Seismic Hazard Analysis for the TDC2/TCC2 Facility at CERN: A Multivariate Geostatistical Approach

A comprehensive seismic hazard analysis was performed at CERN to assess the potential of earthquake-induced ground motions and their impact on the site's structures and facilities. This study focuses on the underground facilities TCC2 and TDC2, critical components of the Super Proton Synchrotron (SPS) complex. Accurate seismic hazard analysis is relevant for the overall risk assessment, ensuring SPS operation also. Seismic data from recording stations located in Switzerland, France, and Italy were collected within a 150-km radius area centred in the TCC2. The collected raw data were then filtered to obtain specific frequency ranges of interest, enabling efficient processing and analysis for accurate seismic hazard analysis of the TCC2 and TDC2. This research proposes an innovative model, synthesizing old ideas and insights from the team led by the senior author of the present paper, Massimo Guarascio, that integrates multivariate statistical analysis methodologies with geostatistical ones, addressing three critical aspects of seismic modelling: directional anisotropy of the value and the arrival time of the Peak Ground Acceleration (PGA), geographical continuity in terms of space correlation function describing the apparently irregular variations between data pairs. The experimental validation of a geostatistical estimator accuracy is carried on checking the estimation errors in all the location points of the recording stations. In these points, the recorded values and estimated ones are both known. This model allows a more complete seismic assessment of critical facilities like the TCC2 and TDC2 to ensure SPS operation and safety of personnel, by providing more accurate seismic analysis