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Mazzoli, Stefano
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Mazzoli, Stefano
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- PublicationOpen AccessGeothermal Model of the Shallow Crustal Structure across the “Mountain Front Fault” in Western Lurestan, Zagros Thrust Belt, Iran(2019)
; ; ; ; ; ; ; ; ; The Zagros thrust belt is a zone of deformed crustal rocks well exposed along the southwest region of Iran. To obtain a better knowledge of this mountain chain, we elaborated a 2D model reproducing the thermal structure of the “Mountain Front Fault”. This study, which is focused on the Lurestan region, is based on a model made by merging published sections and available information on the depth of the Moho. We present the isotherms and the geotherms calculated using an analytical methodology. The calculation procedure includes the temperature variation due to the re-equilibrated conductive state after thrusting, frictional heating, heat flow density data, and a series of geologically derived constraints. In order to perform the temperature calculations, the crustal structure in the Lurestan region is simplified as composed of two domains: A lower unit made by crystalline basement and an upper unit including all the lithostratigraphic units forming the sedimentary cover. The resulting model is compared with the numerical results obtained by previous studies to improve the description of the thermal structure of this geologically important area.62 21 - PublicationRestrictedStructural inheritance controlling active crustal deformation in the Val d’Agri area (southern Apennines, Italy): new insights from finite element modelling(2017-03)
; ; ; ; ; The availability of a large amount of surface geological data and subsurface information gathered by the oil industry, together with seismic and geodetic data, allowed us to define and analyse the active structures in the Val d'Agri area of the southern Apennines. Taking into account that the study of interseismic deformation can be significant to identify locked fault areas that can potentially slip, in this study we present 2D elastoplastic finite-element models to reproduce interseismic characteristics of the study area. This hosts the largest Europe's onshore oil field and is characterised by an active extensional tectonic regime, as inferred from earthquake focal mechanisms and fault slip data from late Quaternary structures. Based on high-quality seismic profiles tied with deep well logs, we constructed a detailed geological section across the study area. Outcropping units are dissected by numerous brittle structures that formed at various stages during the tectonic evolution of the Apennines, while the deep ones are dominated by deeply rooted major faults. The rheological behaviour has been constrained by the reconstruction of the thermal structure of the fold and thrust belt, using available information from the foreland Apulian Platform and from temperature data from a series of wells. Starting from the geological model, we reproduced interseismic deformation by means of finite-element numerical modelling, varying boundary conditions and unlocking different fault segments. Our numerical models provide new insights into the controversial and widely debated active tectonic setting of the Val d'Agri area, confirming the major role played by structural inheritance and reactivation processes. In fact, recent low-magnitude seismicity tends to illuminate fault segments consisting of pre-existing reverse faults reactivated as normal faults in the present-day stress field. These long-lived, mature fault systems occurring in the buried Apulian Platform carbonates (and underlying basement) represent major brittle structures that cumulated displacements of up to a few kilometres over geologic time. As a result of their reactivation within the late Quaternary extensional stress field, these long-lived crustal structures are capable of nucleating also moderate- to large-magnitude earthquakes. The decoupling between deep and shallow structural levels, and the different inherited structures affecting them, explain the apparent contrast between the subdued surface expression of active fault systems and the known occurrence of large magnitude seismic events in the study area, thus reconciling apparently contrasting geological and geophysical constraints.173 28 - PublicationRestrictedPetrogenesis and deformation history of the lawsonite-bearing blueschist facies metabasalts of the Diamante-Terranova oceanic unit (southern Italy)The Neotethyan oceanic Diamante-Terranova unit (DIATU; southern Apennines–Calabria–Peloritani Terrane system) includes basic rocks that during the Cenozoicwere subducted and metamorphosed to lawsonite-blueschist facies conditions.Petrological and structural observations (both at the meso- and micro-scale) showthat lawsonite growth was continuous during three distinctive ductile deformationstages (D1–D3).....
