通海地磁台地磁日变化记录准确度标定

2011年10月12日,通海地震台用Mingeo-DIM磁力仪对台站的M15和GM4的日变化记录准确度进行标定.从标定结果看,两套仪器的基线值均受到地磁日变化的影响.     

摆线漏电对拾震器的影响及排除方法

安徽灵壁地震台的测震摆房在距记录室300m 的山脚下。300m 摆线为8芯电缆。1984年10月以后在标定时发现拾震器空气阻尼 D_(10)的值在不断增大,历次仪器标定时 D_(10)的值见表1,无阻尼状态自由振荡的记录波形见图1。脉冲检查也发现仪器放大倍率相对变化多次超过15%。1985年10月进行仪器标定时发现拾震器 D_(10)的 EW 分向最大达到0.08198,好象在回路中并连了一个300kΩ的阻尼电阻在起阻尼作用。为了解决这个问题我们采取了以下措施。     

地震前兆观测仪器标定问题的探讨

标定工作，在地震前兆观测仪器的研究，使用及所得数据的处理中均已成为一个不可少的环节，但缺少有关标定问题的基石性研究和讨论。本文就标定的定义、种类、目的、要求、存在的问题等做一粗线的讨论，以期今后加强这一工作的深入研究。     

电阻率测量导线漏电的模拟实验

线路漏电是地电台站日常观测中常见的并且对观测结果有显著影响的干扰因素。为保证观测质量,规范规定每条外线路的绝缘指标应在50MΩ/Km以上。应该说,这一指标是不低的,即只要达到了这个指标,线路即使有漏电也不会对测量结果产生显著的影响。但在实践中却难以达到,即在极端天气条件下线路的绝缘度难以保证大于50MΩ。在努力改善线路绝缘性能的同时,人们也开始对指标本身进行了研究。本实验试图     

763地震仪标定软件

763地震仪标定时的计算量非常大，为了减轻其难度和保证计算正确性，编写了763地震仪标定软件，经过红山台的具体应用收到很好效果，操作简单方便，结果准确清楚。     

中国的地震烈度衰减率分区

本文采用1900年至1980年发生在中国的198个地震的等震线图,用公式 lnIi/I0=a——blnRi——cRi计算了烈度随距离的衰减率。式中I0为震中烈度,Ri为某烈度Ii等震线昕围面积的等效半径。按上式结果可将中国分成12个区,对于等震线明显受构造控制的地区,用上式分别计算了沿等震线长、短轴方向上不同的衰减率。在近场区,采用了一个与深度有关的修正量（深度因子）D,将上式改写为 ln（Ii/I0）=a——bln（Ri+D）——cRi得出了更适用的结果。对所得的分区结果和上两式中各量的意义进行了某些研究。     

湿饱和流中的Richardson数和不稳定的研究

本文推导了干、湿饱和流中的Ri数方程.选取华北的一次降水过程,利用模式输出资料计算并对比分析干空气、湿饱和流中Ri方程中的各项,发现干过程中水平风速的垂直切变对干Ri数的变化和不稳定的影响占主导地位,而在湿过程中,湿饱和Ri的分子(Brunt_Vaisala frequency, 简称BVF)对Ri数的变化及不稳定的影响可达到与分母相当的量级. 既然BVF在湿过程中对不稳定有非常重要的影响,我们寻找了更符合湿过程中实际情况的BVF表达式,以对Ri进行修正,从而更好地判断湿过程的不稳定.研究发现,由于考虑了气块的虚温效应和总的水物质混合比的变化,即考虑降水过程中部分液态水脱离气块,有效地减小了雨区的稳定性,使得修正后的湿Ri公式可能更适合于诊断雨区的不稳定.     

浙江珊溪水库地震：震源参数测定及断层结构和应力状态描述

利用遗传算法,搜索符合Brune ω^2模型的拐角频率（fc）及零频幅值（Ωc）的最佳值,测定浙江珊溪水库震区88条小震（1．5≤ML≤4．6）的地震矩（M0）、震源尺度（r）及静态应力降（△σ）。地震矩M0在10^10～10^14N·m范围内,与拐角频率fc遵循Mo∝fc^-3的规律;震源尺度和地震矩、应力降之间呈现多重标度特征,地震矩大于临界值2．3×10^12N·m（相应的震源尺度特征值约160m）时,震源尺度与地震矩的关系较强;而应力降（△σ）在震源尺度大于160m后基本趋向恒定,不随震源尺度的增大而增大。浙江珊溪水库震区自2002年7月以来,经历2次大规模的震群活动。震群释放的应力降大小与该震群的规模成正比关系,大的应力降集中在发震断层中段5～6km深度的区域,其发生时间既可以在主震之前,也可以在主震之后。     

模拟微分输入与地震仪标定仪器

引言标定地震仪放大倍数可以使用不同的地震仪自动标定仪器,如DZB-1型、CZ-1型等地震仪。计算地震仪动态放大倍数通常使用简化公式,这个简化公式是根据地震仪自动标定仪器的电压输出模式以及基本理论公式推导得出。从过去几年新疆地震局测震资料中可以看出,部分台站标定者对输入信号是否符合微分条件是模糊的,选择计算动态放大倍数的公式也不恰当,从而造成地震仪标定计算结果不够准确。文中根据地震仪标定的基本原理,结合不同的地震仪标定仪器,就如何推导计算地震仪动态放大倍数的简化公式进行了讨论。1　地震仪放大器的测定在标定地震仪…     

微型土压力传感器标定方法研究

离心模型试验常用微型土压力传感器测量地基或土与结构接触边界上的土压力。传感器使用之前应进行标定。传统的液标或气标方法不能准确反映传感器埋置过程对土体的扰动或传感器周围人为土拱边界条件形成,导致测试结果不甚理想。故针对试验条件,设计制作一套标定微型土压力传感器的方法和装置,以水、粉质黏土和福建标准砂为标定介质,考虑有无刚性靠背两种工作状态对多个传感器进行室内标定,得到标定系数。结果表明:水标未出现卸载滞后,砂标和土标均出现卸载滞后,且表现为非线性;引入滞后比R评价微型土压力传感器的滞后性,认为标定介质和传感器类型是影响滞后比的两个主要因素;传感器自身材料特性和几何特性、地基土的制备和传感器放置、加载预压和加卸载循环等对土体密实度、土体强度等的改变、工作介质和状态等对标定结果有影响。建议尽量模拟试验工作介质和工作状态,逐个标定传感器,以得到更准确的土压力测量值。     

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.