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Moratti, Giovanna
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Moratti, Giovanna
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- PublicationRestrictedSeismotectonics of the 1755 Meknes earthquake (Morocco)(2002-05)
; ; ; ; ; ; ; ; ; The November 1st, 1755 Lisbon earthquake has been largely studied, its source constrained to be a 200 long structure, its magnitude estimated around 8.7, and the stress regime argued as a NNW-SSE directed compression. Less well knoll is the Meknes earthquake, occurred a few days later in Morocco and considered the effect of a strong aftershock in Portugal. It had destructive effects in the Meknes region, along the E-W trending Rides Prérifaines, the main frontal thrust of the Rif. Historical data indicate an E-W elongation of the epicentral macroseismic area, where we surveyed the major recent faults. Historical descriptions of the earthquake indicate ground ruptures in two areas of the Rides Prérifaines. Field work and air photo interpretation allowed us to relate these ruptures with the local thrust front, so that they may be assumed to correspond to coseismic surface faulting of the Meknes earthquake82 1 - PublicationOpen AccessLate Pliocene-Quaternary evolution of outermost hinterland basins of the Northern Apennines (Italy), and their relevance to active tectonics(2009)
; ; ; ; ; ; ; ; ; ; ; ;Sani, F. ;Bonini, M. ;Piccardi, L. ;Vannucci, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Delle Donne, D. ;Benvenuti, M. ;Moratti, G. ;Corti, G. ;Montanari, D. ;Sedda, L. ;Tanini, C. ; ; ;; ; ; ; ; ; ;We examine the tectonic evolution and structural characteristics of the Quaternary intermontane Mugello, Casentino, and Sansepolcro basins, in the Northern Apennines fold-andthrust belt. These basins have been classically interpreted to have developed under an extensional regime, and to mark the extension-compression transition. The results of our study have instead allowed framing the formation of these basins into a compressive setting tied to the activity of backthrust faults at their northeastern margin. Syndepositional activity of these structures is manifested by consistent architecture of sediments and outcrop-scale deformation. After this phase, the Mugello and Sansepolcro basins experienced a phase of normal faulting extending from the middle Pleistocene until Present. Basin evolution can be thus basically framed into a two-phase history, with extensional tectonics superposed onto compressional structures. Analysis of morphologic features has revealed the occurrence of fresh fault scarps and interaction of faulting with drainage systems, which have been interpreted as evidence for potential ongoing activity of normal faults. Extensional tectonics is also manifested by recent seismicity, and likely caused the strong historical earthquakes affecting the Mugello and Sansepolcro basins. Qualitative comparison of surface information with depth-converted seismic data suggests the basins to represent discrete subsiding areas within the seismic belt extending along the axial zone of the Apennines. The inferred chronology of deformation and the timing of activity of normal faults have an obvious impact on the elaboration of seismic hazard models.892 746 - PublicationRestrictedOverview and new data on the active tectonics of Bulgaria: towards a comprehensive seismotectonic map(2013)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; This paper presents a discussion on some aspects of the active tectonics in Bulgaria based on available literature data as well as recent research mainly focused on the identification and characterization of active faults in selected key areas. In particular, through tectonic, GPS and remote sensing data, also coupling geological observations with seismological data, we present here 1) a comprehensive map of major active faults in Bulgaria, although still in progress, and 2) a detailed study of various active structures, in particular in the Sofia Graben, Struma valley and surrounding regions. Our research highlights the occurrence in south-west Bulgaria of several major active faults, the majority of which are normal faults accommodating a roughly N-S to NNE-SSW extension, in line with GPS data and analysis of the instrumental seismicity. The extensional stress field, with associated tectonic and seismic activity, is likely to be related to the northern extent of the Aegean extensional system and its recent evolution. In the Balkan mountains area the tectonic activity is somehow more complex, responding to the interplay of the northward propagation of the Aegean extension and the influence of a roughly E-W compression, which determines local shear zones.124 2 - PublicationRestrictedMessinian-Early Pliocene crustal shortening along the Tyrrhenian margin of Tuscany, Italy(2009)
