structural setting of the bay of naples italy seismic reflection data implications for campanian volcanism abstract this paper focuses on the recent tectonic evolution of the bay of naples with the aim of exploring the connection between local tectonics and volcanism we reprocessed the seismic reflection dataset acquired in the area in the late 1973 the new processing was highly successful in obtaining a decisive strong reduction of random noise removal of coherent noise and reduction of spatial aliasing classical interpretative schemes and complex attributes of seismic traces were used to reconstruct fault kinematics and reflector patterns the results show that the faults affecting the bay of naples exhibit prevailing ne structural strikes with the exception of the pozzuoli caldera where nw patterns are also common many faults are subvertical and show seismic evidence of volcanic activity along them a main alignment of conjugate ne sw faults named here as magnaghi sebeto line intersects several submarine volcanic banks and separates the bay into two sectors characterized by important geological geophysical and petrochemical differences the structural configuration of the bay may reflect the occurrence of either oblique extension or a transfer zone of the nw se fault system along which in the campanian lucanian apennine chain great vertical displacements occur

transverse versus longitudinal extension in the foredeep peripheral bulge system role of cretaceous structural inheritances during early miocene extensional faulting in inner central apennines belt this study reports on the rocca di cave extensional fault system which is located in the prenestini mountains central italy of the apennines fold and thrust belt and presently represents the oldest exposure of early orogenic foreland fault system of the apennines this fault system was oriented perpendicular to the strike of the foredeep peripheral bulge system indicating that the onset of convergence was marked by a foredeep parallel extension instead of the commonly observed foredeep perpendicular stretching associated with lithosphere flexuring the studied fault system is formed by a 10 km long and 2 km wide e w elongated area that includes two mutually orthogonal sets of faults oriented about e w and n s respectively e w and mainly n s striking faults developed during a preorogenic santonian to campanian in age e w oriented extension kinematics which caused first uplift and erosion and then drowning of the cretaceous carbonate platform and the onset of a pelagic environment both fault sets were later reactivated in the early miocene when the area was forming part of the foreland region ahead of the eastward migrating apennines fold and thrust belt and was undergoing local n s oriented i e foredeep parallel stretching this extensional stage implied the sedimentation of hundreds of meters of synkinematic strata in the northern block of the rocca di cave fault system coevally with episodes of subaerial erosion in areas of the southern block further extensional and right lateral reactivation of inherited faults occurred in the late miocene during the progressive incorporation of the area into the apennines belt

pre quaternary orogen parallel extension in the southern apennine belt italy abstract the southern apennine fold and thrust belt differs from other parts of the peri tyrrhenian orogen in most of the peri tyrrhenian belt hinterland extension is oriented at a high angle to the orogen axis and appears to be related to rifting and formation of oceanic crust within the tyrrhenian basin the southern apennines share the late stage development of normal faults related to the opening of the tyrrhenian sea but also experienced an episode of extension parallel to the strike of the tectonic belt the orogen parallel extension was apparently formed in response to the increase in length of the deformed belt during arcuation arcuation ostensibly was related to asymmetrical rifting in the hinterland which was greater in the southern tyrrhenian sea than in areas to the north and proportionately greater shortening in the frontal parts of the southern belt as compared to regions in the north during arcuation extension was spatially concentrated within structural domains and was accomplished by displacement on low angle detachment faults cutting through a previously imbricated thrust stack during the miocene pliocene nnw sse extension in the interior of the southern appennine belt formed coveally with ene wsw shortening in the foreland longitudinal extension ceased in the pleistocene when younger high angle normal faults formed in response to the easterly migration of tyrrhenian sea rifting and ne sw extension associated with lithospheric stretching

geometry kinematics and deformation rates along the active normal fault system in the southern apennines implications for fault growth throw rates throws and kinematic data have been collected from a localised system of active normal faults in the southern apennines italy to assess how its growth history differs from that for a distributed fault system in the central apennines both show evidence for fault interaction in that 1 faults located centrally along strike have higher throws and throw rates than distal faults and 2 cumulative throw and throw rate profiles summed across strike show central maxima with values decreasing to zero at fault system tips however although throw rates increased through time in the central apennines we are unable to resolve such changes if they exist for the southern apennines specifically throw rates derived from offsets of 18 ka geomorphic surfaces are consistent with total throws in the southern apennines when extrapolated back through time but overestimate total throws in the central apennines by a factor of 2 4 suggesting an increase in throw rate through time for the latter we discuss why some fault systems appear to have throw rates that are constant through time whilst others accelerate during growth interaction

