Simulation of underground gravity gradients from stochastic seismic fields

TL;DR

This paper uses finite-element simulations of seismic fields to analyze underground gravity gradients, aiming to improve noise subtraction in gravitational-wave detectors through optimized seismometer placement.

Contribution

It introduces a finite-element simulation approach combining stochastic seismic models to accurately predict underground gravity gradients for gravitational-wave detector noise mitigation.

Findings

Finite-element simulations effectively model seismic displacement and gravity gradients.

Optimal seismometer placement improves gravity-gradient noise subtraction.

Error analysis guides practical seismometer array design.

Abstract

We present results obtained from a finite-element simulation of seismic displacement fields and of gravity gradients generated by those fields. The displacement field is constructed by a plane wave model with a 3D isotropic stochastic field and a 2D fundamental Rayleigh field. The plane wave model provides an accurate representation of stationary fields from distant sources. Underground gravity gradients are calculated as acceleration of a free test mass inside a cavity. The results are discussed in the context of gravity-gradient noise subtraction in third generation gravitational-wave detectors. Error analysis with respect to the density of the simulated grid leads to a derivation of an improved seismometer placement inside a 3D array which would be used in practice to monitor the seismic field.