地震检测与震相自动拾取研究

针对微震事件易受噪声干扰等特点，本文将STA/LTA方法和基于方差的AIC方法（var-AIC）相结合，在震相到时初步拾取的基础上，使用台站的德洛内（Delaunay）三角剖分及台站间最大走时差约束来减少噪声干扰的影响. 利用到时进行地震定位之后，根据台站预测到时，在设定的时间窗内对地震震相进行更精细的分析. 特别是针对微震事件信噪比低的特点，设计了基于偏振分析的拾取函数，根据窗内STA/LTA方法和var-AIC方法的拾取结果自动选择合适的值作为震相到时. 最后，对西昌流动地震台阵2013年304个单事件波形数据的分析处理和检验结果表明，本文方法较传统方法具有更高的地震事件检测能力和更高的震相拾取精度. 

Earthquake detection and automatic phase picking

With the continuous development of digital seismic networks and the application of mobile seismic array observation technology, arrival picking of seismic phases and detection of seismic events are paid more and more attention. Based on the preliminary results obtained by STA/LTA and AIC method, this paper combines the Delaunay triangulation and the maximum travel-time difference between stations to reduce the influence of noise. The arrival time predicted in every station is obtained by earthquake location on the basis of the preliminary results. Moreover, in accordance with the feature of low signal noise ratio of microseismic events, this paper developed a new phase picker which is based on the polarization. According to the results of STA/LTA method and AIC method in the time window, it automatically selects the appropriate values as arrival times. The analysis and processing of 304 seismic events recorded by Xichang portable seismic array in 2013 demonstrate that the new method proposed in this paper has stronger earthquake detection capability and higher seismic picking accuracy than traditional methods.