the sessano intra montane basin new multi proxy data for the quaternary evolution of the molise sector of the central southern apennines italy abstract an integrated geomorphological geological structural and stratigraphic approach was applied to the sessano intra montane basin molise central southern apennines to understand the quaternary environmental and sedimentary evolution of the basin and the surrounding areas the morpho evolutionary and sedimentary changes were mainly controlled by tectonics and strongly influenced by the huge amount of volcaniclastic input from the roccamonfina volcano located ca 50 km to the south west as well as by climatic changes chronological constraints supported by 40ar 39ar ages of tephra layers archaeo tephro stratigraphy and pollen analysis permit identification of the main phases of the geological geomorphologic evolution of the sessano basin from the middle pleistocene onwards the sedimentation within the basin was controlled by ne sw extensional tectonics and occurred from the end of oxygen isotope stage ois 15 to the beginning of ois 11 allowing the deposition of ca 85 m of fluvial to lacustrine sediments mainly made up of reworked volcaniclastic material the first phase of sedimentation was lacustrine while an important sedimentary change from lacustrine to fluvial marshy environment occurred during ois 14 after this phase the variable input of volcaniclastic material from the roccamonfina volcano together with climatic influences caused repeated changes from palustrine to fluvial sedimentation and the formation of various palaeosols present mainly in the upper portion of the infill towards the end of ois 11 nnw sse extensional tectonics caused the tilting of the fill succession and the drying up of the basin the fill succession was then affected by fluvial erosion and denudation that generated an erosion surface nowadays hanging at 700 720 m asl this surface can be related to the limbs of a palaeo surface at about 600 m asl present in the adjacent carpino le piane intra montane basin and referred to a fourth order tyrrhenian ward oriented palaeo landscape this palaeo landscape can be dated to ca 350 300 ky and therefore represents an important morpho chronological stage it provides a robust maximum and minimum age framework for reconstructing the geological and geomorphological evolution of the study area and in general of the molise apennines including the boiano carpino le piane and sessano intra montane basins in particular the morpho chronological data from the sessano basin allow us to date more precisely the main tectonic phases that occurred during the middle pleistocene in this sector of the apennine chain finally the multi proxy data derived from the sessano basin can be compared and integrated with those referring to other proximal intra montane basins in order to improve our knowledge on the relationships between tectonics volcanism and climate and the stratigraphic sedimentary features geomorphologic evolution and palaeoenvironmental changes that characterized the central southern apennines during middle pleistocene

seismic evidence of longitudinal extension in the southern apennines chain italy the 1997 1998 sannio matese seismic sequence 1 we present evidence of longitudinal extension in the apennines based on data from the 1997 1998 sannio matese seismic sequence the earthquakes occurred between the nw se faults responsible for larger historical earthquakes inversion of focal mechanisms indicates a stress field with a prevailing normal stress characterized by a nnw sse sub horizontal 3 this stress regime is consistent with normal movements along ne sw faults these features suggest that the ne sw faults located in between the nw se faults cannot be interpreted as transfer faults or old faults reactivated during the eastward migration of the chain we propose that the deformation due to the eastward chain migration concentrates along nw se normal faults which are responsible for the largest earthquakes whereas the deformation related to the chain curvature concentrates along ne sw normal faults which are responsible for the lower energy seismic sequences

the complete apennines orogenic cycle preserved in a transient single outcrop near san fele lucania southern italy orogenic cycles may be viewed as comprising two extensional stages that are separated by a stage of contraction this sequence has characterized the evolution of most mountain belts resulting from continental collision and the structural signature of individual stages is recognized on a wide variety of scales i e from microscopic to regional whereas the history of mountain belts is generally inferred from observations carried out at different sites the entire sequence of deformation is very rarely recorded in single exposures the double switch in tectonic regime that led to the development of the lucanian apennines in southern italy from pre orogenic drifting through synorogenic thrusting to post orogenic extension is preserved in a superb metre scale outcrop at serra manarella in the vicinity of san fele a late jurassic synsedimentary normal fault is sealed by strata affected by a mid pliocene thrust related fold this composite structure in turn is truncated by a mid pleistocene normal fault observation of these relationships represents a unique opportunity to unequivocally establish the relative chronology of deformations in the lucanian apennines and may provide useful constraints for regional cross section restoration

seismicity at the border between central and southern apennines italy re evaluation of the early 1984 instrumental earthquake abstract we re evaluate the 1984 abruzzo lazio earthquake on the basis of original seismological data discussed in light of previous interpretations from other authors this sequence characterized by two distinct mainshocks ms 5 8 and ms 5 2 neis having low spatial and temporal separation developed at the border between central and southern apennines the sequence originated in a narrow area adjacent to the main nw se structures belonging to the apenninic chain crossed by fault segments with different orientation the spatio temporal evolution of the seismicity the focal mechanisms of some aftershocks never obtained before and waveform analysis suggest that the sequence developed in several stages the beginning of the two main stages was marked by two events ms 5 8 and ms 5 2 and the entire sequence was strongly controlled by the structural heterogeneity in the medium involved in the stress release process the ruptures nucleated on a ene wsw striking fault segment belonging to the nne striking ortona roccamonfina tectonic line and propagated towards ene the presence of the nw se structures belonging to the apennine chain and their geometry acted as a barrier to the spread of the aftershocks northeastward as a consequence a local concentration of static stress in the area enclosed between the northern edge of the rupture segment of the first mainshock and the nw striking structures triggered the ms 5 2 event on a w e pre existing fault segment in turn the static stress changes due to the second mainshock activated adjacent ne sw and nw se fault segments the nw striking structures belonging to the apennines acted as a structural barrier halting the propagation of the ruptures nucleating on a fault segment that belongs to the nne striking ortona roccamonfina tectonic line

