烟熏记录地震仪的技术改造：ARA放大器的应用之二

对六十年代生产的烟熏记录地震仪进行技术改造:保留烟熏记录,保留65摆(或DD—1摆)以ARA积分放大器代替线性放大器,以线性笔头代替积分记录笔,增配电子报警器及交直流自动切换电源,组成新的地震观测仪器系统。技术改造方案在广东地震台网实施、两年来仪器运行正常、效果很好。     

Preliminary analysis of the first digital recordings obtained in the Portuguese seismographic network — Attenuation studies

During experiments with digital stations in the period 1985–1987, twenty five earthquakes with magnitudes m _b in the range 2.9 to 4.8 and epicentres located within the area 36°–42.3° (N) and 4.5°–13.6° (W) were recorded at Montemor (MOE) and Montachique (MTH). The three-component recordings were obtained by Geotech S13 instruments with 1 second period. A preliminary analysis of the recordings consisted in the determination of amplitudes and spectral contents of P and S waves, and led to the following observations: (1) The attenuation of waves is expressed by the equation V = exp(C ₂).R ^C ₁. exp(C ₃.M), where V stands for acceleration, velocity or displacement; M-magnitude; R-focal distance; C ₁, C ₂ and C ₃ are constants to be obtained by least square fitting. The application of this equation led to C ₁ of the order 1.7 for displacement, 1.8 for velocity and 2.0 for acceleration, with an average mean square error 0.8. (2) The ratios L/T (longitudinal/transversal amplitudes), for velocity and displacement, showed a tendency to reduce with increasing focal distance, being 2 for short distances (<50 km) and 1 for long distances (400 km). (3) The ratios S/P (S-wave/P-wave amplitudes), although with a large dispersion, showed a slight tendency for increasing with focal distance. (4) The predominant frequencies also showed a slight tendency to decrease with increasing focal distance and with magnitude. (5) The dependence of C ₁ with frequency (3 to 12 Hz) is well behaved from 0.95 to 1.75 (for the velocity trace).     

用DFS-V地震仪辅助道记录折射地震信号的方法

用DFS-v地震仪辅助道记录折射地震信号的方法在国内尚属首次采用。本文把此法与其它折射地震信号记录方法的优缺点进行了比较分析,进而对采用此法的有关技术问题及其技术意义作出阐述。     

人工与自动观测静风的差异分析与应用

利用2000—2010年全国2195个国家站人工观测转为自动观测时期各站2年的资料,对2 min风向、风速进行对比分析,统计了人工与自动观测静风的差异,研究了引起差异的原因,并探索了年静风频率的应用方法。结果表明:全国人工观测的平均年静风频率为26.3%,自动观测为10.0%,平均风速越大,年静风频率越低,自动与人工观测的差异越小。湖北省平行观测期第一、第二年人工观测的平均年静风频率分别为29.1%、28.8%,自动观测较人工观测分别少18.1%和1 2.4%。造成该差异的主要原因是人工观测风速时,采取四舍五入保留整数位的方式,当风速0.5 m·s~(-1)时记录为静风,而自动观测风速≤0.2 m·s~(-1)时记录为静风。评估湖北省平行观测期第二年自动与人工观测年静风频率差异,将自动观测静风按人工观测方式处理后平均年静风频率为22.8%,与平行观测期第二年人工观测的对比差为-6.0%,较订正前(-12.4%)有明显减少。     

煤田三维地震勘探的观测系统设计现状与讨论

根据煤田三维地震观测系统设计现状,指出常规的的评价参数已不能完整反映观测系统的性能。在煤田精细构造和岩性勘探中,还需增加对采集脚印、反射弥散、目的层照明度和照明率等属性的分析。通过对几种观测系统从循环节、唯一炮检距覆盖次数、炮检距变化系数等属性的分析讨论,认为：①对目前常用的1/2横向滚动的束状观测系统应通过减少滚动线数进行优化;②在低信噪比和静较正问题突出、勘探目的以构造为主的地区,应采用有利于构造成像的窄方位观测系统,在高信噪比和静较正问题不突出的地区,应采用有利于提高分辨率和储层预测的宽方位观测系统;③同类型观测系统就其面元属性而言,斜交型观测系统普遍优于正交型观测系统。     

自动观测与人工观测的短历时雨量差异分析

利用湖北省内黄石等11个国家气象站2005—2007年自动观测、人工观测同期分钟雨量数据,分别逐年滑动提取5、10、15、20、30、45、60、90、120、150、180 min这11个短历时的最大雨量值及开始时间。从时间偏差、雨量偏差、设定时间偏差范围三方面分析两种观测下的短历时雨量差异,并利用分析结果建立了自动观测、人工观测短历时雨量关系方程。结果表明:(1)从自动观测、人工观测分钟数据中提取短历时雨量时,对降水过程判断基本一致,选取同一降水过程,各降水历时70%以上样本数据的开始时间偏差基本在0~10 min。(2)各历时自动观测、人工观测短历时雨量提取结果比较吻合,两者雨量偏差范围在±10%以内的情况占样本总数的68.6%,且自动较人工观测短历时雨量偏大的情况居多,占样本总数的60.9%。(3)设定时间偏差范围为0~5 min,自动观测、人工观测短历时雨量提取结果非常吻合。将时间偏差缩小到0~2 min,吻合度进一步提高。(4)分别建立了11个降水历时自动观测、人工观测短历时雨量关系方程,两套数据相关系数达到0.92以上,自动观测、人工观测短历时雨量变化非常一致。     

Evaluation framework for regulatory requirements related to data recording and traceability designed to prevent illegal, unreported and unregulated fishing

In 2001 FAO published the “International Plan of Action to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing”. Based on this plan, national and supranational authorities have developed legislation to fight the so called IUU fishing. A key aspect of the legislation proposed so far is the mandatory recording of some data elements and the requirement that these data should be available for access through a traceability system. This article outlines a general framework for evaluation of these types of requirements, using a predictor-outcome N-way matrix. A “good practise” system is described, against which the existing systems and practises can be evaluated. The framework can be used to assess if the regulatory requirements ensure that the relevant IUU fishing identification data are made available, and it can also be used to evaluate the requirements imposed on the traceability system.     

多波束回波强度数据记录方式比较

分析了三种不同多波束测深系统回波强度的记录方式及数据结构,基于各自生成声纳图像的特点规律的差异,按其声纳图像不同用途对多波束测深系统进行了归类,其结果可为用户结合自身需求,正确购置多波束测深系统及合理应用声纳图像提供参考.     

钻孔应变台站记震能力研究

以昌平台体应变为例,研究了体现钻孔应变台站记震能力的方法,并对计算步骤和处理方法进行了说明.选取20套中国大陆观测时间较长且数据较好的钻孔体应变仪观测记录作为研究对象,计算出其各自的记震能力线,给出各台对6级地震的响应范围.此公式不仅可以量化钻孔应变仪的对地震的反应能力,而且是对地震仪器的一种新的科学评估方法.同时,基于地震前兆释放能量小于地震发生时释放的能量的基本理解,此结果对于确定地震前兆的位置和震级范围也有参考价值.     

永春井水位对远大地震的记震能力及同震效应特征分析

以永春井水位记录到的远大地震的同震效应为研究对象,分析该井水位的记震能力,发现2007年9月前后该水位记震能力有所提高,可能原因是2007年后福建省地震强度和频度明显增强.在地震孕育过程中由于区域应力场的变化使得含水层受力状态发生变化,从而引起井孔记震能力发生变化.研究还得出该水位同震效应特征:水位同震效应最大震幅总体...