paleoseismology along the 1980 surface rupture of the irpinia fault implications for earthquake recurrence in the southern apennines italy the irpinia fault was the source of the ms 6 9 1980 irpinia earthquake and produced the first unequivocal historical surface faulting in italy trenching of the 1980 fault scarp at piano di pecore a flat intermontane basin about 5 km south of the 1980 instrumental epicenter provides the first data on earthquake recurrence intervals slip per event and slip rate on a major normal fault in the southern apennines fault zone the trenches exposed evidence of four pre 1980 paleoearthquakes that occurred during the past 8600 years a best estimate average recurrence interval is 2150 years although the time interval between individual events varies by as much as a factor of 2 each paleo earthquake is similar to the 1980 surface rupture in amount of slip and style of deformation which suggests that the 1980 event is characteristic for the irpinia fault slip per event values average 61 cm the net vertical displacement of 2 12 2 36 m since 8600 cal year b p observed in the trenches gives a vertical slip rate of 0 25 0 35 mm yr a dip slip rate of 0 29 0 40 mm yr and an extension rate of 0 14 0 20 mm yr although fault behavior data are only available for the irpinia fault they provide a starting point for evaluating earthquake recurrence and rates of deformation in southern apennines they suggest that 1 fault specific earthquake recurrence intervals based on the historical seismic record overestimates the occurrence of large magnitude m7 earthquakes and 2 the holocene rate of extension across the apennines is 1 mm yr the 1980 earthquake and the paleoseismologic observations show that repeated and localized surface faulting occurs in southern apennines and leaves subtle but distinct geomorphic evidence that can be detected with detailed and careful investigation

revised hypocentre and fault rupture geometry for the 1980 november 23 campania basilicata earthquake in southern italy summary the fault rupture nucleation point of the 1980 november 23 campania basilicata earthquake is relocated following the recent identification of 20 km of surface faulting the carpineta and picentini fault scarps in addition to the 15 km previously documented on the marzano and san gregorio faults all of which have nw strike and 60 ne dip this relocation indicates a range of revised origin times and nucleation point positions at 10 12 km depth that are 5 9 km se of previously documented coordinates between 18 34 52 0 0 3 s with latitude 40 724 1 4 km and longitude 15 414 1 4 km preferred and 18 34 52 5 0 3 s with latitude 40 742 1 4 km and longitude 15 373 1 4 km my preferred nucleation point coincides with a downdip projection of the se end of the carpineta fault and indicates that this fault ruptured first rather than the marzano fault as was previously thought with the fault rupture nucleation point adjusted to this new preferred position field and seismological estimates of seismic moment match well both overall and for individual fault scarps and suggest the following sequence of fault rupture subevents the initial fault rupture nucleated at or near the se end of the carpineta fault and propagated nw releasing 2 5 1018 n m seismic moment rupture continued apparently without interruption onto the adjoining marzano fault farther nw where 6 5 1018n m of seismic moment was released rupture then paused for 0 5s before continuing nw along the picentini fault where 4 5 1018n m more seismic moment was released probably early in this sequence of nw propagating ruptures a se propagating rupture released 2 1018 n m seismic moment on the san gregorio fault each of these fault scarps and the corresponding rupture subevent was associated with intense aftershock activity the existence of another aftershock cluster nw of the picentini scarp suggests a fifth mainshock rupture subevent at castelfranci which released up to 2 1018 n m more seismic moment rupture at this locality appears necessary to explain the form of ground acceleration recorded nearby also following these ruptures on steep ne dipping normal faults two additional ruptures occurred on faults with different orientations 20 s and 40 s after the initial mainshock rupture the 40 s subevent involved release of 3 1018 n m of seismic moment on a steep normal fault that dips sw at 70 and projects to the earth s surface 11 km ne of the marzano fault the 20 s subevent apparently involved release of 4 1018 n m of seismic moment on a surface dipping ne at 20 at the base of the brittle upper crust beneath this steep antithetic fault points where normal fault ruptures nucleated on the steep ne dipping normal faults coincide with en echelon steps of 1 km and abrupt 15 changes in strike the marzano and carpineta faults which have strike 315 took up a small component of left lateral slip as is revealed by the first motion focal mechanism teleseismic waveform modelling striations measured in the field and consistent rightward stepping their slip vector azimuth is n37 e assuming the same slip vector azimuth a component of right lateral slip is expected on the san gregorio and picentini faults that have strike 300

an inverse problem for the determination of the stress tensor from polyphased fault sets and earthquake focal mechanisms abstract a new method for determining the stress tensor from fault slip data is presented the solution is obtained by minimizing the deviation between the stress ratio and a value corresponding to the maximum of a probability density function the method can be used to separate successively different tectonic phases and is developed for calculating the stress tensor from earthquake focal mechanisms

palaeoseismology review of the state of the art abstract historical seismicity provides only a partial indication of the seismotectonic character i e earthquake potential of a given region even in italy where a relatively long historical record exists available catalogues are generally unsatisfactory for this purpose fortunately strong earthquakes often leave geological evidence herein referred to as seismites that are mainly related to surface faulting folding or other deformation and occasionally to secondary ground failures e g landslides liquefaction features etc these features may be preserved and therefore palaeoseismological studies may detect and date them thereby permitting extension of knowledge beyond the local historical threshold up to 2000 years in the most fortunate cases this paper provides a summary of criteria which may aid in the identification of areas suitable for palaeo earthquake investigation historical seismicity and the presence of well developed tectonic geomorphic features are recognized as the most reliable criteria for identifying active faulting however lack of these characteristics cannot be considered conclusive evidence for lack of activity palaeoseismological techniques aim at identifying not only the obvious effects of surface faulting such as offset of young geologic units but also the more subtle tectonic or non tectonic features including liquefaction structures gravity features and coseismic uplift and or subsidence finally we discuss some questions that pertain to palaeoseismicity evaluation techniques among these are the reliability of the quaternary dating techniques the evaluation of the seismic energy released minimum magnitude and principally the unequivocal identification of a seismic origin for the considered geological structures

defining seismogenic sources from historical earthquake felt reports abstract we present a method that uses macroseismic intensity data to assess the location physical dimensions and orientation of the source of large historical earthquakes intensity data contain a great deal of information that can be used to constrain the essential characteristics of the seismic source in particular both the seismological theory and its practice suggest that the orientation of the source of significant earthquakes is reflected in the elongation of the associated damage pattern a plausible and easily manageable way of describing a seismic source is by representing it as an oriented rectangle the length and width of which are obtained from moment magnitude through empirical relationships this rectangle is meant to represent either the actual surface projection of the seismogenic fault or at least the projection of the portion of the earth crust where a given seismic source is likely to be located the systematic application of this method to all the m 5 5 earthquakes that occurred in the central and southern apennines italy in the past four centuries returned encouraging results that compare well with existing instrumental direct geological and geodynamic evidence the method is quite stable for different choices of the algorithm parameters and provides elongation directions that in most cases can be shown to be statistically significant in particular the resulting pattern of source orientations is rather homogeneous showing a consistent appennines parallel trend that agrees well with the ne sw extension style of deformation active in the central and southern portions of the italian peninsula

the campania lucania extensional fault system southern italy a suggestion for a uniform model of active extension in the italian apennines 1 by integrating new field data seismic lines interpretation and a critical review of the literature this work highlights a regional array of normal faults in the southern apennines of italy which have been active during the quaternary and are referred to as the campania lucania extensional fault system clefs the clefs consists of three main nw se striking alignments of normal faults which for the first time are considered genetically linked and methodically described in their geometry kinematics and displacement the crop04 seismic profile crossing the central part of the clefs was strictly constrained by detailed geological surveys and reinterpreted to define the downdip trajectory of the major normal faults these latter have been observed to splay from an east dipping low angle detachment surface penetrating the upper crust to depths of 12 13 km the time space evolution of the faults and the associated basins was defined through a review of the stratigraphic data on the syntectonic deposits as regards the overall geometry and the associate sense of shear top to east the clefs sensibly differs from the extensional features described previously in this region but shows surprising affinities with the etrurian fault system an extensional megastructure of the northern apennines remarkable similarities concern the extent the surface and subsurface geometry the timing of activity and the amount of the associated deformation these common characters recognized over a belt nearly 600 km long lead to formulation of a low angle normal fault driven extension geometrical kinematic model which is sound for the whole active extensional belt of italy

