Detection of Earth's Free Oscillation Modes Based on NTFT
Large earthquakes can simultaneously excite numerous normal modes of Earth's free oscilla-tions.Due to the Earth's ellipticity,rotation,and internal anisotropy,these normal modes undergo splitting,with frequencies of splitting modes becoming very close(only a few pHz apart).This impo-ses higher demands on the detection of Earth's free oscillation modes.This article derives and verifies a new method for detecting free oscillation modes based on normal time-frequency transform(NTFT).Taking the detection of 3S1 splitting modes as an example,compared with the classical FT spectrum method and the latest OSE method,our method has higher frequency resolution for detecting free os-cillation modes.
normal time-frequency transformFourier transformoptimal sequence estimationpeak splittingmode detection
万方数据
维普
