release fault a variety of cross fault in linked extensional fault systems in the sergipe alagoas basin ne brazil abstract two types of cross faults are herein recognized transfer faults and the newly termed release faults transfer faults form where cross faults connect distinct normal faults and horizontal displacements predominate over vertical ones in contrast release faults form where cross faults associated with individual normal faults die out within the hangingwall before connecting to other normal faults and have predominantly vertical displacements release faults are geometrically required to accommodate variable displacements along the strike of a normal fault thus they form to release the bending stresses in the hangingwall and do not cut normal fault planes nor detachment surfaces at depth release faults have maximum throws adjacent to normal faults and may be nearly perpendicular or obliquely oriented to the strike of the latter such geometry appears not to depend upon pre existing weaknesses but such variable orientation to normal faults is an inherent property of release faults release faults commonly appear as simple normal faults in seismic sections without implying extension along the strike of rift and basins three dimensional strain deformation occurs in the hangingwall only between the terminations of an individual normal fault but regionally release faulting is associated with plane strain deformation in linked extensional fault systems

isotope data from ice station weddell implications for deep water formation in the weddell sea helium isotope data 3he 4he ratios and 4he concentrations and h218o h216o ratios obtained from stations occupied during the drift of ice station weddell february to june 1992 are used together with hydrographic data to study formation of deep and bottom water in the western weddell sea the data indicate deep and bottom water formation along the entire track of the ice station 71 4 to 65 8 s 53 w ice shelf water isw seems to contribute significantly to the formation of weddell sea deep water wsdw and weddell sea bottom water wsbw in the southern part of the drift track toward the north the fraction of isw contained in wsdw wsbw decreases this trend is overlaid by high isw fractions in the deep and bottom waters found in the vicinity of the larsen ice shelf the fraction of western shelf water wsw in wsbw shows the opposite trend increasing from south to north the combined fraction of isw and wsw in waters with potential temperatures below 0 c is about 20 corresponding to a roughly 200 m thick layer overall wsw seems to contribute approximately 2 to 3 times more water than isw to the water column below the 0 c isotherm using the estimated flow of isw over the sill north of the filchner depression of 1 sv foldvik et al 1985a together with the ratio of wsw plus winter water ww to isw we calculate a value of about 5 sv for the formation rate of wsbw with a potential temperature of 0 7 c about one third of this flux represents near surface waters wsw ww which have recently been equilibrated with the atmosphere whereas pure isw contributes about 10

strain compatibility and fault linkage in relay zones on normal faults relay zones on normal faults are unlikely to have tabular geometries as depicted in idealised models rotation of a relay ramp between non parallel and non planar relay bounding faults will inevitably lead to strain compatibility problems causing open gaps or overlaps within the relay zone linkage of relay bounding faults does not evolve from a single branch point rather linkage occurs at multiple points along the fault tip lines giving rise to initially discontinuous branch lines where linkage occurs along a discontinuous slip aligned branch line displacement at different levels within the relay zone is partitioned between variable amounts of ramp rotation and slip across the branch line the linking fault propagates when strain compatibility can no longer be maintained by continuous deformation processes such as thickening or thinning of incompetent layers within the relay ramp step like changes in vertical displacement vs distance d x profiles on horizons containing apparently intact relay ramps are probably indicative of incipient breaching and can be used predict the presence of a slip aligned branch line in the sub surface despite the complexity of the strain distribution within relay zones the total vertical displacement across the relay remains geometrically coherent at all levels

unravelling the complexity of apenninic extensional fault systems a review of the 2009 l aquila earthquake central apennines italy the 2009 l aquila sequence activated a normal fault system 50 km long in the central apennines composed of two main nw trending faults 12 16 km long the main high angle l aquila segment and the campotosto listric fault the mw 6 1 l aquila mainshock nucleated on the paganica fault at a depth of 8 6 km and cut through the upper crust producing coseismic surface slip of up to 10 cm observed along a strike length of 13 km analysis of historical seismicity and data collected in paleo seismological trenches suggest that this event filled a 500 year gap in contrast the blind campotosto listric fault is composed of different fault segments displaying abrupt changes in dip at a depth where major events nucleate suggesting a rheological and geometrical control on stress concentration a foreshock sequence that started around 4 months before the l aquila mainshock activated the deepest portion of the paganica fault and marked the onset of large variations in elastic properties of the crustal volume the variations have been modelled in terms of dilatancy and diffusion processes corroborating the hypothesis that fluids play a key role in the nucleation process of extensional faults in the crust