anatomy of a siliciclastic turbidite basin the gorgoglione flysch upper miocene southern italy physical stratigraphy sedimentology and sequence stratigraphic framework abstract the gorgoglione flysch is a tortonian siliciclastic turbidite formation well exposed in the lucania apennines southern italy with an average thickness of 1500 m it is one of the few examples of collisional basin succession for which field sedimentological investigations and visual correlations have permitted the reconstruction of the physical stratigraphy of proximal to distal turbidite deposits a northern and a southern turbidite complex have been identified they are divided by a structural high and both consist of three turbidite systems the middle and upper systems are composed of growth stages that show proximal to distal downcurrent facies variations the stacking pattern of each turbidite stage of growth consists of 5 10 cycles with thicknesses between 10 and 100 m mesocycles each of which is composed of cycles with a thickness of less than 10 m microcycles stratigraphical and sedimentological data are fitted to a sequence stratigraphy scheme represented by two nonconformity bounded depositional sequences internally composed of type i ii and iii stages of growth with aggradational to retrogradational and progradational stacking patterns the sequence stratigraphy scheme can be used as a model for turbidite collisional basins and is predictive of the stratigraphical features geometry and stacking patterns of depositional units formed when physiographic sedimentary basin evolution occurs under a regime of tectonic control this process consists of three phases i formation of the basin on top of a argille varicolori formation thrust system ii in sequence substratum thrust propagation towards the foreland basin confinement and elongation aggradational type i and retrogradational type ii stages of growth with two main sediment entry points iii deformational regime change with deactivation of in sequence thrusting decrease of deformation rate and decrease of lateral and vertical mobility the basin assumes a foreland ramp type configuration with development of a thick type iii pelitic stage of growth related to a predominant eustatic control

precipitation landsliding and erosion across the olympic mountains washington state usa abstract in the olympic mountains of washington state landsliding is the primary surface process by which bedrock and hillslope regolith are delivered to river networks however the relative importance of large earthquakes versus high magnitude precipitation events to the total volume of landslide material transported to valley bottoms remains unknown in part due to the absence of large historical earthquakes to test the hypothesis that erosion is linked to precipitation approximately 1000 landslides were mapped from google earth imagery between 1990 and 2015 along a 15 km wide 85 km long 1250 km2 swath across the range the volume of hillslope material moved by each slide was calculated using previously published area volume scaling relationships and the spatial distribution of landslide volume was compared to mean annual precipitation data acquired from the prism climate group for the period 1981 2010 statistical analysis reveals a significant correlation r 0 55 p

fault geometries from the space distribution of the 1990 1997 sannio benevento earthquakes inferences on the active deformation in southern apennines in this study we analyze the recent 1990 1997 seismicity that affected the northern sector sannio benevento area of the southern apennines chain we applied the best estimate method bem which collapses hypocentral clouds to the events of low energy md max 4 1 seismic sequences in order to constrain the location and geometry of the seismogenetic structures the results indicate that earthquakes aligned along three main structures two sub parallel structures striking nw se 1990 1992 benevento sequence and one structure striking ne sw 1997 sannio sequence the southernmost nw se structure which dips towards ne overlies the fault that is likely to be responsible for a larger historical earthquake io max xi mcs 1688 earthquake the northernmost nw se striking structure dips towards sw the ne sw striking structure is sub vertical and it is located at the northern tip of the fault segment supposed to be responsible for the 1688 earthquake the spatio temporal evolution of the 1990 1997 seismicity indicates a progressive migration from se benevento to nw sannio associated to a deepening of hypocenters i e from about 5 to 12 km hypocenters cluster at the interface between the major structural discontinuities e g pre existing thrust surfaces or within higher rigidity layers e g the apulia carbonates available focal mechanisms from earthquakes occurred on the recognized nw se and ne sw faults are consistent with dip slip normal solutions this evidences the occurrence of coexisting nw se and ne sw extensions in southern apennines

structural evolution of the lucanian apennines southern italy abstract in this paper we present a study of an entire segment of the southern apennines of italy extending from the pollino mountain range to the south to the agri valley to the north in which all the units of the chain are represented combining regional information with detailed structural data obtained from the different tectonic units forming the orogenic belt the structure as well as the tectonic evolution of this portion of the orogenic belt are proposed the overall architecture of this segment of the southern apennines mountain chain represents the result of a complete orogenic cycle in which oceanic subduction syn collisional and post collisional events are well recorded structurally this segment of the orogenic belt exhibits two distinct structural levels separated by a major detachment surface the sole thrust of the accretionary wedge that occur at the surface in the allochthonous nappes and at depth in the adria continental margin the upper level is characterized by an imbricated fan system affecting the allochthonous terranes emplaced during oceanic subduction and the first stages of continent continent collision the lower level is represented by a duplex geometry that has developed in the post collisional stage during evolution of the foreland migrating thrust system involving the carbonate platform basin system of the adria block during the last stages of the mountain building process when the foreland thrust migration was locked by the thickening of the colliding continental crusts the southern apennines were thus affected by a severe strike slip tectonics that dissects the entire mountain belt deeply modifying the previous thrust geometry