77 1 - PublicationOpen AccessGeothermal 3D model of the shallow crustal structure in the Val d’Agri oil field (Basilicata region)(2017-07-10)
; ; ; ; ; ; ; A good understanding of the geothermal gradient in any region is of primary importance for hydrocarbon/geothermal reservoir management and further applications in the fields of (e.g.) subsurface CO2 storage and nuclear waste disposal. In the particular case of the Basilicata oil fields area, the analytical definition of the geotherms carried out in this study is particularly relevant, both for industrial applications and for seismotectonic modelling in a region characterized by a magnitude 7 historical earthquake. In fact, the thermal state plays a fundamental role in controlling the modes of strain accommodation in the crust, which in turn controls the partitioning and distribution of seismic vs. aseismic strain. A geothermal model for the area of the Val d’Agri oil fields has been obtained by an analytical procedure. The model takes into account both the temperature variation due to the re-equilibrated conductive state after thrusting and frictional heating. Input parameters include heat flow density data and a series of geologically derived constraints – thrust depth, timing of thrusting, slip rate – obtained by the integration of surface and subsurface datasets. This work, representing a first attempt to reconstruct a geothermal 3D model for the Val d’Agri seismic zone of the Basilicata region, provides thermal constraints that could constitute a basis for future studies in the area.130 136 - PublicationOpen AccessGeothermal 3D model of the shallow crustal structure of the Alta Val d’Agri area (southern Apennines)A geothermal model for the area of the Val d’Agri oil fields has been obtained by an analytical procedure. The model takes into account both the temperature variation due to the re-equilibrated conductive state after thrusting and frictional heating. Input parameters include heat flow density data and a series of geologically derived constraints - thrust depth, timing of thrusting, slip rate - obtained by the integration of surface and subsurface datasets. The results of this work, representing a first attempt to reconstruct a geothermal 3D model for the Val d’Agri zone of the Basilicata region, emphasize two main regional features: (i) the isotherms relative to temperatures lower than 350 °C are roughly parallel and sub-horizontal across the whole study area, tending to deepen just along the NE-most edge of the investigated region; (ii) the isotherms relative to temperatures greater than 350 °C tend to deepen toward the center of the valley. Therefore, while the thermal structure at mid crustal depths appears to be perturbed and roughly mirroring the surface valley, the seismogenic upper crust of the study area is characterized by an unperturbed, roughly homogeneous and regular thermal structure.
131 168 - PublicationRestrictedTesting thrust tectonic models at mountain fronts: where has the displacement gone?(2006)
; ; ; ; ; ; ;Tozer, R.; School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK ;Butler, R.; School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK ;Chiappini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy ;Corrado, S.; Dipartimento di Scienze Geologiche, Universita` degli Studi di Roma Tre, Largo San Leonardo Murialdo 1, 00146 Rome, Italy ;Mazzoli, S.; 5Dipartimento di Scienze della Terra, Universita` di Napoli ‘Federico II’, Largo San Marcellino 10, 80138 Naples, Italy ;Speranza, F.; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vi; ; ; ; ; The alternative relationships that can exist between a mountain front and the adjacent foreland basin have been recognized for many years. However, seismic reflection data from such areas are commonly of poor quality and therefore structural models may contain large uncertainties. In view of scientific and commercial interest in mountain belts, we have reviewed the methods for discriminating between alternative interpretations using a case study from the Montagna dei Fiori in the central Apennines, Italy. In this area Mesozoic and Tertiary carbonate sediments are juxtaposed with a foredeep basin containing up to 7 km of Messinian and Plio-Pleistocene siliciclastic sediments. A new structural model for this area demonstrates how the structures in this area form a kinematically closed system in which displacement is transferred from the thrust belt to blind structures beneath the present-day foreland. Growth strata show that Pliocene shortening was initially rapid (15 mm a 1) followed by slower rates during the final stages of deformation. Variations in structural elevation indicate a component of basement involvement during thrusting, and this is further supported by magnetic modelling. The results illustrate the interaction of thin- and thick-skinned structures in the central Apennines, and the methods for discriminating between alternative structural models.167 30 - PublicationOpen AccessFault motion reversals predating the Mw 6.3 2009 L'Aquila earthquake: insights from synthetic aperture radar data(2021)
