geodynamic implications of earthquake data in the southern tyrrhenian sea abstract data from short period seismic stations operating in calabria sicily and the aeolian islands have been used to investigate earthquake properties of the southern tyrrhenian lithosphere the results have been analyzed taking into account other geophysical and geological information available in the literature for the same region with the main purpose of contributing to the definition of local geodynamic processes space distribution and focal mechanisms of earthquakes support the hypothesis of southeastward migration of the southern tyrrhenian lithosphere shared by several authors in their tectonic modelling of the area we find that most seismicity appears to be related to two main faults crossing the aeolian island archipelago sisifo and vulcano and propose that these faults are important dislocation structures associated with the lithosphere migration process we also give a detailed picture of the seismic behaviour of the above mentioned fault systems by analyzing the earthquake depth distribution focal mechanisms seismic clustering and strain release some degree of activity was also detected at the eastern boundary of the southern tyrrhenian area calabrian arc in particular our results demonstrate that in this highly stressed zone of contact between different tectonic units tyrrhenian and ionian basins strain is released under seismic form up to depths of the order of 25 km in the crust and not just in the shallowest structures as proposed by other authors

the results of the taormina 2006 seismic survey possible implications for active tectonics in the messina straits abstract the straits of messina and its surroundings are considered as one of the most tectonically active area of the mediterranean but in spite of their hazard potential modern geophysical data aimed at investigating their hidden structures are lacking in order to bridge this gap we carried out a marine multichannel seismic survey primarily aimed at i studying the regional fault pattern in the area of the messina 1908 earthquake and ii checking the existence of a potentially seismogenic fault the taormina fault which many authors locate offshore along the coast between taormina and messina our seismic profiles show a great structural complexity within the messina straits with the best imaged faults occurring on the calabrian side in particular a more than 30 km long nw trending fault located at the sw tip of calabria is cutting the sea floor moreover our data did not image any extensional fault plane attributable to the taormina fault rather the whole slope has been tilted east ward the geodynamic implication is that extension in south eastern sicily on the ionian side of the hyblean plateau and extension in southern calabria and messina straits belong to two different tectonic systems and cannot be mechanically linked

modelling coseismic displacements during the 1997 umbria marche earthquake central italy summary we propose a dislocation model for the two normal faulting earthquakes that struckthe central apennines umbria marche italy on 1997 september 26 at 00 33 mw 5 7 and 09 40 gmt mw 6 0 we t coseismic horizontal and vertical displacements resulting from gps measurements at several monuments of the igmi istituto geogra co militare italiano by means of a dislocation model in an elastic homogeneous isotropic half space our best tting model consists of two normal faults whose mechanisms and seismic moments have been taken from cmt solutions it is consistent with other seismological and geophysical observations the rst fault which is 6 km long and 7 km wide ruptured during the 00 33 event with a unilateral rupture towards the se and an average slip of 27 cm the second fault is 12 km long and 10 km wide and ruptured during the 09 40 event with a nearly unilateral rupture towards the nw slip distribution on this second fault is non uniform and is concentrated in its se portion maximum slip is 65 cm where rupture initiated the 00 33 fault is deeper than the 09 40 one the top of the rst rupture is deeper than 1 7 km the top of the second is 0 6 km deep in order to interpret the observed epicentral subsidence we have also considered the contributions of two further moderate magnitude earthquakes that occurred on 1997 october 3 mw 5 2 and 6 mw 5 4 immediately before the gps survey and were located very close to the 09 40 event of september 26 we compare the pattern of vertical displacements resulting from our forward modelling of gps data with that derived from sar interferograms the t to sar data is very good con rming the reliability of the proposed dislocation model

recent crustal deformations and tectonics of the messina strait area summary the tectonics of the region at the convergence of the tyrrhenian and ionian basins is very complicated the seismicity is particularly interesting in the area 38 39 30 n 14 30 16 30 e where both deep events occur with compressive mechanism and crustal events with predominant normal faulting in excess of magnitude 7 0 the tectonic origin of this apparently contradictory behaviour can be traced to a remanent downgoing slab in the southern tyrrhenian basin which is now inactive but is still undergoing considerable horizontal bending sedimentological studies suggest the bending to be accompanied by a marked uplift of calabira reaching its highest rates in the area of the strait of messina we performed a spirit levelling campaign in the strait and found that a differential uplift of the inner lands with respect to coastlines took place in the period 1970 82 the question regarding the possibilities of either an absolute uplift of inner lands or a subsidence of coastlines can only be resolved after detailed tidal studies the available tidal data seem to support the uplift hypothesis but they are substantially incomplete the apparent pattern of vertical deformations seems to be a marked steady uplift with episodic subsidence periods in connection with large normal faulting earthquakes furthermore our measurements and the results of a recently completed trilateration campaign tend to confirm the hypothesis of the existence of an angular graben in the strait and a southnorth right lateral slip of sicily with respect to calabria