assessing the collection efficiency of ross sea sediment traps using 230th and 231pa abstract annual fluxes of particulate 230th and 231pa collected by sediment traps deployed at two locations in the ross sea are compared to expected fluxes derived by combining the seasonal depletion of 230th and 231pa in surface waters with the steady state production of each nuclide by radioactive decay of its respective dissolved uranium parent conservative minimum estimates of the expected 230th flux are greater than the flux collected by sediment traps deployed at 200 m by factors of 3 and 6 at the two sites the actual discrepancy may be much larger the discrepancies between expected and measured fluxes of 231pa are slightly smaller but comparable in magnitude to those for 230th the discrepancies between expected and measured fluxes for these natural radionuclides are similar in magnitude to those determined previously using the same sediment traps for particulate organic carbon which suggests that the sediment traps undercollected the actual flux of sinking particles

pre existing cross structures and active fault segmentation in the northern central apennines italy abstract the multideformed axial zone of the apennines provides a great opportunity to explore the influence of pre existing cross structures inherited from pre quaternary tectonic phases on the segmentation of quaternary active seismogenic extensional faults detailed geological and structural data and their comparison with seismological data show that although the attitudes strike and dip of oblique pre existing faults are certainly an important factor in determining a segment boundary the size of the inherited oblique structures seems to be more crucial pre existing cross structures with lengths ranging from several kilometers to a few tens of kilometers show a twofold behavior they can act as segment barriers during the rupture of a single fault segment or they can be reactivated as transfer zones inducing the activation of two adjacent segments that belong to the same fault system regional basement crustal oblique pre existing cross structures with lengths ranging from several tens of kilometers to hundreds of kilometers commonly nne striking may act as persistent structural barriers that halt both fault segment and fault system propagation thus determining their terminations and maximum sizes in the northern central apennines the nne striking ancona anzio valnerina and ortona roccamonfina tectonic lineaments although having been repeatedly reactivated since the mesozoic represent the most important examples of these structures moreover probably due to their misorientation with respect to the present extensional stress field regional nne striking pre existing structures appear to be less likely to produce strong magnitude events no surface evidence for quaternary faulting has been found thus far and historical and instrumental seismicity shows only m m 7 event on the other hand is more likely to occur along the n nw s se trending normal fault systems lastly we propose a model that can explain the different sizes of fault segments and fault systems on the basis of their location with respect to the persistent structural barriers and their spacing in this view our results may contribute to a more reasonable assessment of the nature and size of future surface ruptures in the northern central apennines which are of critical importance to estimating seismic hazard

the 2001 seismic activity near isernia italy implications for the seismotectonics of the central southern apennines abstract we analyze the seismic activity that occurred in 2001 near the city of isernia southern apennines with the aim to add information on the seismotectonics of the transition zone between central and southern apennines seismic activity lasted for 9 months showing the typical behaviour of swarms a large number of events of low magnitude without a distinct main shock and clustered in space and time the maximum magnitude md of the events was 3 3 comparable with the magnitude md of the background seismicity of the area hypocentral distribution of the events maximum depth 15 km suggests that seismic activity took place along a best fitting plane striking n33 e and steeply dipping eastward the results of the strain analysis performed on selected well constrained focal mechanisms indicate that most of the ruptures associated to the 2001 seismic sequence occurred along n s to ne sw striking faults characterized by strike slip to normal movements this kinematics is consistent with a prevailing nw se extension this direction of extension already observed in the 1997 98 seismic sequence which occurred at about 35 km toward se from the 2001 epicentral area is not consistent with that one assumed at regional scale on the basis of the analysis of focal mechanisms of stronger earthquakes the results of the 1997 98 and 2001 seismic sequences discussed in light of the available geological and geophysical data evidence that i in this portion of the apennine chain low magnitude seismic sequences cluster along ne sw striking faults that move in response to a nw se extension and ii the ne sw striking faults along which the 1997 98 and the 2001 seismic sequences occurred mark the southeastern and northwestern tips of the nw se fault segment responsible for the 1805 earthquake

mechanisms for folding of high grade rocks in extensional tectonic settings abstract this review of structures developed in extensional high grade terrains combined with results of centrifuge analogue modelling illustrates the range of fold styles and mechanisms for folding of amphibolite to granulite facies rocks during rifting or the collapse of a thrust thickened orogen several extensional fold mechanisms such as folding within detachment shear zones are similar to those in contractional settings the metamorphic p t t path and not fold style or mode of formation is therefore required to determine the tectonic setting in which some folds developed other mechanisms such as rollover above and folding between listric normal shear zones and folding due to isostatic adjustments during crustal thinning are unique to extensional tectonic settings several mechanisms for folding during crustal extension produce structures that could easily be misinterpreted as implying regional contraction and hence lead to errors in their tectonic interpretation it is shown that isoclinal recumbent folds refolded by open upright folds may develop during regional extension in the deep crust folds with a thrust sense of asymmetry can develop due to high shear strains within an extensional detachment or from enhanced back rotation of layers between normal shear zones during back rotation folding layers rotated into the shortening field undergo further buckle folding and all may rotate towards orthogonality to the maximum shortening direction this mechanism explains the presence of many transposed folds folds with axial planar pegmatites and folds with opposite vergence in extensional terrains examples of folds in high grade rocks interpreted as forming during regional extension included in this paper are from the grenville province of canada norwegian caledonides albany mobile belt and leeuwin complex of western australia ruby mountains in the basin and range province of nevada the at sund area of greenland the napier complex of enderby land in east antarctica and the kigluaik mountains in western alaska