unlocking the spatial dimension digital technologies and the future of geoscience fieldwork the development of affordable digital technologies that allow the collection and analysis of georeferenced field data represents one of the most significant changes in field based geoscientific study since the invention of the geological map digital methods make it easier to re use pre existing data e g previous field data geophysical survey satellite images during renewed phases of fieldwork increased spatial accuracy from satellite and laser positioning systems provides access to geostatistical and geospatial analyses that can inform hypothesis testing during fieldwork high resolution geomatic surveys including laser scanning methods allow 3d photorealistic outcrop images to be captured and interpreted using novel visualization and analysis methods in addition better data management on projects is possible using geospatially referenced databases that match agreed international data standards collectively the new techniques allow 3d models of geological architectures to be constructed directly from field data in ways that are more robust compared with the abstract models constructed traditionally by geoscientists this development will permit explicit information on uncertainty to be carried forward from field data to the final product current work is focused upon the development and implementation of a more streamlined digital workflow from the initial data acquisition stage to the final project output

test of the frictional reactivation theory for faults and validity of fault slip analysis the notion that slip on faults is controlled by the balance between resolved shear stress and the magnitude of frictional resistance is examined in the light of the published orientations of ancient faults and slip lineations by compiling data from more than 1500 faults used in 228 stress analyses we observe that natural fault planes as well as lineations formed by fault slip display characteristic patterns of preferred orientation when rotated into the reference frame defined by the principal stress axes these patterns vary systematically according to the relative magnitudes of principal stresses determined by fault slip analysis furthermore these patterns are strikingly similar to those predicted by a frictional model for fault reactivation in which the potential for slip is equated to the ratio of the components of shear stress and normal stress on the fault plane our findings therefore make a compelling case for the concept of frictional slip tendency for the prediction of fault reactivation and lend support to the validity of fault slip methods for paleostress analysis

earthquake synchrony and clustering on fucino faults central italy as revealed from in situ cl 36 exposure dating we recover the holocene earthquake history of seven seismogenic normal faults in the fucino system central italy we collected 800 samples from the well preserved limestone scarps of the faults and modeled their 36cl concentrations to derive their seismic exhumation history we found that 30 large earthquakes broke the faults in synchrony over the last 12 ka the seven faults released strain at the same periods of time 12 9 ka 5 3 ka and 1 5 1 ka on all faults the strain accumulation and release occurred in 3 6 ka supercycles each included a 3 5 ka phase of slow 0 5 2 mm yr strain accumulation in relative quiescence followed by a cluster of three to four large earthquakes or earthquake sequences that released most of the strain in 1 2 ka the large earthquakes repeated every 0 5 0 3 ka during the paroxysmal phases and every 4 3 0 9 ka between those phases earthquakes on the northern faults produced twice larger surface slips 2 m and had larger magnitudes mw 6 2 6 7 than those on the southern faults on most faults the relative strain level was found to control the amount of slip and the time of occurrence of the next large earthquake faults entered a phase of clustered activity once they had reached a specific relative strain threshold the tre monti fault is identified as the most prone to break over the next century our data document earthquake synchrony and clustering at a broader space and time scale than has been reported to date

anomalous stress field and active breaching at relay ramps a field example from gediz graben sw turkey relay ramps form at different scales in extensional terrains to accommodate the differential stretching among the overlapping bounding normal fault segments the major boundary structure of the gediz graben sw turkey is segmented with formation evolution and active breaching of relay ramps the akcapinar relay ramp is an example of these processes that forms within a 2 km wide overlap zone between e w trending segments on the southern margin of the gediz graben change of structural style at the ramp area is clearly evident from variations in the orientation of fractures and faults of the relay ramp as a site of local stress field anomaly n s trending structures in the akcapinar relay ramp are conformable with the extension that is parallel to the bounding faults of the relay ramp these structures are also superimposed onto the e w trending regional structural style by an obvious cross cutting relationship suggesting both spatial and temporal variation of the state of stress at the ramp area during the relay ramp formation the regional stress field and the resulting regional structural style characterize the earlier stages of ramp evolution during which segment interaction is limited as segment interaction and relay ramp formation advances towards the breaching phase an anomalous local stress field arises and the relay ramp area experiences extension parallel to the bounding normal faults that is transverse to the regional direction of extension this creates a new structural style at the ramp area

