Coseismic Stability Assessment of a Damaged Underground Ammunition Storage Chamber Through Ambient Vibration Recordings and Numerical Modelling

In the past decade, ambient vibration measurements found numerous applications on unstable rock slopes and developed into a powerful tool for site characterization of slope instabilities. this study, first time were applied to mass strongly disturbed damaged by subsurface explosions. The above ammunition storage chamber at Mitholz (Switzerland) is especially interesting because geology below seismic array well known, including location caverns, degree degradation caused explosions in 1947 around 40 t TNT ammunition. Measurement data analyzed using current state-of-the-art single-station methods, focusing surface-wave dispersion analysis, wave field polarization, amplification site-to-reference spectral ratios analysis normal mode behavior. results allow calibrating elastic properties 2D numerical mechanical model which was used simulate stability during loading. Therefore, can contribute not only better understanding subsurface, but also assessment earthquake risk.