extensional detachment faulting on the tyrrhenian margin of the southern apennines contractional belt italy the tectonic evolution of the campania margin during the late pliocene pleistocene is characterized by extensional deformation coeval with the opening of the marsili oceanic basin the initial stages of stretching are represented in the analysed area by the development of low angle normal faults that extended the belt in the same direction as the direction of spreading recognized for the oceanic basin detachment faulting was accompanied by the onset of magmatic activity and by major uplifts that resulted in the accumulation of thick conglomerate successions in the half grabens that developed in the upper plate of the extensional detachment deformation continued during the mid pleistocene with the formation of strike slip and normal faults trending almost parallel to the spreading direction of the marsili basin these faults dissected the extensional detachment and promoted counter clockwise block rotations about vertical axes which accommodated the ese directed stretching of the marsili basin and the consequent sinistral shear imposed on the southern apennine chain the development of a regional detachment fault along the tyrrhenian margin of campania explains the complex patterns of subsidence and uplift that characterize this area during the pleistocene and fits well within the regional geodynamic framework of the southern tyrrhenian sea

upper triassic platform margin biofacies and the paleogeography of southern apennines abstract the upper triassic dolomitic successions of the monti della maddalena area southern apennines consist of white heavily recrystallized and cataclastic dolomites generally unsuitable for detailed facies analysis nevertheless evidences of bioconstructions can be found in several localities these evidences are represented by rudstones and possibly boundstones whose main components are fragments of sponges sphinctozoans inozoans chaetetids and corals generally encrusted by foraminifera red algae and problematica this association is much more diversified with respect to that of the microbial serpulid buildups which characterize the platform margin facies of most upper triassic successions of the southern apennines the monti della maddalena biofacies can be more readily compared with the bioconstructed facies of sicily and in general with the dachstein type reef of the tethyan realm the studied successions are interpreted according to the model of cirilli et al 1999 as formed at the margin of a carbonate platform facing a deep basin having good connection with the open sea while the microbial serpulid buildups formed on the margin of intraplatform restricted troughs with poorly oxygenated bottom waters our study discusses the relative paleogeographic position of the apennine platforms and the lagonegro basin the overall picture of the bioconstructed triassic facies distribution in southern apennines together with biofacies data from resedimented facies of lucania are compatible with paleogeographic reconstructions interpreting the monti della maddalena successions as representing the more external sector of the apennine platforms system flanking the lagonegro basin the latter bordered on its external side by apulia was part of a deep mesozoic domain comprising the imerese sicani basin of sicily and connected westward with the east mediterranean branch of western tethys our data exclude the possibility that the lagonegro basin was located in an internal position with respect to all the apenninic and apulian platforms system

large scale longitudinal extension in the southern apennines contractional belt italy during late cenozoic thrusting the interior of the peri tyrrhenian orogenic belt in the southern apennines underwent two episodes of nearly orthogonal extension early extension was oriented subparallel to the axis of the tectonic belt and formed in response to progressive thrust belt arcuation the length of the tectonic belt increased by 50 and the longitudinal strain was accommodated by low angle normal faults concentrated in tectonic domains recording up to 150 200 extension younger extension oriented at a high angle to the orogen was accompanied by pliocene pleistocene uplift and by southeasterly migration of tyrrhenian sea rifting

compressional and extensional tectonics in an arc system example of the southern apennines abstract adopting the southern apennines as a case example we determine the relationships between extensional and compressional structures within an arc system based on tectonic analysis in the field we show that in addition to the well known occurrence of inner extensional structures during frontal accretion two other types of extensional structures are present in the southern apennines we classify the three types of extensional structures depending on their chronologies with the accretion of the thrust unit and we characterize them in terms of palaeostresses some normal faults of the mountain chain are old extensional structures formed in a foreland basin in the matese mountains such faults with offsets ranging several hundred metres are sealed by a late neogene thrust sheet these foredeep structures were created by extension trending almost perpendicular to the axis of the present day foreland basin other normal faults located closer to the tyrrhenian sea developed simultaneously with the pliocene quaternary accretion of thrust sheets at the front of the belt in the salerne graben a tyrrhenian basin structure extension occurred perpendicular to the compression that prevailed at the front of the mountain belt a stress gradient existed between the outer part of the arc with 1 trending ene wsw and the inner part with 2 trending ene wsw in the southern apennines middle pleistocene holocene normal faults post date all compression and thrusting the corresponding recent stress field ne sw extension results from uplift of the previously subsiding adriatic lithosphere we conclude that a given thrust unit of this nw se trending mountain chain may have successively undergone ne sw extension in the foreland basin ne sw compression during the accretion nw se extension in the back arc region and ne sw extension during the recent evolution of the prism the succession of these tectonic regimes has induced complex structures as commonly observed in an arc system