fault scarps and deformation rates in lazio abruzzo central italy comparison between geological fault slip rate and gps data abstract we compare new and literature data concerning the integrated deformation rate since 18 ka for the central apennines with deformation rate data derived from a 6 year gps campaign we constructed topographic profiles across the majority of the active faults in the area we derived deformation rate data from displaced post glacial sediments and slopes associated with the last major glacial retreat that occurred in the region about 18 kyr ago paleoseismic investigations in this region clearly show that offset of these features is the cumulative effect of repeated surface faulting earthquakes with magnitudes in the range 5 5 ms 7 0 a cumulative throw rate diagram incorporating both our values and the values extracted from the literature i e previously published trenching studies scarp profiles and offset terraces is presented providing a regional picture of the spatial deformation rate distribution in the central apennines during the latest pleistocene and holocene by converting cumulative throw rates into heave rates we calculate maximum extension rates of ca 2 mm year at the location of the same transect where 6 2 mm year has been measured with gps over 6 years this discrepancy between geodetic and geological fault slip rate data implies that we have to be cautious whenever we use gps data for seismic hazard assessment purposes or when attempting to reconstruct the tectonic processes in an area because geodetic data may be unrepresentative of the longer term deformation rates on the other hand this discrepancy may provide insights into the mechanics of the seismic cycle we discuss various scenarios that may explain the mis match between long term and short term measurements

influence of topography on coseismic displacements induced by the friuli 1976 and the irpinia 1980 earthquakes italy analyzed through a two dimensional hybrid model 1 we investigate the perturbations introduced by the local topography on the coseismic displacement components induced by crustal seismic faults the approach proposed by tinti and armigliato 2002 is applicable to homogeneous two dimensional domains with arbitrary topography of the free surface it uses both analytical results valid for homogeneous spaces and half spaces bounded by a flat free surface ffs and a numerical code solving the equations of equilibrium of linear elasticity through a finite element fe scheme a major characteristic of our hybrid method is that it allows for the correct representation of the displacement components in correspondence with the fault which does not need to be explicitly introduced in the fe mesh we show that in the case of homogeneous domains this makes our approach preferable to pure fe schemes our hybrid approach is here applied to two different disastrous events of the recent italian seismic history for which topography is expected to play an important role namely the 6 may 1976 ms 6 5 friuli and the 23 november 1980 ms 6 9 irpinia basilicata earthquakes for each event we selected hypotheses for the parent fault proposed in the literature and compared the coseismic displacements computed through the widely used analytical models dealing with ffs and through our hybrid approach accounting for the effect of realistic topographies the most relevant effects are observed in the case of the irpinia earthquake depending on the profile chosen the computed misfits can be as high as 19 and 13 for the horizontal and vertical displacements respectively with absolute differences up to 9 and 10 cm

time intervals to assess active and capable faults for engineering practices in italy abstract the time span necessary to define a fault as active and capable can mainly be derived from the framework of the regulations and the literature produced since the 1970s on risk estimation in engineering planning of strategic buildings within this framework two different lines of thought can be determined which have mainly developed in the usa on the one side there is a tendency to produce narrow chronological definitions this is particularly evident in the regulatory acts for the planning of nuclear reactors the much more effective second line of thought anchors the chronological definitions of the terms active and therefore capable to the concept of seismotectonic domain as the domains are different in different regions of the world the chronological definition cannot be univocal i e different criteria are needed to define fault activity which will depend on the characteristics of the local tectonic domain and of the related recurrence times of fault activation current research on active tectonics indicates that methodological aspects can also condition the chronological choice to define fault activity indeed this practice implies the use of earth science methods the applications of which can be inherently limited for example limits and constraints might be related to the availability of datable sediments and landforms that can be used to define the recent fault kinematic history for the italian territory we consider two main tectonic domains a the compressive domain along the southern margin of the alpine chain and the northern and northeastern margins of the apennines which is characterised by the activity of blind thrusts and reverse faults and b the extensional domain of the apennines and the calabria region which is often manifest through the activity of seismogenic normal and normal oblique faults in case a the general geomorphic and subsurficial evidence of recent activity suggests that a reverse blind fault or a blind thrust should be considered active and potentially capable if showing evidence of activity during the quaternary i e over the last 2 6 myr unless information is available that documents its inactivity since at least the last glacial maximum lgm ca 20 ka the choice of the lgm period as the minimum age necessary to define fault inactivity is related to practical aspects the diffusion of the lgm deposits and landforms and to the evidence that ca 20 kyr to assess fault inactivity precautionarily includes a number of seismic cycles in the extensional domains of the apennines and calabria region the general geological setting suggests that the present tectonic regime has been active since the beginning of the middle pleistocene therefore we propose that a normal fault in the italian extensional domain should be considered active and capable if it displays evidence of activation in the last 0 8 myr unless it is sealed by deposits or landforms not younger than the lgm the choice of the lgm as the minimum age to ascertain fault inactivity follows the same criteria described for the compressive tectonic domain

regional state of stress and characteristic fault kinematics instabilities shown by aftershock sequences the aftershock sequences of the 1978 thessaloniki greece and 1980 campania lucania italia earthquakes as examples abstract usual analysis of fault kinematics in terms of stress supposes that the slip occurs in the direction of the shear stress resolved on the fault plane due to an homogeneous state of stress however as a block moves this yields perturbations of the static stress conditions the resulting displacement may produce interactions of blocks and may induce complex fault motions such as those demonstrated by the aftershock sequences of the thessaloniki and campania lucania earthquakes each of which shows a main group of focal mechanisms whose normal fault motions are modelled using a stress deviator tm in agreement both with the motion of the main seismic fault and with the regional stress pattern deduced from quarternary and recent faults it is therefore considered as representative of the mean state of stress acting in the epicentral area but two other families of fault motions are also demonstrated one shows reverse motions explained by a compressional stress deviator tc the other involving normal motions is explained by a tensional stress deviator te these deviators are not representative of the mean regional state of stress the compressional 1 axis of tc and the tensional 3 axis of te are roughly orthogonal to the 3 axis of the mean state of stress tm these tc and te deviators may be deduced from the mean state of stress tm by adding respectively td1 and td2 deviators to this latter this means that on each fault plane having a reverse c or a normal e motion this motion may be deduced from the normal kinematics m it should have occurred in the mean regional state of stress tm by adding local pushes d1 and d2 respectively the deviator td2 being nearly axisymmetric around a vertical 3 axis the local reverse pushes d1 are nearly dip slip and td2 having a high angle dipping 2 axis the local pushes d2 are essentially strike slip approximated solutions of these td1 and td2 deviators have been calculated by taking tm td1 tc and tm td2 te the mean state of stress tm being divided into two parts tv and ts which respectively produce the dip slip and essentially strike slip components of the stress resolved on the fault plane a first approximation of the data shows that td1 kv tv and td2 ks ts with kv and ks equal to 2 this approximation supposes that tm tc and te are coaxial and that td1 and td2 are respectively axisymmetric around the vertical 3 axis and planar in the horizontal plane actually the data give kv 2 and ks in the order of 4 5 it is suggested that the local reverse and strike slip pushes are induced by the reaction of the rocky body surrounding small blocks moving as a consequence of a motion on a major fault particularly as there are incompatibilities of motion of adjacent small blocks however data are not sufficient to demonstrate the mechanical and geometric conditions which control the observed different behaviors of the small seismic faults numerical simulations or experiments could probably precise these conditions whatever under certain conditions the stable solution m is replaced by kinematics instabilities e and c however it is usually observed that faults studied in the field in a simple way often yield a single stress deviator this is probably due to the nature of the measured striations which are often growth fibers and oblique stylolithes resulting from creep fault motions in this case incompatibilities of block motions are probably accommodated by a pressure dissolution phenomena therefore it is suggested that the bifurcation parameter which controls the occurrence of the characteristic instabilities possibly depends on a ratio of the deformation rate versus the pressure dissolution rate of the material a question remains unanswered are these instabilities scale invariant or is there a changeover in the behavior between minor and major faults

