Evidence of metamaterial physics at the geophysics scale: the METAFORET experiment
Open access
Date
2020-02Type
- Journal Article
Abstract
The METAFORET experiment was designed to demonstrate that complex wave physics phenomena classically observed at the meso- and microscales in acoustics and in optics also apply at the geophysics scale. In particular, the experiment shows that a dense forest of trees can behave as a locally resonant metamaterial for seismic surface waves. The dense arrangement of trees anchored into the ground creates anomalous dispersion curves for surface waves, which highlight a large frequency band-gap around one resonant frequency of the trees, at ∼45 Hz. This demonstration is carried out through the deployment of a dense seismic array of ∼1000 autonomous geophones providing seismic recordings under vibrating source excitation at the transition between an open field and a forest. Additional geophysical equipment was deployed (e.g. ground-penetrating radar, velocimeters on trees) to provide essential complementary measurements. Insights and interpretations on the observed seismic wavefield, including the attenuation length, the intensity ratio between the field and the forest and the surface wave polarization, are validated with 2-D numerical simulations of trees over a layered half-space. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000396481Publication status
publishedExternal links
Journal / series
Geophysical Journal InternationalVolume
Pages / Article No.
Publisher
Oxford University PressSubject
Numerical modelling; Spatial analysis; Acoustic properties; Guided waves; Wave scattering and diffractionNotes
It was possible to publish this article open access thanks to a Swiss National Licence with the publisher.More
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