normal faulting in the upper continental crust observations from regions of active extension abstract observations of present day normal faulting in regions of active continental extension may be helpful when interpreting the geological record in older extensional basins the most obvious manifestation of active extension is normal faulting in earthquakes earthquake foci are mostly confined to the upper seismogenic continental crust whose thickness imposes a scale on the observed deformation large earthquakes move faults with lengths similar or large compared with the thickness of the seismogenic layer large seismogenic normal faults on the continents appear to be restricted to a dip range of around 30 60 dips significantly gentler than 20 have not been observed in fault plane solutions of large earthquakes large seismographic normal faults are approximately planar in cross section and cut through the base of the upper seismogenic layer rotating about a horizontal axis as they move a reasonable estimate of the regional extension can often be made from the dip of the large normal faults and the tilt of the blocks they bound the domino model such faults are rarely continuous for more than 15 20 km but commonly change strike or step in an en echelon fashion this segmentation may occur on a scale controlled by the thickness of the seismogenic layer and is an important influence on sedimentation and drainage these observations are common to large seismogenic normal faults from a variety of tectonic settings and suggest that the kinematics of normal faulting may not be strongly influenced by the forces responsible for the extension which can vary widely in nature and magnitude small earthquakes which move faults that are small compared with the seismogenic layer thickness show no simple pattern and often can be interpreted as internal deformation of blocks bounded by large faults in some places the seismogenic basement faults do not reach the surface but are decoupled from the sedimentary cover by layers of weak lithology faults in the sedimentary cover may be strongly curved in cross section requiring their hangingwalls to deform internally estimating extension from such faults is not straightforward and requires a knowledge of the hangingwall deformation estimates made in this way are often very non unique and prone to large errors we postulate that the thickness of the seismogenic upper crust controls both the maximum length of large normal fault segments along strike and the maximum size of blocks that can rotate coherently about a horizontal axis

sedimentary and tectonic evolution of plio pleistocene alluvial and lacustrine deposits of fucino basin central italy abstract the fucino basin was the greatest lake of the central italy which was completely drained at the end of 19th century the basin is an intramontane half graben filled by plio quaternary alluvial and lacustrine deposits located in the central part of the apennines chain which was formed in upper pliocene and in quaternary time by the extensional tectonic activity the analysis of the geological surface data allows the definition of several stratigraphic units grouped in lower units and upper units the lower units upper pliocene are exposed along the northern and north eastern basin margins they consist of open to marginal lacustrine deposits breccia deposits and fluvial deposits the upper units lower pliocene holocene consist of interbedded marginal lacustrine deposits and fluvial deposits thick coarse grained fan delta deposits are interfingered at the foot of the main relief with fluvial lacustrine deposits most of the thickness of the lacustrine sequences more than 1000 m thick is buried below the central part of the fucino plain the basin is bounded by e w wsw ene and nw se fault systems velino magnola fault e w and tremonti celano aielli fault wsw ene and s potito celano fault nw se in the north the trasacco fault the pescina celano fault and the serrone fault nw se in the south east the geometry and kinematic indicators of these faults indicate normal or oblique movements the study of industrial seismic profiles across the fucino basin gives a clear picture of the subsurface basin geometry the basin shows triangular shaped basin fill geometry with the maximum deposits thickness toward the main east boundary fault zones that dip south westward serrone fault trasacco fault pescina celano fault on the basis of geological surface data borehole stratigraphy and seismic data analysis it is possible to recognize and to correlate sedimentary and seismic facies the bottom of the basin is well recognized in the seismic lines available from the good and continuous signals of the top of meso cenozoic carbonate rocks the shape of sedimentary bodies indicates that the filling of the basin was mainly controlled by normal slip along the nw se boundary faults in fact the continental deposits are frequently in on lap contact over the carbonate substratum several disconformable contacts occurred during the sedimentary evolution of the basin the main faults with antithetic and synthetic fault planes displace the whole sedimentary sequence up to the surface indicating a recent faults activity 1915 avezzano earthquake ms 7 0 the stratigraphic and tectonic setting of the fucino basin and neighboring areas indicates that the extensional tectonic events have had an important role in driving the structural sedimentary evolution of the plio quaternary deposits the geometry of the depositional bodies of the fault planes and their relationships indicate that the fucino basin was formed as a half graben type structure during plio quaternary extensional events some internal complexities are probably related to the fold and thrust structures of the apenninic orogeny formed in messinian time in this area and to a different activity timing of the e w and wsw ene fault systems and the nw se fault systems we believe based on the similarity of the surface characteristics that the structural setting of the fucino basin can be extrapolated to the other great intramontane basins in central italy e g rieti l aquila sulmona sora isernia basins