first evidence of post seismic deformation in the central mediterranean crustal viscoelastic relaxation in the area of the 1980 irpinia earthquake southern italy summary comparison between measured vertical displacements obtained from two levelling campaigns performed in 1981 and 1985 in the epicentral area of the 1980 irpinia earthquake ms 6 9 and predictions from viscoelastic earth models reveal the occurrence of post seismic deformation due to stress relaxation in the ductile part of the crust two regions of broad uplift and subsidence accumulated during the time interval characterize the deformation pattern in the footwall and hangingwall of the major fault the spatial wavelength of the deformation pattern favours relaxation occurring in the lower crust rather than in a weak upper mantle the uplift in the footwall explains the 30 mm of upwarping of the crust measured along the levelling line crossing the area where the fault pierces the earth s surface

source parameters of the cache valley logan utah earthquake of 30 august 1962 abstract the cache valley utah earthquake of 30 august 1962 m s 5 7 has been reexamined our revised focal mechanism with dip 43 strike 193 and rake 101 confirms oblique normal faulting with nodal planes striking approximately north and south this mechanism is based mainly on polarities from records at u s air force lrsm stations which are a valuable scientific resource inversion of long period teleseismic body waveforms indicates centroid focal depth 10 km and seismic moment 3 1 10 24 dyne cm 0 31 10 18 nm corresponding to m w 5 6 the cache valley like other north south trending extensional features in the epicentral region is bounded on its east side by a major active normal fault the east cache fault which has several km of neogene throw however our revised source coordinates for the cache valley earthquake indicate it occurred too far east to have involved slip on this fault its hypocenter was near a downdip projection of the subparallel temple ridge fault a less prominent feature with only 500 m of neogene throw oriented subparallel to the west dipping nodal plane of our focal mechanism we suggest that this fault is continuous and approximately planar between 10 km depth and the earth9s surface with 40 dip and moved in the cache valley earthquake with a component of right lateral strike slip with slip vector azimuth n 65 w

seismotectonics of the calabrian arc abstract relocation of intermediate and deep earthquakes of tyrrhenian sea area through joint hypocenter determination for the period 1962 1979 has allowed a more detailed definition of the geometry of this peculiar benioff zone earthquakes dip along a quasi vertical plane to 250 km depth there is a 50 dip in the 250 340 km depth range and a low dip angle to 480 km depth the structure sketched from the hypocenters is almost continuous but most energy has been released in the 230 340 km depth interval an evaluation of fault plane solutions of intermediate earthquakes in this area indicates predominance of down dip compressions in the central part of the slab at the border strike slip motion occurs independent of depth some earthquakes that occurred at intermediate depth less than 100 km along the ionian margin of calabria show predominance of reverse faulting with the p axis oriented se nw however shallow earthquakes in the calabria sicily region indicate a more complex motion with predominance of normal faulting a possible interpretation of these features according to the available geological history which involves subduction of continental lithosphere is discussed

irpinia italy 1980 earthquake waveform modelling of strong motion data summary several strong motion records of the irpinia southern italy 1980 earthquake have been modelled for a total time duration of about 180 s with the use of the rnultimode summation of waves of p sv and sh type if waveform modelling is applied to unfiltered accelerations the best that can be done at present is amplitude envelope matching in time and frequency domain the early phase of the studied event can be synthesized by 12 main episodes of different sizes modelling the rupturing process the space time distribution of such episodes suggests that the rupturing process did propagate in a bilateral fashion this model of the seismic source gives rise to synthetic velocity records which match quite well the experimental ones to avoid the problems connected with the large instability of displacements obtained from direct numerical integration of observed accelerograms the synthetic signals can be first used to perform acceleration or velocity fitting of experimental data an estimate of the ground displacement above 1 hz can then be obtained by analytical integration of the synthetic velocities

stress pattern at campi flegrei from focal mechanisms of the 1982 1984 earthquakes southern italy abstract campi flegrei is a holocene volcanic area in the campanian plain southern italy within the apennine chain a neogenic thrust belt built up since the middle miocene the volcanic complex consists of a c 12 km diameter caldera containing several monogenetic volcanoes the youngest of which monte nuovo erupted in 1538 since at least roman times the area has also been affected by slow vertical movements bradiseismic activity between 1982 and 1985 this slow motion was interrupted by a period of more rapid displacement which caused a maximum uplift of 180 cm in the town of pozzuoli to model the local stress field associated with the uplift the angelier inversion technique has been applied using the focal mechanisms of forty nine earthquakes which occurred between april 1982 and december 1984 the results show that doming coupled with a regional extensional strain can account for the seismic phenomena that affected the area

integrated near surface geophysics across the active mount marzano fault system southern italy seismogenic hints here we describe an original geophysical multi method approach applied to the mount marzano fault system this is one of the most hazardous seismogenic faults of the apennines irpinia southern italy and it was responsible for the 1980 mw 6 9 earthquake along with many others before we carried out electrical resistivity tomography ert ground penetrating radar gpr measurements and horizontal to vertical spectral ratio hvsr microtremor analysis along several common transects designed across the potential and or certain fault traces the data obtained from these non invasive inexpensive expeditious methods mutually integrate with and complement each other providing a valuable subsurface image of the near surface fault architecture ert depicts the general shallow image of the fault zone and of the fault controlled sedimentary basin with the depth of the buried bedrock cross correlated through ambient noise hvsr results gpr delineates the very shallow geometry of the fault and of the associated deformation coupled with previous paleoseismological studies these data allow the evaluation of some fault parameters and the precise locating of the fault trace to aid future paleoseismological investigations aimed at seismic risk reduction programs

the constantine northeast algeria earthquake of october 27 1985 surface ruptures and aftershock study abstract an earthquake of magnitude m s 6 0 csem strasbourg occurred at constantine algeria on 27 october 1985 this seismic event is the strongest felt in the tellian atlas since the el asnam seismic crisis of october 10 1980 a team from the centre de recherche d astronomie d astrophysique et de geophysique craag algeria utilising 8 portable stations registered the activity a few days after the main shock the aftershocks follow a n045 direction and show the existence of three ruptured segments cross sections display a remarkable vertical fault plane and suggest asperities in the rupture process surface breaks were found affecting quaternary deposits the principal segment is about 3 8 km long showing enechelon cracks with left lateral displacement while the main direction of the rupture is n055 although the vertical motion is small the northwestern block shows a normal component of the main surface faulting while the left lateral displacement is about 10 cm the strike slip focal mechanism solution determined from the global seismic network and field observations are in good agreement

geomorphic evidence of quaternary tectonics within an underlap fault zone of southern apennines italy abstract a composite seismic source the irpinia agri valley fault zone located in the axial sector of the fold and thrust belt of southern apennines italy is investigated this composite source is made up of a series of nearly parallel nw striking normal fault segments which caused many historical earthquakes two of these fault segments known as the san gregorio magno and pergola melandro and the fault related mountain fronts form a wedge shaped right stepping underlap fault zone this work is aimed at documenting tectonic geomorphology and geology of this underlap fault zone the goal is to decipher the evidence of surface topographic interaction between two bounding fault segments and their related mountain fronts in particular computation of geomorphic indices such as mountain front sinuosity s mf water divide sinuosity s wd asymmetry factor af drainage basin elongation b s relief ratio r h hypsometry hi normalized steepness k sn and concavity is integrated with geomorphological analysis the geological mapping and structural analysis in order to assess the recent activity of the fault scarp sets recognized within the underlap zone results are consistent with the nw striking faults as those showing the most recent tectonic activity as also suggested by presence of related slope deposits younger than 38 ka the results of this work therefore show how the integration of a multidisciplinary approach that combines geomorphology morphometry and structural analyses may be key to solving tectonic geomorphology issues in a complex fold and thrust belt configuration

comment on the southern italy earthquake of 23 november 1980 an unusual pattern of faulting by r s crosson m martini r scarpa and s c key

