A new active volcano in the Tyrrhenian Sea?

A strong earthquake occurred in 2002 offshore from the northern coast of Sicily in the Southern Tyrrhenian Sea (Italy), and was followed by a series of hundreds of aftershocks. Communications through the fibre-optic cable between Palermo and Rome were interrupted a few hours after the occurrence of the main shock. After the required technical checks, the failure point was found a few kilometres away from the seismic sequence area. A few days later, a specialised cable ship reached the failure area. One side of the cable was completely burnt, while about three kilometres of cable was found locked. Tests on slices of cable showed that the temperature at which the cable was heated went well above 700oC. We can speculate that the earthquakes triggered off the emission of a submarine lava flow that buried, trapped and burnt the fibre-optic cable. The revising of the bathymetric survey made before the cable’s deployment allowed for the identification of a seamount in the vicinity of the rupture. This structure could represent the lava flow’s source volcano

Foreland deformational pattern in the Southern Adriatic Sea

Two major deformation belts occur in the portion of the Adriatic Sea offshore the Gargano Promontory. Although these two belts display similar characters on seismic profiles, they are different in other respects. The NE-SWtrending Tremiti Deformation Belt, located north of the Gargano Promontory, originated during the Plio-Quaternary, while the E-W-trending South Gargano Deformation Belt, located south of the Gargano Promontory, formed in a time span that goes from Eocene to early Pliocene. On the ground of structural and stratigrafic evidence these deformation belts are interpreted as originated by tectonic inversion of Mesozoic extensional faults. This inversion tectonics, of Tertiary age, can be related to the evolution of the fold-and-thrust belts that surround the Adriatic Sea. A moderate seismic activity, recorded around the Tremiti Island, and historical seismological data suggest that the whole of study area is, at present, seismically active. Therefore, this portion of the Adriatic block still represents a preferental site of deformation

Foreland tectonics in the southern Adriatic Sea

Two major deformation belts occur in the portion of the Adriatic Sea offshore the Gargano Promontory. The NE-SW - trending Tremiti Deformation Belt, located north of the Gargano Promontory, originated during the Plio- Quaternary, while the E-W-trending South Gargano Deformation Belt, located south of the Gargano Promontory, formed in a time span from Eocene to Early Pliocene. These deformation belts may have originated by tectonic inversion of Mesozoic extensional faults. This inversion tectonics, of Tertiary age, can be related to the evolution of the fold-and thrust belts surrounding the Adriatic Sea. The whole of the study area is, at present, seismically active and represents a preferential site of deformation

Stromboli: a natural laboratory of environmental science

The science of environment is per se multi- and inter-disciplinary. It is not possible to separate the role of the physical, chemical, biological, and anthropic factors, respectively. Research must therefore rely on suitable natural laboratories, where all different effects can be simultaneously monitored and investigated. Stromboli is a volcanic island slightly North of Sicily, within a tectonic setting characterised by a Benioff zone, curved like a Greek theatre, opened towards the Tyrrhenian Sea, with deep earthquakes. Moreover, it is a unique volcano in the world in that since at least ~ 3000 years ago, it has exploded very regularly, about every 15^20 min. Hence, it is possible to monitor statistically phenomena occurring prior, during, and after every explosion. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) has recently established a permanent Laboratory and an extensive interdisciplinary programme is being planned. A few main classes of items are to be considered including: (1) matter exchange (solid, liquid, gas, chemistry); (2) thermal and/or radiative coupling; (3) electromagnetic coupling; (4) deformation; (5) biospheric implications; and (6) anthropic relations since either the times of the Neolithic Revolution. Such an entire multidisciplinary perspective is discussed, being much beyond a mere volcanological concern. We present here the great heuristic potential of such a unique facility, much like a natural laboratory devoted to the investigation of the environment and climate.Published429-442JCR Journalreserve