a kinematic model for the plio quaternary evolution of the tyrrhenian apenninic system implications for rifting processes and volcanism abstract during the frontal accretion due to the late miocene quaternary thrusting the interior of the apenninic chain underwent large scale extension which produced the opening of the tyrrhenian oceanic basin a back arc basin in respect to the late cenozoic apenninic chain and the onset of the quaternary volcanic activity in the campanian plain and more generally in the tyrrhenian area to outline the space time distribution and the geotectonic setting of the tyrrhenian volcanics we approached the problem from a kinematic point of view a synthesis of the available geological and geophysical data leads us to suggest that the progressive migration of the apenninic arcs is responsible for the extension phenomena which took place during the last 5 ma at first the extension resulted from the kinematic interaction between the northern apenninic arc and the southern apenninic arc during the late pliocene then from the early pleistocene the extension was controlled by the se migration of the southern arc only and therefore it can be regarded as part of the general southern tyrrhenian extension phenomenon due to the intense thinning the isotherms migrated upward very rapidly within the toscana latium and campania lithosphere where the melting point was reached giving rise to the onset of volcanic activity at the end of the early pleistocene

seismic study of the 41st parallel fault system offshore the campanian latial continental margin italy abstract a set of seismic reflection lines collected in the southern tyrrhenian sea offshore the campanian latial continental margin has been selected and interpreted the aim is to characterize 1 the structural features of the 41st parallel line 41pl an e w elongated magnetic anomaly zone separating the northern tyrrhenian domain from the southern tyrrhenian domain and 2 to study the relationships between the 41pl and the ortona roccamonfina line orl a tectonic structure transversal to the apennines along which the northern apennine arc merges the southern arc the interpretation of the seismic lines is discussed in light of the available geological stratigraphic and structural and geophysical gravimetric and magnetic information results show that the campanian latial continental margin is characterized by a series of structural lows and highs that match with the main structures on the mainland mt massico horst the volturno and garigliano depressions the study area is characterized by ese wnw to e w and ne sw striking faults the activity of these faults developed during pliocene early pleistocene times ese wnw to e w faults display structures consistent with strike slip movements these faults which are located on the maximum gradient of the e w elongated magnetic alignment of 41pl are responsible for the sse translation of the offshore sector of the mt massico horst the horizontal dislocation of mt massico suggests left lateral movements for the ese wnw to e w faults the ne sw faults that affect the mt massico horst which represents the southern tip of orl show seismic features consistent with normal movements as also revealed by inland data since 1 background seismicity is virtually absent along the study area and 2 the uppermost seismic reflectors seem unaffected by faults it is very likely that both the orl and 41pl fault zones are now inactive at least in the campanian latial area seismic data indicate that orl is older than 41pl and support the interpretation that the 41pl represents a deep seated transfer fault system formed in response to the different rates of opening of the tyrrhenian sea the strike slip movements along the 41pl faults and the normal movements along the orl faults are consistent with a nw se extension which is responsible for the longitudinal extension in the southern apennines belt

seismic activity in the transition zone between southern and central apennines italy evidences of longitudinal extension inside the ortona roccamonfina tectonic line abstract we analyze the 1997 2006 seismicity of the transition zone between southern and central apennines which is one of the most active seismic areas of italy our aim is to add information on the seismotectonic picture of this area seismic activity is characterized by single events with m

tectonic history of the lagonegro domain and southern apennine thrust belt evolution abstract the tectonic history of the lagonegro domain in southern italy is an intriguing topic for the mesozoic mediterranean paleogeography and is important for reconstructions of the tethys previous interpretations postulate the paleogeographic position of a deep lagonegro molise sicilide basinal domain between the external apulia carbonate platform to the east and the internal apenninic carbonate platform i e the alburno cervati maddalena mountains to the west a second and separate deep basin more to the west was the home of the liguride units which cover extensive areas of the southern apennines following an extensive review of previously published concepts and on the base of the structural interpretation of the southern apennines thrust belt using additional subsurface data and extensive field mapping the authors now suggest that all deep basinal units of the southern apennines i e the ligurides the lagonegro units and the molise sicilide units derive from internal areas located to the west with respect to a coeval wide carbonate platform slope shallow basin complex which in its pre middle miocene reconstruction extended from apulia well beyond the present day tyrrhenian coast of southern italy the basinal units were first assembled as an accretionary wedge and overthrusted during the late miocene over the carbonate platform slope shallow basin complex the liguride lagonegro molise sicilide accretionary wedge was later cut by an envelopment thrust which overthrust the previously underlying platform complex over the previously emplaced complex accretionary wedge our hypothesis in part revives an old concept proposed by selli 1962 and requires further testing and research we conclude that paleogeographic reconstructions of the southern apennines and the mediterranean tethys are still in a state of flux