the campania lucania southern italy earthquake of 23 november 1980 abstract we present the main seismological results of our study of the campania lucania earthquake of 23 november 1980 a complete set of far field and local data has been analysed from long period body waves data we determine the fault plane solution 1 140 1 60 2 75 2 54 a depth of 15 km and calculate a seismic moment of 6 1025 dyne cm and a source duration of 6 s from data of a local network deployed immediately after the event we determine aftershock locations they are aligned in a direction nw se that fit extremely well with the focal solution determined above we can choose as fault plane the plane striking 140 and dipping at 60 and the event is a normal event with a large component of left lateral strike slip the source area evaluated from this aftershock distribution 14 km 40 km is quite suitable for an earthquake of a seismic moment of 6 1025 dyne cm

surface rupture of the 1857 southern italian earthquake in october 1862 robert mallet published an extensive study of a large earthquake that occurred on 16 december 1857 150 km south east of naples this event is one of the most destructive ever recorded in italy although continental earthquakes of similar size are almost invariably associated with surface faulting mallet did not identify any surface rupture and subsequent workers have also failed to find surface traces using satellite images and aerial photographs as a guide we examined two prominent quaternary normal fault systems in the field flanking the val d agri and the val di diano both trend nw se and dip to the sw the distribution of damage suggests that one or both moved in 1857 on one fault segment in val d agri we found a 2 5 m high scarp whose youthfulness and height suggest it is due to the 1857 earthquake comparison of the observed slip with rates derived from geomorphic evidence suggests a recurrence time for 1857 type events of about 3000 years while the new data we provide are consistent with the event having a magnitude of ms 7 0 there are also grounds for supposing it might have been bigger

faulting geometry for the complex 1980 campania lucania earthquake from levelling data summary the destructive 1980 campania lucania earthquake was a complex event consisting of at least three subevents while the main features of the first 0 s and of the last 40 s subevents are widely accepted the second subevent 20 s is still controversial fault geometries are here determined from levelling data using a global minimization technique even if uplifts of southernmost benchmarks the most sensitive to the 20 s subevent are small new proper statistical analysis allows us to draw a few robust conclusions our results agree with previously accepted models as regards the 0 and 40 s subevents as regards the 20 s subevent previous models always assumed a northeast dipping fault while levelling data show that it could have been equivalently caused by a rupture dipping either southwest or northeast the statistical significance of the two models is about the same and strike and dip of the two faults are consistent with the two focal planes previously obtained from teleseismic data aftershock distribution seems to favour the southwest dipping fault model

seismic and ground deformation monitoring in the seismogenetic region of the southern apennines italy abstract the 23 november 1980 magnitude m s 6 9 southern italy earthquake has been associated by crosson et al 1986 with a faulting system consisting predominantly of two high angle sub perpendicular normal faults forming the corner of down dropped crustal block this model was inferred from a detailed analysis of the space time distribution of aftershocks and their focal mechanisms some features of the acceleration field the focal mechanism of the main shock and the observed displacements along two leveling profiles quantitative modelling of ground displacements which amounted to up to 70 cm was performed through a forward analysis with a dislocation source consisting of several fault segments and by inverse methods with a priori information allowing the parameters of a multiple rectangular fault system to be retrieved quantitative modeling of vertical displacements observed in a nearby seismic region showed a similar mechanism with coseismic movements of up to 12 cm which are consistent with uniform dislocation on two rectangular faults coinciding with the focal mechanism location and magnitude of the earthquakes which occurred in august 1962 m s 5 7 6 1 and 5 4 a system for monitoring ground displacements and related seismic activities has been in place since 1982 in this region and has recently been improved on the basis of our knowledge of the seismic source mechanisms the aim is to study the stress regime during interseismic phases to gain a better understanding of the physics of earthquake processes and to discover any patterns in earthquake occurrences in the seismogenetic regions of the apennines

detailed study of the potentino seismic zone in the southern apennines italy abstract most relevant macroseismic and instrumental data concerning past and current seismic activity of the potentino southern italy have been collected in order to study the seismic behaviour of this area ten among the most important recent and historical earthquakes occurred in the area from 1826 to 1990 have been studied by means of macroseismic methodologies macroseismic fields for all the events indicate a general isoseismal lengthening in the direction of the apennines chain northwest southeast a rapid attenuation of intensity westward of the studied area and a strong propagation eastwards this configuration is strongly dependent on the source mechanisms of the seismic events and the geological dishomogeneities of the concerned areas as regards earthquakes which have been instrumentally recorded in the campania basilicata area from 1980 to 1991 more than 1300 accurate hypocentral locations have been computed for events with m d 2 5 using data from osservatorio vesuviano o v and istituto nazionale di geofisica i n g seismic networks special emphasis is put on the potenza may 5 1990 earthquake m s 5 4 neic national earthquake information center i vii msk which was the strongest recent event in the area and was felt in a large sector of southern italy as regards the seismic sequence following this event about 110 aftershocks with m d 1 9 have been located very close to the town of potenza northeast of it with a clustering type space distribution the occurrence of the events is strongly time concentrated in so defining a main shock aftershocks typical sequence moreover the macroseismic investigation of the main event has allowed to map out isoseismal lines bounding vii vi v and iv msk areas the isoseismals pattern shows that attenuation and amplification of intensity are observed in the same areas as for the previous events beginning from may 26 1991 an increase of seismicity initiated by an earthquake of m l 4 7 neic and i vi vii msk was observed nearly in the same area as the 1990 sequence accurate locations of 84 events with m d 1 9 have been computed however this sequence seems to have a slightly different character from the 1990 one in that events are scattered in time and seismic energy release is comparable to a swarm type seismic sequence as regards the previous sequences fault plane solutions for the highest magnitude events and for appropriate groups of events have been worked out the mechanisms indicate normal faulting motion with t axes oriented orthogonal to the apenninic chain in conclusion detailed analyses on the historical and recent seismicity of the potentino area and adjacent ones have allowed to identify at least four seismogenic zones which show activity with different features such zoning represents a contribution to the seismic hazard assessment in the southern apennines on a regional scale

fault mechanism of the 40 seconds subevent of the 1980 irpinia southern italy earthquake from levelling data a model for the 40 s subevent of the 1980 irpinia earthquake is obtained from levelling data an inverse method has been used to compute fault parameters based on the computation of the probability density on strike and dip angles and midpoint fault location the highest probability model consists of a fault almost parallel to the one associated to the first subevent this fault dips about 80 sw forming a small graben like structure with the main fault fault strike and dip parameters appear well constrained by levelling data to within 10 at 95 confidence level it is noteworthy that seismological and accelerometric data were not able to well constrain the fracture mechanism of this subevent which was the most controversial one in literature crosson et al 1986 westaway 1987 crosson et al 1987 westaway and jackson 1987 bernard and zollo 1989

evolution of the late quaternary san gregorio magno tectono karstic basin southern italy inferred from geomorphological tephrostratigraphical and palaeoecological analyses tectonic implications the pantano di san gregorio magno is a 4 7 km 2 large tectono karstic basin located in the axial belt of the southern apennines an area affected by intense seismicity the basin was formed in the middle pleistocene and is presently undissected it is filled by lacustrine sediments clays silts and pyroclastic sands passing laterally into alluvial fan deposits geomorphological investigations were integrated with tephrostratigraphical palynological and palaeoecological analyses of a 61 m thick core not reaching the bedrock the multiproxy analysis of the s gregorio magno record shows that over the last 200k yr the basin hosted a freshwater lake with an oscillating level age constraints provided by the tephrostratigraphic record allowed estimation of the sedimentation rate which varied strongly through time evolution of the basin resulted from the complex combination of tectonic subsidence karst processes and changing amounts of sedimentary inputs the latter was influenced by allogenic contributions related both to primary and reworked volcanoclastic inputs and was climate driven the overall evidence which indicates that in the long term the accumulation rate substantially counterbalanced the accommodation space created by faulting suggests that the basin evolution was also modulated by changing subsidence rates copyright 2006 john wiley sons ltd