A new active volcano in the Tyrrhenian Sea

A strong earthquake occurred in 2002 offshore from the northern coast of Sicily in the Southern Tyrrhenian Sea (Italy), and was followed by a series of hundreds of aftershocks. Communications through the fibre-optic cable between Palermo and Rome were interrupted a few hours after the occurrence of the main shock. After the required technical checks, the failure point was found a few kilometres away from the seismic sequence area. A few days later, a specialised cable ship reached the failure area. One side of the cable was completely burnt, while about three kilometres of cable was found locked. Tests on slices of cable showed that the temperature at which the cable was heated went well above 700oC. We can speculate that the earthquakes triggered off the emission of a submarine lava flow that buried, trapped and burnt the fibre-optic cable. The revising of the bathymetric survey made before the cable's deployment allowed for the identification of a seamount in the vicinity of the rupture. This structure could represent the lava flow's source volcano

Multiparametric seafloor exploration: the Marsili Basin and Volcanic Seamount case (Tyrrhenian Sea, Italy)

Exploration of ocean seafloor is of paramount importance for a better understanding of the geodynamic evolution of our Planet. The pilot experiment of ORION-GEOSTAR 3 EC project was the first long-term continuous geophysical and oceanographic experiment of an important seafloor area of Southern Tyrrhenian Sea, the Marsili abyssal plain. The latter hosts the Marsili Seamount which is Europe’s one of the largest underwater volcano of Plio-Pleistocenic age. In spite of its dimensions, it is rather unknown about the present characteristics and activity. For this reason, we deployed a deep-sea observatory network, composed by two bottom observatories, on the seafloor at the base of the seamount at 3320 m b.s.l., in the period December 2003-May 2005. Some of the instruments on board the observatory were: broad-band seismometers, hydrophones, gravity meter, two magnetometers (scalar and vectorial), 3D single-point current meter, ADCP, CTD, automatic pH analyser and off-line water sampler for laboratory analyses. The first successful scientific objective was to obtain long-term continuous recordings under a unique time reference. The data analysis shows that they are generally of good quality and really continuous (only a few gaps). As a first step we performed a classification of seismic waveforms, a first inversion of magnetic variational data, and a first analysis of gravity meter, chemical and oceanographic data. Analysis of individual time series has shown interesting results, i.e. depth of the magnetic Moho under the Marsili, attenuation of recorded seismic body waves and clues of hydrothermal circulation. We show examples of the preliminary data analysis together with first results and comparisons among data coming from different sensors.PublishedCambridge, UK, February 24-26, 20091.8. Osservazioni di geofisica ambientale3.8. Geofisica per l'ambienteope

Observing Volcanoes from the Seafloor in the Central Mediterranean Area

The three volcanoes that are the object of this paper show different types of activity that are representative of the large variety of volcanism present in the Central Mediterranean area. Etna and Stromboli are sub-aerial volcanoes, with significant part of their structure under the sea, while the Marsili Seamount is submerged, and its activity is still open to debate. The study of these volcanoes can benefit from multi-parametric observations from the seafloor. Each volcano was studied with a different kind of observation system. Stromboli seismic recordings are acquired by means of a single Ocean Bottom Seismometer (OBS). From these data, it was possible to identify two different magma chambers at different depths. At Marsili Seamount, gravimetric and seismic signals are recorded by a battery-powered multi-disciplinary observatory (GEOSTAR). Gravimetric variations and seismic Short Duration Events (SDE) confirm the presence of hydrothermal activity. At the Etna observation site, seismic signals, water pressure, magnetic field and acoustic echo intensity are acquired in real-time thanks to a cabled multi-disciplinary observatory (NEMO-SN1 ). This observatory is one of the operative nodes of the European Multidisciplinary Seafloor and water-column Observatory (EMSO; www.emso-eu.org) research infrastructure. Through a multidisciplinary approach, we speculate about deep Etna sources and follow some significant events, such as volcanic ash diffusion in the seawater

Multiparametric seafloor exploration: the Marsili Basin and Volcanic Seamount case (Tyrrhenian Sea, Italy)

