Low coherency of wind induced seismic noise: Implications for gravitational wave detection

TL;DR

Wind-induced seismic noise is incoherent over short distances, significantly impairing the effectiveness of seismic arrays in reducing low-frequency noise for future gravitational wave detectors.

Contribution

This study quantifies the incoherence of wind-induced seismic noise across various frequencies and locations, revealing limitations for seismic noise mitigation strategies.

Findings

Wind noise coherence length is 2-40 m at 0.06-0.1 Hz.

Seismic noise coherence length reduces to 1-16 m at 16.6 Hz.

Incoherence significantly hampers Newtonian Noise cancellation at low frequencies.

Abstract

Seismic noise poses challenges for gravitational wave detection. Effective vibration isolation and methods to subtract unsheildable Newtonian Noise are examples. Seismic arrays offer one way to deal with these issues assuming seismic coherency. In this paper we find that wind induced seismic noise is incoherent and will dramatically reduce the projected low frequency sensitivity of future gravitational wave detectors. To quantify this, we measure the coherence length of wind induced seismic noise from 0.06--20~Hz in three distinct locations: close to a building, among tall trees and in shrubs. We show that wind induced seismic noise is ubiquitous and reduces the coherence lengths form several hundred meters to 2--40~m for 0.06--0.1~Hz, from $>$60~m to 3--16~m for 1.5--2.5~Hz and from $>$35~m to 1--16~m around 16.6 Hz frequency bands in the study area. This leads to significant loss of velocity and angular resolution of the array for primary microseism, 5 times worse Newtonian Noise cancellation by wiener filtering at 2~Hz, while it does not pose additional challenge for Newtonian Noise cancellation between 10--20~Hz.