M₂ Seismic Waves

Seismic noise emission induced by seismic waves

The in situ rock undergoing different kinds of deformation accumulates elastic energy that can be released spontaneously o r under artificial effect. Triggering of energy can also be performed by means of a dynamic excitation caused by elastic waves. W e carried out special field investigations with the use of seismic vibrators (Vibroseis-like sources) to study the effect of the energy release ...

Seismic Surface Waves

Seismic holes for controlling surface waves

The concept of controlling seismic waves is in progress and first full-scale experiments had confirmed the interest which we can have for this new axis of research. The possibility of imagining a seismic 2D or 3D metamaterial made of a grid of inclusions or empty boreholes in the soil, interacting with a part of the earthquake signal is becoming realistic. Here we show the dynamic response of a...

Observation of equipartition of seismic waves.

Equipartition is a first principle in wave transport, based on the tendency of multiple scattering to homogenize phase space. We report observations of this principle for seismic waves created by earthquakes in Mexico. We find qualitative agreement with an equipartition model that accounts for mode conversions at the Earth's surface.

Seismic shear waves as Foucault pendulum

Earth’s rotation causes splitting of normal modes. Wave fronts and rays are, however, not affected by Earth’s rotation, as we show theoretically and with observations made with USArray. We derive that the Coriolis force causes a small transverse component for P waves and a small longitudinal component for S waves. More importantly, Earth’s rotation leads to a slow rotation of the transverse pol...