Abstract We attempt to detect the Quasi-Love wave by the normal time-frequency transform(NTFT). Surface waves come from two stations installed in Italy after the 2004-12-26 Sumatra MW9.0 earthquake. The results show that the NTFT has the ability to detect the Quasi-Love wave. The Quasi-Love wave in the NTFT is obvious, and we can also observe the characters of time-frequency change in the NTFT spectrum. Finally, we define similarity coefficient method based on the NTFT to estimate the correlation between the two signals. Compared with the cross correlation(CC) method, the similarity coefficient(SC) method performs well in the case of low SNR. We estimate the correlation between the Quasi-Love and Love wave and calculate the delay time by SC.