the geometrical evolution of normal fault systems abstract the purpose of this paper is to examine the kinematic behaviour of normal fault systems and see what general conditions govern their geometrical evolution we pay particular attention to seismological and surface data from regions of present day active normal faulting as the instantaneous three dimensional geometry at the time of fault movement is better known in active regions than in areas where the faults are now static most normal faults are concave upward or listric this shape can be produced by geometric constraints either because the faults reactivate curved thrusts or because they must be curved to accommodate rotations another effect which will produce curved faults is the variation of rheology with depth brittle failure at shallow depths produces less fault rotation than does distributed creep in the lower part of the crust an important geometric feature of normal faulting is the uplift of the footwall the amount of such uplift is related not only to the elastic properties of the lithosphere but also to the throw and dip of the fault a striking feature of active normal faults is that they occur in groups in which all the faults dip in the same direction this behaviour arises because the faults cannot intersect if they do one must cease to be active the rotation which such fault systems produce reduces the dip of the faults until a new steeply dipping fault is formed once a new fault cuts pre existing faults the earlier faults become locked and a new set of faults must propagate rapidly across the whole region involved many of these geometric constraints also apply to thrust faulting

new paleoseismic data from the irpinia fault a different seismogenic perspective for southern apennines italy abstract the irpinia fault i e mount marzano fault system mmfs was responsible for the devastating 1980 earthquake mw 6 9 that caused the longest surface faulting ever observed in italy 30 km early paleoseismological studies have revealed a 2 kyr recurrence time for 1980 like characteristic earthquakes on this fault system during the holocene however this appears to clash with both the catastrophic historical seismicity and high gps derived strain rate of the area to explain this apparent discrepancy we investigated the mmfs through a multidisciplinary approach first on the basis of recent archives and archaeological research we reassessed the historical seismicity of the area analysing the highest intensity distribution of the major earthquakes of the upper ofanto valley with respect to the mmfs hanging wall then we carried out a step by step survey along the entire 43 km long fault system through both high precision topographic levelling along the compound fault scarp and geostructural analyses finally we excavated trenches and pits across different fault segments to explore the recent paleoseismological history of the structure based on the combined results that we have obtained we propose a different point of view concerning the seismogenic behaviour of the mmfs from the holocene to the present at the end fault parameters have been compared with those of all the apennines active faults and cross checked with the newest gps results in peninsular italy providing some relevant observation of the relationships between seismogenesis and geodetic deformation

future trends in paleoseismology integrated study of the seismic landscape as a vital tool in seismic hazard analyses this paper forms the introduction to this special issue of tectonophysics devoted to selected scientific research presented during events sponsored by the inqua subcommission on paleoseismicity in the past few years in this note we summarize the contents of the contributed papers and use the issues they raise to review the state of the art in paleoseismology from a quaternary geology perspective in our opinion the evolution of paleoseismological studies in the past decade clearly demonstrates that in order to properly understand the seismic potential of a region and to assess the associated hazards broad based multidisciplinary studies are necessary to take full advantage from the geological evidence of past earthquakes a major challenge in future paleoseismic research is to build detailed empirical relations between various categories of coseismic effects in the natural environment and earthquake magnitude intensity these relations should be compiled in a way that is fully representative of the wide variety of natural environments on earth in terms of climatic settings quaternary tectonic evolution rheological parameters of the seismogenic crust and stress environment for instance available data indicate that between earthquake magnitude and surface faulting parameters different scaling laws exist and they are a function of the local geodynamic setting including style of faulting typical focal depths heat flow in this regard we discuss in some detail the concept of seismic landscape which provides the necessary background for developing paleoseismological research strategies the large amount of paleoseismological data collected in recent years shows that each earthquake source creates a signature on the geology and the geomorphology of an area that is unequivocally related with the order of magnitude of its earthquake potential this signature is defined as the seismic landscape of the area e g serva l vittori e ferreli l michetti a m 1997 geology and seismic hazard in grellet b mohammadioun b hays w eds proceedings of the second france united states workshop on earthquake hazard assessment in intraplate regions central and eastern united states and western europe october 16 1995 nice france 20 24 ouest editions nantes france michetti a m hancock p l 1997 paleoseismology understanding past earthquakes using quaternary geology

use of long period surface waves for rapid determination of earthquake source parameters 2 preliminary determination of source mechanisms of large earthquakes ms 6 5 in 1980 an inversion method for fast retrieval of earthquake source parameters developed earlier has been applied to 28 large m s 6 5 shallow earthquakes which occurred in 1980 rayleigh waves recorded by the ida international deployment of accelerographs network were used for the analysis for very shallow events the inversion is ill conditioned and two of the moment tensor elements m zx and m zy are unresolvable of the 28 events a solution is obtained for 25 with the constraints m zx m zy 0 although these constraints limit the solution to be either vertical strike slip or 45 dip slip the method provides a useful first approximation to the mechanism solution for deeper events all of the elements of the moment tensor can be determined after the seismograms have been retrieved the solution can be obtained in 10 min for most events the method would be adequate for preliminary cataloging purposes

seismic imaging of a fluid storage in the actively extending apennine mountain belt southern italy a picture of the upper crustal structure of the irpinia active faults system in southern italy was obtained by combining new geological evidences lithological properties and microseismicity distribution p and s wave velocity models indicate high vp vs and low vp vs values suggesting fluid accumulation within a 15 km wide rock volume where intense microseismicity is located the 1980 irpinia ms 6 9 earthquake nucleated within the same fault bounded volume we suggest that concentration of background seismicity is mainly controlled by high pore fluid pressure its increase in fluid filled cracks around major faults leads to earthquakes nucleation seismic pumping along major faults carries fluids through the conduit system represented by the intensely fractured damage zone conversely the cross fault barrier behavior of the low permeability fault core leads to pore fluid pressures building up within the fault bounded block thus producing a positive feedback triggering earthquake nucleation within the volume which behaves as an earthquake reservoir

the southern italy earthquake of 23 november 1980 an unusual pattern of faulting abstract a complex rupture history for the 23 november 1980 magnitude 6 9 italian earthquake resulted in an unusual pattern of two high angle subperpendicular normal faults forming the corner of a down dropped crustal block evidence for this interpretation is from aftershocks the pattern of strong ground motion focal mechanism of the mainshock and two critically placed leveling profiles quantitative modeling of leveling profiles using smoothly varying dislocation segments provides confirmation of the fault pattern and specific verification of the existence of a secondary fault which is suborthogonal to the primary fault rupture began on the nw trending main fault with downward motion of the northeast block about 40 sec after initial motion began rupture initiated on an orthogonal ne trending subsidiary fault propagating away from the main fault this fault pattern is consistent with tectonic extension in a northeasterly direction

late quaternary faulting within the southern apennines seismic belt new data from mt marzano area southern italy abstract an integrated geomorphological and geophysical investigation was performed in order to reconstruct the pliocene quaternary geomorphologic evolution and recent tectonics of mt marzano massif southern apennines italy the study area belongs to a region of high seismic energy release the last event being the strong ms 6 9 1980 irpinia earthquake most of the main faults of the area ceased their activity before development of the late pliocene age palaeosurfaces widely spread over the massif beginning in the lower part of the middle pleistocene strong extensional tectonics took place in the southern portion of the massif wnw trending faults created the buccino and s gregorio magno depressions which underwent subsidence until the holocene according to abundant morphostructural evidence during the late quaternary the n150 trending mt valva mt carpineta fault and the n110 100 trending mt ogna fault previously sealed by pliocene palaeosurfaces also were re activated morphostructural data were integrated with a high resolution seismic survey across the piano di pecore basin which is dammed by a fault that slipped 70 cm during the 1980 earthquake this fault produced no more than 50 60 m of throw during quaternary times most probably starting from 100 to 150 kyr bp

the database of individual seismogenic sources diss version 3 summarizing 20 years of research on italy s earthquake geology abstract this paper describes the main characteristics the evolution and the structure of the database of individual seismogenic sources diss and particularly of its release of early 2007 the database contains the results of the investigations of the active tectonics in italy during the past 20 years the first two sections of this paper document the recent evolution in mapping and archiving italian active fault data in relation to important achievements in the understanding of italian tectonics some of which were spurred by significant earthquakes the central sections describe the current structure of the database the reasons for its assumptions and data categories its current contents its evolution through several years of improvements the last section describes how the current contents of the database correspond with the existing strain and stress data available from focal mechanism borehole breakout and gps data for the whole of italy the database supplies a fresh and unified view of active and seismogenic processes in italy by building on basic physical constraints concerning rates of crustal deformation on the continuity of deformation belts and on the spatial relationships between adjacent faults both at the surface and at depth