history and tectonic implications of low angle detachment faults and orogen parallel extension picentini mountains southern apennines fold and thrust belt italy late miocene to pliocene movement on low angle extensional faults within the internal southern apennines orogenic belt was superposed on an earlier miocene imbricate thrust stack the low angle faults formed within the interior of the belt during orogen parallel extension as thrust imbrication continued in the foreland extreme tectonic thinning defines discrete structural domains of hyperextension which are linked by a complex system of extensional and transcurrent faults some of the best examples of hyperextension structures in the southern apennines are exposed in the picentini mountains in this area detailed mapping fault kinematic analysis and excellent stratigraphie control contributed to the construction of restorable cross sections and forward models of deformation with these constraints it is possible to document extensional displacement on shallowly dipping supercrustal faults whose orientation is a primary feature and is not due to later tilting during movement upper plate rocks were disarticulated by listric and planar normal faults that soled into a ramp flat detachment system the depth of the basal detachment increased in the direction of upper plate motion and ranged from 5 to 10 km displacement on the low angle detachment was accompanied by block tilting in the upper plate assemblage incisement and excisement of the upper and lower plate rocks as fault trajectories changed through time and the progressive cataclasis of hanging wall and footwall assemblages preexisting thrusts were only locally reactivated during extension and faults emanating from the underlying decollement systems cross the imbricated thrust sheets at moderate to high angles longitudinal extension resulted in thinning of the thrust stack to less than half the original thickness and had a cumulative magnitude of between 200 and 250 beta 2

late quaternary incision and deposition in an active volcanic setting the volturno valley fill southern italy abstract article history received 30 january 2012received in revised form 1 august 2012accepted 5 october 2012available online 17 october 2012editor g j weltjekeywords incised valleysequence stratigraphyforaminifer and ostracod analysisvolturno riverquaternary extensive illustration of depositional facies ostracod and foraminiferal assemblages and late quaternarystratigraphic architecture is offered for the rst time from beneath the modern coastal plain of volturnoriver the longest river in southern italy proximity to an active volcanic district including quiescent vesuviusvolcano provides an easily identi able stratigraphic marker campania grey tuff or cgt up to 55 m thick emplaced39 ky cal bpbyalarge volumeexplosivepyroclasticeruption identi cationoftopcgttoamaximumdepthof30 mallowstracingouttheshapeofa15 20 kmwidelatequaternarypalaeovalleyincisedbyvolturnoriver into the thick ignimbritic unit immediately after its deposition a terraced palaeotopography of the valley anksisreconstructedonthebasisofcoredata abovethebasal uvialdeposits theearlyholocenetransgressivefacies consist of asuite of estuarine freshwater to brackish deposits these are separated from overlyingtransgressive barrier sands by a distinctive wave ravinement surface upwards a distinctive shallowing upward succession of middle late holocene age is interpreted to re ect initiation and subsequent progradationof a wave dominated delta system with anking strandplains in response to reduced rate of sea level rise theturnaround from transgressive to highstand conditions is identi ed on the basis of subtle changes in themeiofauna theseenabletrackingofthemaximum oodingsurfaceintoitsupdip lagoonal estuarine counterpart thus highlighting the role of re ned palaeontological criteria as a powerf ul tool for high resolution sequence stratigraphic studies 2012 elsevier b v all rights reserved

thrust tectonics in the picentini mountains southern apennines italy abstract detailed geological mapping carried out in the picentini mountains southern apennines italy allowed to reconstruct the geometry of the fold and thrust belt in this region contractional structures were formed during multiple episodes of ene to nne shortening and were cut during later extension by low and high angle normal faults based on timing of emplacement and geometrical relationships between thrust units we worked out a kinematic model of thrust tectonics basinal sicilid and lagonegro units were thrust eastward onto a carbonate platform basin system cpbs starting in the serravallian tortonian and were in turn overridden by the cpbs units by means of deeper decollement thrusts later contraction starting from late tortonian messinian times built up a 15 km thick antiformal stack during ssw nne shortening we applied the forward kinematic model of thrust imbrication to perform a qualitative palinspastic restoration of a regional cross section through this area based on published interpreted seismics and other subsurface data the thrust tectonics of the picentini mountains and more northward regions was controlled in the internal sectors mostly by envelopment thrusting of carbonate platform thrust sheets which formerly were the floor complex of the tortonian thrust belt while multiple progressive decollement of the basinal roof complex occurred in the external part of the belt shallow crustal extension on low angle faults with transport direction oblique to orthogonal to contractional transport was responsible for contemporaneous thinning during the accretion of the antiformal stack at deeper structural levels

