Performance of a Rotational Sensor to Decipher Volcano Seismic Signals on Etna, Italy

Abstract

Volcanic activity is often accompanied by a wide range of seismo-volcanic signals such as very long-period (VLP) events, long-period (LP) events, volcano-tectonic (VT) events and tremor (Chouet, 2003). These signals contain information about physical processes at depth and are used to define the activity state of a volcano (Saccorotti & Lokmer, 2021). Monitoring observatories analyze these events continuously and use the number, amplitude, location and their variation in time for early warning purposes (Wassermann, 2012). These volcano-seismic events have distinct characteristics and underlying processes. VT earthquakes often have a broad and dominant frequency content between 2 and 20 Hz and an impulsive onset. They are similar to tectonic earthquakes in terms of failure mechanism (Saccorotti & Lokmer, 2021) and are interpreted as shear failure. LP events are defined in a narrow, low frequency band from 0.5 to 5 Hz (Chouet & Matoza, 2013

Fiber optic sensing for volcano monitoring and imaging volcanic processes

“…4). A similar agreement is also observed using the single station method at co-located sensors (Currenti et al, 2021;Eibl et al, 2022).…”

“…In 2019, a DDSS interrogator, a dense seismic array consisting of 26 Trillium Compact -120 s broadband seismometers and a rotational sensor were jointly deployed at Etna summit. This deployment provides a unique opportunity to observe and accurately quantify the strain and rotational ground motions generated by volcanic activity (Currenti et al, 2021;Eibl et al, 2022). The direct DDSS and rotational measurements associated with an LP event on 27 August 2021 correspond well with the indirect strain and rotation estimates derived by the dense seismic array (see Fig.…”

“…The following section describes methods for sensing the translational, strain and rotational components of the seismic wave field at a point, followed by methods for distributed sensing of strain and temperature. rotational sensor and broadband seismometer deployed at Etna volcano (Eibl et al, 2022) The Fabry-Perot interferometer is an optical cavity composed of two parallel light reflectors. It was designed by Perot and Fabry (1899) and has since then been utilized in numerous fiber optic point sensing devices to measure strain variation (Nur et al, 2016).…”

“…Rotational sensors can also help to correct for tilt contamination of records from nearby conventional seismometers (Bernauer et al, 2020), to correct measurements on the seafloor (Lindner et al, 2016), or to directly study microseisms generated in the ocean (Hadziioannou et al, 2012;Tanimoto et al, 2015). Rotational sensors have been shown to measure meaningful volcano-seismic signals on volcanoes, such as in Hawaii, USA (Wassermann et al, 2020), on Stromboli, Italy (Wassermann et al, 2022) and at Etna, Italy (Eibl et al 2022).…”

Six‐Component Earthquake Synchronous Observations Across Taiwan Strait: Phase Velocity and Source Location

“…Ring Laser Gyroscopes (RLG) have the highest sensitivity, and can observe the teleseismic signals (Belfi et al., 2017; Igel, 2005; Igel et al., 2021; Schreiber et al., 2009; Simonelli, et al., 2016). Fiber optical seismometers have the characteristics of high sensitivity, wide frequency band and portability, and are widely used in the observation of earthquakes and volcanic seismology (Bernauer et al., 2018; Cao et al., 2021; Eibl et al., 2022; Izgi et al., 2021). On the other hand, rotational seismic observation has put forward higher requirements for environmental noise.…”