Dynamics of Vulcano Island investigated by long-term (40 years) geophysical data

Vulcano island is a composite volcanic edifice located in the south-central sector of the Aeolian Archipelago (Tyrrhenian Sea, Italy) and it is an important tourist destination. Historic activity has been characterized by frequent transitions from phereatomagmatic to minor magmatic activity. The last eruption in 1888-90 was characterized by energetic explosive pulses and defines the “vulcanian” type of activity. Since then, volcanic activity has taken the form of fumarolic emanations of variable intensity and temperature, mainly concentrated at “La Fossa” crater, with maximum temperatures ranging between 200° and 300° C; temperature increases and changes in the gas chemistry, were often observed. The most recent episode began in the 80’s when fumarole temperature progressively increased to 690°C in May 1993. Vulcano is active and this favoured monitoring and research studies, in particular focussed on the most recent structures. In the frame of DPC-INGV “V3” project, we investigate the Vulcano dynamics through ca. 40 years of ground deformation and seismicity data collected by the discrete and continuous INGV monitoring networks. We considered levelling, GPS, EDM, seismic and tilt data. EDM and levelling measurements began in the middle 1970s and since the late 1990s the EDM benchmarks have been measurered using GPS. We observed three scales of ground deformation: the first one seems to be linked to the regional tectonics, with a general transpressive kinematics; the second one affects the northern half of the island and could be related to the caldera dynamics; the third one affects only the cone of La Fossa. Regional tectonic stress seems to play an important role in the transition of the volcanic system from a phase of stability to a phase of unrest, inducing the heating and the expansion of shallow hydrothermal fluids. Ground deformation at Vulcano may be linked to the geothermal system rather than magmatic sources

Ischia island: strain field by GPS and Levelling data.

Geophysical Research Abstracts Vol. 13, EGU2011-13941-3, 2011 EGU General Assembly 2011 © Author(s) 2011 Ischia island: strain field by GPS and Levelling data. Francesco Obrizzo and the INGV (CNT-OV) Geodesy Team Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy In this paper, we discuss the results obtained by means high precision levelling and GPS surveys performed at Ischia island in June 2010. The levelling survey has been carried out on the whole network of the island. The compensated heights for each benchmark (bm), referred to bm 1 located at Ischia harbour, were compared to those obtained in the previous levelling survey performed during 2003. The GPS network operating on Ischia Island consists of 21 3D vertices homogeneously distributed on the island. Six different GPS surveys of the whole network were carried out since 1997, in order to investigate the subsidence phenomena. The comparison among the 1997, 1998, 1999, 2001, 2003 and 2010 surveys results show that some GPS points present significant horizontal displacements confirming slow but continuous deformations in the Southern and North West sectors of the island. The results show significant ground subsidence of various amplitude affecting different areas of the island. In addition, a further comparison with the measurements performed in 1987 confirms the existence of such differential movements characterised by subsidence velocity constant over time. Finally, we found a good agreement between levelling and GPS velocities, calculated in time span 1997-2010. Therefore, the integration of GPS and levelling data allowed to define the strain field on the island over the past 20 years

Experimental study for evaluation of a suitable ground displacement monitoring system: Pilot hole Campi Flegrei Deep Drilling Project case

The paper presents an experimental study carried out in 2012 during the drilling activity for a pilot hole performed in the framework of the Campi Flegrei Deep Drilling Project. A monitoring network has been installed to test and choose a suitable ground deformation system for the subsequent deep drilling of about 3.5 km in the Campi Flegrei Caldera (Italy). We describe the seismic network installed to characterize the structure of the pilot hole area and the ground deformation monitoring system chosen for the small drilling area. Data analysis and results obtained indicate that Total Station is a suitable tool for this case.Published4V. Dinamica dei processi pre-eruttiviN/A or not JC

NeVoCGPS network: contributions to the Deformation Analysis in Neapolitan Volcanic area based on Continuous GPS measurements

