unveiling the sources of the catastrophic 1456 multiple earthquake hints to an unexplored tectonic mechanism in southern italy we revisited data related to the 1456 seismic crisis the largest earthquake to have ever occurred in peninsular italy in search of its causative source s data about this earthquake consist solely of historical reports and their intensity assessment because of the age of this multiple earthquake the scarcity and sparseness of the data and the unusually large damage area no previous studies have attempted to attribute the 1456 events to specific faults existing analytical methods to identify a likely source from intensity data also proved inappropriate for such a sparse dataset since historical evidence suggests that the cumulative damage pattern contains at least three widely separated events we subdivided the 1456 damage pattern into three independent mesoseismal areas each of these areas falls onto east west tectonic trends previously identified and marked by deep 10 km right lateral slip earthquakes based on this evidence we propose 1 that the 1456 events were generated by individual segments of regional east west structures and are evidence of a seismogenic style that involves oblique dextral reactivation of east west lower crustal faults 2 that each event may have triggered subsequent but relatively distant events in a cascade fashion as suggested by historical accounts hence 3 that the 1456 sequence reveals a fundamental but unexplored mechanism of tectonic deformation and seismic release in southern italy this style dominates the region that lies between the northwest southeast system of large extensional faults straddling the crest of the southern apennines and the buried outer front of the chain although the quality of the available information concerning the 1456 earthquake is naturally limited we show that the overlap of the damage distribution the orientation and characteristics of regional tectonic structures the seismicity patterns and the focal mechanisms all concur with our interpretations and would be difficult to justify otherwise

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

spatial variation in stresses in peninsular italy and sicily from background seismicity abstract we have retrieved the stress tensor orientation in the italian region applying the fmsi technique gephart j 1990b fmsi a fortran program for inverting fault slickenside and earthquake focal mechanism data to obtain the regional stress tensor comput geosci 16 953 989 to fault plane solutions of 298 small earthquakes 2 5 m d istituto nazionale di geofisica in the period 1988 1995 first we verified that the stress inversion procedure generally applied to a large number of focal mechanisms of earthquakes recorded in a local seismic network could be successfully used in italy using background seismicity recorded over large 100 200 km regions then comparing the stress inversion results with other stress indicators we find that they are geologically sound for many regions in italy even if the misfit values are relatively large we also find that the largest misfit values are determined by a few earthquakes only 10 20 of the total number excluding these earthquakes from inversion the average misfit becomes much lower by 30 40 the results obtained in this study confirm the large variations of the stress field over a relatively short distance in italy but also confirm the existence of regions extending for a few hundred kilometres within which the stress is homogeneous among these most of the apennines are dominated by extension perpendicular to the trend of the mountain belt only in the northern apennines is there any clear distinction between an area of extension in the inner portion of the belt and an area under horizontal compression along the adriatic margin of the belt more rapid variations occur around calabria and sicily as expected because of the complexities linked with the tyrrhenian subduction and with active volcanism in the ionian calabrian coastal region there are hints of active nw se compression although constrained by a few data whereas in the messina strait we observe e w extension and a vertical 1 in northern and western sicily our results indicate n s to nw se compression roughly consistent with the general convergence between the european and the african plates

inversion of field data in fault tectonics to obtain the regional stress iii a new rapid direct inversion method by analytical means summary a new method for determining the reduced stress tensor with four degrees of freedom the orientations of the three principal stress axes as well as the ratio of principal stress differences using fault slip data or focal mechanisms of earthquakes is presented from a computational point of view the inversion of fault slip data is made in a direct way by purely analytical means as a result the determination process is extremely fast and adaptable on small microcomputers from a physical point of view the method aims at simultaneously i minimizing the angles between theoretical shear stress and actual slip vector and ii having relative magnitudes of shear stress large enough to induce slip despite rock cohesion and friction examples of application to actual fault slip data sets with good or poor variety of fault slip orientations are shown the double significance of the basic criterion adopted results in a more realistic solution of the inverse problem than the single minimization of the shear stria angle

relay ramps in active normal fault zones a clue to the identification of seismogenic sources 1688 sannio earthquake italy relay ramps commonly occur in areas of active extension they have relevance in terms of fault segmentation fault linkage and related seismic potential we propose consideration of field evidence of an active relay ramp in a seismic area as a clue to the definition of a seismogenic normal fault we have chosen the calore river valley as our study area it is located within the core of the apennine chain of the italian peninsula and is characterized by active extension and associated severe seismicity in particular a destructive earthquake struck the study area in 1688 we integrated data deriving from a geological field survey with original geomorphic and mesostructural analyses and new radiometric dating 40 ar 39 ar results indicate that brittle deformation detected in the northern part of mt camposauro could represent the surface expression of the ne dipping main fault of an active extensional system we refer to as the calore river fault system its structural connection with the neighboring boiano basin extensional fault system is marked by an area of complex deformation which links them and can be described as a stage 3 relay ramp given that the boiano basin fault system is a seismogenic source the identification of a relay ramp implies a seismogenic role also for the calore river fault system in turn these results allow us to suggest a new hypothesis for the seismogenic source of the 1688 sannio earthquake finally we discuss the implications on the seismic potential of two seismogenic structures linked by a relay ramp

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

regional stratigraphy of the zagros fold thrust belt of iran and its proforeland evolution the latest neoproterozoic through phanerozoic stratigraphy of the zagros fold thrust belt of iran has been revised in the light of recent investigations the revised stratigraphy consists of four groups of rocks each composed of a number of unconformity bounded megasequences representing various tectonosedimentary settings in the lowest group ranging in age from latest precambrian to devonian the uppermost neoproterozoic to middle cambrian rocks constitute a megasequence of evaporites siliciclastic deposits and interlayered carbonates which were deposited in pull apart basins that developed by the najd strike slip fault system this megasequence is overlain by a second one middle to late cambrian in age which consists of shallow marine siliciclastic and carbonate rocks representing deposition in an epicontinental platform the overlying shales siltstones and partly volcanogenic sandstones of ordovician silurian and devonian age are local remnants of stratigraphic units that were extensively eroded during development of several major unconformities the second group consists of two megasequences one permian and the other triassic composed of widespread transgressive basal siliciclastic rocks and overlying evaporitic carbonates of an equatorial epi pangean very shallow platformal sea the third group is composed of four megasequences formed of shallow and deep water carbonates with some siliciclastic and evaporite deposits which accumulated on a neo tethyan continental shelf during earliest jurassic through late turonian time the fourth group comprises siliciclastic and carbonate deposits of a largely underfilled nw to se trending forward and backward migrating late cretaceous to recent proforeland basin which has evolved as an integral part of the zagros orogen this last group consists of three megasequences ix x and xi with distinctive lateral and vertical facies variations which reflect specific tectonic events megasequence ix comprises uppermost turonian to middle maastrichtian prograding and retrograding siliciclastic and carbonate deposits whose accumulations reflect emplacement obduction of ophiolite slivers and subsequent collisional events in the zagros orogen megasequence x consists of uppermost maastrichtian to upper eocene siliciclastic and carbonate rocks which deposited first progradationally in front of the zagros orogenic wedge with reduced contractional tectonic activity and then retrogradationally due to intensified thrust stacking in the interior parts of the orogen megasequence xi consists of oligocene and lower miocene carbonate strata deposited retrogradationally shortly after a period of intensified late eocene thrust faulting in the deformational wedge and an overlying succession of upward coarsening northeasterly derived siliciclastic deposits of lower miocene to recent age which are composed of erosional byproducts of the southwest vergent zagros thrust sheets

extension in compressional orogenic belts the eastern alps extension in the eastern alps encompasses the following 1 extension accompanying simple shear crustal stacking subhorizontal stretching occurs along flat lying foliations and regionally consistent stretching lineations with associated high strains on a local scale stretching results from extrusion of ductile sediments squeezed between rigid basement blocks basement blocks during thrust sheet imbrication the overall geometric effect is crustal thickening 2 classical extensional tectonics extension first occurs as a consequence of accretion and underthrusting of continental and oceanic material and represents gravitational adjustment of an unstable orogenic wedge extension then occurs as a consequence of terminal continental collision and is accommodated by lateral extrusion of crustal of crustal blocks the overall geometric effect is crustal thinning extension is generally oriented subparallel to the strike of the orogen