fault linkage in continental rifts structure and evolution of a large relay ramp in zavarotny lake baikal russia abstract the internal structure of a large 10 40 km relay ramp has been described between two border faults of the baikal rift zone the relay ramp which is located partly onshore and partly offshore has been investigated using a dense grid of high resolution seismic profiles and a digital terrain model containing topographic as well as bathymetric data the structure of the relay ramp in zavarotny is characterised by the development of secondary faults striking approximately parallel to the main faults in combination with this breaching occurred through the development of a new connecting fault the breaching in zavarotny has not lead to the destruction of the relay ramp but a clear further evolution has been observed e g a similar morphology of the lake floor and the basement inside the relay ramp as well as the development of a second connecting fault the strike direction of the secondary faults in the relay ramp has likely been influenced by the pre existing basement fabric in the area

3d characterization of fracture systems using terrestrial laser scanning an example from the lewisian basement of nw scotland fractured gneiss lithologies form a basement cored high the rona ridge in the faroe shetland basin basement structures are known to play an important role in the petroleum system for the overlying giant clair field an onshore analogue exposure in the lewisian gneiss complex at kinlochbervie in nw scotland provides an example of a hanging wall damage zone of a large basement hosted normal fault in this study we used remote sensing 2d outcrop line sample methods 1d and a virtual outcrop created by terrestrial laser scanning methods 3d to characterize spatial variations of the fracture systems spacing distributions from 1d line samples collected from exposures and pseudo wells constructed through the virtual outcrop show power law distributions the virtual outcrop data enable us to extend the scale invariant description from 1 to 3 orders of magnitude we developed a novel box counting workflow to provide an assessment of 2 and 3d variations in the fracture properties fracture density and fractal dimension are elevated whereas the number of intersections is decreased within a 220 m wide volume adjacent to the fault we discuss how the methods and results from this study can aid the development of analogue for basement reservoirs in the offshore uk continental shelf

a proposal for the kinematic modelling of w dipping subductions possible applications to the tyrrhenian apennines system in w dipping subduction zones there is a general eastward progression of the back arc basin accretionary wedge foredeep complex with the forward progression early stages of the complex are revealed by slices of upper crust and sedimentary cover abandoned to the west left floating above a new section of mantle a major shear zone should form at the new moho separating upper crust slices of earlier accretionary stages and the eastward flowing mantle the mantle wedging at the top of the subduction plane could be responsible for the uplift of the central parts of the belt the retreating of the subduction hinge is interpreted as due to the push generated by the eastward mantle flow detected in the hot spot reference frame the foredeep depth is mainly a function of the radius of curvature of the subduction hinge the frontal wedge is constructed from the stacking of the upper layers of the subducting plate and the syntectonic clastics that fill the foredeep which are progressively involved in thrusting and later by extension in order to preserve volume balance the lithosphere of the eastern plate before subduction has to be the same size as that which has been subducted due to the longer length of the arc with respect to the original length of the linear margin between the two converging plates laterally stretched subducted lithosphere is predicted at depth w dipping subductions usually have a short life probably due to their inherent capability to produce new lateral heterogeneities of the lithosphere the thin back arc which are a key factor in controlling and generating new subductions both e and w dipping this model is applied to the apennines tyrrhenian sea system

active crustal extension in the central apennines italy inferred from gps measurements in the interval 1994 1999 we present the first gps estimate of crustal extension in the central apennines italy through the analysis of the deformation of a sub network of the national gps geodetic network igm95 in the interval 1994 1999 the selected sub network spans the entire active deformation belt perpendicularly to its axis and allows the evaluation of 1 the total extension rate absorbed in this sector of the apennines and 2 the seismogenic potential of the normal faults active in the late pleistocene holocene interval within the network results of this reoccupation are consistent with an extensional strain rate of 0 18 10 6 yr 1 concentrated in an area of about 35 km width giving an average extension rate of 6 2 mm yr across the central apennines the pattern of active deformation suggests active elastic strain accumulation on the westernmost of the two fault systems active in the late pleistocene holocene interval and may also suggest the presence of another active fault system not recognized so far

