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  • 1
    Electronic Resource
    Electronic Resource
    Time variation of b and Q"c at Mt. Etna (1981-1987)
    Amsterdam : Elsevier
    Physics of the Earth and Planetary Interiors 71 (1992), S. 137-140 
    Details
    ISSN: 0031-9201
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0031-9201(92)90070-C
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Seismological Evidence of Active Faulting in the Tendaho Rift (Afar Triangle, Ethiopia) (1997)
    Springer
    Pure and applied geophysics 149 (1997), S. 357-374 
    Details
    ISSN: 1420-9136
    Keywords: Key words: Afar Triangle, Tendaho Rift, microearthquakes, S-wave splitting.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —A temporary network has been used to study the seismic activity in the central-northern part of the Tendaho Rift (Afar Triangle, Ethiopia). Small size earthquakes (M 〈 2.5) characterize the seismicity during the time interval 1993–1994 when the seismic array was operating. Shocks are mainly located in the central part of the Tendaho rift and their epicentral distribution highlights a remarkable coincidence with NW-SE trending tectonically active structures. Focal depths are confined in the range of 3–8 km.   The few acceptable fault plane solutions suggest the occurrence of both strike-slip and dip-slip rupture mechanisms, which are often characterized by a nodal plane oriented approximately NW-SE.  A detailed study of earthquake waveforms using polarization analysis showed the occurrence of splitting phenomena for the S waves. Despite the differences in focal mechanisms, the similarity of the faster S-wave directions (NW-SE to NNW-SSE) suggests that the direction of geological structures and/or the systems of fractures adjacent to the faults could bias shear-wave propagation. The splitting time between fast and slow shear waves shows no systematic relationship with either hypocentral distance or focal depth, suggesting that the anisotropic volume is constrained to depths shallower than 3 km.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000240050030
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Attenuation of short period seismic waves at Etna as compared to other volcanic areas (1987)
    Springer
    Pure and applied geophysics 125 (1987), S. 1039-1050 
    Details
    ISSN: 1420-9136
    Keywords: Q ; volcanic earthquakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract CodaQ for Etna volcano is frequency dependent and theQ frequency pattern and the numerical values ranging from about 100 at 1 Hz to about 300 at 18 Hz are similar to the values obtained for other volcanoes: Campi Flegrei, Aeolian Islands and Hawaii. Moreover the frequency pattern and the numerical values of coda quality factor, for most of the seismically active zones of Italy are very different from those of the volcanic zones. Several studies of the location of magma chambers show the presence of magma pockets beneath Lipari and Vulcano Islands of the Aeolian archipelago and an anomalous low velocity body beneath Etna. These evidences suggest that a possible interpretation of the characteristic frequency pattern ofQ on volcanic areas is that the presence of magma can modify the scattering environment and consequently the codaQ estimates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879367
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Volcanic tremor at Mt. Etna: State-of-the-art and perspectives (1987)
    Springer
    Pure and applied geophysics 125 (1987), S. 1079-1095 
    Details
    ISSN: 1420-9136
    Keywords: Mt. Etna ; volcanic tremor ; eruptive precursors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Volcanic tremor on Etna seems to have its origin within the main magma feeding system. On the basis of both spectral analyses at two permanent seismic stations and periodical measurements along the slopes of the volcano, two distinct sources are proposed. The former, characterized by low frequency contents (f〈1.5 Hz), is located in a 2 km deep flat magma chamber, whereas the latter source seems to be linked to the upper part of the active vents. Turbulent motions in the magma-gas mixture, induced by escaping gases within the conduits, is one proposed cause of volcanic tremor on Etna (Seidl et al., 1981). From spectral analyses we propose approximate models of the feeding system of the main summit craters. Time variations of tremor energy were also investigated, and no regular patterns have been observed for the studied eruptions. More systematic information seems to be needed for a better knowledge of both the source model and location, and correlation between tremor features and volcanic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879369
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    Paper (German National Licenses)
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  • 5
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    Improving Seismic Surveillance at Mt. Etna Volcano by Probabilistic Earthquake Location in a 3D Model (2013)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2013-08-01
    Description: The increasing accuracy of 3D velocity models developed recently for Mt. Etna has enabled their use today in routine earthquake locations. In this work, we tested the potential and performance of a global-search probabilistic earthquake location method (NonLinLoc) in a 3D velocity model, to improve earthquake locations for seismic surveillance. In addition, NonLinLoc hypocenter locations and those obtained by standard iterative-linear 3D locations, SimulPS-14, have also been compared. To this end, a dataset of 328 selected earthquakes, occurring during the 2002–2003 Etna flank eruption, and the recent highest resolution 3D velocity model, have been used. The results revealed that the differences in hypocentral coordinates between the two methods are typically of the same order or smaller than the spatial location uncertainty. To evaluate the consistency of results between the two 3D location algorithms, synthetic datasets with real source–receiver configuration are also considered. Furthermore, by using NonLinLoc we estimated the influence of the source–receiver geometry on the quality of hypocenter locations. If we vary the network geometry in a dense and well-distributed network like at Etna, reducing the number of stations (by 20% and 50%), it is significant that no large systematic hypocentral shifts of the relocated earthquakes are observed if they occur within the network. NonLinLoc is a fast and promising approach for automatic earthquake locations and surveillance purposes at Mt. Etna, because (1) it works well with a reduced number of seismic pickings, which are usually available in the automatic locations; (2) it is not particularly sensitive to tolerable levels of random noise in arrival times; and (3) it produces full location uncertainty and resolution information with respect to standard iterative-linear 3D locations.
