Based on the analysis of earthquakes with M≥5 in Huayingshan fault zone and the present moderate and small seismicity, the background and regional seismicity characteristics in this area are discussed. It is considered that the southern section of the fault zone is the main seismicity area, especially in Yibin, followed by the middle and northern sections. The distribution characteristics of “quiet-active” period of earthquakes with M≥5, the law of “weak activity-enhancement” of earthquakes with M≥3, and the acceleration of strain energy release rate after Changning MS6.0 earthquake in 2019 provide references for the prediction of earthquakes with M≥5 in this area.

本文简单介绍了Hilbert-Huang变换(简称HHT)的概念,并且以九寨沟Ms7.0级地震和宁强Ms5.3级地震为例,对收集到的陕西南部不同的15个测震台站所记录的地震波利用HHT进行数据分析,探索地震波形蕴含的信息.结果表明:①HHT在地震数据滤波处理上有很好的效果;②HHT方法能精准地刻画地震波在不同时间节点上的变化状态;③清晰展现了地震时间-频率-振幅之间的相互关系;④利用HHT方法得到九寨沟地震与宁强地震的主频范围并得出不同频率所释放的能量大小,两次地震频率范围分别为0.0313～2 Hz和0.0313～4 Hz.

In consideration of the situation that a massive increase in the amount of data caused by the improvement of the sampling rate of the precursor instrument,based on the daily data collection of all the precursor observation stations in Shaanxi Province,the study on the quality quantitative analysis algorithm is carried out from two aspects:continuity and stability. Through the designed program,the anomalies of the observation data are automatic detected and the complete rate is calculated. Finally,the stability evaluation results of each item of each station are given in the condition of removing interference data. All results are saved in the database in which tables are newly added and designed according the standard format of precursor database. In order to provide the basis for data sharing services,both information support for the dynamic management of the station and technical exploration for other related observation data are provided.

High-speed railway construction is a major strategic measure to achieve sound and rapid economic development in the new era. A high-speed railway network as long as 16 000 km will be constructed all over China in the coming future. Geo-electric field observation is an important way for earthquake precursory observation and 110 geo-electric field stations have been in operation since 2010. It is inevitable for the high-speed railway lines to interfere with geo-electric field observation. Therefore, studying and analyzing the influence on the geo-electric field observation by the high-speed railway design is a new issue, which has practical signifi- cance for applying the observation data, exploring the anti-interference method and selecting the site of new stations. The interference with the observation in Baoji geo-electric field by the high-speed railway construction is analyzed and the conclusion is given out in the paper.