tectonic deformation by rotating parallel faults the bookshelf mechanism abstract in various tectonic environments extension of crustal parts and shear distortion has been accommodated by the rotation of an array of parallel faults because of its kinematic resemblance to the tilting of a row of books on a shelf the tectonic process may be referred to as a bookshelf mechanism its most important manifestions are cross faulting between normal faults or parallel wrench faults the extension of deltaic slope deposits and all forms of tilted block tectonics kinematically there are two basic modes of the mechanism a the dilational mode where rotating faults tend to open up and possibly become paths for fluid migration and b the domino style where reclining faults remain closed in both cases formation and rotation of the faults may take place in one tectonic event fault displacements may therefore often remain small and difficult to detect from the mechanical point of view bookshelf operations that accommodate shearing between parallel and predominantly parallel moving rock boundaries bookshelf mechanisms proper have to be differentiated from those operations responding to an imposed crustal extension or shortening after a review of geological evidence the process is addressed from a geomechanical point of view in order to determine the geological operating conditions and controlling parameters the crucial mechanical factor in the bookshelf mechanism is the component of normal stress that acts in the direction of the imposed displacement component parallel to the driving boundary plates in contrast to the usual assumption the driving shear stress on the boundary plates not only depends on the normal stress on the plates but it also varies with the value of the normal stress that acts inside the sheared material in the direction of the plate parallel displacement component it is the relationship between the two normal stresses that also determines the type of rotating parallel faults large scale rotation of parallel normal faults in domino style tilted block tectonics is primarily associated with the extension of ductile substrata from mechanical arguments and sand box experiments it has been inferred how the process and in particular the dip direction of the parallel faults is controlled by the way substratal extension progresses by means of the direction of a substratal squeeze flow the presence of a surface slope the strength anisotropy associated with fore set beds and by the configuration of competent boundaries of the extending overburden

earthquake swarms in the southern apennines chain italy the 1997 seismic sequence in the sannio matese mountains abstract in this paper we analyze a seismic sequence that occurred in the sannio matese mountains southern apennines italy one of the most dangerous seismic areas of the italian peninsula on 19 march 1997 at 23 10 utc a seismic event of md 4 1 hit a zone near the border between the campania and the molise regions swarm type earthquake activity followed the main event and lasted for more than six months with alternation of intense activity and relative quiescence periods evolution of the seismic sequence both in time and space has allowed us to divide it into three stages with rather similar characteristics the seismic energy release process of this sequence exhibits the typical swarm pattern of the minor seismic sequences occurring in the southern apennines and involving relatively minor faults located in the marginal border of the chain such pattern unlike the main shock aftershock model consists of low energy events closely clustered in time and space without a single main shock about 2800 micro earthquakes were recorded from march to september 1997 by the seismic networks of the istituto nazionale di geofisica and of the osservatorio vesuviano among them only 20 events had md 3 0 a selection of 370 earthquakes recorded at a minimum of five stations with at least three s phase readings have been located between latitudes 41 20 and 41 30 and longitudes 14 36 and 14 42 the events are clustered along a nearly vertical plane striking nne ssw and dipping towards the east their hypocentral depths range from 5 to 15 km the focal mechanisms of 67 events show a variety of different solutions even if a prevalence of normal dip slip solutions with a strike component is observed the t axes distribution of all mechanisms show two trends the prevalent one is aligned along a nnw sse direction whereas the other one is along a nne ssw direction the hypocentral distribution the prevalence of focal mechanisms with fault planes striking about ne sw as well as the t axes distribution suggest that earthquakes relative to this sequence took place along nne ssw oriented faults and that the local stress field acting in this sector of the southern apennines is prevalently transtensional and is strongly controlled by local faults heterogeneities

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 geology and structural evolution of a caledonian fold and ductile thrust zone kyle of tongue region sutherland northern scotland the middle to upper proterozoic metasedimentary rocks of the northern highland moine in sutherland are disposed in a series of major caledonian c 470 430 ma metamorphic thrust nappes produced by nw wnw directed shortening and reworking of parts of a pre existing precambrian c 1000 ma orogen lewisian inliers occur throughout sutherland and represent tectonically interleaved units of the original basement gneisses upon which the moine cover sequence was deposited in the western moine nappe of the kyle of tongue region the rocks are deformed by two main episodes d1 and d2 which are thought to represent the effects of precambrian and caledonian orogenesis respectively little basement cover interleaving or large scale folding occurred during the d1 event in the moine nappe but the associated metamorphism to ut leust garnet grade produced peak metamorphic mineral assemblages subsequent caledonian reworking d2 produced a foreland propagating system of wnw directed ductile thrusts and related major f2 sheath folds both of which resulted in much of the observed moine lewisian interleaving metamorphism associated with d2 decreases in grade westwards occurring at similar or slightly lower grades than the earlier d1 event this retrogressive overprint is most obvious at the w margin of the moine nappe the d2 folds and ductile thrusts are geometrically and kinematically similar to the caledonian structures recognized within the moine thrust zone to the west the very low 5 ramp angles suggesting that the thrusts must have very shallow dipping trajectories through the crust f2 fold formation is attributed to an early phase of wnw directed overthrusting compression which was then progressively superseded by a regional ductile extensional strain contemporaneous with continued wnw directed thrusting the occurrence of internal extension in the orogenic wedge during active thrust related foreshortening implies that the shear strength of the material close to the basal detatchment s was continuously reduced i e wedge motion became supercritical in this context strain softening processes within the ductile thrust mylonites were probably of major significance

fault plane solutions and seismicity of the italian peninsula abstract a new fault plane solution map of the italian peninsula is presented in this paper the earthquakes analyzed are included in the period 1905 1980 with magnitudes ranging 4 7 75 earthquakes are located in the crust while 31 are related to the deep and intermediate zone of the calabrian arc the large seismic events of the italian peninsula are generally associated with normal faulting while strike slip motion is mostly related to small earthquakes located along lateral segments of the mountain chain the deep and intermediate earthquakes of the tyrrhenian sea indicate predominant down dip compression and strike slip motion at the boundaries of this benioff zone this last is interpreted as a remnant of a subduction zone active since oligocene extending to 500 km depth with a very small lateral size about 300 km the present tectonics of this benioff zone is strongly conditioned by the lateral bending more so than the gravitational sinking process the coexistence of thrust and normal faulting motion associated to the earthquakes within a few tens of kilometers of each other seems to be explained by the strong lateral inhomogeneities of the crustal rocks present in this region more so than to the depth of the seismogenetic zone and the nature of the faulting process

integration of spectral spatial and morphometric data into lithological mapping a comparison of different machine learning algorithms in the kurdistan region ne iraq abstract lithological mapping in mountainous regions is often impeded by limited accessibility due to relief this study aims to evaluate 1 the performance of different supervised classification approaches using remote sensing data and 2 the use of additional information such as geomorphology we exemplify the methodology in the bardi zard area in ne iraq a part of the zagros fold thrust belt known for its chromite deposits we highlighted the improvement of remote sensing geological classification by integrating geomorphic features and spatial information in the classification scheme we performed a maximum likelihood ml classification method besides two machine learning algorithms mla support vector machine svm and random forest rf to allow the joint use of geomorphic features band ratio br principal component analysis pca spatial information spatial coordinates and multispectral data of the advanced space borne thermal emission and reflection radiometer aster satellite the rf algorithm showed reliable results and discriminated serpentinite talus and terrace deposits red argillites with conglomerates and limestone limy conglomerates and limestone conglomerates tuffites interbedded with basic lavas limestone and metamorphosed limestone and reddish green shales the best overall accuracy 80 was achieved by random forest rf algorithms in the majority of the sixteen tested combination datasets

insights into present day crustal motion in the central mediterranean area from gps surveys summary in this paper we present observations of crustal motion related to a large gps network located in the central western mediterranean area velocities are obtained by the analysis of more than 30 observing sites at which at least three different gps campaigns were carried out in the time span 1991 1999 the results are presented both in the itrf96 reference frame and with respect to a eurasian fixed reference frame the sites located along the northern african margin in sicily and southern italy show prevalent northeastward movements with a mean velocity of roughly 0 7 cm yr 1 the relatively dense network available in the southern apennines led us to try a tentative estimate of the average strain rate in this zone resulting in a maximum extension of 0 021 0 006 10 6 yr 1 normal to the chain in ionian greece the two sites located south of the kephallinia discontinuity lefkas and kastro ilias consistently indicate a south to southwestward motion at an average rate of roughly 15 mm yr 1

active stress map of italy we present a new map of the present day stress field in italy obtained from all the available data the map reports 200 horizontal stress directions inferred from 109 borehole breakout data 44 centroid moment tensor solutions 34 other focal mechanisms most of which are from polarity distributions seven stress inversions of microearthquake data two averages of t and p axes of earthquake focal mechanisms in zones of diffuse seismic activity and four fault slip data the integration of breakout data which yield horizontal stress directions with fault plane solutions which reflect the stress regime allows us to obtain an improved map of the present day stress in italy this stress field map can be used for a better comprehension of active tectonic processes for seismic hazard assessment and to foresee the behavior of faults recognized with other methods stress directions obtained from different data although relative to different depth intervals e g 0 7 km for breakouts and 0 20 km for most of the earthquakes and to different tectonic units are consistent since many regions in italy are characterized by an extensional stress regime we report the minimum horizontal stress shmin orientations the map shows that an extensional regime affects most of the apenninic belt conversely a compressional or transpressional regime characterizes the eastern alps the eastern side of the northern apennines and the southern tyrrhenian to northern sicily zone an abrupt change in stress directions marks the transition between northern and southern apennines suggesting that the two arcs are characterized by a different tectonic setting and recent evolution in this paper we report all the data analyzed to date with their geographic coordinates and average stress directions and we describe the main stress provinces in italy in the framework of the tectonic evolution of the region

