In-Situ Tests with Analytical Modeling and Computation for Natural Meta-forestation and Interaction of Ground-Resonators on Seismic Wave Propagation and Umklapp Scattering

The expanding realm of metamaterials now covers numerous cross-disciplinary and real-life applications from nanoscale to macroscale sizes in optic/electromagnetic, acoustic/elastic, and, more recently, seismic systems. The dynamic properties of seismic metamaterials are investigated as potential shields to protect strategic buildings, historic structures, civil infrastructures, etc. Because it is still at an infancy stage, a detailed investigation involving in-situ soil exploration, ground conditions, and the interaction of seismic waves with surface resonators is necessary. There is currently no analytical solution available that accurately predicts seismic wave propagation and interaction with ground resonators. Further, the composite stratified layered saturated/unsaturated porous medium makes the problem highly nonlinear owing to the complex wave mechanism that is largely unknown. Thus, an accurate analytical, computational, and experimental approach for predicting the behavior of seismic wave propagation and interaction with ground resonators is highly desirable. Although there exist some preliminary models for seismic wave propagation in unsaturated and saturated porous media including the Umklapp process, an in-depth understanding of the frequency characteristics and interaction with natural forest still require extensive analysis in theory, numerical analysis and experiment. It will provide physical insights for the effectiveness of forest trees as potential seismic metamaterials, termed meta-forestation. More generally, we wish to establish a new natural antiseismic meta-forestation subject of study. Our findings may motivate the local and global communities, government organizations, and environmental activists for a more systematic and scientific forestry approach in line with earthquake protection and an effort for effective meta-forestation. There are also great potentials and spin-off applications in other cross-disciplinary areas including ultrasonic inspection, geological investigation, mechanical vibration, and surface acoustic wave devices, to name a few. The proposed project is expected to have the following outcomes in addition to technical papers. It will (i) offer new insights for seismic wave propagation in in-situ composite porous media and for interaction with seismic ground-resonators. An in-depth theoretical and computational investigation assisted by laboratory and practically manageable full-scaled experiments for the Umklapp process will be conducted, and the feasibility of meta-forestation as effective earthquake protection will be explored. (ii) Research students will be trained. The successful completion of this project will (iii) provide a new platform for researchers to further expand the applications of seismic metamaterials for potential earthquake-proof designs and to protect a specific geographical region from seismic hazards. There will be other spin-off research benefits including applications in (iv) ultrasonics, geology, mechanical vibration and acoustics.