山西数字测震台站观测动态范围和台基背景噪声分析

通过对山西数字测震台网台基背景噪声的计算和分析,得出各台基背景噪声地动速度均方根值(RMS)、有效测量动态范围、噪声信号功率谱。该研究结果为山西省主动震源技术发展和应用提供基础资料,也为测震台网的规划建设提供理论依据。     

黑龙江省测震台站背景噪声及动态范围分析

通过对黑龙江省测震台站台基背景噪声数据的计算和分析,得到当前各参评台站台基背景噪声地动速度均方根值（RMS）、台基噪声等级以及有效测量动态范围,并对存在突出问题的PSD曲线进行分析。通过计算各台站功率谱密度,得出台站在不同频段受干扰的情况。分析认为,黑龙江省29个台站环境地噪声水平为Ⅰ级,碾子山地震台环境地噪声水平为Ⅱ级（受当地采矿业机械震动影响）,七台河地震台环境地噪声水平为Ⅳ级;除七台河地震台观测动态范围小于130 dB,其他台站均大于130 dB。     

台站测震观测资料质量管理系统

地震速报和地震观测报告是地震台站测震资料两项十分重要的产出。这些产出不仅影响地震目录的编制工作 ,也对大震快速应急反应产生直接的影响 ,因此 ,加强台站观测资料质量管理 ,提高资料的产出质量 ,为地震科研提供连续、准确的观测数据也是十分必要的。为了科学的、定量的对地震资料质量进行管理 ,我们研制了一套检测台站测震观测资料质量的管理系统 ,采用该系统对各地震台的地震观测资料进行质量管理 ,既公正、准确 ,又提高了管理工作的效率 ,最重要的是通过这项工作可以更科学地对测震资料的产出进行质量评比 ,对于促进台站提高地震速报…     

风电机组对测震台站观测影响的实验研究

为了在测震台址勘选中对规避风电机组这类新生的常见干扰源有定量参考依据,以减少盲目性,提高台址勘选效率,在野外开展了定量实验,取得了实地测试数据,并初步探讨了风电机组干扰源的振动衰减关系。研究认为,对于风电机组这类干扰源,测震基岩固定台站Ⅰ级环境地噪声水平的建议规避距离为800 m。     

数字测震系统动态范围分析及适配

本文在讨论了影响数字测震系统动态范围因素分析的基础上,给出了在期望的台网监测能力的情况下,实现数字测震系统中地震计的适配的方法。并指出其具有同时监测微震及中强地震的能力。此外,本文还给出了数字测震系统标定结果的描述方法。     

基于ArcGIS的呼和浩特—乌兰察布地区测震台站布局优化

选取内蒙古测震台网呼和浩特—乌兰察布地区8个固定台站及呼和浩特附近地区野外观测项目建设的31个流动台站,计算各台站地震监测能力,分析加密区监测能力变化,针对监测能力较弱区域,利用ArcGIS的空间分析功能,实现新建台站选址的点位确定,提出未来合理布局方案。     

台站地磁观测数据精度提高方法

在当前多种地磁日常数据处理方法基础上,探讨提高地磁观测数据精度的问题.通过使用一种改进的地磁观测基线值计算方法,能有效减小外磁场变化对观测结果的影响,考虑到基线值日变化等因素,使用高阶多项式拟合基线值日变化曲线.利用该方法处理的地磁数据与实测数据进行结果比对后,发现此方法能有效提高地磁观测数据的精度和质量.     

基于ArcGIS的呼和浩特-乌兰察布地区测震台站布局优化

选取内蒙古测震台网呼和浩特-乌兰察布地区8个固定台站及呼和浩特附近地区野外观测项目建设的31个流动台站,计算各台站地震监测能力,分析加密区监测能力变化,针对监测能力较弱区域,利用ArcGIS的空间分析功能,实现新建台站选址的点位确定,提出未来合理布局方案。     