structurally controlled hydrothermal fluid flow in an extensional tectonic regime a case study of cretaceous qamchuqa formation zagros basin kurdistan iraq abstract shallow water carbonate rocks of the lower cretaceous qamchuqa formation host a significant reserve of oil in the nne arabian plate southwestern zagros sutured belt in the kurdistan region iraq such carbonates consist of several dolostone bodies with unique and complex arrays of saddle and zebra dolomite textures especially in fractured intervals integration of field core description microstructural analysis petrographic stable c o and sr isotopes and fluid inclusion analyses reveals two main phases of multiple fluxes of hydrothermal fluid circulation during the zagros orogeny at the end of cretaceous and cenozoic times an early regional non focused hydrothermal dolomitization and a subsequent fault and fracture controlled hydrothermal fluid flow which led to replacement and cementation by a range of saddle dolomite and zebra textures several generations of matrix dolomite saddle dolomite and calcite cement were identified the host dolostone has been affected by shortening folding fracturing and thrust faulting saddle dolomite pipes in particular were found to be associated with en echelon folding the morphology and areal extent of the zebra dolomite are controlled by the pore geometry of the host dolostone in relationship to fracturing and faulting both matrix and saddle dolomite cements have comparable overlapping stable isotopic values ranging from 0 39 to 3 57 and 0 12 to 3 11 vpdb respectively for 13c and 18o values range from 10 53 to 4 47 and 12 87 to 7 79 vpdb respectively 87sr 86sr ratios of pervasive matrix dolomite range from 0 707702 to 0 707839 fall close to late cretaceous seawater values slightly more radiogenic values of saddle dolomites ranging from 0 707759 to 0 708024 resulted from mixing of basinal brines with connate waters isotopic signatures of later calcite cements show more radiogenic sr ratios from 0 707755 to 0 708198 and negative 13c values 1 76 to 7 45 possibly related to late diagenetic processes due to incursion of meteoric waters during subaerial exposure fluid inclusion data of pervasive matrix dolomite and saddle dolomites show homogenization temperatures th with a wide range from 71 3 to 169 7 c and 82 3 to 188 2 c and salinity between 14 4 to 25 4 and 15 6 to 27 9 wt nacl eq respectively these values demonstrate the effect of hydrothermal fluid flow of the alteration of host dolomite and formation of saddle dolomite in fractures and faults

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

the 2002 molise earthquake sequence what can we learn about the tectonics of southern italy abstract on october 31 2002 a m l 5 4 earthquake occurred in southern italy at the margin between the apenninic thrust belt to the west and the adriatic plate to the east in this area neither historical event nor seismogenic fault is reported in the literature in spite of its moderate magnitude the earthquake caused severe damage in cities close to the epicenter and 27 people out of a total of 29 casualties were killed by the collapse of a primary school in s giuliano di puglia by inverting broadband regional waveforms we computed moment tensor solutions for 15 events as small as m l 3 5 m w 3 7 the obtained focal mechanisms show pure strike slip geometry mainly with focal planes oriented to ns sinistral and ew dextral in several solutions focal planes are rotated counterclockwise in particular for later events occurring west of the mainshock from the relocated aftershock distribution we found that the mainshock ruptured along an ew plane and the fault mechanisms of some aftershocks were not consistent with the mainshock fault plane the observed stress field resulting from the stress tensor inversion shows a maximum principal stress axis with an east west trend n83 w whereas the minimum stress direction is almost n s considering both the aftershock distribution and moment tensor solutions it appears that several pre existing faults were activated rather than a single planar fault associated with the mainshock the finite fault analysis shows a very simple slip distribution with a slow rupture velocity of 1 1 km s that could explain the occurrence of a second mainshock about 30 h after finally we attempt to interpret how the molise sequence is related to the normal faulting system to the west along the apennines and the dextral strike slip mattinata fault to the east

apparent western termination of the north pyrenean fault and tectonostratigraphic units of the western north pyrenees france and spain the surface geology of the north pyrenees southern france is markedly different east and west of longitude 0 25 w a line just west of lourdes east of this longitude the north pyrenean fault npf the major structure in the north pyrenees is clearly identifiable and this fault and other faults in the north pyrenean zone are subvertical west of longitude 0 25 w the npf is not identifiable at the earth s surface suggesting to some that the npf is not continuous and is not a regionally significant feature and that low angle as well as high angle faults are present in the fault zone while east of lourdes there is both a relatively continuous belt of mesozoic metamorphic rock and a geophysically detected 15 km step in depth to the moho neither is clearly recognized west of lourdes again bringing into question the continuity of the npf however in order to accommodate opening of the bay of biscay as much as 400 km of translation along a continuous npf or north pyrenean fault zone npfz is required we have compiled a map covering a 100 km long area in the western pyrenees the compilaation is based on our mapping and published maps by others the compilation and our field work provide the data to delineate four new tectonostratigraphic units these units are coherent stratigraphic sequences characterized by marked differences in stratigraphic thickness and depositional history each unit is bounded by regional faults that delineate four tectonic sheets the principal stratigraphic differences between the four tectonostratigraphic units were produced during deposition in cretaceous basins along the northern pyrenees the regional bounding faults are reverse and were formed during the main phase of the pyrenean orogeny that is during late cretaceous and tertiary times some are reactivated basin boundary faults and some of these are reactivated faults of cretaceous or older age in the western pyrenees the npf which was an active left slip fault during the late jurassic and early cretaceous is cut by these faults and is covered by tectonic sheets these sheets formed during the paleogene account for the apparent termination of the npf near longitude 0 25 w and obscure the step in the moho

deformation within foreland thrust sheets by populations of minor faults the dominant deformation mechanism within foreland thrust sheets is the displacement of blocks of weakly deformed rock on discrete mineral coated minor faults in highly deformed layers at the bases of three southern appalachian foreland sheets such minor faults are members of families or populations of consistently oriented structures the deformation style is similar in all three sheets rock nearest each thrust was shortened in the direction of sheet transport and thickened by a family of faults oriented at low angles to the thrusts rock further above each thrust experienced only the first of these two deformation stages statistical analyses of fault populations from these three sheets demonstrate that their deformation is quantitatively as well as qualitatively similar deformation due to movement on minor faults is statistically homogeneous at the scale of an outcrop in one of these sheets strain due to minor faults can be measured in that sheet a strain profile across this sheet is similar to strain profiles across continuously deformed sheets from internal portions of mountain belts suggesting that their responses to emplacement are similar

fracture patterns and petrophysical properties of carbonates undergoing regional folding a case study from kurdistan n iraq abstract the zagros taurus fold and thrust belt hosts a prolific hydrocarbon system most hydrocarbon reserves are stored in naturally fractured reservoirs and such fracture systems can therefore have a significant impact on reservoir performance fractures are one of the most important paths for fluid flow in carbonate reservoirs and industrial geoscientists and engineers therefore need to understand and study fracture patterns in order to optimise hydrocarbon production the observed fracture patterns in outcrops may have implications on fluid flow and reservoir modelling in subsurface reservoirs and we have therefore undertaken a case study of fracturing associated with regional folding in iraqi kurdistan in this area some exploration wells currently target upper triassic dolostones kurra chine formation and or lower jurassic limestones and dolomitised limestones sehkaniyan formation in both units hydrocarbon production comes mainly from secondary porosity created by dolomitisation dissolution and fracturing both formations have undergone multiple phases of deformation associated with burial uplift folding and thrusting we investigate some fracture pattern characteristics and some petrophysical properties of these units using selected outcrops around the gara ora and ranya anticlines that form folds directly traceable for 25 70 km our outcrop data is compared with subsurface fracture and petrophysical datasets reported from wells in the nearby shaikhan and swara tika fields the 1 2 3d fracture attributes collected from outcrops are fracture orientation type spacing intensity length and cross cutting and abutting relationships fracture orientations show a clear relationship to the local fold axis in both the outcrop and subsurface although in some cases they appear to relate more to the present day in situ maximum horizontal stress direction or local strike slip faulting three stages of fracturing are proposed pre folding early folding and post folding fractures in addition we report petrophysical properties porosity permeability and acoustic velocity of both the kurra chine and sehkaniyan formations in relation to their structural position within folds and faults and stratigraphic level the highest porosities and permeabilities are recorded in the hinges and backlimbs of the gara anticline the best reservoir quality highest porosity and permeability is often found in areas associated with replacement dolomite i e solution vugs and intercrystalline porosity the kurra chine formation displays similar trends in velocity porosity data at both outcrop and the subsurface however the sehkaniyan formation displays lower acoustic velocity for a given porosity at outcrop compared to the subsurface