complex geometry and kinematics of subsidiary faults within a carbonate hosted relay ramp abstract minor fault geometry and kinematics within relay ramps is strongly related to the stress field perturbations that can be produced when two major fault segments overlap and interact here we integrate classical fieldwork and interpretation of a virtual outcrop to investigate the geometry and kinematics of subsidiary faults within a relay ramp along the tre monti normal fault in the central apennines although the tre monti fault strikes parallel to the regional extension ne sw it shows predominant dip slip kinematics suggesting a nw se oriented extension acting at sub regional scale 1 10 km conversely the slickenlines collected on the front segment of the relay ramp highlight right lateral kinematics the subsidiary faults in the relay ramp show a complex geometry variable attitudes and slickenlines describe multiple kinematics left lateral dip slip right lateral independently of their orientation our fault slip analysis indicates that a local stress field retrieved from the kinematic inversion of the slickenlines collected on the front segment and likely promoted by the interaction between the overlapping fault segments that bound the relay zone can explain most of the geometry and kinematics of the subsidiary faults further complexity is added by the temporal interaction with both the regional and sub regional stress fields

investigating fault reactivation during multiple tectonic inversions through mechanical and numerical modeling an application to the central northern apennines of italy abstract within inversion tectonic contexts the reactivation of pre existing discontinuities depends upon many structural stratigraphic and mechanical factors among these a fundamental aspect is represented by the orientation and attitude of pre existing discontinuities with respect to the new stress field the aim of this work is to evaluate the stress regimes and the mechanical conditions that controlled the reactivation of segmented pre thrusting normal faults in the central northern apennines of italy these faults were involved both in positive and negative inversion tectonic events during tertiary quaternary times mechanical slip tendency analysis and numerical using coulomb 3 3 software models allowed us to reconstruct a 3d stress field for both inversion events and to evaluate the effect of many parameters orientation of faults fault dip angle and mechanical parameters on fault reactivation our results highlighted that the orientation of pre existing faults with respect to the stress axes represents the main factor controlling inversion tectonic phenomena where other mechanical and geometric variables exert a subordinate role the models well reproduce the neogene quaternary deformation history reconstructed from detailed geological and structural analyses for the central northern apennines of italy and could be applied to other regions that have experienced inversion tectonic processes

reply to comment by v picotti and f j pazzaglia on shale diapirism in the quaternary tectonic evolution of the northern apennine bologna italy 1 we appreciate the comment of picotti and pazzaglia 2007 on our work borgia et al 2006 which considers shale diapirism as one of the fundamental processes in the tectonic evolution of the northern apennine indeed their comment shows the relevance of our conclusions even if some of the details we provided could have been improved in our reply we will not engage in unfruitful polemics instead we will address only the main issues they raise leaving to future work a more detailed discussion 2 point 1 refers to their statement that the rheology of the liguiran shale precludes it from behaving like a clay glacier this is a very important point in fact once it was realized that the chaotic shales were ductile most of the field observations which appeared to be contradictory became pieces of a puzzle that came together shales and gypsum tend to be rigid if subject to small stresses in the order of 10 pa small lengths in the order of 10 10 m and short periods of time in the order of 10 years for larger stresses in the order of 10 pa lengths in the order of 10 m and longer periods of time in the order of 10 years such as those encountered in the apennine they tend to deform even if at slow rates in general given sufficient stress and duration all rocks deform just like the earth s mantle also the silicon putty we used for the experiments fractures if stresses are applied very rapidly being perfectly fluid for longer periods of time correspondently for any reasonable human scale experience a viscosity of 10 pa s as the one we attribute here to the shales cannot be distinguished from that of a truly rigid body within the time frame and stress field we are concerned with the plastic and liquid limits are not relevant regarding the concern that the train tunnels have not deformed in the past 10 years we underscore the relevance of actual differential uplift within the tunnel s length not of absolute uplift and the fact that 10 years is probably too short a time to register a deformation that is averaged over 10 years 3 point 2 refers to their statement the field observations of a basal detachment for the ligurian units we agree that many outcrops show the base of a detachment however we see no evidence of detachment in our study area in addition where the base of a detachment is observed the top of the detachment is not present this is because the deformation is distributed within the viscous chaotic shaly units as a whole and not just along a focused detachment plane with footwall and associated overlying hanging wall we argue that many of the observations reported and the criticisms made by picotti and pazzaglia may be correctly interpreted in terms of a gravitational diapiric tectonic model we will provide a detailed response to these points in a forthcoming paper 4 point 3 refers to their statement field and seismic data of a deformed rather flat rigid basement of the ligurian units the fact that the basement is deformed by regional tectonics is not in contrast with the fact that this basement behaved rigidly on a 10 to 100 times shorter timescale and at a later time 5 point 4 refers to their statement an incorrect age for uplifted and deformed marine surfaces we do not agree with this comment of picotti and pazzaglia we believe our interpretation is correct however we feel that they have misinterpreted some of our statements 6 we believe the evidence of diapiric tectonics is so compelling that as picotti and pazzaglia state in the past some authors had to consider their existence the paradigm of rigid tectonism that is still pervading the geologic literature of the apennine left them no alternative but to call them mud volcanoes or pseudodiapirs pini 1999

