基于改进的希尔伯特-黄变换的地震强震动特征提取

Feature extraction of strong ground motion based on improved Hilbert-Huang Transform

2021年5月21日漾濞M s6.4地震是云南近10 a以来继M s6.5鲁甸地震和M s6.6景谷地震后发生的又一次破坏性浅源地震,其震中位于滇西北地区维西-乔后断裂带附近。震源机制结果显示:此次地震属于走滑型破裂,符合区域构造特征。为进一步研究该地震强震动特征,特引入改进后的希尔伯特-黄变换(HHT),以不同角度客观分析强震动的尺度和频域特征。研究结果表明:希尔伯特-黄变换在对实际地震动记录进行特征提取后,得到的边际谱和时频谱可在一定程度上保留原始数据的主要信息,该方法可为类似破坏性浅源地震的强震动特征分析提供更有效的信息参数,保证了信号分解的稳定性,更适于处理非平稳信号,可为现代信号应用分析于强震动特征提供另一种新思路。

The Yangbi M s6.4 earthquake on May 21,2021 is another destructive shallow earthquake that occurred in Yunnan after the M s6.5 Ludian earthquake and the M s6.6 Jinggu earthquake in the past 10 years.Its epicenter was located near the Weixi-Qiaohou fault zone in northwestern Yunnan.The results of the focal mechanism show that the earthquake belongs to a strike-slip type rupture,which is in line with the regional tectonic characteristics.In order to further study the characteristics of the strong ground motion,an improved Hilbert-Huang transform(HHT)was introduced to objectively analyze the scale and frequency domain characteristics of the strong ground motion from different perspectives.The research results show that the marginal spectrum and the time-spectrum obtained by the Hilbert-Huang transform can retain the main information of the original data to a certain extent after the feature extraction of the actual ground motion records,and this method can be used for similar destructive shallow sources.The analysis of strong ground motion characteristics provides more effective information parameters,ensures the stability of signal decomposition.The analysis of strong ground motion characteristics is more suitable for processing non-stationary signals,and provides another new idea for modern signal application analysis to strong ground motion characteristics.