fluid expulsion and dilatancy pumping during thrusting in the pyrenees pb and sr isotope evidence pb and sr isotope data have been collected from fluid inclusions trapped in syntectonic quartz veins associated with the gavarnie thrust in the central pyrenees and from lithologies in the footwall and hanging wall of the thrust these data suggest the occurrence of three distinct phases of fluid movement related to different periods in the structural evolution of the thrust zone during the first phase fluid interacting with the silurian graphitic slates in the immediate hanging wall of the gavarnie thrust moved along a carbonate mylonite zone beneath the thrust enriching the deforming carbonates in 87 sr and 207 pb the second phase of fluid movement occurred during imbricate thrusting and intense veining beneath the gavarnie thrust isotope data from quartz hosted fluid inclusions show a trend toward high 208 pb 204 pb ratios with increasing 207 pb 204 pb and 206 pb 204 pb and decreasing 87 sr 86 sr the inclusions contain fluids equilibrated with several source lithologies deformed cretaceous and silurian rocks within the thrust zone devonian phyllites located above the silurian slates in the thrust hanging wall and triassic redbeds located beneath cretaceous limestones in the thrust footwall the mixture of fluids reflects both the transient chemical interaction of previously isolated rock types in the footwall and hanging wall via fault and fracture networks and dilatancy pumping of fluid into opening veins the last phase of fluid movement resulted in the precipitation of late carbonate vein fills and a return to more local fluid movement as stresses relaxed and fracture networks healed overpressured fluids trapped within and partially expelled from the thrust zone during phase 1 were still present during phases 2 and 3 this suggests that average permeabilities within the mylonites were low and that transient high permeability zones related to fracture networks were of limited extent

an integrated analysis of transverse structures in the northern apennines italy abstract the northern apennines have been the object of numerous studies both from a morphological and a structural point of view at present much debate is going on about the existence and interpretation of ne sw alignments described by geomorphologists boccaletti m coli m napoleone g 1977 nuovi allineamenti strutturali da immagini landsat e rapporti con l attivita sismica negli appennini boll soc geol it 96 679 694 signorini r 1953 linee tettoniche trasversali nell appennino settentrionale rend acc naz lincei 6 42 45 and partly denied by structural geologists we show new microtectonic and morphological data which contribute to a more comprehensive interpretation of these elements stress axis determination and different morphotectonic analyses have been combined the analysis of the drainage networks and of two different digital elevation models have also been considered the results lead us to interpret the ne sw alignments as large and diffuse deformation zones which may represent old transfer zones active with left lateral strike slip movements during the mountain building

evolution of a turbiditic foreland basin and analogy with an accretionary prism example of the eocene south pyrenean basin the south pyrenean tertiary basin was an east west trending foreland trough which developed from early eocene to miocene times in a north south trending compressive regime a turbiditic series of lower and middle eocene age hecho group enables us to define the typical features of the tectono sedimentary evolution of the basin 1 slope and shelf derived carbonate turbidites and megaturbidites bear witness to the seismic activity of the basin borders 2 the southern basin border evidenced by the onlap of the turbidites onto slope and shelf deposits migrated progressively southwards in time and 3 the deformation pattern is characterized in the meso cenozoic sediments by a complex thrust fold system of thin skinned tectonics style its specific geometry and kinematics were influenced by the pre deformation geometry onlap this thrust fold system is related to south directed basement nappes and its front advanced progressively southwards in time from this data we infer an evolutionary model for this highly mobile basin it was a flexural basin linked to the northward bending of the lithosphere in the foreland of a south directed crustal accretionary prism as the nappes advanced the basin migrated progressively southwards in the foreland direction as for the actual basin evolution many analogies with accretionary prism trench systems of active margins exist

dense brine refluxing a new genetic interpretation of widespread anhydrite lumps in the oligocene lower miocene asmari formation of the zagros foreland basin ne iraq abstract the asmari formation in the zagros basin of ne iraq contains a thick sequence of oligocene lower miocene carbonates and it forms one of the best known carbonate reservoirs in the world the formation mainly consists of dolostones limestones sandstones and mudstones and there is a general upward increase in the abundance of evaporites generally in the form of anhydrite lumps in the dolostones of the upper part the anhydrite types and textures provide evidence on the salinity depth temperature environment and sea level fluctuations which can be used for paleoenvironmental and climatic interpretations and they also exert a significant control on reservoir quality which has attracted the attention of many petroleum industries previous studies suggested that the anhydrite lumps in the upper asmari formation aquitanian burdigalian were synsedimentary deposits in a hypersaline setting of a sabkha salt flat however this paper shows that 1 the upper asmari formation was deposited in an inner to mid ramp setting based on the sedimentological petrographical and paleontological characteristics 2 the anhydrite lumps are irregular and variable in size and are generally found within or associated with karst systems and 3 fossil assemblages indicate that the synsedimentary salinity was normal or only slightly hypersaline which means that the anhydrite was not directly deposited from the synsedimentary marine water after comprehensive analysis of the anhydrite lumps it is proposed in this paper that the anhydrite lumps were formed within the upper asmari formation aquitanian burdigalian due to downwards seepage of the overlying hypersaline water which is termed as dense brine refluxing a new genetic model it is suggested 1 that the upper asmari formation aquitanian burdigalian was deposited in an inner to mid ramp setting and subjected to eogenetic karstification generating karst systems in local area with relative high landscape due to sea level change 2 that during the middle miocene tectonic compression resulted in the zagros basin isolated and the seawater becoming hypersaline with higher salt concentrations and a high density and 3 the hypersaline water seeped downwards through the underlying porous sediments forming anhydrite lumps and resulting in a decrease in the porosity of the upper asmari formation aquitanian burdigalian this paper provides new perspectives on the origin of anhydrite lumps and the resulting effects on reservoir quality in the zagros foreland basin

episodic discrete and distributed deformation consequences and controls in a thrust culmination from the central pyrenees abstract the pic de port vieux culmination is a 0 5 km long thrust culmination in the footwall of the gavarnie thrust in the central pyrenees the culmination comprises a set of blind thrusts that imbricate a 50 m thick mesozoic cover sequence comprising triassic red beds and upper cretaceous limestone sandwiched between underlying hercynian basement and the overlying palaeozoic strata of the gavarnie thrust sheet an intense cleavage developed within the culmination associated with the oblique tip lines of the thrusts as they climbed from the basement into the cover strata detailed mapping shows that the distributed strain associated with the fault tips locally re activated earlier folded thrusts creating upper detachments to the system and produced a set of new overstepping isolated faults the main detachment occurred along the roof of the culmination using the back limbs of folds in the roof thrust the movement on these detachments can be demonstrated to have been episodic with periods of fault slip producing splays that were then folded during periods when distributed deformation was dominant the main control on this episodic deformation is modelled as the result of feedback between increase in fluid pressure associated with inelastic porosity reduction during cleavage development and fluid pressure bleed off associated with fault zone dilatancy in the culmination

thrust tectonics in the south central pyrenees abstract surface structural data and published stratigraphies are combined to construct two balanced and restored sections through the nogueras zone of the south central pyrenees the allochthonous nogueras zone units are interpreted as the foreland dipping margin of a major antiformal stack in the palaeozoic rocks of the pyrenean axial zone their structural evolution is summarized in a hangingwall sequence diagram this reinterpretation of the nogueras zone is incorporated into a new n s balanced and restored section from the centre of the pyrenean axial zone to the ebro basin a classical rocky mountains piggy back thrust model is employed and the resulting section is a significant departure from those previously published it is argued that gravity gliding has never been an important mechanism in the alpine pyrenees section restoration casts doubt on the correlation of the surface expression of the north pyrenean fault and the seismically detected moho step beneath it

comparison between the galicia and aquitaine margins abstract there is a great similarity between the galicia margin and the aquitaine margin i e the aquitaine basin and the north pyrenean zone in particular the timing of the rifting as well as the resulting structures exposure of perodotite tilted fault blocks normal and transverse faults half grabens are practically the same this comparison leads to the interpretation that the northern side of the pyrenean fold belt is inherited from the mesozoic deep passive margin of europe the cenozoic thrust sheets and reverse faults of the northern pyrenees zone are tentatively interpreted as former rift structures tilted blocks and listric faults which were removed during the convergence of the iberian and european plates during the paleocene and eocene

transition from near surface thrusting to intrabasement decollement schlinig thrust eastern alps west directed thrusting along the schlinig thrust amounts to a minimum displacement of 45 km a discrete plane of brittle thrusting is observed in the frontal part where the otztal unit overrides the sediments of the engadine dolomites both shortening of the more ductile lower and middle triassic and very substantial stretching by domino type normal faults in the brittle upper triassic dolomites are contemporaneous with and caused by thrusting extension is related to extrusion of parts of the sediments in the footwall of the schlinig thrust a relatively rapid transition into an intrabasement shear zone which is as much as 2 km thick occurs farther to the east in a region where a paleotemperature of 300 c is indicated for cretaceous metamorphism still farther to the east localized shearing is transformed into a wider area affected by large scale folding this second transition corresponds to estimated temperatures in excess of 550 c since the changes in structural style and deformation mechanisms toward the hinterland go hand in hand with increasing metamorphic grade we regard thrusting as contemporaneous with metamorphism this view is supported by geochronological data the age of thrusting and metamorphism 90 ma indicates very rapid heating after the deposition of the youngest sediments cenomanian involved in cretaceous deformation our data suggest that localized detachment along a discrete thrust plane and within broader mylonite zones cannot always be traced indefinitely to greater depth the transformation of localized shearing into large scale folding indicates a fundamentally different deformational style for lower crustal levels