seismic reflection images of high angle faults and linked detachments in the trans hudson orogen postcollisional 1 8 1 7 ga intracontinental deformation in the trans hudson orogen canada produced a series of orogen parallel high angle faults and folds in seismic reflection profiles the faults are imaged by subvertical zones of diffractions and truncated reflections that extend to 4 8 s 12 24 km the folded and faulted upper part of the crust is underlain by laterally coherent shallow dipping reflections that are locally bounded by discrete highly reflective zones these zones are interpreted as detachments shear zones and can be traced from the upper to lower crust where some of them appear to pass into laterally continuous reflections that define the moho two distinct regimes of postcollisional crustal deformation are inferred from the seismic images high angle faulting and lateral block extrusion in the upper crust and low angle ductile shearing in the mid lower crust the surface geology indicates that the faults resulted in southwest orogen parallel extrusion of the orogen s internal zone relative to the bounding archean hearne and superior cratons faulting was concurrent with the development of upright folds with trends that are subparallel to the extrusion direction the seismic images suggest that the high angle fold fault structures are kinematically linked to low angle detachments represented by laterally coherent highly reflective zones the detachment shear zones are inferred to have a top to the southwest sense of shear associated with a subhorizontal northeast southwest extension direction parallel to those observed for 1 83 1 80 ga collisional shear zones exposed in major postcollisional fold culminations long lived orogen parallel extension is interpreted as a consequence of the boundary conditions imposed by the northeast trend of both the superior and hearne margins

pattern recognition approach to the subsequent event of damaging earthquakes in italy abstract in this study we investigate the occurrence of large aftershocks following the most significant earthquakes that occurred in italy after 1980 in accordance with previous studies vorobieva and panza 1993 vorobieva 1999 we group clusters associated with mainshocks into two categories type a if given a main shock of magnitude m the subsequent strongest earthquake in the cluster has magnitude m 1 or type b otherwise in this paper we apply a pattern recognition approach using statistical features to foresee the class of the analysed clusters the classification of the two categories is based on some features of the time space and magnitude distribution of the aftershocks specifically we analyse the temporal evolution of the radiated energy at different elapsed times after the mainshock the spatio temporal evolution of the aftershocks occurring within a few days and the probability of a strong earthquake an attempt is made to classify the studied region into smaller seismic zones with a prevalence of type a and b clusters we demonstrate that the two types of clusters have distinct preferred geographic locations inside the italian territory that likely reflected key properties of the deforming regions different crustal domains and faulting style we use decision trees as classifiers of single features to characterize the features depending on the cluster type the performance of the classification is tested by the leave one out method the analysis is performed on different time spans after the mainshock to simulate the dependence of the accuracy on the information available as data increased over a longer period with increasing time after the mainshock

geolithological and anthropogenic controls on the hydrochemistry of the volturno river southern italy the present work aims to study the main chemical and physical water parameters in the upper and middle volturno river catchment southern italy between the capo volturno springs and the confluence with the calore river this study makes use of morphology geolithology tectonic land use and physico chemical ph ec eh temperature major ions and 222rn data for the identification of the main sources of surface and ground waters in the volturno catchment and of their evolution and mixing both in base flow and peak flow conditions the study was also performed to assess whether the alteration due to potential anthropogenic contamination may hamper the identification of natural primitive sources of surface waters especially in the populated and farmed plains far from the river headwaters our data suggests that water chemistry of this stretch of the volturno river is dominated mainly by lithology and only marginally by the intense exogenous activities and that this trend is appreciable in both base flow and peak flow conditions the proposed simple geochemical approach based on easy to sample matrices and on cost effective standard methods is a valuable tool to address catchment functionality especially in upland areas where complex geologic and structural settings heterogeneous groundwater flow and logistical issues are the rule rather than the exception since the upper and middle volturno catchment is comparable to numerous valleys of the mediterranean area this study could be a reference for analogous applications this article is protected by copyright all rights reserved

mode of extensional tectonics in the southeastern betics se spain implications for the tectonic evolution of the peri alboran orogenic system the gibraltar arc which closes the westernmost part of the mediterranean basin is a miocene a type subduction arc formed by the continental collision of various pre miocene terranes in the major zone of collision between the iberian and african cratons the hanging wall block known as the alboran domain has undergone more than 300 km migration from a more easterly position where it was the continuation of the alpine cretaceous paleogene orogen contemporaneous with thin skinned thrusting in the footwall the alboran domain underwent two episodes of nearly orthogonal extension in which extensional systems developed with directions of extension varying from a nnw sse system orthogonal to the belt axis in the late burdigalian langhian to a wsw directed orogen parallel one in the serravallian the superposition of these two systems resulted in a chocolate tablet megastructure this extensional pattern is not satisfactorily explained in previously proposed models for the evolution of the arc orthogonal extension is plausible in a process of the gravitational collapse of an overthickened crust nevertheless orogen parallel extension is more difficult to explain in this context we advocate that the wsw directed low angle normal faults formed during large scale extension in connection with important westward arc migration the driving force of extension in a general context of convergence is controversial and varies between a convective removal model and a delamination model constraints on both the timing and the kinematics of extension as presented in this paper seem to support the contribution of both mechanisms convective removal may have started the process but continued n s convergence could have resulted in westward tectonic escape and asymmetric lateral inflow of asthenospheric material accompanying lithospheric delamination