First deep underground observation of rotational signals from an earthquake at teleseismic distance using a large ring laser gyroscope

TL;DR

This paper reports the first underground detection of rotational seismic signals from a distant earthquake using a large ring laser gyroscope, demonstrating the potential of rotational seismology for geophysical research.

Contribution

It introduces GINGERino, a new underground RLG observatory, and presents unprecedented measurements of rotational seismic signals from a teleseismic earthquake.

Findings

First underground observation of rotational signals from a teleseismic earthquake.

Demonstration of RLG sensitivity for seismological applications.

Potential for rotational seismology to complement traditional ground motion measurements.

Abstract

Recent advances in large ring laser gyroscopes (RLG) technologies opened the possibility to observe rotations of the ground with sensitivities up to $10^{-11}$ $\frac{rad}{s}$ over the frequency band of seismological interest (0.01-1Hz), thus opening the way to a new geophysical discipline, i.e. rotational seismology. A measure of rotations in seismology is of fundamental interest for (a) the determination of all the six degrees of freedom that characterize a rigid body motion, and (b) the quantitative estimate of the rotational motions contaminating ground translation measurements obtained from standard seismometers. Within this framework, this paper presents and describes GINGERino, a new large observatory-class RLG located in Gran Sasso underground laboratory (LNGS), one national laboratories of the INFN (Istituto Nazionale di Fisica Nucleare). We also report unprecedented observations and analyses of the roto-translational signals from a tele-seismic event observed in such a deep underground environment.