local pattern of stress field and seismogenic sources in the pergola melandro basin and the agri valley southern italy summary our study area is a ca 50 km long section of the central southern apennines tectonic belt that includes the pergola melandro basin pm and the agri valley av this region is located between the areas affected by the 1980 ms 6 9 irpinia and the 1857 m 7 0 val d agri earthquakes and is characterized by rare historical events and very low and sparse background seismicity in this study we provide new seismological and geophysical information to identify the characteristics of the seismotectonics in the area as the prevailing faulting mechanism and the fit of local to regional stress field these data concern focal mechanisms from waveform modelling and p wave polarities analyses of borehole breakouts and detailed investigation of two seismic sequences all the data cover a significantly broad range of magnitudes and depths and suggest that no important local variation in stress orientation seems to affect this area which shows a ne sw direction of extension consistent with that regionally observed in southern italy such local homogeneity in the stress field pattern is peculiar to the study area the variations of orientation and or type of stress observed in the northern apennines or less than only 100 km toward the northwest within the same tectonic belt are absent here furthermore there is a suggestion for a northeastward sense of dip of the seismogenic faults in the region an interesting constraint to the characterization of seismic sources

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

post emplacement extension within a thrust sheet from the central pyrenees secondary faults and related veins in a small thrust sheet the pic de port vieux thrust sheet in the footwall of the gavarnie thrust in the central pyrenees are used to infer the deformation sequence that accompanied its emplacement initial deformation was characterized by distributed bedding parallel simple shear this was superseded by localized deformation involving arrays of extensional faults the first faults to form were x shears and were succeeded first by conjugate faults x x9 shears and then arrays of r shears that locally cut the thrust i e developed subsequent to its emplacement extension veins are used to infer the orientation of the ambient stress system during the deformation sequence a forward rotation of the stress sytem towards the vertical was associated with the x and x x9 shears and is considered to reflect loading of the 4 km thick overlying gavarnie thrust sheet a later backward rotation of the stress system then occurred returning 1 to 45 obliquity to the pic de port vieux thrust and was associated with the r shear development this later event produced extensional shearing of the thrust sheet and is equated with a proposed episode of spreading gliding within the overlying thrust pile a model for this spreading gliding relates it to the active tectonics of the developing south pyrenean thrust belt

thick and thin skinned tectonics in the pyrenees abstract a comparison is made between the gavarnie thrust and the merens fault in the axial zone of the pyrenees the former has a gentle dip and quite a large displacement at least 12 km but does not cut through either hercynian or alpine isograds the latter has a smaller displacement 5 km but dips steeply and cuts through both hercynian and alpine isograds at a high angle on this basis and on the basis of shear zone geometries immediately north of it it is proposed that the merens fault nucleated as a steeply 65 80 dipping structure while the gavarnie thrust nucleated with a shallow attitude the merens fault is not a backward rotated thrust fault nor is it the root zone for any major nappe structure similar steep ductile structures occur within the gavarnie nappe and may reflect considerable internal strain in basement lithologies the relationship between steep and shallow structures is not yet clear the shear zones may pre date the thrusting in which case they may be thick skinned structures affecting the whole lithosphere or they may be contemporary with thrusting reflecting only local thickening above a decollement rheological models can be used to test proposed geometrical and kinematic models for the lithosphere scale evolution of the pyrenees suggested models are dominated by a cool rigid high level mantle wedge beneath the north pyrenean zone which probably controlled the location of north dipping thrust faults thick skinned shortening is possible in thick crust in the axial zone but is very unlikely in the north pyrenean zone where steeply rooted structures would have to cut through the strongest part of the lithosphere

three dimensional earthquake locations and upper crustal structure of the sannio matese region southern italy abstract the sannio matese region is one of the most seismically active regions of italy and has been struck by large historical earthquakes at present the area is characterized by low magnitude background seismicity and small seismic sequences following m 4 main events in this paper we show vp and vp vs models and 3d locations for a complete set of earthquakes occurring in the period 1991 2001 we observe a significant crustal heterogeneity with large scale east verging high vp fault related folds stacked by the pliocene compression the relocated earthquakes cluster along a 70 east dipping nw striking plane located at the border of the high vp thrust units normal fault earthquakes related to the young and active extension occur within these high vp zones interpreted as high strength material we expect large future earthquakes to occur within these high vp zones actually characterized by low magnitude seismicity at their borders

syntectonic vein development in a thrust sheet from the external french alps abstract the geometry and age relations of syntectonic veins within calcareous rocks of one imbricate sheet within a thrust belt in the external french alps are described the earliest veins developed during the main ductile deformation by cleavage parallel extension the majority of the syntectonic veins developed towards the end of the deformation and after the formation of second folds they include a conjugate set of normal shears an abundant set of upright extension veins and en echelon sets the dominantly simple shear strain making up the main ductile phase of deformation occurred by a mechanism of grain to grain pressure solution the stretching lineation records the overall direction of thrust sheet movement a change in the microchemical mechanism of pressure solution is thought to have caused the change from first to second phase deformation as recorded by slaty cleavage and crenulation folds in the field from the shear and vein geometries directions of principal stress have been inferred the directions rotated throughout the deformation the maximum principal stress being inclined to bedding during simple shear strain becoming normal to bedding during the phase of abundant vein growth and becoming vertical at the very end of the deformation

the september 27 2012 ml 4 1 benevento earthquake a case of strike slip faulting in southern apennines italy abstract on september 27 2012 at 01 08 utc a m l 4 1 earthquake started a seismic sequence approximately 10 km east of the city of benevento in southern apennines italy during the following four days about 40 events with m l ranging between 1 3 and 4 1 were detected in the same area where the seismic hazard is one of the largest of the italian peninsula and where several historical and destructive events took place in order to investigate the seismicity spatio temporal pattern and to identify the seismogenic source geometry a detailed analysis was performed integrating data recorded at three different seismic networks the earthquakes were relocated using the double difference technique and focal mechanism solutions were obtained by the moment tensor inversion also to better understand the rupture process seismic source parameters were estimated and apparent source time functions were inverted to retrieve the slip distribution for the largest magnitude event our results show the existence in the study area of roughly e w striking fault plane with a right lateral strike slip kinematics seated at mid crustal depths 10 20 km revealing a characteristic seismicity quite different from that typically associated to the outcropping nw se striking active normal faults that are responsible of moderate to large earthquakes in the southern apennines axial sector in this work we address questions concerning i the presence in the benevento area of a mid crust seismogenic strike slip fault previously unrecognized ii its link to the regional seismotectonic setting and iii the existence of a strike slip tectonic regime that uniformly extends in the footwall of the apennines thrust at relevant depth not only in the apulian foreland as demonstrated to date but also under the mountain chain axial zone

fluid mixing and recycling during pyrenean thrusting evidence from fluid inclusion halogen ratios abstract syntectonic fluids have been sampled through fluid inclusion microthermometry and crush leach analyses cations and halogens from a 50 km n s transect through the central southern pyrenees the fluid inclusions are contained in syntectonic quartz veins in triassic redbeds cretaceous carbonates and hercynian basement rocks with some calcite and dolomite data from limestones and evaporites in more external parts of the belt the main datasets come from 1 alpine shear zones cutting the neouvielle granodiorite in the hercynian axial zone at the north end of the transect 2 an imbricate zone beneath the alpine gavarnie thrust at the pic de port vieux 3 several localities in the footwall and hangingwall of the gavarnie thrust on the southern margin of the axial zone the inclusion fluids generally decrease in salinity from 27 35 at the northern end of the transect to 7 22 on the southern margin of the axial zone the majority of the inclusions have cl br ratios lower than seawater and are interpreted as relict fluids after seawater evaporation and halite precipitation in the upper trias this interpretation is supported by cl br na systematics which are consistent with a change from halite to halite sylvite precipitation with progressive evaporation fluids in the basement shear zones are interpreted to have essentially the same evaporitic origin as those still contained in sedimentary formations although it is possible that final concentration of brines in the neouvielle massif involved retrograde hydration reactions with removal of water by precipitation of hydrous minerals the fluids are also very similar in salinity and halogen chemistry to those found in veins associated with mesozoic pb zn f deposits which predate the thrusting the lower salinities seen at the southern margin of the axial zone are interpreted to reflect mixing of the brines with a higher level fluid connate or meteoric water circulating within the mesozoic carbonates of the higher thrust sheets at one locality where triassic evaporites are still present high cl br ratios at relatively low salinities are present in inclusions within the underlying triassic redbeds but low cl br ratios at higher salinities are seen lower in the sequence this is consistent with dissolution of halite by a dilute fluid but with limited penetration downwards we suggest that the fluid history of the pyrenees evolved through a series of stages 1 upper triassic evaporite formation with sinking of brines into underlying redbeds and fractured basement rocks 2 circulation of brines with formation of pb zn deposits along faults at some time between the triassic and the upper cretaceous 3 renewed extension with erosion of triassic rocks in many areas and further drawing down of triassic brines into the basement 4 deposition of u cretaceous and palaeocene carbonates containing connate waters of marine origin 5 formation of the pyrenean thrust belt with overpressuring and expulsion of the brines along shear zones and faults 6 creation of topography with a high level circulation system in the mesozoic thrust sheets driven largely by topography at the southern margin of the axial zone there was limited mixing of the deeper overpressured brines with these more dilute hydrostatically pressured fluids an important point is that because of their density hypersaline brines are difficult to expel from the upper crust and may be involved in a succession of alteration and mineralisation events in the same general area over hundreds of millions of years

