Four Years of Continuous Seafloor Displacement Measurements in the Campi Flegrei Caldera

Abstract

We present 4 years of continuous seafloor deformation measurements carried out in the Campi Flegrei caldera (Southern Italy), one of the most hazardous and populated volcanic areas in the world. The seafloor sector of the caldera has been monitored since early 2016 by the MEDUSA marine research infrastructure, consisting of four instrumented buoys installed where sea depth is less than 100 m. Each MEDUSA buoy is equipped with a cabled, seafloor module with geophysical and oceanographic sensors and a subaerial GPS station providing seafloor deformation and other environmental measures. Since April 2016, the GPS vertical displacements at the four buoys show a continuous uplift of the seafloor with cumulative measured uplift ranging between 8 and 20 cm. Despite the data being affected by environmental noise associated with sea and meteorological conditions, the horizontal GPS displacements on the buoys show a trend coherent with a radial deformation pattern. We use jointly the GPS horizontal and vertical velocities of seafloor and on-land deformations for modeling the volcanic source, finding that a spherical source fits best the GPS data. The geodetic data produced by MEDUSA has now been integrated with the data flow of other monitoring networks deployed on land at Campi Flegrei.

Validation of Repetitive Volcanoseismic Signals in Aso Volcano, Japan With Distant Stations: Implications of Source Characterization and Remote Sensing in Uninstrumented Volcanoes

“…Lastly, seismic monitoring of submarine volcanoes (e.g., D’Alessandro et al., 2009; Dziak et al., 2008, 2012; Fukao et al., 2018; Konter et al., 2004; Kudo et al., 1991; Lindsay et al., 2005; Wright et al., 2008; Watts et al., 2012; Wilcock et al., 2016; Yamasato et al., 1991) or axial volcanoes in mid‐ocean ridges (e.g., Schlindwein et al., 2005; Schmid et al., 2017; Tolstoy et al., 2001, 2006) can benefit from the deployment of ocean bottom sensors (e.g., seismometers, hydrophones), although observations have predominantly focused on volcanotectonic earthquakes (VTs) and tremors. While a systematic detection and monitoring of repetitive volcanoseismic signals such as VLP or LP remain to be explored, future seismic monitoring may be coupled with hydroacoustics monitoring (e.g., Lyons et al., 2019; Tepp et al., 2020; Wech et al., 2018), sea‐floor geodesy (e.g., Bürgmann & Chadwell, 2014; Chadwick et al., 2012; De Martino et al., 2020; Nooner & Chadwick, 2009) and global analysis of nondouble‐couple events (e.g., Sandanbata et al., 2021; Shuler et al., 2013) to untangle the magma storage and ascent beneath submarine and axial volcanoes that remain largely unexplored.…”

An Innovative Fiber-Optic Hydrophone for Seismology: Testing Detection Capacity for Very Low-Energy Earthquakes

“…The emerging part of the buoy hosts 5 GHz and UMTS-4G communication systems, solar panels, a weather station, and control electronics. In addition, on the top of the buoy a geodetic GNSS receiver monitors the seafloor movements produced by the volcanic activity of the area [ 23 , 24 ].…”

An Innovative Fiber Optic Hydrophone for Seismology: Testing Detection Capacity for Very Low-Energy Earthquakes

“…The emerging part of the buoy hosts a 5 GHz and UMTS-4G communication systems, solar panels, weather station and control electronics. In addition, on the top of the buoy a geodetic GNSS receiver monitors the seafloor movements produced by the volcanic activity of the area [9,10].…”