提高测震观测资料质量的几点想法

通过对台站观测资料评比标准变化的分析比较,认识到要提高测震观测资料的质量就要在震相分析、震级测定、单台报告和数据报送4个方面做好工作,就要注意地震初至波到时精度在地震观测质量中的重要性。管理人员要仔细调整观测仪器系统状态,核准本台台址的经纬度和高程参数,注意时间服务精度,使得仪器处于良好工作状态,同时提出改善地震初至波到时精度的几个建议。     

新疆数字地震台站观测动态范围和台基噪声的分析

介绍了新疆数字地震台仪器的配置,对新疆23个数字地震台站台基噪声进行分析计算。台站的观测动态范围,反映了观测仪器本身的性能和台基环境干扰背景的水平,有效动态范围大小反映记录地震信号的最大能力。台站(台网)的监测能力不仅取决于仪器的性能,而且还与台基的噪声背景有关。得出了各地震台台基的脉动噪声的均方根值、观测动态范围、地噪声功率谱。有效观测动态范围的大小与数字地震仪的种类和配置有关。新疆23个数字地震台中的21个台的台基地动噪声在1~20 Hz内符合中国数字测震台网技术规程的要求,而另外2个台,即二宫和石河子数字地震台没有达到规定指标。     

Measuring accelerometer dynamic range from seismic data using Allan deviation

We propose a new approach for calculating the dynamic range of an accelerometer based on an Allan deviation analysis of production seismic data. This test is intended as a field audit technique and does not require an unconditioned dataset from a low‐noise environment. We first show that Allan deviation can measure white noise levels using two commercial accelerometers. The analysis accurately captures the manufacturing noise density specifications and known relationships between white noise, preamplifier gain, and group forming. We then show that a production seismic dataset is suitable for an Allan deviation analysis because the results are not critically affected by a recording filter. Finally, we illustrate the proposed technique by calculating the dynamic range of an accelerometer channel in a seismic streamer using a production dataset.     

用多通道AD分级采集扩展地震数据采集器的动态范围

地震数据采集是地震信号数字化必不可少的环节,动态范围是其一个重要的性能指标.实际地震信号的动态范围在160 dB以上,而目前普遍使用的24位地震数据采集器动态范围相对较小且在50 Hz采样率时最大只达到135 dB,致使24位地震数据采集器在实际使用中对小信号分辨率不够,不能有效提取地震信息;在大地震时又容易使数据采集器出现饱和限幅失真的现象而失去地震监测记录功能.本文针对在地震监测和地震研究中需要具有高分辨率和高动态范围的地震数据采集器这个亟待解决的问题,提出一种采用多通道AD转换器并行分级采集的方法,讨论了通道间失配及其标定.对研制实验样机的测试表明,其动态范围在50 Hz采样时可以达到157 dB以上,线性度优于0.005%.     

Application of the method of dynamic calibration for IMS stations in regions with lower seismic activity

The Method of Dynamic Calibration (MDC) of stations of the International Monitoring System (IMS) was developed for calibrating regions where no underground nuclear explosions were carried out, with the purpose of providing conditions for implementation of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in nontrivial cases. Initially, the MDC had been presented in [Kedrov, 2001; Kedrov et al., 2001; Kedrov O.K. and Kedrov E.O., 2003] and then considered in detail in [Kedrov et al., 2008]. The core of MDC relates to adapting diagnostic parameters for the identification of underground nuclear explosions (UNE) and earthquakes elaborated for the region of Eurasia, taken as a basic region (BR), for other researched regions that differ from BR in the character of the attenuation of seismic waves. The unique characteristic of this method lies in the fact that calibration of diagnostic parameters with the help of attenuation coefficients b _Δ at varied source-station traces is implemented using only natural seismicity data within the limits of an explored region and does not require special underground chemical explosions. The MDC algorithm is implemented in the research program ”Kalibr”, which was tested by using the experimental data from Eurasia region. It is shown in this work that MDC can be used for calibration of regions where a very low level of natural seismicity is observed. According to the results of the calibration of diagnostic parameters at IMS stations in several regions of North America, Africa, and Asia, the approximate classification of propagation conditions for seismic signals at source-station traces in platform and tectonically active regions is made. The results for the development of two research programs, “Spektr” and “Signal”, are presented; this software is intended for automation of calculation procedures for spectral diagnostic parameters of UNEs’ and earthquakes’ identification by amplitude spectra of P waves and by the maximal amplitudes of P, S, and LR signals. The application of these programs allowed us to accelerate the whole calibration procedure for a particular source-station trace using the ”Kalibr” program.     