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

concurrent deformation processes in the matese massif area central southern apennines italy abstract we investigated the interseismic gps velocity field across the transition zone between central and southern apennine comprising the meta mainarde venafro and alto molise sannio matese mounts the kinematic field obtained by combining gps network solutions is based on data collected by the unpublished episodic campaigns carried out on southern apennine geodetic network sagnet from 2000 to 2013 igm95 network giuliani et al 2009 from 1994 to 2007 and continuous gps stations the data collected after the 29 december 2013 earthquake mw 5 0 until early 2014 allowed estimating displacements at 15 sagnet stations the extension rate computed across the matese massif along an anti apennine profile is 2 0 0 2 mm yr the interseismic velocities projected along the profile show that the maximum extension does not follow the topographic high of the apennines but is shifted toward the eastern outer belt no significant gps deformation corresponding to inner faults systems of the matese massif is detected taking into account our results and other geophysical data we propose a conceptual model which identifies the 2013 2014 seismic sequence as not due to an extensional deformation style usual along the apennine chain in fact we have measured too large coseismic displacements that could be explained as the result of tectonic regional stress co2 rich fluid migration and elastic loading of water in the karst matese massif we recognized a tensile source as model of dislocation of 2013 2014 earthquakes it represents a simplification of a main fault system and fracture zone affecting the matese massif the dislocation along ne dipping north matese fault system nmfs could be the driving mechanism of the recent seismic sequences moreover to the first time the sagnet gps data collected from 1994 to 2014 are share and available to the scientific community in the open access data archive

pseudotachylyte bearing strike slip duplex structures in the fort foster brittle zone s maine abstract detailed 1 60 scale mapping of the fort foster brittle zone in the mylonitic rye formation of southernmost maine has revealed the intricate internal duplex structure of a system of probable paleozoic age dextral strike slip faults that have produced abundant pseudotachylyte and minor breccia the internal configuration of this brittle zone consists of a mosaic of individual pseudotachylyte generation zones as slab duplex structures individual duplex zones are up to 100 m in length and 1 m or less in width and are defined by pairs of layer parallel slip surfaces along which frictional melts were produced these slab duplex structures are interpreted as zones of displacement transfer between long overlapping layer parallel en echelon strike slip fault surfaces contractional duplexes develop layer parallel compressional structures that tend to shorten and thicken the fault bounded slabs by the formation of lateral ramps and conjugate faults kinks and asymmetric folds extensional duplexes develop layer parallel stretching and thinning by the formation of oblique dextral shears high angle conjugate pairs and localized fault breccias the production of pseudotachylyte by friction melting along layer parallel fault surfaces in these exposures is attributed to rapid slip during paleoseismic events the rupture structures developed during these events may be characteristic of fault structure and mechanics at near focal depths in a strike slip seismogenic zone

the seismogenic structure of the 2013 2014 matese seismic sequence southern italy implication for the geometry of the apennines active extensional belt

a low magnitude seismic sequence near isernia molise central italy in january 1986 following the increase in seismic activity which occurred near isernia molise central italy in january 1986 a digital seismic network of four stations with three component short period seismometers was installed in the area by the osservatorio vesuviano the temporary network had an average station spacing of about 8 10 km and in combination with permanent local seismic stations allowed the accurate determination of earthquake locations during an operating period of about one month among the 1517 detected earthquakes 170 events were selected with standard errors on epicentre and depth not greater than respectively 0 5 and 1 5 km the most frequent focal depths ranged between 4 and 8 km while the epicentres distribution covered a small area ne of isernia of about 10 km2 a main rupture zone could not be clearly identified from the spatial distribution of the earthquakes suggesting a rupture mechanism involving heterogeneous materials the activity was characterized by low energy levels the largest earthquake on january 18 1986 havingmd 4 0 the time sequence of events and pattern of seismic energy release revealed a strong temporal clustering of events similar to the behaviour commonly associated with seismic swarms

constraints on the age of movement of the montsech and cotiella thrusts south central pyrenees spain palaeocene to oligocene thrusting in the pyrenees was synchronous with the development of the south pyrenean foreland basin collectively the tremp graus ainsa and jaca basins sedimentological and stratigraphical evidence from the foreland basin is used to constrain the age of movement of the montsech cotiella and external sierras thrusts movement on the emergent imbricate fan at the montsech front began in the early eocene illerdian during an early phase of thrusting that detached in the triassic evaporites in that region this phase of thrusting defined the tremp graus basin as a thrust sheet top basin following the early thrusting cuisian age tectonics in the tremp graus and ainsa basins was dominated by minor normal fault movements during flexural subsidence associated with thrust sheet loading growth of the boltana anticline to the west of the ainsa basin indicates that the ainsa basin had become detached as a thrust sheet top basin in the lutetian movement on the pena montanesa thrust and by inference on the cotiella thrust began in post lutetian times during the propagation of lower thrusts that involved pre triassic variscan basement thrusting in the external sierras caused folding and faulting of oligocene sediments indicating the continued southward propagation of basement involved thrusts in the upper eocene and oligocene many faults in the southern pyrenees have evidence of early normal and later reverse senses of movement indicating reactivation of normal faults during thrusting

role of shear in development of the helvetic fold thrust belt of switzerland the geometric features of the helvetic nappes of the alps show intense internal deformation set up predominantly by simple shear during nappe transport the nappes are bounded by thrusts that parallel incompetent layers and ramp upward stratigraphically across competent units in the direction of tectonic transport stratal layering is oblique to nappe boundaries thrust surfaces formed after ductile shear zones developed in underlying pre triassic gneissic basement the broad zone of shearing narrowed down as deformation increased to form zones of intense shear and ultimately to form thrust faults contraction along competent layers obliquely inclined to shear surfaces produced buckle folds the geometry of these folds was modified by further shearing as their normal limbs became aligned in the extension field of the strain ellipse for simple shear producing normal faults

an improved method for determining the regional stress tensor using earthquake focal mechanism data application to the san fernando earthquake sequence the orientations of fault planes and slip directions indicated by a population of earthquake focal mechanisms can be used to determine best fit regional principal stress directions and r 2 1 3 1 a measure of relative stress magnitudes under the assumption of uniform stress in the source region this analysis allows for the possibility that failure occurs on preexisting zones of weakness of any orientation in the inversion we perform a grid search of stress models to find the one which requires the smallest total rotation of all the fault planes that is needed to match the observed and predicted slip directions the method allows for errors in orientations of both the fault planes and slip directions we have an objective means for identifying the more likely of the two possible fault planes from each focal mechanism relative to a given stress model thus we do not face the problem of ambiguity of nodal planes which plagues other analyses of this kind by using a grid search of stress models rather than a linearization scheme we are able to perform a realistic error analysis and thus establish confidence limits for the preferred regional stresses the method can be used to investigate possible stress inhomogeneities during earthquake sequences by analyzing subsets of the data population the technique has been applied to 76 events from the san fernando earthquake sequence for which we have found best fit stresses plunge and azimuth 1 7 187 2 27 281 3 62 84 and r 0 65 the average misfit between this stress model and all the data is about 8 and all but eight of the aftershocks have misfits of less than 20 these values are considerably less than the uncertainty of the focal mechanism determinations therefore significant stress inhomogeneities are not required by the data our analysis does not support the suggestion of a change in stresses during the aftershock sequence as proposed by others on the basis of an apparent change in focal mechanisms

partitioning of deformation within several external thrust zones of the appalachian orogen mesoscopic contractional and extensional faults dominate many external thrust zones the fault arrays occur in the hanging walls of some thrusts and in the footwalls of others in a thrust zone from the little mountains fold thrust belt of new york state mesoscopic faults cut and offset a major thrust contact and involved rocks from the thrust s hanging wall and its footwall simultaneously the little mountains exposure indicates that minor faults were active during thrust slip and are not early formed features which were passively translated with the remainder of a sheet when both contractional and extensional mesoscopic faults occur in thrust zones foreland dipping extensional faults overprint contractional faults contractional and extensional microfaults with r 1 and r 2 riedel shear geometries are common in external thrust zone cataclasites and resemble the mesoscopic fault patterns though the evolution of cataclasite layers differs from that of mesoscopic fault arrays contraction and ext

paleostresses associated with faults of large offset abstract in order to test empirically the limitations of paleostress analysis we used etchecopar s computer program to compute the orientations and relative magnitudes of paleostress principal values in two southern appalachian u s a thrust zones from minor fault and slickenside attitudes in both thrust zones faults are closely spaced many faults have offsets whose magnitudes exceed the distance to adjacent faults of comparable size and deformation was strongly non coaxial while even in the less deformed thrust zone bulk strains due to fault movement have axial ratios as high as 10 1 nearly 75 of the fault slickenside pairs in each thrust zone conform with paleostress tensors that indicate 1 sequential transport parallel compression transport parallel extension and extension oblique to transport and 2 low resolved shear stresses on the thrusts finite strains measured in one thrust zone share a principal plane with the first two tensors and the inclinations of the paleostress and finite strain principal directions in that plane are consistent with thrust parallel shearing relative magnitudes of paleostress and strain principal values do not correlate well moreover the locations and inferred origins of fault slickenside pairs inconsistent with paleostress tensors suggest that stresses in rocks between faults were not as is assumed in paleostress analyses uniform this complexity may also occur in faulted rocks where bulk strains are small paleostress tensors from rocks with large bulk strains may be viable but they must be interpreted cautiously

