Preliminary Analysis of Observations on the Ultra-Low Frequency Electric Field in the Beijing Region
Preliminary Analysis of Observations on the Ultra-Low Frequency Electric Field in the Beijing Region
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DOI：
10.1007/s00024-004-2674-3
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发表时间：
2005-06
影响因子：
2
通讯作者：
J. Zhuang;D. Vere-Jones;Huaping Guan;Y. Ogata;Li Ma
中科院分区：
文献类型：
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作者：
J. Zhuang;D. Vere-Jones;Huaping Guan;Y. Ogata;Li Ma
本文对中国地震局台站近20年来的超低频地电信号观测资料进行了初步分析。简要介绍了仪器、操作程序和数据处理程序。分析的数据包括24小时内电信号的总强度（累积振幅）的估计值。阈值设置得足够低，以便在大多数情况下返回零观测值。非零观测值与电磁暴、偶尔的人为电效应以及一些震前、同震或震后信号有关。分析的主要目的是调查的程度，电信号可以被认为是presesteurs在字符。为此目的，来自五个台站的电信号与所选台站周围圆形区域内的当地地震目录一起进行分析。Ogata的Lin-Lin算法的一个版本用于估计和测试震前信号的存在。该模型允许测试电信号的影响，即使在考虑地震聚集的影响之后。结果表明，虽然影响地震发生的最大单一效应是成簇趋势，但电信号中仍有显著的前兆成分。另外的试验表明，这种明显的效应不是震后的特性，即使在分析中使用的模型和时间段发生变化的情况下，这种效应也会持续存在。提供了数据样本，并在当地网站上提供了完整的数据集。
This paper presents a preliminary analysis of observations on ultra-low frequency ground electric signals from stations operated by the China Seismological Bureau over the last 20 years. A brief description of the instrumentation, operating procedures and data processing procedures is given. The data analyzed consists of estimates of the total strengths (cumulated amplitudes) of the electric signals during 24-hour periods. The thresholds are set low enough so that on most days a zero observation is returned. Non-zero observations are related to electric and magnetic storms, occasional man-made electrical effects, and, apparently, some pre-, co-, or postseismic signals. The main purpose of the analysis is to investigate the extent that the electric signals can be considered as preseismic in character. For this purpose the electric signals from each of five stations are jointly analyzed with the catalogue of local earthquakes within circular regions around the selected stations. A version of Ogata’s Lin-Lin algorithm is used to estimate and test the existence of a pre-seismic signal. This model allows the effect of the electric signals to be tested, even after allowing for the effects of earthquake clustering. It is found that, although the largest single effect influencing earthquake occurrence is the clustering tendency, there remains a significant preseismic component from the electrical signals. Additional tests show that the apparent effect is not postseismic in character, and persists even under variations of the model and the time periods used in the analysis. Samples of the data are presented and the full data sets have been made available on local websites.