Author(s): Achilleas G. Tsakiris; A. (Thanos) N. Papanicolaou; Timothy J. Lauth
Keywords: Acoustic; bedload particle; geophone; mode of transport; rolling; saltation
Abstract: The purpose of this study is to develop a relationship for predicting the bedload rate from the acoustic signal of a geophone, under the rolling and saltating bedload transport modes. Controlled experiments corresponding to near-incipient, marginal, and general bedload motion were conducted. The geophone recorded impacts and resulting acoustic signal impulses at the lower “Frequency 1” (100–200 kHz) and the higher “Frequency 4” (380–480 kHz) ranges. Rolling particles produced stronger responses in Frequency 1 and weaker in Frequency 4 due to rotational vibrations. Instead, saltating particles generated stronger responses in Frequency 4 and weaker in Frequency 1 because of spheroid vibrations. The impulse in both Frequency 1 and 4 was related to bedload transport, as it accounts for the number and magnitude of the signal spikes due to the particle impacts. This study complements efforts for quantifying bedload transport using geophones by relating bedload to impulse for rolling and saltation.