Exploration of ocean seafloor is of paramount importance for a better understanding of the geodynamic evolution of our Planet. The pilot experiment of ORION-GEOSTAR 3 EC project was the first long-term continuous geophysical and oceanographic experiment of an important seafloor area of Southern Tyrrhenian Sea, the Marsili abyssal plain. The latter hosts the Marsili Seamount which is Europe’s one of the largest underwater volcano of Plio-Pleistocenic age. In spite of its dimensions, it is rather unknown about the present characteristics and activity. For this reason, we deployed a deep-sea observatory network, composed by two bottom observatories, on the seafloor at the base of the seamount at 3320 m b.s.l., in the period December 2003-May 2005. Some of the instruments on board the observatory were: broad-band seismometers, hydrophones, gravity meter, two magnetometers (scalar and vectorial), 3D single-point current meter, ADCP, CTD, automatic pH analyser and off-line water sampler for laboratory analyses. The first successful scientific objective was to obtain long-term continuous recordings under a unique time reference. The data analysis shows that they are generally of good quality and really continuous (only a few gaps). As a first step we performed a classification of seismic waveforms, a first inversion of magnetic variational data, and a first analysis of gravity meter, chemical and oceanographic data. Analysis of individual time series has shown interesting results, i.e. depth of the magnetic Moho under the Marsili, attenuation of recorded seismic body waves and clues of hydrothermal circulation. We show examples of the preliminary data analysis together with first results and comparisons among data coming from different sensors

Observing Volcanoes from the Seafloor in the Central Mediterranean Area

The three volcanoes that are the object of this paper show different types of activity that are representative of the large variety of volcanism present in the Central Mediterranean area. Etna and Stromboli are sub-aerial volcanoes, with significant part of their structure under the sea, while the Marsili Seamount is submerged, and its activity is still open to debate. The study of these volcanoes can benefit from multi-parametric observations from the seafloor. Each volcano was studied with a different kind of observation system. Stromboli seismic recordings are acquired by means of a single Ocean Bottom Seismometer (OBS). From these data, it was possible to identify two different magma chambers at different depths. At Marsili Seamount, gravimetric and seismic signals are recorded by a battery-powered multi-disciplinary observatory (GEOSTAR). Gravimetric variations and seismic Short Duration Events (SDE) confirm the presence of hydrothermal activity. At the Etna observation site, seismic signals, water pressure, magnetic field and acoustic echo intensity are acquired in real-time thanks to a cabled multi-disciplinary observatory (NEMO-SN1 ). This observatory is one of the operative nodes of the European Multidisciplinary Seafloor and water-column Observatory (EMSO; www.emso-eu.org) research infrastructure. Through a multidisciplinary approach, we speculate about deep Etna sources and follow some significant events, such as volcanic ash diffusion in the seawater.Published2983A. Ambiente MarinoJCR Journalrestricte

GEOSTAR, an observatory for deep sea geophysical and oceanographic researches: characteristics, first scientific mission and future activity

GEOSTAR (GEophysical and Oceanographic STation for Abyssal Research) is a project funded by in the 4th Framework Programme of the European Commission, with the aim of developing an innovative deep sea benthic observatory capable of carrying out long-term (up to 1 year) scientific observations at abyssal depths. The configuration of the observatory, conceived to be a node of monitoring networks, is made up of two main subsystems: the Bottom Station, which in addition to the acquisition and power systems and all the sensors also hosts the communications systems; and the Mobile Docker, a dedicated tool for surface-assisted deployment and recovery. At present the Bottom Station is equipped with a triaxial broad-band seismometer, two magnetometers (fluxgate and scalar), CTD, transmissometer, ADCP, but it can easily host other sensors for different experiments. The first phase of the project, started in November 1995, was concluded with the demonstration mission in Adriatic Sea at shallow water depth (42 m) in August - September 1998. Some preliminary results of this first scientific experiment are presented and discussed. The second phase, started in 1999, will end with a long-term deep sea scientific mission, scheduled during 2000 for 6-8 months at 3400 m.w.d. in the southern Tyrrhenian bathyal plain.Published491-4973A. Ambiente MarinoN/A or not JCRrestricte