(中国地震局地球物理研究所,北京 100081)

MEMS烈度计; STA/LTA; 拾取; 运算时间

The Applicability Analysis of STA/LTA Algorithm for MEMS Seismic Intensity Instruments
ZHONG Yuan,HU Xingxing,TENG Yuntian,CHEN Bo,HE Zhaobo,SHEN Xiaoyu

(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

MEMS seismic intensity instruments; STA/LTA; picking; computing-time


为解决用于高密度布设的低成本MEMS烈度计集成软、硬件资源有限,且难以嵌入较为复杂算法的这一问题,基于Matlab的仿真计算,通过讨论在不同特征函数、时窗长度和短窗位置下STA/LTA值的变化趋势、拾取效果和运算时间,以选取能提高算法灵敏性、改善地震事件拾取效果和提高算法计算效率的参数,并将改进的STA/LTA算法应用于实际地震数据处理。结果表明:不同的特征函数对事件拾取率、拾取时间偏差和算法运算时间影响不同; 长短时窗长度相差越大,STA/LTA值的变化越明显; 时窗越长,算法运算时间越长; 短窗置后可以增大STA/LTA值的变化幅度、减少算法计算量,改善算法拾取时间。改进的STA/LTA算法拾取效果更好,计算效率更高,占用内存资源更小,更适用于集成资源有限的MEMS烈度计。
Though a number of forecasting techniques are used for the detection of seismic events,each of them has its own pros and cons.Since the MEMS seismic intensity instrument which features low cost and follows the principle of high-density deployment has limitation in integrating software and hardware resources,it is difficult to embed some more complex algorithms.Based on the simulation calculation of Matlab,this paper aims to select the parameters that can improve algorithmic sensitivity,picking-effect of seismic events and calculation efficiency according to different factors of STA/LTA algorithm including variation tendency of the STA/LTA value,picking-effect and computing-time in various situations such as different characteristic functions,different window lengths and different short-window locations.And the improvement of STA/LTA algorithm is applied to practical seismic-data processing.The final analysis suggests that diverse characteristic functions have corresponding effects on facets like event picking-rate,picking-time deviation and computing-time of algorithms; the greater difference between the lengths of long-time windows and short-time ones,the more obviously the values of STA/LTA tend to change; the computing-time of algorithm depends on the length of the window(positive correlation); putting short windows after long ones can intensify variation range of STA/LTA values,reduce calculation amount and improve the picking time.In conclusion,the improved STA/LTA algorithm can improve the picking-effect,calculation efficiency and use less memory resources,so it is more suitable for MEMS intensity instruments with limited integrated resources.