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Flat lens effect on seismic waves propagation in the subsoil
Stéphane Brûlé1, Emmanuel H Javelaud2, Stefan Enoch3
1Ménard, 91620 Nozay, France. stephane.brule@menard-mail.com.
Scientific Reports
|December 24, 2017
Summary
Seismic energy, specifically Rayleigh surface waves, can be focused using structured soil with a grid of holes. This discovery paves the way for seismic metamaterials to mitigate earthquake damage.
Area of Science:
- Geophysics
- Materials Science
- Wave Physics
Background:
- Seismic waves pose significant threats during earthquakes.
- Controlling seismic wave propagation is crucial for earthquake protection.
Purpose of the Study:
- To investigate the focusing of seismic energy using structured soil.
- To explore the potential of seismic metamaterials for earthquake mitigation.
Main Methods:
- Large-scale field tests using a low-frequency artificial source (<10 Hz).
- Employing structured soil with a grid of cylindrical, vertical holes.
- Analyzing seismic energy distribution within the structured soil.
Main Results:
- Observed focusing of seismic energy (Rayleigh surface waves) within the structured soil.
- Identified energy distribution consistent with dynamic anisotropy and an effective negative refraction index.
- Demonstrated a 'flat lens' effect for seismic waves.
Conclusions:
- Structured soil can act as a seismic flat lens, focusing wave energy.
- This phenomenon opens new possibilities for seismic metamaterials.
- Potential to counteract destructive seismic wave components for improved earthquake resilience.
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