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

extensional duplexing in the york cliffs strike slip fault system southern coastal maine abstract a 150 m long sinistral strike slip fault system consisting of left stepping en echelon fault segments cuts deformed paleozoic metasediments and early mesozoic dike intrusions in coastal terrace outcrops in southern maine the longer fault segments follow the vertical bedding in the metasediments and accommodate approximately 1 m of displacement detailed mapping at scales down to 1 6 indicates that overlap zones between offset layer parallel fault segments consist of high dilation angular breccias rounded attrition breccias and extensional duplexes where the offset segments straddle upright quartzite layers in one 10 m long duplex r and r shears cut the layering in the quartzite at 28 and 69 respectively relative to the dominant layer parallel fault segments creating a doubly tapered imbricate r shear lens segmentation structure individual imbricate lenses accommodate additional layer parallel extension through conjugate x x shear fractures with average orientations of 109 and 60 respectively relative to the dominant fault segments extensional fractures oblique to the dominant fault segments are rare within this duplex but commonly form distinctive horsetail arrays at fault terminations that average 44 to the layer parallel faults strain analysis shows that approximately 60 80 cm of measured strike slip displacement is accommodated internally within this duplex as layer parallel extensional strain using the r shear and x x shear fracture mechanisms the strain distribution and observed cross cutting relations suggest an outward symmetric growth of the duplex structure from left stepping sinistral fault segments that developed sequences of tip to plane r shear overlap linkages during continued displacements cyclic r r to x x shear fracturing may relate to stress reorientation following r shear ruptures during episodic growth of the duplex and incremental slip of the fault system

uniform sense normal simple shear of the continental lithosphere geophysical studies suggest that the thin crust characteristic of the basin and range province extends eastward beneath the west margin of the colorado plateau and rocky mountain regions in arizona and utah zones perhaps over 100 km wide may be defined bounded on the west by the east limit of upper crustal normal faults that account for more that 10 extension and on the east by the east limit of thinning beneath the colorado plateau a discrepancy exists within these zones between the negligible extension measurable in the upper crust and the substantial extension apparent from crustal thinning assuming the discrepant zone crust was as thick as or thicker than the colorado plateau rocky mountain crust prior to extensional tectonism if various theories appealing to crustal erosion are dismissed mass balance problems evident in the discrepant zones are most easily resolved by down to the east normal simple shear of the crust moving lower and middle crustal rocks that initially were within the zones up and to the west to where they now are locally exposed in the basin and range province west of the discrepant zones in both arizona and utah east directed extensional allochthons with large displacement are exposed these geophysical and geological observations complement one another if it is accepted that the entire crust in both arizona and utah failed during extension on gently east dipping east directed low angle normal faults and shear zones over a region several hundred kilometres wide large scale uniform sense normal simple shear of the crust suggests the entire lithosphere may do the same such a hypothesis predicts major lithospheric thinning without crustal thinning will occur in plateau areas in the direction of crustal shear in the case of the arizona utah and red sea extensional systems and possibly the death valley extensional terrain a broad topographic arch typically 1500 2000 m higher than the extended terrain is present suggesting lithospheric thinning in areas predicted by the hypothesis

a transitional volume beneath the sannio irpinia border region southern apennines different tectonic styles at different depths abstract in this paper we investigate the border between the sannio and irpinia seismogenic regions a sector of the southern apennine chain considered among the most active seismic areas of the italian peninsula to shed further light on its complex seismotectonic setting we integrated recent seismicity with literature data a detailed analysis of the seismicity that occurred in the 2013 2016 time interval was performed the events were relocated after manual re picking using different approaches to retrieve information about the stress field active in the area inversion of fault plane solutions was also carried out hypocentral distribution of the relocated events ml 3 5 whose depth is included between 5 and 25 km with the deepest ones located in the nw sector of the study area shows a different pattern between the northern sector and the southern one the computed fault plane solutions can be grouped in three depth ranges 18 km dominated by strike slip kinematics stress field inversion across the whole area shows that we are dealing with an heterogeneous set of data apparently governed by distinct stress fields we built an upper crustal model profile through integration of geological data well logs and seismic tomographic profiles our results suggest the co existence of different tectonic styles at distinct crustal depths the upper crust seems to be affected mostly by normal faulting whereas strike slip faulting prevails in the intermediate and lower crust we infer about the existence of a transitional volume located between 12 and 18 km depth between the sannio and irpinia regions acting as a vertical transfer zone

thrust sequences in the eastern spanish pyrenees detailed mapping of the south pyrenean zone in the eastern spanish pyrenees shows that a great number of alpine thrusts affect the basement and the cover the geometry of the thrust structures and their propagation sequence can be interpreted from balanced sections the folding dies out downwards from the higher thrust sheets to the lower ones and demonstrates a piggy back thrusting sequence these thrusts form a duplex the sole thrust of this duplex is the vallfogona thrust the roof thrust is rooted somewhere within the axial zone the thrusts climb southwards from the axial zone basement up into tertiary cover sediments these thrusts have been folded so that they now dip to the south and form the southern side of the axial zone antiformal stack locally smaller antiformal stacks developed and produced strong folds in the higher thrust sheets the south pyrenean zone studied is equivalent to the gavarnie nappe and the connection between them below the detached south pyrenean central unit may be the nogueres zone

strain models within spreading nappes abstract internal strain within nappes and thrust sheets is especially important in the understanding of emplacement mechanisms in this paper strain patterns within spreading nappes are investigated theoretically and experimentally three types of spreading nappe are distinguished using various boundary conditions spreading gliding spreading and extruding spreading nappes each type is placed in its proper natural environment strain components and strain gradients are summarized from the use of scale models performed with analogue materials mathematical computations from experimental modelling allow the calculation of 1 1 the schistosity trajectories in vertical flow planes 2 2 the relationship between stretch and transport direction and 3 3 the spatial distribution of different types of strain ellipsoid these provide some tests which make it possible to demonstrate in the field whether nappes are or are not gravity induced finally some field examples from the central alps and the pyrenees are briefly discussed they provide good support to the strain models presented in the present paper

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

evolution of the nw zagros fold and thrust belt in kurdistan region of iraq from balanced and restored crustal scale sections and forward modeling abstract we present the first regional balanced and restored sections across the northwestern part of the zagros fold and thrust belt in kurdistan region of iraq and a 2d kinematic model that illustrates the evolution of the belt since late cretaceous time the balanced cross section based on surface and sub surface data is characterized by multi detachment folds detached above a lower triassic basal ductile level with intermediate detachment levels that induced internal complexities like accommodation thrusting and or disharmonic folding our work suggests that the two main structural steps in the detachment level in the high folded zone may be related to low angle thrusts rooted at the brittle ductile transition growth strata of late cretaceous and paleocene times have been recognized for the first time in the kurdistan fold and thrust belt this allows us to constrain timing of deformation and to estimate the evolution of the shortening and the advance of the deformation front since late cretaceous deformation of the zagros belt is characterized by a combination of thin and thick skinned tectonics that reactivated the late cretaceous paleogene obduction belt

