Comment on "Solving the mystery of booming sand dunes"

TL;DR

This paper critiques the use of non-dispersive bulk propagation models for sand dune seismic analysis, emphasizing the importance of dispersive surface modes and challenging the resonance-based explanation for booming sand frequencies.

Contribution

It demonstrates that surface wave propagation in sand dunes is dispersive and provides evidence against resonance as the cause of booming sounds.

Findings

Surface wave propagation in sand dunes is dispersive.

Resonance does not explain the booming frequencies.

Standard non-dispersive models are inadequate for sand dune analysis.

Abstract

We show here that the standard physical model used by Vriend et al. to analyse seismograph data, namely a non-dispersive bulk propagation, does not apply to the surface layer of sand dunes. According to several experimental, theoretical and field results, the only possible propagation of sound waves in a dry sand bed under gravity is through an infinite, yet discrete, number of dispersive surface modes. Besides, we present a series of evidences, most of which have already been published in the literature, that the frequency of booming avalanches is not controlled by any resonance as argued in this article. In particular, plotting the data provided by Vriend et al. as a table, it turns out that they do not present any correlation between the booming frequency and their estimate of the resonant frequency.