Providing priors to Bayesian array optimization for the Sardinian candidate site of the Einstein Telescope

Gravity fluctuations produced by ambient seismic fields will limit the sensitivity of the next-generation, gravitational-wave detector Einstein Telescope at frequencies below 20 Hz. In addition to hosting the detector underground, mitigation will be required by monitoring the seismic field, using the data to estimate the associated gravity fluctuations, and subtracting the estimate from the detector data. In this paper, I present the plan for a Bayesian seismic-array design. I am focusing on a calculation of correlations between the surface displacement of a seismic field and the associated gravitational fluctuations using the spectral-element SPECFEM3D Cartesian software. These simulated seismic correlations will be implemented as priors in a Gaussian Process Regression and combined with observed seismic correlations for Bayesian inference of correlations everywhere in the medium.