Understanding physical processes prior and during eruptions remains challenging, due to uncertainties about subsurface structures and undetected processes within the volcano. Here, the authors use a dedicated fibre-optic cable to obtain strain data and identify volcanic events and image hidden near-surface volcanic structural features at Etna volcano, Italy. In the paper Jousset et al. (2022), we detect and characterize strain signals associated with explosions, and we find evidences for non-linear grain interactions in a scoria layer of spatially variable thickness. We also demonstrate that wavefield separation allows us to incrementally investigate the ground response to various excitation mechanisms, and we identify very small volcanic events, which we relate to fluid migration and degassing. We recorded seismic signals from natural and man-made sources with 2-m spacing along a 1.5-km-long fibre-optic cable layout near the summit of actives craters of Etna volcano, Italy. Those results provide the basis for improved volcano monitoring and hazard assessment using DAS. This data publication contains the full data set used for the analysis. This data set comprises strain-rate data from 1 iDAS interrogator (~750 traces), velocity data from 15 geophones and 4 broadband seismometers, and infrasonic pressure data from infrasound sensors. For further explanation of the data and related processing steps, please refer to Jousset et al. (2022). Waveform data are available from the GEOFON data centre, under network code 9N.
“1-month seismological experiment on Etna, Italy in 2019" is a 1-month seismological experi-ment realized near the Pizzi Deneri Observatory on Etna, Italy, by Eva Eibl and Daniel Vollmer (University of Potsdam) in collaboration with Philippe Jousset from GFZ Potsdam Germany and Gilda Currenti and Graziano Larocca from INGV-OE, Italy. From August to September 2019, we recorded the volcano-seismic events accompanying the volcanic activity using a rotational sensor and a co-located seismometer. The aim of the seismological experiment was to study LP events, VT events and tremor. We used a 3-component broadband seismometer (Nanometrics Trillium Compact 120 s) and a 3-component rotational sensor (iXblue blueSeis-3A) and stored the data on a DataCube and CommunicationCube, respectively. Sensors were installed on the same 35 * 35 * 3 cm3 granitic base plate at about 40 cm depth enclosed by backfilled pyroclastic material to avoid wind noise. The instruments recorded at 200 Hz sampling rate and were located about 2 km from the craters on Etna. The setup was powered using 3 solar panels of 140W each and three batteries of 75Ah each. We oriented the rotational sensor and seismometer using a Quadrans fiber-optical gyrocompass. The Quadrans is not affected by magnetic minerals in the ground and our sensors are hence properly aligned to geographic north. We converted the seismometer data to MSEED using Pyrocko’s Jackseis program and created a catalogs of LP events and VT events that were further investigated in Eibl et al. 2022. Waveform data are available from the GEOFON data centre, under network code ZR.
The TOMO-ETNA experiment was focused on the base of generation and acquisition of seismic signal (active and passive) at Mt. Etna volcano and surrounding area. The terrestrial campaign consists in the deployment of 80 short-period three-component seismic stations (June 15 to July24), 17 Broadband seismometers (June 15 to October 30) provided by Helmholtz Centre Potsdam (GFZ) German Research Centre for Geosciences using the German Geophysical Instrument Pool Potsdam (GIPP Gerätepool Geophysik), and the coordination with 133 permanent seismic station belonging to the “Istituto Nazionale di Geofisica e Vulcanologia” (INGV) of Italy. This temporary seismic network recorded active and passive seismic sources. Active seismic sources were generated by an array of air-guns mounted in the Spanish Oceanographic vessel “Sarmiento de Gamboa” with a power capacity of up to 5.200 cubic inches. In total more than 26.000 shots were fired and more than 450 local and regional earthquakes were recorded. Until July the Oceanographic Vessel “Sarmiento de Gamboa” and the hydrographic vessel “Galatea” were responsible for the offshore activities, that included deployment of OBSs, and several marine activities. The vessel “Aegaeo” performed additional seismic, magnetic and gravimetric experiments until the end of November 2014. This experiment was part of the “Task 5.3 - Mt. Etna structure” of the “EU MED-SUV Project” concerned with the investigation of Mt. Etna volcano (seismic tomography experiment - TOMO-ETNA) by means of passive and active refraction/reflection seismic methods. It focused on the investigation of Etna’s roots and surrounding areas by means of passive and active seismic methods. Therefore, this experiment included activities both on-land and offshore with the main objective to obtain a new high-resolution tomography in order to improve the 3D image of the crustal structures existing beneath the Etna volcano and the northeast Sicily (Peloritani - Nebrodi chain) up to the Aeolian Islands. Waveform data are open and available from the GEOFON data centre, under network code 1T.