Osservatorio Vesuviano, department of Istituto Nazionale di Geofisica e Vulcanologia, installed a permanent GPS network (NeVoCGPS), constituted of 25 stations, in Neapolitan volcanic area, where three active volcanoes (Somma-Vesuvius, Campi Flegrei caldera and Ischia Island) rise, each characterized by a peculiar type of ground movements activity. The Somma-Vesuvius system exhibits now a low level of ground deformation; the Campi Flegrei, caracterized from over 2000 years by slow up and down vertical movements (bradyseism), at present is in a very slow uplift phase; Ischia, finally, shows subsidence in the specific areas (Southern and North-West sectors of the island). The presence of these volcanoes and the dense urbanization of the area make the ground deformation monitoring a crucial point for risk mitigation and modelling aims. The 3D ground displacements are calculated using CGPS data, acquired with a 30s rate and with the daily and weekly vertexes position estimate. All the stations are managed by remote control and the data are automatically downloaded and processed using Bernese software package. The entire chain of acquisition, processing and data analysis is accurately described and some results obtained in the last years are shown

Concurrent deformation processes in the Matese massif area (Central-Southern Apennines, Italy)

We investigated the interseismic GPS velocity field across the transition zone between Central and Southern Apennine comprising the Meta–Mainarde-Venafro and Alto Molise–Sannio-Matese mounts. The kinematic field obtained by combining GPS network solutions is based on data collected by the unpublished episodic campaigns carried out on Southern Apennine Geodetic network (SAGNet from 2000 to 2013), IGM95 network (Giuliani et al., 2009 from 1994 to 2007) and continuous GPS stations. The data collected after the 29 December 2013 earthquake (Mw 5.0) until early 2014 allowed estimating displacements at 15 SAGNet stations. The extension rate computed across the Matese massif along an anti-Apennine profile is 2.0±0.2 mm/yr. The interseismic velocities projected along the profile show that the maximum extension does not follow the topographic high of the Apennines but is shifted toward the eastern outer belt. No significant GPS deformation corresponding to inner faults systems of the Matese massif is detected. Taking into account our results and other geophysical data, we propose a conceptual model, which identifies the 2013–2014 seismic sequence as not due to an extensional deformation style usual along the Apennine chain. In fact, we have measured too large “coseismic” displacements, that could be explained as the result of tectonic regional stress, CO2-rich fluid migration and elastic loading of water in the karst Matese massif. We recognized a tensile source as model of dislocation of 2013–2014 earthquakes. It represents a simplification of a main fault system and fracture zone affecting the Matese massif. The dislocation along NE-dipping North Matese Fault System (NMFS) could be the driving mechanism of the recent seismic sequences. Moreover, to the first time the SAGnet GPS data collected from 1994 to 2014, are share and available to the scientific community in the open access data archive.INGV and DPCS1-C1 - 2012-2021.Published2282342T. Deformazione crostale attivaJCR Journa

Cultural climate in Naples between the birth and development of volcanology

With the Industrial Revolution the laws of physics were introduced to explain natural phenomena. At that time the Vesuvian Observatory emerged as the first volcanological observatory in the world to monitor the activity of Vesuvius on a permanent basis. Naples became an attractor for scholars, who were to analyze volcanic phenomena by developing relationships between the science of laws and those of processes. After World War I interest in Naples-based volcanology further increases, as attested by the founding in the city of Immanuel Friedlaender’s International Institute of Volcanology. Following the twenty-year Fascist period, Italy had two objectives: to reconstruct the network of science laboratories and rebuild the approach to studying Earth Sciences through comparison with more advanced countries. Significant and original contributions were made regarding the new theory of global tectonics and the mitigation of natural risks.Published64-786V. Pericolosità vulcanica e contributi alla stima del rischioN/A or not JC

Sciences of Laws and Sciences of Processes for Earth Science

Geologists, geophysicists and volcanologists have long drawn on historical and archaeological data concerning earthquakes, tsunamis, volcanic eruptions, landslides and floods. These are important data, which help scientists to gain further knowledge about natural events, their evolution, and their effects on the built environment. Such studies - in which “time” is the dimension informing investigations of the dynamics of extreme events and their impact on the environment - stand at intersections among different disciplines.PublishedCatania1VV. Altr

GPS time series at Campi Flegrei caldera (2000-2013)

The Campi Flegrei caldera is an active volcanic system associated to a high volcanic risk, and represents a well known and peculiar example of ground deformations (bradyseism), characterized by intense uplift periods, followed by subsidence phases with some episodic superimposed mini-uplifts. Ground deformation is an important volcanic precursor, and, its continuous monitoring, is one of the main tool for short time forecast of eruptive activity. This paper provides an overview of the continuous GPS monitoring of the Campi Flegrei caldera from January 2000 to July 2013, including network operations, data recording and processing, and data products. In this period the GPS time series allowed continuous and accurate tracking of ground deformation of the area. Seven main uplift episodes were detected, and during each uplift period, the recurrent horizontal displacement pattern, radial from the “caldera center”, suggests no significant change in deformation source geometry and location occurs. The complete archive of GPS time series at Campi Flegrei area is reported in the Supplementary materials. These data can be usefull for the scientific community in improving the research on Campi Flegrei caldera dynamic and hazard assessment

Ischia island: strain field by GPS and Levelling data.

