4 ms·

> It looks like two or more frequencies mixed ... Eh? Do seismologists not have FFT signal processing tools at their finger tips.

• bsamuels 8y ago
  one of the pictures is literally a fft graph, so yes
• njarboe 8y ago
  Seismologists invented FFT signal processing. Rumors circulate at oil companies that many companies discovered it independently and were using it internally years before the method was openly published. It would be hard to underestimate the value of FFT processing to that industry.
  • gpvos 8y ago
    *overestimate