; ; ; ; ; ; ; ; ; ;Sani, F.; Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Florence, Italy ;Bonini, M.; CNR, Consiglio Nazionale delle Ricerche, Istituto di Geoscienze e Georisorse, U.O. Firenze, Florence, Italy ;Cerrina Feroni, A.; CNR, Consiglio Nazionale delle Ricerche, Istituto di Geoscienze e Georisorse, Pisa, Italy ;Mazzarini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Moratti, G.; CNR, Consiglio Nazionale delle Ricerche, Istituto di Geoscienze e Georisorse, U.O. Firenze, Florence, Italy ;Musumeci, G.; Dipartimento di Scienze della Terra, Università degli Studi di Pisa, Pisa, Italy ;Corti, G.; CNR, Consiglio Nazionale delle Ricerche, Istituto di Geoscienze e Georisorse, U.O. Firenze, Florence, Italy ;Iatta, F.; Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Florence, Italy ;Ellero, A.; CNR, Consiglio Nazionale delle Ricerche, Istituto di Geoscienze e Georisorse, Pisa, Italy; ; ; ; ; ; ; ; This paper illustrates the results of structural studies carried out in the western margin of Tuscany along a major crustal structure. Surface deformation of sediments filling different basins aligned on top of this major structure (from north to south: the Fine Basin, the Sassa–Guardistallo basin, the Rio Guardigiano area in the Lustignano basin) allow us to date its tectonic activity to the Messinian-Early Pliocene. In these areas, structures such as reverse and strike-slip faults and mesoscopic folds are widely developed. Structural analysis determined a compressive stress field with the σ1 oriented from E-W to NE-SW active from Messinian to Early Pliocene. At the southern end of this crustal structure, the Gavorrano antiform and the granitic pluton (radiometric age of granite ~4.4 Ma) coring this fold correlate with a thrust ramp anticline at depth, and thus constrain thrust activity to the Early Pliocene. These data document a Messinian–Early Pliocene compressive activity that contrasts with models invoking continuous extensional tectonics affecting the hinterland since the Late Oligocene-Middle Miocene in the frame of a back-arc-slab retreating process. The results presented therefore raise the question of which geodynamical model could account for such a complex structural evolution of Northern Apennines hinterland.339 19 - PublicationRestrictedThe 1755 “Meknes” earthquake (Morocco): field data and geodynamic implications.(2003)
; ; ; ; ; ; ; ;Moratti, G.; C.N.R—Istituto di Geoscienze e Georisorse, Sezione di Firenze, Via G. La Pira 4, 50121 Firenze, Italy ;Piccardi, L.; C.N.R—Istituto di Geoscienze e Georisorse, Sezione di Firenze, Via G. La Pira 4, 50121 Firenze, Italy ;Vannucci, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Belardinelli, M. E.; cDipartimento di Fisica, Universita` degli Studi di Bologna, Settore di Geofisica ;Dahmani, M.; Ministe`re de l’Energie et des Mines, Direction de la Ge´ologie, B.P. 6208, Rabat-Institut, Morocco ;Bendkik, A.; Ministe`re de l’Energie et des Mines, Direction de la Ge´ologie, B.P. 6208, Rabat-Institut, Morocco ;Chenakeb, M.; Ministe`re de l’Energie et des Mines, Direction de la Ge´ologie, B.P. 6208, Rabat-Institut, Morocco; ; ; ; ; ; The source of the famous 1 November, 1755 ‘‘Lisbon’’ earthquake has been constrained to be an up to 200 km long structure in the offshore west of Cabo de S. Vincente.The magnitude of this earthquake was estimated in the range of 8.5–9.4. The stress regime argued for this shock would have been characterised by an around NNW–SSE-oriented compression.Less well studied is the successive ‘‘Meknes’’ earthquake, which occurred a few days later in Morocco (27 November), and was erroneously confused by the European contemporary reports with a strong aftershock, occurred on 18 November, of the main seismic sequence of the 1 November earthquake.The Meknes earthquake had destructive effects in the region of Meknes and Fes and along the E–W trending Rides Pre´rifaines, the main frontal thrust of the Rif.Historical data indicate a macroseismic field closed around the towns of Meknes and Fes. Our structural–geological fieldwork and remote sensing analysis in the epicentral area of the Meknes earthquake, along the local major recent faults, indicate that the E–W-oriented thrusts of the Rides Pre´- rifaines are active.Throu gh a re-examination of historical sources compared with field work and air photo interpretation, we could individuate the traces of coseismic surface faulting of the 1755 Meknes earthquake in two areas of the Rides Pre´rifaines, both part of the local thrust front: the Jebel Zerhoun area and the Jebel Zalagh area.Tectonic data on the Quaternary stress fields derived from our fieldwork and from literature, consistently with the revised focal mechanisms in the region, indicate active shortening oriented NNW–SSE to N–S in northern Morocco.The data collected seem therefore to indicate the thrusts of the Rides Pre´rifaines, located within the macroseismic area of the Meknes earthquake, as the most probable seismic source of that event.As such, the activation of the thrusts of the Rides Pre´rifaines would be consistent with this stress regime, which in turn would be similar to the stress field maintained as responsible for the 1 November, 1755 Lisbon earthquake.W e also attempted an estimate of the change due to the Lisbon earthquake of the Coulomb Failure Function (CFF) on the Meknes structure, as identified in this paper, in order to evaluate if the Meknes earthquake could have been induced by the 1 November, 1755 Lisbon earthquake, or a local distinct earthquake.Our modelling suggests that the latter hypothesis is the more likely one.654 76