  Some properties of electromagnetic metamaterials have been translated, using
some wave analogies, to surface seismic wave control in sedimentary soils
structured at the meter scale. Two large scale experiments performed in 2012
near the French cities of Grenoble [Brule et al., PRL 112, 133901, 2014] and
Lyon [Brule et al., Sci. Rep. 7, 18066, 2017] have confirmed the usefulness of
this methodology and its potential influence on soil-structure interaction. We
present here a new perspective on the in-situ experiment near Lyon, which
unveils energy corridors in the seismic lens. We further introduce a concept of
time-modulated seismic metamaterial underpined by an effective model based on
Willis's equations. As a first application, we propose that ambient seismic
noise time-modulates structured soils that can be viewed as moving media. In
the same spirit, a design of an analogous seismic computer is proposed making
use of ambient seismic noise. Seismic signals transmitted between remote
seismic computers can help forming an Internet of Things. We further recall
that ancient Roman theaters and forests of trees are examples of large scale
structures that behave in a way similar to electromagnetic metamaterials:
invisibility cloaks and rainbows, respectively. Seismic metamaterials can thus
not only be implemented for shielding, lensing and cloaking of potentially
deleterious Rayleigh waves, but they also have potential applications in energy
harvesting and analogous computations using ambient seismic noise and this
opens new vistas in seismic energy harvesting via natural or artificial soil
structuring.
