地震波初至拾取是地震预警、地震定位等地震资料处理工作的重要基础,其实时性和准确性直接影响地震资料处理工作的效率.实际应用中,地震波初至拾取受日益增多的噪声干扰较大,传统地震波初至拾取算法很难兼顾实时性、准确性.针对上述问题,本文提出一种基于Delaunay三角(简称为D三角)剖分的天然地震波初至实时拾取算法.首先,本文对STA/LTA-AIC(Short-Term Average/Long-Term Average-Akaike Information Criterion)算法特征函数进行参数分析,引用包含平方项和差分项的特征函数,增强算法的实时性;其次,通过改进时窗位置并加入取消时窗的方式,增加算法抗短时强噪声干扰的能力;最后,考虑到地震波在两台站间的最快传播速度,由台间距和地震波最大走时设置走时残差阈值,并依据D三角关系,提出D三角触发判别准则剔除部分干扰噪声.川渝地区现场数据验证表明,本文改进的STA/LTA-AIC算法提高了单台拾取地震波初至的抗短时强噪声能力,基于D三角剖分的天然地震波初至拾取算法能排除各台站误拾取信号,实时、准确、可靠拾取出实际地震波初至时刻.
Real time picking algorithm for natural seismic wave first arrival based on Delaunay triangulation
Picking up the first arrival of seismic waves is an important foundation for earthquake warning,earthquake positioning,and other seismic data processing work.Its timeliness and accuracy directly affect the efficiency of seismic data processing work.In practical applications,the first arrival picking of seismic waves is greatly affected by increasing noise interference,and traditional seismic wave first arrival picking algorithms are difficult to balance real-time and accuracy.In response to the above issues,this article proposes a real-time picking algorithm for natural seismic wave first breaks based on Delaunay triangulation(abbreviated as D-triangulation).Firstly,this article conducts parameter analysis on the feature functions of the STA/LTA-AIC(Short Term Average/Long Term Average Akaike Information Criterion)algorithm,citing feature functions containing square and difference terms to enhance the real-time performance of the algorithm;Secondly,by improving the position of the time window and adding the method of canceling the time window,the algorithm's ability to resist short-term strong noise interference is increased;Finally,considering the fastest propagation speed of seismic waves between two stations,a residual threshold for travel time is set based on the distance between stations and the maximum travel time of seismic waves.Based on the D-triangle relationship,a D-triangle triggering criterion is proposed to remove some interference noise.The on-site data verification in the Sichuan Chongqing region shows that the improved STA/LTA-AIC algorithm in this article improves the ability of a single station to pick up seismic waves with strong short-term noise resistance.The natural seismic wave first arrival picking algorithm based on D-triangulation can eliminate the false picking signals of each station,and accurately and reliably pick up the actual seismic wave first arrival time in real time.
Picking up the first arrival of seismic wavesDelaunay triangulationSTA/LTA-AIC algorithmCharacteristic functionTime window
万方数据
维普