Means of synchronization of independent seismic stations in seismic arrays

Basic reasons for different kinds of failures of record synchronization of the independent seismic stations, operating as elements both of domestic and foreign seismic arrays, are established. Proceeding from it, software and hardware are proposed for ensuring reliable and precise synchronization of stations. Their operation is based on periodic fine tuning of the station’s analog-to-digital converter (ADC) sampling cycle by an exact time signal obtained from the GPS receiver. This procedure is executed with minimum or even no additional load on the controller of the seismic recorder. Such an approach allows not only matching each ADC sample to astronomical time, but also to provide simultaneous ADC sampling of all stations in the seismic array with an accuracy of 10 μs, which is especially important for solving a number of geophysical problems. Experimental researches and trial operation of the created equipment are carried out. High reliability of the equipment and compliance of technical characteristics to the purposes of the development are confirmed.     

智能地震台站试验性研究

通过安装在台站的软硬件设备和远程测控平台,智能地震台站综合智能监控系统可以对无人职守地震台站设备的工作状态和环境进行实时监控,并能够自动判定台站故障点及发出报警信息,实现异地操作台站电源及观测设备等.试点运行结果表明,该系统运行稳定可靠,可以对台站的观测设备进行有效地保护,并极大地提升了数字地震台网中心的工作效能.     

基于Sentinel模块传感器在地震台站电源中的应用

在地震观测仪器设备的电源中,大量使用了蓄电池以保证地震监测仪器电源不间断供电,从而保证了地震观测数据的连续率。但是如何对蓄电池的性能进行在线检测呢?蓄电池电量监测智能传感器Sentinel提供了解决问题的办法。本文介绍了电量监测智能传感器Sentinel在攀枝花南山台的使用情况。     

关于地震台站极性校正的问题

国内外的台网中总是一些台站，其极性读取似乎是由大量台站Ｐ波初动的整体分布确定的震源机制相矛盾，这些矛盾通常被作为坏读（ｂａｄ ｒｅａｄｉｎｇ）处理，造成台站的极性问题的复杂原因究竟是什么，利用ＮＥＩＣ的核爆资料，文中给出两种可能推测：台站仪器本身的不可和地震本身的复杂性。     

遥测地震台站的防雷思考

测震作为地震监测的主要手段,在地震的监测预测中有着非常重要的作用.为满足测震需要,无人值守遥测地震台站建设不断增多.然而.测震台台基的选择和避雷接地电阻的要求是一对矛盾.台基好电阻率一般较高.要达到较低的接地电阻很难,涉及的经费开支也较大.本文应用雷害风险评估方法,讨论遥测地震台站防雷问题,提出因地制宜限制投资的防雷设...     

地震遥测系统提高抗干扰能力的措施

提高地震遥测设备的抗干扰能力可以通过采用频率参差技术、增大天线等间隔技术以及采用定向天线的办法。     

Very broadband seismic background noise analysis of permanent good vaulted seismic stations

This paper describes the results of a preliminary study conducted to analyze seismic background noise at sites of recently deployed very broadband stations of the Egyptian National Seismological Network (ENSN). The main purpose of the study is to assess the effects of permanent seismic vault construction and also to establish characteristics and origin of seismic noise at those sites. Another goal of this study is to determine the time needed for noise at those sites to stabilize. The power spectral densities of background noise at short period band (SP), very broadband (VBB), and ultra long period band (ULP) for each component of each broadband seismometer deployed in the different investigated sites are calculated. A MATLAB code has been developed that manages data processing and data analysis and compares the results with the high-noise model (NHNM) and low-noise model (NLNM) of Peterson (1993). Based on the obtained analysis, the noise stability and the efficiency of each station to record regional and teleseismic events are measured. The results of this study could be used in the future to evaluate station quality, to improve those processes that require background noise values, such as automatic association, and to improve the estimation of station and network detection and location thresholds.