Experimental Analysis of the Concept of Meta-City Considering a Geophysical Scale Analog City-Like Environment

Date: 4/26/2019

Time: 04:15 PM

Room: Pine

At the city scale, the seismic vibration of the buildings induce a complexity in the ground motion due to Site-City interaction phenomenon: buildings act like secondary sources contaminating the free field and influencing the wave propagation. The aim of this study is to extend current knowledge of the site-city interaction to meta-city concept using a very dense network experiment deployed in a analog city-like environment constituted by resonators: the METAFOREST experiment. Experimental data retrieved from a pine-tree forest were analyzed in order to understand the impact of such as resonators on the seismic ground motion. We proved the concept that considers trees acting like resonant meta-materials at the geophysical scale. Buildings like trees can be considered as meta-resonators. We investigated the ambient noise and seismic ground motion recorded by 3-components geophones through two configurations: a square and a line seismic deployment of 100 receivers each, crossing the open field-forest boundary. The spatial variability between the field and the forest is studied. Significant differences are highlighted through ground motion intensity measures (Aria intensity, Fourier Amplitude Spectra, Spatial Coherency, etc.), wide band-gaps are identified proving that Rayleigh waves interact naturally with the trees resulting in a strong attenuation of the seismic ambient energy within the forest.

Presenting Author: Philippe Guéguen

Authors