After a large (M7ish) quake:

• obtain waveform data from a broadband station
• plot a spectrogram (OK, actually a continuous wavelet transform)
• and optionally overlay theoretical Rayleigh wave arrival times to demonstrate multiple passages of surface waves (and make a pretty plot)

Set plot_rayleigh = True to see predicted Rayleigh wave arrival times:

Example script, waveforms, and plot provided for March 2021 M8.1 earthquake near the Kermadec Islands, New Zealand recorded on GSN station IU.ANMO.

requires ObsPy:

https://docs.obspy.org/

https://github.com/obspy/obspy/wiki#installation

Predicted Rayleigh wave arrival times in t-vs-u.csv were digitized from Oliver (1962) Fig 2: https://pubs.geoscienceworld.org/ssa/bssa/article/52/1/81/101314