fault geometry and active stress from earthquakes and field geology data analysis the colfiorito 1997 and l aquila 2009 cases central italy the fault segmentation pattern and the regional stress tensor acting since the early quaternary in the intra apennine area of central italy was constrained by integrating two large geological and seismological fault slip data sets collected for the areas struck by the two most energetic seismic sequences of the last 15 years colfiorito 1997 m w 6 0 and l aquila 2009 m w 6 1 the integrated analysis of the earthquake fault association and the reconstruction of the 3d shape of the seismogenic sources were exploited to identify homogeneous seismogenic volumes associated with subsets of geological and focal mechanism data the independent analysis of geological and seismological data allowed us to observe and highlight similarities between the attitude of the long term e g quaternary and the instantaneous present day seismogenic extensional deformations and to reveal their substantial coaxiality coherently with the results from the kinematic analysis the stress field inversion also noted a prevailing tensional seismotectonic regime associated with a subhorizontal ne sw minimum stress axis a minor very local and shallow 5 km strike slip component of the stress field was observed in the colfiorito sector where an inherited n s oriented right lateral fault was reactivated with sinistral kinematics instead an almost total absence of strike slip solutions was observed in the l aquila area these results do not agree with those indicating quaternary regional strike slip regimes or wide areas characterized by strike slip deformation during the colfiorito and l aquila seismic sequences

the geometry kinematics and rates of deformation within an en echelon normal fault segment boundary central italy abstract the geometry kinematics and rates of deformation have been investigated within an en echelon fault segment boundary between two left stepping major normal faults in the central apennines italy examination of faulted post glacial sediments and geomorphic features attributed to glacial retreat 18 ka reveals that the two major faults dominate the recent slip with rates that are 5 10 times greater than the other faults at the centres of the major faults slip is parallel to the regional extension direction ne sw defined by focal mechanisms and borehole breakouts slip vector azimuths defined by striations on faults in the stepover zone indicate ne sw extension on nw se faults sub parallel to the regional extension direction together with significant and contemporaneous nw se extension along the strike of the apennines on ese wnw and ene wsw faults thus distributed three dimensional strain occurs in the stepover between the two major bounding faults extension rates summed across the stepover are 0 68 mm y parallel to the regional extension compared to 2 mm y at the centre of one of the major faults extension rates along strike of the fault zone are 0 14 mm y within the stepover and zero at the centres of the two major bounding faults the above information is used to discuss how extension is partitioned between different structures during the growth and linkage of normal faults

laser scanning and digital outcrop geology in the petroleum industry a review abstract the use of lidar light detection and ranging systems for modelling petroleum reservoir analogues has become increasingly popular over the past few years and there has been a proliferation of articles on the subject both on techniques and applications a review of the literature of recent years has been conducted focussing on the use of lidar data not only in petroleum geology related projects but also looking to the wider field of lidar usage to examine what other approaches may be of use to the petroleum geologist benefits of digital data acquisition are considered as well as a basic overview of data collection approaches use of a variety of attributes intensity colour dip azimuth co linearity co planarity among others is discussed as an aid to both manual and automated interpretation approaches integration of lidar data with other data types from traditional field data sedimentary logs for example and other digital data types such as multispectral and hyperspectral imagery and ground penetrating radar are discussed as a way of increasing the amount of information in the digital dataset the application of artificial intelligence approaches such as smart swarms and neural networks are considered as well as current developments in both hardware and software a variety of examples are given where lidar has been used in an innovative or interesting way showing the strength of this data acquisition approach when combined with appropriate interpretation and modelling techniques

