ALBERT

Beschreibung: The marine sector of the Campi Flegrei caldera has started to be monitored over the long-term with a seafloor equipment deployed in the Gulf of Pozzuoli from 2008. The equipment includes a set of geophysical, oceanographic and environmental sensors integrated in a marine platform that was specifically designed for real-time monitoring. This platform, named CUMAS (Cabled Underwater Multidisciplinary Acquisition System), was installed in the center of the Gulf at about 2.5 km south of Pozzuoli where the sea depth is about 100 m [Iannaccone et al., 2010]. The CUMAS system consists of a seafloor module connected by cable to a buoy (elastic beacon type) equipped with autonomous power supply systems, real-time data- transmission devices and a weather station. The core of CUMAS is the seafloor module that contains geophysical and oceanographic sensors, in particular, a three-component broadband seismometer, a best in class three axis MEMS accelerometer, a low-frequency hydrophone and a high-resolution sea bottom pressure recorder. A single-point acoustic, three-component, water-current meter and a water-temperature sensor were also installed to monitor some water local physical parameters. A set of status sensors, which also included a digital compass and a two-component digital tilt-meter, were added to track the attitude of the module over the course of the experiment. The marine monitoring system transmits the data in real-time and is integrated into the Monitoring Center in Naples managed by INGV-Osservatorio Vesuviano. A continuous GPS station has been installed since the end of 2011 on the top of the buoy. The elastic beacon buoy forms a structure which is rigidly connected by a mechanical cable to the ballast on the sea bottom, a submerged float at the base of the buoy maintains tension on the cable and ensure the overall buoyancy of the system. In this way, any vertical movement of the seafloor propagates rigidly to the emerged part of the buoy itself, allowing measurement of the vertical movement of the sea floor by the GPS station. The analysis of about 17 months of continuous GPS data, from January 2012 to May 2013, revealed an overall uplift of about 3-4 cm allowing a first measurement of vertical seafloor displacement in the Campi Flegrei caldera [De Martino et al., 2014]. A new opportunity to enhance the deployed system was given by a national project, EMSO-MedIT, which is providing the necessary resources to expand the data acquisition to other areas of the Gulf of Pozzuoli. New improved systems similar to CUMAS are going to be deployed in three additional marine sites of the Gulf of Pozzuoli and the existing tide gauges network will be renewed with state-of-art sensors. The overall new monitoring infrastructure will allow to extensively map the seafloor vertical displacement and to improve the interpretative models of the bradyseism phenomenon including a more accurate location of earthquakes in the marine areas and extending to lower magnitude values the detection of the seismic activity.

Beschreibung: INGV, Comune di Nicolosi, Parco dell'Etna, Funivia dell'Etna

Beschreibung: Published

Beschreibung: Nicolosi (Catania) -I TALY

Beschreibung: 1IT. Reti di monitoraggio e Osservazioni

Beschreibung: open

Beschreibung: During volcanic eruptions, measurements of the rate at which magma is erupted underpin hazard assessments. For eruptions dominated by the effusion of lava, estimates are often made using satellite data; here, in a case study at Mount Etna (Sicily), we make the first measurements based on terrestrial laser scanning (TLS), and we also include explosive products. During the study period (17–21 July 2012), regular Strombolian explosions were occurring within the Bocca Nuova crater, producing a ~50 m-high scoria cone and a small lava flow field. TLS surveys over multi-day intervals determined a mean cone growth rate (effusive and explosive products) of ~0.24 m3·s−1. Differences between 0.3-m resolution DEMs acquired at 10-minute intervals captured the evolution of a breakout lava flow lobe advancing at 0.01–0.03 m3·s−1. Partial occlusion within the crater prevented similar measurement of the main flow, but integrating TLS data with time-lapse imagery enabled lava viscosity (7.4 × 105 Pa·s) to be derived from surface velocities and, hence, a flux of 0.11 m3·s−1 to be calculated. Total dense rock equivalent magma discharge estimates are ~0.1–0.2 m3·s−1 over the measurement period and suggest that simultaneous estimates from satellite data are somewhat overestimated. Our results support the use of integrated TLS and time-lapse photography for ground-truthing space-based measurements and highlight the value of interactive image analysis when automated approaches, such as particle image velocimetry (PIV), fail.

Beschreibung: Published

Beschreibung: 14967 - 14987

Beschreibung: 3V. Dinamiche e scenari eruttivi

Beschreibung: JCR Journal

Beschreibung: open