Displacement rise time determines the sound frequency a quake produces.

Evidence

If the displacement does occur in a millisecond, frequency components of 1000 or 2000 Hz are expected. On the other hand, if 1 ms underestimates the time of arrival, we must correspondingly reduce the high frequencies. A 10-ms arrival would be expected to have frequency components as high as 100 or 200 Hz, still quite capable of creating a boom or pop. In that case, the compression front in the rock would be about 75 m thick. — Eric J. Heller, Why You Hear What You Hear- An…, 699

Categorization

• XREF: A concrete worked example of the general Fourier/timescale relation between a transient’s rise time and its spectral content.