40ar 39ar muscovite dating of thrust activity a case study from the axial zone of the pyrenees abstract the pyrenees belt features well exposed deformation structures that make it ideally suited to study thrust faults in this paper we present the first 40ar 39ar age of the pic de port vieux thrust ppvt located in the south western part of the pyrenean axial zone the ppvt is a secondary thrust related to the major gavarnie thrust gt with a footwall comprising upper cretaceous limestones and a hanging wall made of lower triassic pelites and sandstones a vertical transect in the fault hanging wall was investigated to characterize the deformation mechanism and to date the thrust activity by using 40ar 39ar step heating technique on muscovite petrographic observations confirm that pressure solution and recrystallization dissolution processes in presence of fluids are the main mechanisms that controlled the chemical textural changes in the fault core zone three groups of muscovite are identified in the fault zone i e detrital diagenetic and newly formed muscovites the detrital and diagenetic muscovites are mainly present in the damage zone while the newly formed muscovite is abundant in the core zone and is synkinematic to the fault activity the fractions 50 16 m 16 2 m 2 0 5 m

normal faults and thrusts reactivated by deep fluids the 6 april 2009 mw 6 3 l aquila earthquake central italy 1 on 6 april 2009 a mw 6 3 earthquake occurred in the central apennines italy damaging the city of l aquila and the surrounding country we relocate the october 2008 to 6 april 2009 foreshocks and about 2000 aftershocks occurred between 6 and 30 april 2009 by applying a double difference technique and determine the stress field from focal mechanisms the events concentrate in the upper 15 km of the crust three main nw se to nnw sse striking 30 45 and 80 90 dipping faults were activated during the seismic sequence among these a normal fault and a thrust were reactivated with dip slip movements in response to ne sw extension the structural maturity of the seismogenic fault system is lower than that displayed by other systems in southern apennines because of the lower strain rate of the central sector of the chain with respect to the southern one vp vs increases progressively from october 2008 to the 6 april 2009 main shock occurrence along a nw se strike because of an increment in pore fluid pressure along the fault planes pore pressure diffusion controls the space time evolution of aftershocks a hydraulic diffusivity of 80 m2 s 1 and a seismogenic permeability of about 10 12 m2 suggest the involvement of gas rich co2 fluids within a highly fractured medium suprahydrostatic high fluid pressure about 200 mpa at 10 km of depth within overpressurized traps bounded by preexisting structural and or lithological discontinuities at the lower upper crust boundary are required to activate the april 2009 sequence traps are the storage zone of co2 rich fluids uprising from the underlying about 20 km deep metasomatized mantle wedge these traps easily occur in extensional regimes like in the axial sector of apennines but are difficult to form in strike slip regimes where subvertical faults may cross the entire crust in the apennines fluids may activate faults responsible for earthquakes up to mw 5 6 deep fluids more than tectonic stress may control the seismotectogenesis of accretionary wedges

a structural interpretation of a section of the gavarnie nappe and its implications for pyrenean geology abstract the gavarnie nappe is a feature of the tertiary pyrenean orogen and is shown to consist of at least two thrust sheets of palaeozoic rocks which are overlain by a southward dipping sequence of cretaceous and eocene sediments showing folded thrust structures the gavarnie nappe covers a basement and mesozoic cover rock sequence which is exposed in the tectonic windows of la larri and the troumouse cirque here previously unrecognized thrusts involving basement were responsible for folding the overlying gavarnie nappe these basement involved thrusts climb up section westwards giving a westward lowering of the gavarnie thrust along strike the structural evolution of the gavarnie nappe in a region extending from heas in france to the valle de pineta in spain can be explained in terms of a piggy back thrusting sequence on a regional scale thrust tectonic models may be used to explain the double vergence of the pyrenean chain where early southward directed thrusting was responsible for structures in the south pyrenean zone a later northward directed back thrusting event or rotation of southward directed thrust sheets by the stacking of lower thrust horses can explain the steepness of structures in the axial zone and the northward verging north pyrenean thrust zone both models suggest that prior to the pyrenean orogeny some of the hercynian structures in the axial zone were flatter lying and have been rotated to their present steepness during the pyrenean orogeny

dynamics of orogenic wedges and the uplift of high pressure metamorphic rocks subduction accretion complexes can be approximated as wedge shaped continua with a rigid buttress behind and a subducting litho spheric slab beneath thick wedges undergoing prograde metamorphism have a negligible long term yield strength and are likely to exhibit a complex nonlinear viscous rheology such a wedge will tend to deform internally until it reaches a stable configuration in which the gravitational forces generated by the wedge geometry balance the traction exerted on its underside by the subducting slab accretion of material at the wedge front will lengthen the wedge and cause it to shorten internally to regain the stable geometry this shortening will be expressed as late out of sequence thrusting backthrusting and folding conversely underplating of sediment or crustal slices will thicken the wedge which may need to extend internally to regain stability extension will cause listric normal faults that may merge downward into zones of ductile extension continued underplating at depth and compensating extension above provides a mechanism for bringing high p low t metamorphic rocks to upper levels in the rear of the wedge where they are commonly observed many major tectonic boundaries in convergent orogens such as the coast range thrust in the franciscan complex major nappe contacts in the alps and the contact between the nevado filabride and higher betic nappe complexes in the betic cordillera show abrupt increases in metamorphic grade downward across them this is consistent with their origin or reactivation as uplift related extensional structures

reactivation of deep faults beneath southern apennines evidence from the 1990 1991 potenza seismic sequences we relocate the 1990 1991 potenza southern apennines belt italy sequences and calculate focal mechanisms this seismicity clusters along an e w dextral strike slip structure second order clusters are also present and reflect the activation of minor shears the depth distribution of earthquakes evidences a peak between 14 and 20 km within the basement of the subducting apulian plate the analysed seismicity does not mirror that of southern apennines which include nw se striking normal faults and earthquakes concentrated within the first 15 km of the crust we suggest that the e w faults affecting the foreland region of apennine propagate up to 25 km of depth the potenza earthquakes reflect the reactivation of a deep preexisting fault system we conclude that the seismotectonic setting of apennines is characterized by nw se normal faults affecting the upper 15 km of the crust and by e w deeper strike slip faults cutting the crystalline basement of the chain

basement blocks and tecto sedimentary evolution in the pyrenees during mesozoic times the alpine tectonics in the pyrenean range is controlled by motions of basement blocks high primary range north pyrenean blocks these blocks belong to different tectonic units they are amygdaloid wedge shaped squeezed at their roots upthrust and displaced with their cover detached or not in a convergent shear zone between the european and iberian plates these basement blocks are distributed within isopic isofacial units with diachronous terrigenous prisms the stratigraphical analysis of their mesozo c cover reveals their relative position during the mid cretaceous continental break up which induced the separation of the two previously joined plates

ground deformation due to tectonic hydrothermal gravity hydrogeological and anthropic processes in the campania region southern italy from permanent scatterers synthetic aperture radar interferometry abstract we apply the permanent scatterers synthetic aperture radar interferometry ps insar technique to the campania region southern italy which includes the southern apennines chain and plio quaternary structural depressions with the aim to detect ground displacements at a regional scale the study area which extends for 13 600 km 2 is characterized by intense urbanization active volcanoes phlegraean fields vesuvius and ischia seismogenic structures landslides hydrogeological instability ps insar technique allows us to identify a set of radar benchmarks ps where accurate displacement measurements can be carried out about 1 7 10 6 ps are identified by processing synthetic aperture radar sar images acquired in ascending and descending orbits from 1992 to 2001 by the european remote sensing satellites ers the ps insar application at regional scale detected ground deformations ranging from 28 to 39 mm yr the calculated velocity values are consistent with the available gps and levelling data from selected areas we identify volcanic areas in which the deformation is mainly related to the depressurization of the local hydrothermal systems and recognize deformations along seismogenic and aseismic nnw sse and nw se faults the deformations localized along the southern apennines chain are mainly related to landslides while those occurring in the plains are due to subsidence processes induced by intensive drainage from wells i e anthropic activity the review of 9 years of sar data shows that tectonic volcanic hydrothermal gravity and anthropic processes are responsible for the ground deformation of campania the proposed joint interpretation of deformation fields related to natural and anthopogenic factors provides a comprehensive view of the dynamics of the earth s surface

improving landslide susceptibility mapping using morphometric features in the mawat area kurdistan region ne iraq comparison of different statistical models abstract susceptibility mapping provides information about vulnerable locations and thus helps to potentially decrease infrastructure damage due to mass wasting during the past decades expansion of settlements into areas prone to landslides in iraq has highlighted the importance of accurate landslide susceptibility studies the main goal of this research is to implement selected morphometric parameters to improve prediction of landslide susceptibility in the zagros mountain region we used the mawat area in the kurdistan region ne iraq to test the added value of morphometric indicators sixteen morphometric factors mainly derived from a digital elevation model dem extracted using the stereo ability of the advanced spaceborne thermal emission and reflection radiometer aster satellite as well as geological and environmental predictive factors were appraised we evaluated and compared frequency ratio fr weight of evidence woe logistic regression lr and probit regression pr approaches in combination with morphometric indices to determine the landslide susceptibility ls the areas under the curve auc of the prediction rate curve prc relative landslide density index r index and true positive percentage tpp for the four models show that all models perform similarly and the focus should be on careful selection of the predictive factors which is far more important than the methods used results indicate that lithology and slope aspects are the more dominant factors that lead to detect possible occurrence of landslides furthermore this work demonstrates that the hypsometric integral performs better than the commonly used slope curvature as a predictor and thus increases the prediction accuracy of the susceptibility map we argue that the use of adequate morphometric parameters can increase the efficiency of the ls mapping in other regions of the world