the rupture process of the 1980 irpinia italy earthquake from the inversion of strong motion waveforms abstract the distribution of slip and the behaviour of rupture propagation during the 23rd november 1980 irpinia earthquake ms 6 9 was investigated by analysing strong motion accelerograms the rupture was assumed to develop on a two dimensional purely normal fault whose geometry was constrained by geologic and geodetic data and by the aftershock space distribution theoretical seismograms have been computed using the isochron approach with a spatially variable slip intensity the asymptotic ray theory is used to evaluate the far field green functions the rupture model was updated following a trial and error approach the fit of observed waveforms with synthetic seismograms allowed several peculiarities in the rupture history to be pointed out the source model resulting from the solution of the forward waveform modelling was then used as starting model for the inversion of ground velocities therefore we performed a linearized inversion for slip velocity and rupture times on the fault by iteratively perturbing the assumed starting model the inverse problem is solved by means of a tomographic back projection technique the inferred source model shows a bilateral rupture which does not propagate uniformly away from the hypocentre the rupture velocity and the slip distribution on the fault plane are rather variable the solution confirms the shallow dislocation gap in the central part of the fault suggested by the behaviour of the surface rupture the results indicate that the rupture propagated northwestward along a further fault fragment for which no surface evidence is observed the aftershocks occurred mostly inside of or near to the edges of the source areas of maximum co seismic slip

moment and duration of shallow earthquakes from love wave modelling for regional distances abstract love waves from five earthquakes in southwest germany italy yugoslavia greece and algeria as recorded at the broadband grafenberg array in eastern bavaria are modelled in detail using an extended reflectivity method the focal mechanisms are taken from the literature or determined from long period wwnss data the theoretical double couple moment function used for modelling increases smoothly during the risetime t from zero to the seismic moment m0 t and m0 are determined by matching the observed and theoretical love wave seismograms in the long period wwnss frequency band t is approximately equal to the rupture duration values from 1 4 to 20 s are found seismic moments generally agree within a factor of about two with those found by other authors from larger data sets the earthquakes in southwest germany and greece were simple events and can be modelled very well by one double couple in the case of the other earthquakes the theoretical love wave seismograms are too short for these earthquakes there is some independent evidence for a multiple event nature this evidence is condensed into source models consisting of two or three double couples representing separate and complete sub earthquakes which then explain the observations quite well in the case of the algerian earthquake the long love wave duration may also be due to complications in structure along the wavepath across the mediterranean and the alps the present results show that accurate love wave modelling for a single station at regional distance from an epicentre is a reliable method for estimation of seismic moment and rupture duration use of a digitally recording station with large dynamic range allows events over a large magnitude interval to be studied the grafenberg array is well suited for such an investigation of european and north african earthquakes

the irpinia italy 1980 earthquake detailed analysis of a complex normal faulting a detailed analysis of near source strong motion and leveling data together with the results of teleseismic waveform modeling by westaway and jackson 1987 and aftershock studies by deschamps and king 1984 allows a satisfactory kinematic description of the complex normal faulting associated with the magnitude ms 6 9 november 23 1980 irpinia earthquake southern italy the three main rupture episodes starting at about 0 20 and 40 s are here associated with better constrained source parameters than in previous studies we first evaluated the triggering time for the 11 closest accelerometers by using the well recorded 40 s strong motion phases this gave the absolute time and location of the dominant episodes of faulting the first rupture propagated mainly toward the northwest on a ne dipping normal fault at a mean velocity close to 3 km s for about 20 km and continued 15 km further on smaller subfaults it was associated with surface breakage in the southeastern part the second rupture started from the southeastern end of the first rupture about 18 s after it and propagated about 20 km toward the southeast on a low angle normal fault dipping 20 ne it was associated with secondary faulting on steeper planes reaching the surface the third and last episode at 39 s nucleated near the first hypocenter at shallower depth and the rupture possibly propagated on a 10 to 15 km long normal fault striking se antithetic to the first activated fault a clear correlation appears between the strength of the geological formations and the existence of surface breakage and shallow aftershock activity

block rotation in western turkey 1 observational evidence western turkey is a region of rapid continental extension where extension rate increasing westward causes counterclockwise vertical vorticity and hence counterclockwise rotation around vertical axes on a regional scale field observations and seismicity of the past century are used to deduce positions and slip senses of major active oblique normal faults in this region which take up extension in the upper crustal brittle layer and allow fault bounded blocks to rotate around vertical axes the principal active normal faults in western turkey strike roughly east west near the aegean coast turning gradually toward westnorthwest eastsoutheast strike across 200 km distance inland to the east slip vector azimuths indicate typical extension direction on these faults is s18 8w they truncate a second set of faults with smaller displacement and roughly orthogonal strike and slip vector azimuth as well as subdividing the brittle layer into blocks that show little internal deformation some major oblique normal faults subdivide it into domains that show different neogene rotation around vertical axes some domains contain sets of major active oblique normal faults that bound blocks that are elongated angular and shaped like tilted dominoes these faults take up extension and can also take up rotation around vertical axes provided they and the blocks between them rotate around vertical axes at the same rate where adequate paleomagnetic observations are available they indicate these domains have rotated counterclockwise as expected by up to 40 roughly equal to the change in strike of the principal set of active faults between the aegean coast and the eastern edge of the actively extending zone however evidence is scarce for the right lateral strike slip expected in some kinematic models on a set of oblique normal faults that takes up extension and counterclockwise rotation instead each fault appears to have the component of strike slip necessary to enable it given its local strike to slip in ue direction in which the region is extending two domains that have rotated clockwise are approximately circular in plan view with diameter 90 km and are bounded by faults with variable orientation each comprises a single block with no internal major active faults

identification of ordovician block tilting in the hercynian fold belt of central brittany france field evidence and computer models abstract the significance of the brioverian lower ordovician unconformity in central brittany has been discussed by many authors a new interpretation in terms of extensional tectonics is presented based on structural sedimentological and stratigraphical data however because sedimentary formations have been strongly folded by hercynian deformation extensional structures are obscured and difficult to recognize to identify the normal faults the geological map is compared with computer models of the folded tilted blocks it is shown that major normal faults had a mean n70 trend dipping toward the se with an almost regular spacing of 7 8 km

source complexity of the 1980 southern italian earthquake from the analysis of strong motion s wave polarization strong motion records from 23 november 1980 earthquake in irpinia basilicata southern italy recorded less than 59 km to the source show strong s wave phases coherent up to 10 hz at more distant stations the signal is only coherent up to 5 hz even when recordings contain signal up to 10 hz hodogram plots of the coherent signal in the 5 to 10 hz range show lissajous figures of sh and sv waves radiated by the nearest point with strong seismic radiation by the terminations of the rupture or by other relatively compact features the largest acceleration recorded at the sturno station is due to high frequency pulses radiated by a source south of the station and 25 km from the epicenter hodogram plots of low frequencies show polarizations due to the propagation of the large scale rupture along the fault lissajous figures help to discriminate p and s arrivals and reveal their direction of propagation on the basis of this kind of analysis it is confirmed that the 1980 irpinia basilicata earthquake ml 6 5 was composed of three main sub events at 0 sec 19 sec and 39 sec in relative time the first and second events broke the same structure striking nw there is also evidence of bilateral propagation the third event broke a second smaller structure also striking nw and placed very close to the alignment of the previous ones