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
    Published by Seismological Society of America (SSA)
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    PAPER CURRENT
  • 6
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    Estimation of Earthquake Early Warning Parameters for Eastern Sicily (2017)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2017-05-31
    Description: Earthquake early warning systems (EEWSs) are becoming a suitable instrument for seismic risk management in real time. In fact, they are implemented or are undergoing testing in many countries around the world because EEWSs represent an effective approach to mitigating seismic risk on a short timescale. EEWSs are based on the use of relationships between some parameters measured on the initial portion of seismic signal after the onsets. Here, we address the first approach to the implementation of EEWS in eastern Sicily, a region that has been hit by several destructive earthquakes. We estimated the peak displacement amplitude of the first portion of P and S waves P d , the ground-motion period parameter c , and the peak ground velocity (PGV) from earthquakes with M L ≥2.8 recorded by the broadband stations operated by the Istituto Nazionale di Geofisica e Vulcanologia. We found that the P d is correlated with the size of the earthquake and may be used to compute the magnitude for an EEWS in this area. We also derived the relationships between c and M L , and between P d and PGV, which can be used to provide on-site warning in the area around a given station and to evaluate the potential damaging effects. These relationships may be deemed a useful guide for future implementation of the EEWS in the region.
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
    Published by Seismological Society of America (SSA)
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    PAPER CURRENT
  • 7
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    The TOMO-ETNA experiment: an imaging active campaign at Mt. Etna volcano. Context, main objectives, working-plans and involved research projects (2016)
    In:  Annals of Geophysics
    Details
    Publication Date: 2020-02-12
    Description: The TOMO-ETNA experiment was devised to image of the crust underlying the volcanic edifice and, possibly, its plumbing system by using passive and active refraction/reflection seismic methods. This experiment included activities both on-land and offshore with the main objective of obtaining a new high-resolution seismic tomography to improve the knowledge of the crustal structures existing beneath the Etna volcano and northeast Sicily up to Aeolian Islands. The TOMO ETNA experiment was divided in two phases. The first phase started on June 15, 2014 and finalized on July 24, 2014, with the withdrawal of two removable seismic networks (a Short Period Network and a Broadband network composed by 80 and 20 stations respectively) deployed at Etna volcano and surrounding areas. During this first phase the oceanographic research vessel “Sarmiento de Gamboa” and the hydro-oceanographic vessel “Galatea” performed the offshore activities, which includes the deployment of ocean bottom seismometers (OBS), air-gun shooting for Wide Angle Seismic refraction (WAS), Multi-Channel Seismic (MCS) reflection surveys, magnetic surveys and ROV (Remotely Operated Vehicle) dives. This phase finished with the recovery of the short period seismic network. In the second phase the Broadband seismic network remained operative until October 28, 2014, and the R/V “Aegaeo” performed additional MCS surveys during November 19-27, 2014. Overall, the information deriving from TOMO-ETNA experiment could provide the answer to many uncertainties that have arisen while exploiting the large amount of data provided by the cutting-edge monitoring systems of Etna volcano and seismogenic area of eastern Sicily.
