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L. Cocchi F. Caratori Tontini C. Carmisciano M. Marani 《Marine Geophysical Researches》2008,29(4):251-266
We show the magnetic model of the Selli-Vavilov region. The Selli Line is known as the northwestern edge of the southern Tyrrhenian
Basin. The tectonic evolution of the Tyrrhenian Basin is dominated by a Tortonian-Quaternary extension through the eastward
movement of the Apennine subduction system. This migration has generated a diffuse stretching of the continental crust with
the emplacement of new oceanic material. This latter occurred in several localized zones where the eastward retreating of
the Ionian subduction system produced a strong depletion of the crust with formation of basins and correlated spreading. Nowadays
the presence of oceanic crust is confirmed through direct drilling investigation but a complete mapping of the oceanic crustal
distribution is still lacking. The Selli-Vavilov region shows a differentiated crustal setting where seamount structures,
the oceanic basement portions and continental crust blocks are superimposed. To this aim, a 2D inversion of the magnetic data
of this region was conducted to define buried structures. The magnetic susceptibility pattern was computed by solving the
least squares problem of the misfit between the predicted and real data for separated wavebands. This method produced two
2D models of the high and low frequency fields of the Selli-Vavilov region. The two apparent susceptibility maps provide different
information for distinct ranges of depth. The results of the inversions were also combined with seismic data of the Selli
region highlighting the position of the highly magnetized buried bodies. The results confirm a role for the Selli Line as
a deep crustal boundary dividing the Sardinian passive domain from the easternmost active region where different oceanic structures
are located. The Selli Line has worked as a detachment fault system which has moved eastward. Finally, the Selli-Vavilov region
may be interpreted as a tectonic result due to a passive asymmetrical rift occurred between the Tortonian and Pliocene. 相似文献
2.
Faggioni Osvaldo Beverini Nicolò Carmisciano Cosmo Giori Italiano 《Marine Geophysical Researches》2001,22(2):63-79
We show the results obtained by means of a seabed reduction technique on the intensity of geomagnetic anomaly fields applied
to a synthetic case and then to the real case of a geomagnetic survey of eastern Ligurian Sea (Italy). The eastern Ligurian
Sea has very intense short waves anomaly fields and a sea bed that varies greatly in depth. As a result the geomagnetic space
signal is characterized by a very large spectral content; in these conditions it is not possible to obtain a full sampled
marine survey and vertical continuation analytic procedures and standard numerical bottom reduction based on a single vertical
incremental parameter, whichever is applicable, fails to give accurate results. The present technique, which has been fine-tuned
over 4 years of experimentation in environmental researchs, aims to provide a simple and efficient means to reduce the distortion
of geomagnetic anomalies field caused by the variation of distance between survey plane and magnetic outcrop source position.
The compensation procedure is based on evaluation, by comparison of two measurements carried out at different altitudes, of
the mean vertical increment typical of each anomaly field principal frequency component bands. The component anomaly fields
are then corrected by application of the corresponding vertical increments and lastly, the anomaly geomagnetic field reduced
to the sea-bed is computed as Inverse Fourier Transform of a spectrum built as synthesis of the component anomaly fields'
spectra. The results obtained have shown a notable increase in definition of anomaly field intensity without the production
of appreciable distortions or false geomagnetic echoes.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
3.
Flooding scenarios due to land subsidence and sea‐level rise: a case study for Lipari Island (Italy)
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Marco Anzidei Alessandro Bosman Roberto Carluccio Daniele Casalbore Francesca D'Ajello Caracciolo Alessandra Esposito Iacopo Nicolosi Grazia Pietrantonio Antonio Vecchio Cosmo Carmisciano Massimo Chiappini Francesco Latino Chiocci Filippo Muccini Vincenzo Sepe 《地学学报》2017,29(1):44-51
Archaeological and instrumental data indicate that the southern sector of the volcanic island of Lipari has been subsiding for the last 2100 years due to isostatic and tectonic factors, at variable rates of up to ~11 mm a?1. Based on this data, a detailed marine flooding scenario for 2100 AD is provided for the bay of Marina Lunga in the eastern part of the island from (1) an ultra‐high‐resolution Digital Terrain and Marine Model (DTMM) generated from multibeam bathymetry (MB) and Unmanned Aerial Vehicles (UAV), (2) the rate of land subsidence from Global Positioning System (GPS) data and (3) the regional sea‐level projections of the International Panel on Climate Change (IPCC). When land subsidence is considered, the upper bound of sea‐level rise is estimated at 1.36 m and 1.60 m for RCP4.5 and RCP8.5 climate change scenarios, respectively. Here, we show the expected impact of marine flooding at Lipari for the next 85 years and discuss the hazard implications for the population living along the shore. 相似文献
4.
L. Cocchi F. Caratori Tontini F. Muccini M. P. Marani G. Bortoluzzi C. Carmisciano 《地学学报》2009,21(5):369-374
Inversion of new high-resolution magnetic data from the Marsili seamount and the surrounding basin in the Tyrrhenian Sea reveals NNE–SSW magnetization stripes ranging from the Matuyama chron to the Brunhes chron, including the short positive Jaramillo subchron. The detailed magnetic chronology shows that from the late Matuyama (1.77 Ma), the average half spreading rate was about 1.5 cm yr−1 , with a slight decrease between the Jaramillo and the Brunhes events, when the growth of the volcanic edifice overcame lateral spreading. Analysis of spreading rate and volume of erupted lava indicates that at the beginning of the Jaramillo subchron (1.07 Ma), the Marsili basin evolved from pure horizontal spreading to a superinflated seamount as a consequence of tearing of the Ionian slab. Our data give us a snapshot of the geodynamic transition from an active backarc spreading phase to the vertical accretion of the seafloor because of a radical change in the subduction dynamics. 相似文献
5.
O.?FaggioniEmail author F.?Caratori.?Tontini P.?Stefanelli C.?Carmisciano L.?Cocchi I.?Giori 《Marine Geophysical Researches》2003,24(3-4):265-277
This paper shows the results of a detailed reprocessing of aeromagnetic data, obtained by the downward projection to the seabed. The area of interest is centered over the Tyrrhenian Basin, whose bathymetric–topographic lay-out is characterized by a somewhat irregular trend. The origin of the intense depth variations depends on the Tyrrhenian structural setting, that is associated with the presence of several tectonic lineaments, seamounts or volcanic islands. The data were characterized by good quality and dense sampling, but they have been reprocessed in order either to solve some problems in the original compilation, and to reduce the distortion of the geomagnetic anomaly field caused by the difference of distance between the survey level and the magnetic source. The reprocessed magnetic map is proposed as an effective analysis tool for the Tyrrhenian area that is characterized by high susceptibility lithotypes. Downward projection of the aeromagnetic data by BTM algorithm increases the definition of the anomalous magnetic signal without distortions in the geometric pattern of the field, thus showing a more stable and effective association between the magnetic anomalies and their geological sources. This effect is particularly true for high frequency anomalies that are directly comparable after the topographic projection because the depth filtering effect is attenuated. Moreover, the BTM method has been applied for the first time to a regional scale survey that shows substantial advantages because no fictitious anomalies in the high frequency sector of the spectrum were generated. This has been a typical effect of the traditional downward projection methods widely used before. The final result is a BTM anomaly map that is able to show the structural connections between the geological magnetic sources of the Tyrrhenian Sea area. 相似文献
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