Geophysical Research Abstracts Vol. 13, EGU2011-13941-3, 2011 EGU General Assembly 2011 © Author(s) 2011 Ischia island: strain field by GPS and Levelling data. Francesco Obrizzo and the INGV (CNT-OV) Geodesy Team Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy In this paper, we discuss the results obtained by means high precision levelling and GPS surveys performed at Ischia island in June 2010. The levelling survey has been carried out on the whole network of the island. The compensated heights for each benchmark (bm), referred to bm 1 located at Ischia harbour, were compared to those obtained in the previous levelling survey performed during 2003. The GPS network operating on Ischia Island consists of 21 3D vertices homogeneously distributed on the island. Six different GPS surveys of the whole network were carried out since 1997, in order to investigate the subsidence phenomena. The comparison among the 1997, 1998, 1999, 2001, 2003 and 2010 surveys results show that some GPS points present significant horizontal displacements confirming slow but continuous deformations in the Southern and North West sectors of the island. The results show significant ground subsidence of various amplitude affecting different areas of the island. In addition, a further comparison with the measurements performed in 1987 confirms the existence of such differential movements characterised by subsidence velocity constant over time. Finally, we found a good agreement between levelling and GPS velocities, calculated in time span 1997-2010. Therefore, the integration of GPS and levelling data allowed to define the strain field on the island over the past 20 years.PublishedVienna-Austria1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attiveope

La piana campana: un monumento geologico di 5.000 km2 dal tirreno all’appennino

Abstract – The Campanian Plain: a geological monument of 5.000 km2 from the Tyrrhenian Sea to the Apennines - The Campanian Plain is the region in Southern Italy which extends between the Apennine Chain and Tyrrhenian Sea over an area of 5,000 km2 from Mt. Massico, in the north, to Sorrento Peninsula in the south of the Plain. The ancient name of this area was Campania Felix. This territory is an extraordinary geological monument characterized by volcanoes, earthquakes, tsunamis, slow ground vertical movements (bradiseism) which generated myths, legends, archeological findings, historical documents. The Campanian Plain is affected by extensional tectonics related to the spreading of the Tyrrhenian Basin. The onset of this process occurred between the Mid–Pliocene and the Early Pleistocene, when large morpho-structural depressions began to develop, giving rise to the Bay of Naples. The whole range of phenomena observed, in particular the recent tectonics and chemism of magmas feeding active volcanoes can be accounted for the local upwelling of the Mantle, the lytosphere plate bending and subsequent collapses. The measure of the collapse in the Campanian Plain, due to the stretching of the crust produced by the Mantle migration, is obtained by the thickness of sediments forming Campanian Plain. These data and the time lapse of the process furnish a value of about 1-2 mm/yr for the velocity of the subsidence during the Quaternary. Coeval to the deformation of this morphostructural depression was the onset of intense magmatic activity with the formation of the polygenic apparatus of Mt. Vesuvius and the volcanic fields of Phlegraean Fields and Ischia Island. In the Phlegrean Fields and Ischia caldera collapses, ignimbrite eruptions, and caldera resurgences occurred; instead at Vesuvius numerous Plinian eruptions were recorded. The most recent eruptions in the Neapolitan area occurred in 1302 at Ischia, 1538 at Phlegrean Fields and 1944 at Vesuvius. At present large fumarolic fields and thermal springs outcrop in several sites, while in the Phlegrean Fields slow oscillations of ground are recorded. The eruptive history of neapolitan volcanoes, the seismic history of Southern Appennines as well as the geological features of Campanian Plain characterize this area as a geological multirisk territory. Thus it is a “laboratory” for volcanic, seismic and hidrogeological risk assessment, from wich to draw lessons for integrated planning of pleasant places in risk areas.PublishedBologna6V. Pericolosità vulcanica e contributi alla stima del rischi