    Language: English
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 8
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    High time resolution fluctuations in volcanic carbon dioxide degassing from Mount Etna (2014)
    Elsevier Science Limited
    Details
    Publication Date: 2020-12-17
    Description: We report here on thefirst record of carbon dioxide gas emission rates from a volcano, captured at≈1 Hz. These data were acquired with a novel technique, based on the integration of UV camera observations (to measure SO2 emission rates) and field portable gas analyser readings of plume CO2/SO2 ratios. Our measurements were performedat the North East crater of Mount Etna, southern Italy, and the data reveal strong variability in CO2 emissions over timescales of tens to hundreds of seconds, spanning two orders of magnitude. This carries importantimplications for attempts to constrain global volcanic CO2 release to the atmosphere, and will lead to an increased insight into short term CO2 degassing trends. A common oscillation in CO2 and SO2 emission rates in addition to the CO2/SO2 ratios was observed at periods of ≈89 s. Our results are furthermore suggestive of an intriguing temporal lag between oscillations in CO2 emissions and seismicity at periods of ≈300–400 s, with peaks and troughs in the former series leading those in the latter by ≈150 s. This work opens the way to the acquisition of further datasets with this methodology across a range of basaltic systems to better our understandingof deep magmatic processes and of degassing links to manifest geophysical signals
    Description: Published
    Description: 115–121
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Carbon dioxide ; Passive degassing ; Volcanic remote sensing ; Plume imaging ; Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
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    The marine activities performed within the TOMO-ETNA experiment (2017)
    Details
    Publication Date: 2021-04-07
    Description: The TOMO-ETNA experiment was planned in order to obtain a detailed geological and structural model of the continental and oceanic crust beneath Mt. Etna volcano and northeastern Sicily up to the Aeolian Islands (southern Italy), by integrating data from active and passive refraction and reflection seismic methodologies, magnetic and gravity surveys. This paper focuses on the marine activities performed within the experiment, which have been carried out in the Ionian and Tyrrhenian Seas, during three multidisciplinary oceanographic cruises, involving three research vessels (“Sarmiento de Gamboa”, “Galatea” and “Aegaeo”) belonging to different countries and institutions. During the offshore surveys about 9700 air-gun shots were produced to achieve a high-resolution seismic tomography through the wide-angle seismic refraction method, covering a total of nearly 2650 km of shooting tracks. To register ground motion, 27 ocean bottom seismometers were deployed, extending the inland seismic permanent network of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and a temporary network installed for the experiment. A total of 1410 km of multi-channel seismic reflection profiles were acquired to image the subsurface of the area and to achieve a 2D velocity model for each profile. Multibeam sonar and sub bottom profiler data were also collected. Moreover, a total of 2020 km of magnetic and 680 km of gravity track lines were acquired to compile magnetic and gravity anomaly maps offshore Mt. Etna volcano. Here, high-resolution images of the seafloor, as well as sediment and rock samples, were also collected using a remotely operated vehicle.
    Description: Published
    Description: S0428
    Description: 3A. Ambiente Marino
    Description: JCR Journal
    Description: open
    Keywords: Scientific cruise report ; Marine geophysical data acquisition ; Etna offshore ; Ionian and Tyrrhenian Seas ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
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    Spatially resolved SO2 flux emissions from Mt Etna (2017)
    American Geophysical Union
    Details
    Publication Date: 2020-12-15
    Description: We report on a systematic record of SO2 flux emissions from individual vents of Etna volcano (Sicily), which we obtained using a permanent UV camera network. Observations were carried out in summer 2014, a period encompassing two eruptive episodes of the New South East Crater (NSEC) and a fissure-fed eruption in the upper Valle del Bove. We demonstrate that our vent-resolved SO2 flux time series allow capturing shifts in activity from one vent to another and contribute to our understanding of Etna’s shallowplumbingsystemstructure.We findthatthe fissureeruptioncontributed~50,000tofSO2 or~30%of the SO2 emitted by the volcano during the 5 July to 10 August eruptive interval. Activity from this eruptive ventgraduallyvanishedon10August,markingaswitchofdegassingtowardtheNSEC.Onsetofdegassingat the NSEC was a precursory to explosive paroxysmal activity on 11–15 August.
    Description: Published
    Description: 7511-7519
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Records of SO2 flux emissions from Etna’sindividualventsallowcapturing shifts in volcanic activity ; Vent-resolved SO2 flux time series provide constraints on geometry of the shallow plumbing system ; Vent-resolved SO2 flux time series demonstrate SO2 flux increase precursory to paroxysmal (lava fountaining) activity ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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