs in Stream Water

Dissolved total carbohydrates (DTCH), dissolved free monosaccharides (DFMS), dissolved organic carbon (DOC), biodegradable DOC (BDOC), and humic substances (HS) were measured in White Clay Creek (WCC), a stream in southeastern Pennsylvania Piedmont, USA. Samples were collected over different seasons and under baseflow and stormflow conditions. DOC concentrations ranged from 1.0 to 12.8 mg/L C with the highest concentrations associated with stormflows. Carbohydrates ranged from 0.42 to 12.4 μM and accounted for 2.9 to 12.7% of the DOC. Humic substances represented the major DOC fraction, accounting for 55 to 72% of the DOC pool under all flow conditions. The humic fraction had a lower carbohydrate content (4.4%) than the non-humic fraction of DOC (7.2%). Stormflow DOC was enriched in carbohydrates relative to baseflow DOC, but the percentage of humic-C changed little. Carbohydrates were primarily present as dissolved polysaccharides (55%), but a significant fraction was bound to humic substances (40%), while a small proportion was present as monosaccharides (5%). The major monosaccharides in stream water, listed in order of decreasing concentration, included glucose, galactose, rhamnose, xylose, arabinose, mannose, and fucose. On average (30.6 ± 7.4)% (n = 44) of the stream water DOC was biodegradable, and carbohydrates accounted for 9.9 to 17.7% of the BDOC.