twenty years of paleoseismology in italy abstract italy has one of the most complete and historically extensive seismic catalogues in the world due to a unique and uninterrupted flow of written sources that have narrated its seismic history since about the end of the iron age seismic hazard studies have therefore always been mainly based upon this huge mass of data nevertheless the italian catalogue probably lacks many m 6 5 events the seismogenetic structures responsible for which are characterized by recurrence times that are longer than the time span covered by our historical sources for these reasons and as in other countries earthquake data that in italy have been derived from paleoseismological studies should finally become a necessary ingredient in seismic risk assessment indeed over the past 20 years some hundred trenches have been excavated supplying reliable and conclusive data on the recent activities of many faults through to many robust datings of surface fault events these studies have provided the ages of several unknown or poorly known m 6 5 earthquakes here we summarize the state of the art of paleoseismology in italy and present a first catalogue of 56 paleoearthquakes pci that occurred mainly in the past 6 kyr the pci integrates the historical instrumental seismic catalogue and extends it beyond the recurrence time of the seismogenetic faults 2000 1000 yr we feel confident that the use of the pci will enhance future probabilistic seismic hazard assessment and thus contribute to more reliable seismic risk mitigation programs

different styles of deformation in the calabrian arc southern italy implications for a seismotectonic zoning abstract the most recent seismic profiles in southern italy show the existence of a sudden thinning of the crust at the boundary between the chain and the tyrrhenian margin the abrupt change in thickness can be followed along a zone which has the same geometry in plan as the calabrian arc by considering these data and the gravimetric anomalies it is possible to associate this crustal anomaly with a deep seated shear zone which determines a crustal shortening of about 40 60 km which can only be a consequence of post tortonian tectonics the surface equivalents of the deep seated shear zone can be recognized from north to south in the alignment of the intra apenninic basins vallo di diano san arcangelo potenza in the crati mesima graben and in the mount kumeta alcantara fault zone the distribution of the seismicity and its connection with the surface structures shows that the largest earthquakes occur along the deep shear zone in particular shocks with the highest magnitude and the longest recurrence intervals are located in those areas where the deep shear zone is at an angle of about 90 with the direction of maximum shortening crati mesima graben the fault zones nearly parallel to the regional compression axis e g mount kumeta alcantara fault zone are characterized by earthquakes of lower magnitude taking into account the neotectonic evolution of the regional structures as well as the orientation of the stress field and its connection with the deep seated shear zone it is possible to distinguish the following seismotectonic zones upper crati mesima graben transverse throughs mount pollino mount raparo fault zone external ionian area san arcangelo basin zone of the external flysch sicani mountains mount kumeta alcantara fault zone caltanissetta basin and iblean plateau bradanic trough murge ridge the definition of the geometry of the shear zone at depth is one of the most important but still unresolved problems

new constraints shed light on strike slip faulting beneath the southern apennines italy the 21 august 1962 irpinia multiple earthquake abstract on 21 august 1962 an earthquake sequence set off near the city of benevento in italy s southern apennines three earthquakes the largest having mw 6 1 struck virtually the same area in less than 40 min at 18 09 18 19 and 18 44 utc respectively several historical earthquakes hit this region and its seismic hazard is accordingly among the highest countrywide although poorly understood in the past the seismotectonics of this region can be revealed by the 1962 sequence being the only significant earthquake in the area for which modern seismograms are available we determine location magnitude and nodal planes of the first event 18 09 utc of the sequence the focal mechanism exhibits dominant strike slip rupture along a north dipping e w striking plane or along a west dipping n s striking plane either of these solutions is significantly different from the kinematics of the typical large earthquakes occurring along the crest of the southern apennines such as the 23 november 1980 irpinia earthquake mw 6 9 caused by predominant normal faulting along nw se striking planes the epicentre of the 21 august 1962 18 09 event is located immediately east of the chain axis near one of the three north dipping e w striking oblique slip sources thought to have caused one of the three main events of the december 1456 sequence io xi mcs the most destructive events in the southern apennines known to date we maintain that the 21 august 1962 18 09 earthquake occurred along the e w striking fault system responsible for the southernmost event of the 1456 sequence and for two smaller but instrumentally documented events that occurred on 6 may 1971 mw 5 0 and 27 september 2012 mw 4 6 further suggesting that normal faulting is not the dominant tectonic style in this portion of the italian peninsula

the tectonic geomorphology of bedrock scarps on active normal faults in the italian apennines mapped using combined ground penetrating radar and terrestrial laser scanning using combined datasets from ground penetrating radar gpr and terrestrial laser scanning tls we document the variety of tectono geomorphic features that contribute to the morphology of bedrock scarps associated with active extensional faulting in central italy measurement of faulted offsets across such scarps can provide important fault slip rate data relevant to seismic hazard analysis if ages can be established for offset features however interpretation of these offsets is challenging when geomorphic processes as well as fault slip contribute to exhumation of the bedrock during scarp development through the integration of surface tls and subsurface gpr datasets we show that the surface expression of three bedrock scarps results from the interaction between footwall incision hangingwall sedimentation channel incision and landsliding as well as fault slip and fault linkage we further illustrate how these processes can be differentiated to identify locations suitable for determining fault slip rates the identification of such features has important implications for our understanding of the relationship between bedrock faulting and geomorphic processes in turn contributing to improved assessment of fault slip rates in the central apennines the use of combined gpr and tls datasets here has shown that the tectono geomorphic features of the studied scarps vary greatly over short distances and we emphasise the need for detailed scarp analysis to elucidate the processes responsible for bedrock exhumation before estimating the rates of fault slip over the timescale of scarp formation

environmental effects from five historical earthquakes in southern apennines italy and macroseismic intensity assessment contribution to inqua eee scale project abstract this paper aims at substantiating the basic postulate of the recent earthquake environmental effects eee scale proposed by the international union for quaternary research inqua that primary and secondary environmental effects of earthquakes provide invaluable information on the earthquake size and intensity field complementing but also independently testing the results of the traditional damage based macroseismic scales the eee scale is applied to five disastrous earthquakes which occurred in southern italy since the end of the xvii century for each considered earthquake the available macroseismic data have been reviewed and integrated through an updated interpretation of the original texts the cataloguing and analysis of the seismically induced environmental effects has provided a a more detailed picture of the macroseismic fields b the chance to test the scaling of the eee scale with the mcs and msk macroseismic scales confirming its good fit with the msk mm c i0 estimates based on eee scale in good agreement with i0 assessments derived from mcs msk scales d further constrains for the new version of the eee scale e useful data for seismic zonation these results have confirmed once more the essential role of eees in the process of seismic hazard assessment and risk reduction

a combined approach using naa and petrography to examine ceramic production and exchange in the american southwest abstract over the past few decades ceramic provenance research has seen the increased use of both chemical and mineralogical analyses however the success of each method is dependent both on the geological environment and the behavioral processes that created the pottery under study the combination of bulk chemical and petrographic datasets may assist in overcoming the shortcomings of each method and improve the assignment of ceramics to specific production locations our research uses a mixed mode approach based on dissimilarity matrices and multidimensional scaling the resulting combined dataset helps us assess the geographic extent of production and distribution of maverick mountain series and roosevelt red ware pottery found in the upper gila and mimbres valleys of southwestern new mexico and southeastern arizona these pottery types have been connected to northern migrants arriving in these areas during the 13th century ad and subsequent regional scale social changes this research provides a case study in the advantages of using complementary analytical techniques and combining their results to answer behavioral questions

surface faulting in the southern italian campania basilicata earthquake of 23 november 1980 the campania basilicata earthquake of 23 november 1980 was the largest ms 6 9 and most destructive earthquake that has occurred in this region of southern italy for over 100 years killing more than 3 000 people the consensus among seismologists geologists and earthquake engineers who have studied1 10 this event is in keeping with previous italian earthquakes that it did not produce faulting at the surface this has led to the establishment of a number of models2 3 11 13 requiring an unusual tectonic setting for the southern apennines however on a recent visit to the epicentral region of the earthquake may 1984 we discovered more than 10 km of surface faulting that is consistent with focal mechanisms for this event based on first motion polarities2 4 5 12 and long period waveform studies14 16 which show that it involved normal faulting with one nodal plane dipping at 60 towards the north east our observations of this the first well documented earthquake fault break to be reported in italy suggest that the deformation associated with earthquakes in the southern apennines takes place in the upper 10 15 km of the earth s crust on steep planar normal faults which break the surface as is widely observed in other areas of active extension outside italy

determination of magnitudes of ancient earthquakes from dimensions of observed seismodislocations abstract equations to estimate the magnitude of ancient earthquakes where seismotectonic crustal deformations normal faults strike slip faults etc have been preserved in the epicentral region are presented the equations are based on the results of over one hundred earthquakes including 96 recent continental earthquakes in the magnitude range 5 2 8 7