terrestrial laser scanning in geology data acquisition processing and accuracy considerations terrestrial laser scanning or lidar is a recent innovation in spatial information data acquisition which allows geological outcrops to be digitally captured with unprecedented resolution and accuracy with point precisions and spacing of the order of a few centimetres an enhanced quantitative element can now be added to geological fieldwork and analysis opening up new lines of investigation at a variety of scales in all areas of field based geology integration with metric imagery allows 3d photorealistic models to be created for interpretation visualization and education however gaining meaningful results from lidar scans requires more than simply acquiring raw point data surveys require planning and typically a large amount of post processing time the contribution of this paper is to provide a more detailed insight into the technology data collection and utilization techniques than is currently available the paper focuses on the workflow for using lidar data from the choice of field area and survey planning to acquiring and processing data and finally extracting geologically useful data because manufacturer specifications for point precision are often optimistic when applied to real world outcrops the error sources associated with lidar data and the implications of them propagating through the processing chain are also discussed

tectonic analysis of fault slip data sets using data that include the direction and the sense of motion on individual fault surfaces determined by slickenside lineations it is possible to reconstruct reduced stress tensors that correspond to the orientation of stress axes and to the ratio 2 3 1 3 between principal stress values 1 2 3 compression being positive no assumption is made concerning the orientation of fault planes relative to stress axes so that reactived faults are taken into account as well as newly created ones qualitative and quantitative methods for analysis of fault slip data were developed during the last 10 years the practical limitation of the methods and the necessity for critical field observations are emphasized these methods can be applied to focal mechanisms of earthquakes a more complex analysis of heterogeneous data sets involving an iterative separation of different stress systems is also discussed this analysis enables one to distinguish successive faulting events careful qualitative study in the field is in all cases essential

structural architecture of the central apennines interpretation of the crop 11 seismic profile from the adriatic coast to the orographic divide 1 we present an interpretation of the eastern half portion of the crop 11 line a deep reflection seismic profile 265 km long that cuts across the central apennines from the tyrrhenian coast to the adriatic coast in the study area the line cuts across a pile of thrust sheets that underwent tectonic transport between the messinian and the pleistocene in its easternmost part the line runs through the plio pleistocene deposits of the adriatic foredeep in the foreland region the crop 11 line integrates previous information on the crustal structure derived from petroleum exploration and from deep seismic sounding refraction experiments in particular the crop 11 line confirms the existence of a very thick sedimentary sequence underlying the mesozoic tertiary carbonates of the apulia platform interpreted as the paleozoic triassic sedimentary cover of a pre cambrian crystalline basement in the mountain chain where the base thrust of the orogenic wedge reaches a depth of about 25 km this sedimentary sequence appears to be the deepest geological unit incorporated in the thrust system this interpretation of the crop 11 profile suggests an unusual thin skin tectonic style implying the detachment from the original basement and the incorporation in the post tortonian tectonic wedge of a very thick paleozoic triassic sedimentary sequence possibly affected by low grade metamorphism in the lower part other new suggestions from the crop 11 seismic data concern the origin of the fucino basin one of the most remarkable plio pleistocene intramontane basins the normal faults bordering this structural depression as other important normal faults present in the central apennines e g the caramanico fault system in the majella region seem to have been controlled by gravitational collapse processes driven by uplift during crustal shortening rather than by a generalized extension subsequent to the apennine compression as usually reported in the geological literature if this interpretation is correct the strong seismic activity in correspondence to the apennine watershed may be related to the very recent increase in the structural relief caused by an out of sequence propagation of the active thrusts

fault structure and slip localization in carbonate bearing normal faults an example from the northern apennines of italy abstract carbonate bearing normal faults are important structures for controlling fluid flow and seismogenesis within the brittle upper crust numerous studies have tried to characterize fault zone structure and earthquake slip processes along carbonate bearing faults however due to the different scales of investigation these studies are not often integrated to provide a comprehensive fault image here we present a multi scale investigation of a normal fault exhumed from seismogenic depths the fault extends for a length of 10 km with a maximum width of about 1 5 km and consists of 5 sub parallel and interacting segments the maximum displacement 370 650 m of each fault segment is partitioned along sub parallel slipping zones extending for a total width of about 50 m each slipping zone is characterized by slipping surfaces exhibiting different slip plane phenomena fault rock development is controlled by the protolith lithology in massive limestone moving away from the slip surface we observe a thin layer