In the Perfect Master’s latest drippings of enlightenment Can animals sense earthquakes?, he mentions mechanisms by which animals could detect earthquakes. However, I believe two of them, “P-waves” and “Low-frequency sound”, are actually the same thing.
They are both longitudinal pressure waves. Qualitatively, p-waves are through the ground and sound is through the air, but the sound is not really separate from the p-waves. The sound (at least any early sound) is directly emanating from the ground and not propagating through the air, given that the speed of sound in air is substantially slower than through rock.