active oblique extension in the central apennines italy evidence from the fucino region the fucino basin is a flat quaternary depression within the central apennines it is surrounded by active normal faults with small oblique slip components surface faulting was observed along the east side of the basin during the ms 7 0 avezzano earthquake of 1915 in order to understand the kinematics of recent strain better and to assess the seismic hazard of this region we carried out a detailed geomorphic and structural study of the faults around the basin fault scarp heights were accurately measured with total station profiles and vertical slip rates were estimated assuming slope offsets to post date the end of periglacial abrasion 14 4 kyr bp to the north the most prominent fault the magnola fault appears to have an average postglacial throw rate of 0 7 0 3 mm yr 1 and together with the velino fault to be capable of generating earthquakes of maximum magnitudes of 6 9 7 3 with recurrence intervals of 1000 3000 yr east of the basin the serrone parasano and ventrino faults form a right stepping horsetail of the giovenco fault current vertical slip rates on the three former faults appear to be between 0 5 and 1 4 0 5 and 1 0 and 0 3 and 1 1 mm yr 1 respectively infrequent maximum magnitude earthquakes on them may also exceed 7 particularly in the case of coupled rupture with loosely constrained recurrence intervals up to several thousand years the right lateral slip components implied by the most recent slickensides and by geomorphic offsets on the nw se trending normal faults of the area suggest that the blocks they bound rotate counterclockwise consistent with oblique left slip on the nnw sse trending giovenco and ovindoli faults to the east sinistral shear parallel to the latter faults the maximum relief across the magnola fault and the postglacial slope offsets measured suggest that the extension rate across the central apennines might be of the order of 6 3 mm yr 1 in a n20 10 e direction more northerly than hitherto inferred

present day kinematics of the plate boundary zone between africa and europe from the azores to the aegean anticlockwise rotation of africa relative to europe around an euler pole in the eastern atlantic causes plate convergence in the central mediterranean towards n20 w at rate considered a priori to be 5 10 mm yr 1 however previous summaries of the present day deformation sense in the central mediterranean are inconsistent with observations in southern italy recent investigations of italy and adjacent parts of north africa enable local deformation sense observed to be reconciled with sense predicted from relative plate motions suggested angular velocity of the african plate relative to europe is 0 07 myr 1 around a pole near 21 n 21 w this predicts 2 6 mm yr 1 maximum extension rate towards n64 e near the azores consistent with the minimum local accretion of new oceanic crust in the past few millions of years and 4 3 mm yr 1 plate convergence towards n20 w in the central mediterranean at 13 e further east the northern margin of the african plate can be regarded as the gargano seismic zone in the central adriatic sea the northern adriatic sea is a microplate rotating anticlockwise relative to europe at 0 3 myr 1 around a pole in northwestern italy causing northeastward shortening in yugoslavia and up to 4 mm yr 1 extension in central and northern italy the african plate is deforming internally in tunisia and northern libya extending obliquely in direction e10 s at rate up to 5 5 mm yr 1 the resultant velocity relative to europe in the ionian and southern adriatic seas 5 mm yr 1 towards n50 e explains the observed relative velocity across southern italy kinematic consistency requires present day shortening rate east of calabria associated with subduction on the tyrrhenian sea benioff zone and tyrrhenian sea extension rate to be both zero or equal to within 1 mm yr 1

earthquake fingerprints along fault scarps a case study of the irpinia 1980 earthquake fault southern apennines abstract fault scarps affecting post lgm last glacial maximum slopes are usually seen as an indication of active tectonics even if they can barely provide analytical data concerning single coseismic fault rupture offset amount and age or significant clues on the seismogenetic behaviour of the causative structure moreover because of the mediterranean climate and of the extensive thousand year long human reworking of the italian landscape i e the imprint of human development overrides the geomorphological signal young fault scarps are poorly preserved in the apennines nonetheless along the active mount marzano fault system southern italy favourable circumstances have allowed the associated multiple scarp to be partly protected by erosive processes and to retain some idiosyncratic features that have resulted in a reliable tool for reconstructing the rupture history of the fault firstly we have identified through topographic levelling across different sectors of this fault scarp several clusters of inflection points then by comparing this succession of consecutive clusters with 1 the historical seismicity of the area and 2 the paleoseismological data that were recently acquired along some key fault segments we offer a new point of view concerning the present slip rate and recurrence time for mw 6 5 earthquakes caused by one of the most hazardous normal faults of the mediterranean region e g mw 6 9 1980 earthquake we are confident that the method applied here would be useful in several similar tectonic and climatic contexts worldwide enriching our knowledge on the seismic hazard of densely inhabited regions

paleoseismicity of the ovindoli pezza fault central apennines italy a history including a large previously unrecorded earthquake in the middle ages 860 1300 a d geomorphic and trenching investigations along the ovindoli pezza fault show that this normal fault is one of the major seismogenic faults in the central apennines we found clear geological evidence for three holocene surface faulting earthquakes on this fault the most recent earthquake occurred in the middle ages between 860 and 1300 a d the penultimate occurred about 1900 b c or shortly after and the oldest probably occurred between 3300 and 5000 b c although the most recent surface faulting earthquake occurred during historical time no evidence for it have been found in the historical record slip per event ranges between 2 and 3 m and the length of the rupture is at least 12 20 km suggesting m 6 5 7 0 for the paleoearthquakes the dip slip rate determined from trenching is 0 7 1 2 mm yr and is consistent with the long term slip rate of 0 9 2 5 mm yr lower values preferred obtained from displaced geomorphic features trench data combined with long term slip rate estimates suggest the recurrence interval is longer than a millennium and possibly as long as 3300 years the time elapsed since the most recent earthquake is 700 1130 years the seismic behavior of the ovindoli pezza fault is consistent with other well known seismogenic faults of the central and southern apennines the lack of mention or mislocation of the most recent event on the ovindoli pezza fault in the historical record of the past two millennia should be attributed mainly to the unsettled cultural and social conditions and poor economic state that characterized the middle ages especially in thinly populated regions such as the central apennines this example highlights an intrinsic limit of the historical data and raises the possibility that other regions considered seismically quiet on the basis of a long historical record may in reality have had large earthquakes that were not recorded

late quaternary tectonics of the vallo di diano basin southern apennines italy italian ministry of university and research project firb research and development of new technologies for protection and defence of territory from natural risks w p c3 crustal imaging in italy

abruzzo italy earthquakes of april 2009 heterogeneous fault slip models and stress transfer from accurate inversion of envisat insar data abstract the seismic sequence that occurred in the abruzzo apennines near l aquila italy in april 2009 caused extensive damage and a large number of casualties more than 300 the earthquake struck an area in the italian apennines chain where several faults belonging to adjacent seismotectonic domains create a complex tectonic regime resulting from the interaction among regional stress buildup local stress changes caused by individual earthquakes and viscous elastic stress relaxation understanding such complex interaction in the apennines can lead to a large step forward in the seismic risk mitigation in italy the abruzzo earthquake has been very well recorded by interferometric synthetic aperture radar insar data much better than the first italian earthquake ever recorded by satellites namely the 1997 umbria marche earthquake envisat environmental satellite data for the abruzzo earthquake are in fact very clear and allow an accurate reconstruction of the faulting mechanism we present here an accurate inversion of vertical deformation data obtained by envisat images aimed to give a detailed reconstruction of the fault geometry and slip distribution the resulting fault models are then used to compute by a suitable theoretical model based on the elastic dislocation theory the stress changes induced on the neighboring faults the correlation of the subsequent mainshocks and aftershocks of the abruzzo sequence with the volumes undergoing increasing coulomb stress clearly evidence the triggering effect of coseismic stress changes on further seismicity moreover this analysis put in evidence which seismotectonic domains have been more heavily charged by stress released by the abruzzo mainshocks the most important faults significantly charged by the abruzzo sequence belong to the sulmona and avezzano tectonic domains taking into account the average regional stress buildup in the area the positive coulomb stress changes caused by this earthquake can be seen as anticipating the next earthquakes in the neighboring domains of 15 20 yr