; ; ; ; ; ; ; ; ; ; ; The millimetre accuracy of Synthetic Aperture Radar (SAR) measurements and related multi-temporal data analyses provide fundamental information on surface displacements caused by strong earthquakes. The multi-temporal analysis of SAR interferometry data allows for the geometry, kinematics and temporal behaviour of earthquake-generating faults to be better constrained, and is being acknowledged as a promising technique in the field of earthquake precursors. We used SAR data obtained by multi-temporal interferometric techniques such as Permanent Scatterers (PS) interferometry for the investigation of pre- to post-seismic ground displacements in the region struck by theMw 6.3, 2009 L’Aquila earthquake.We analysed Europen Remote Sensing (ERS) and Envisat PS-datasets from ascending and descending orbits, and COSMO-SkyMed PS-datasets from descending orbit, collectively covering a > 20 year long time span. On a yearly scale, a reversal of motions that affected the hanging-wall and footwall blocks of the earthquake-generating fault is detected. In particular, the hanging-wall block is characterized by pre-seismic uplift – which we document as being independent of any hydrological control – and eastward horizontal motion for about six years, followed by subsidence and westward motion (starting six to eight months prior to the earthquake). We suggest that such a ground displacement pattern may represent an earthquake precursor signal.121 27 - PublicationOpen AccessThermal Structure of the Northern Outer Albanides and Adjacent Adriatic Crustal Sector, and Implications for Geothermal Energy Systems(2020-11)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Using an analyticalmethodology taking into account heat flowdensity data, frictional heating, temperature variations due to the re-equilibrated conductive state after thrusting and geological constrains, we calculated surface heat flow, geotherms and isotherms along a balanced and restored regional geological cross-section. Our results highlight the impact of frictional heating produced by thrusts on the thermal structure of the study area, leading to a raising of the isotherms both in the inner Albanides to the E and in the Adriatic sector offshore. Minimum values of Qs in the surroundings of Tirana and the reconstructed 2D thermal structure suggest less favorable conditions for exploitation of geothermal energy, besides the direct use (Borehole Heat Exchanger-Geothermal Heat Pump systems). Nevertheless, the occurrence of the “Kruja geothermal zone”, partially overlapping this area and including hot springmanifestations, emphasize the structural control in driving hot fluids to the surface with respect to the regional thermal structure.68 22 - PublicationRestrictedA note on central-northern Marche seismicity: new focal mechanisms for events recorded in years 2003-2009(2011-12)
; ; ; ; ;Santini, S.; Dipartimento di Matematica, Fisica e Informatica, Università “Carlo Bo”, Urbino, Italy ;Saggese, F.; Dottorato di Ricerca in Scienze della Terra, Università “Carlo Bo”, Urbino, Italy ;Megna, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Mazzoli, S.; Dipartimento di Scienze della Terra, Università “Federico II”, Napoli, Italy ;; ; A focal mechanism study was carried out for seismic events that occurred in the central-northern Marche region between 2003 and 2009. The study is based on earthquake data, having magnitude M ≤ 3.5, recorded by the seismic network of the Istituto Nazionale di Geofisica e Vulcanologia. The results show that events tend to cluster into different sectors, each being characterized by a roughly homogeneous seismological behaviour. The new data confirm the occurrence of an extensional stress regime in the axial zone of the mountain belt, generally characterized by vertical or sub-vertical P-axes. On the other hand, a different stress regime appears to dominate in the outer Apennine sector, extending from the high valley of the Marecchia River to the foothills west of Ancona. Here, the well-known extensional domain of the axial zone of the Apennine mountain belt gives way, through an area characterized by oblique-slip faulting and variably plunging P-axes, to a regime dominated by roughly horizontal P-axes along the Adriatic onshore. Roughly horizontal P-axes characterize also the adjacent Adriatic Sea sector, although some variability in the maximum compression direction occurs in the offshore area.163 35 - PublicationOpen AccessTwo-Dimensional Geothermal Model of the Peruvian Andes above the Nazca Ridge Subduction(2023)
; ; ; ; ; ; ; ; ; The aseismicNazca Ridge produces localized flat-slab subduction beneath the South American margin at latitudes 10 to 15 S. The geological evolution and the spatio-temporal pattern of deformation of the upper plate have been strongly influenced by the presence of the flat slab. In this study, we investigated the lithospheric thermal structure of this region by elaborating a 2D geothermal model along a section across the top of the Nazca Ridge, the Peru–Chile trench, the Andean Cordillera, and the Amazonian Basin, for a total length of 1000 km. For the sake of modelling, the crust of the overriding plate was subdivided into two parts, i.e., a sedimentary cover (including the entire lithostratigraphic sequence) and a crystalline basement. Applying an analytical methodology, we calculated geotherms and isotherms by setting (i) thickness, (ii) density, (iii) heat production, and (iv) thermal conductivity for each geological unit and considering (v) heat flux at theMoho, (vi) frictional heating produced by faults, and (vii) plate convergence rate. The resulting model could make a significant advance in our understanding of how flat slab geometry associated with the Nazca Ridge subduction affects the thermal structure and hence the tectonic evolution of the region.22 8