contribution of structural analysis to understanding the geodynamic evolution of the calabrian arc southern italy abstract a marked curvature of crustal structures characterizes the calabrian arc in southern italy the overall deformation of the arc seems mostly controlled by the sangineto shear zone to the north and by the mt kumeta alcantara shear zone to the south which both separate different crustal sectors other important fault systems cut the iblean foreland scicli ragusa fault zone and many others dissect the crystalline units of central calabria neotectonic structural analyses have been carried out in order to recognize the character of the plio pleistocene tectonic phases and their bearing on the present configuration of the arc after the middle miocene extensional phase an early middle pliocene compressional phase is detectable in many parts of the arc right and left lateral displacements respectively characterize the mt kumeta alcantara and sangineto shear zones and right lateral movements are also detectable within the scicli ragusa fault system finally the pleistocene tensional regime seems to have been controlled mainly by uplift the structural and neotectonic data allow us to propose a model of the recent evolution of the arc which was bent mainly as a result of opposed wrench faulting along the sangineto and mt kumeta alcantara shear zones

cenomanian early turonian carbonate platform of northern oman stratigraphy and palaeo environments abstract the jebel akhdar and adam foothills outcrops in northern oman arabian peninsula offer the opportunity to study in detail the lateral and vertical changes of a cenomanian early turonian carbonate platform formed by the natih formation wasia group eleven sections with less than 5 km offset were logged to express metre scale lithological and biostratigraphical vertical changes the first rudist zonation is established complementing classical benthonic foraminifer and ammonite biozones typical cenomanian rudist association caprinids and radiolitids occur in the natih e c d a lower part whereas lower turonian hippuritid rudists are represented in the upper part of the natih a a sedimentological and palaeoecological approach leads to identification and interpretation the facies and discontinuities of the natih carbonate platform and to a reconstruction of its spatial organization application of the concepts of sequence stratigraphy allows interpretation of the units of the natih in terms of systems tracts an attempt is made to correlate the sequence stratigraphical model to eustatic sea level changes and regional tectonic events three palaeoenvironmental models taking into account bio and lithofacies are proposed

fault parameters in the messina strait southern italy and relations with the seismogenic source abstract the messina strait is characterized by strong deformations in pliocene and pleistocene times but considering the historical seismicity significant uncertainity exists as to whether any of the surface fault systems reflects the location geometry and mechanisms of the seismogenic source based on field data and structural analyses the parameters length l displacement d age of activity t minimum slip rate min and total geological moment m g have been derived for all the faults exposed on the sicilian and calabrian sides of the strait the analysis of these parameters shows that the highest rates of activity pertain to interconnected faults of different orientation and length which bound the uplifted crystalline basement relative to the pliocene pleistocene foundered zones of the calabrian side the comparison between the fault slip rates and the regional uplift rates shows that each single fault contributes for a limited fraction only to the whole deformation release in the area the contribution of the whole fault population expressed as cumulative m g release is still one order of magnitude less than the seismic moment release taking into account the underestimation of the geological parameters the lack of information on the offshore faults and the role of anelastic deformation by aseismic creep the data suggest that the long term recurrence of seismic breaks is partitioned at the surface in a complex array of interconnected faults some of these faults might represent basement inherited structures repeatedly and preferentially reactivated over geological time

the late cenomanian maximum flooding neolobites bioevent a case study from the cretaceous of northeast egypt abstract late cretaceous environmental changes are manifested in several bioevents which have been used as important tools for basin analysis sequence stratigraphic interpretation and global correlations one of these events is the hitherto poorly known late cenomanian neolobites bioevent the present study introduces the first detailed documentation for this bioevent from northeast egypt the neolobites bioevent consists of three limestone marly limestone couplets with autochthonous biogenic concentrations within the study area the bioevent displays a wide geographic distribution in sinai and the eastern desert with a thickness range from 8 to 4 5 m the neolobites bioevent is characterised by diagnostic faunal change condensed deposits and rich molluscan content in addition to abundant oysters cephalopods are present and are very commonly represented by the ammonite neolobites vibrayeanus lower upper cenomanian index of the bioevent and the nautiloid angulithes mermeti sequence stratigraphic analysis of the studied succession shows that the occurrence of the neolobites bioevent formed within late the transgressive to early highstand interval of a third order depositional sequence and not during a transgressive stage as previously described therefore the bioevent is considered here as a maximum flooding bioevent which commonly occurs in mixed siliciclastic carbonate systems palaeoecology and sedimentary facies of the bioevent indicate shallow marine conditions deep lagoon to shallow subtidal during a maximum rise of sea level interval with euhaline moderate water energy and well oxygenated stable sea floor sediments the marker ammonite neolobites vibrayeanus shows a wide palaeogeographic distribution in western tethys and north atlantic oceans the maximum flooding position of the neolobites bioevent provides a high potential for an excellent interbasinal correlation

implications of selected subsurface data on the structural form and evolution of some basins in the northern basin and range province nevada and utah

quantitative relations of seismic source parameters and a classification of earthquakes abstract relations between earthquake parameters moment m0 fault area s fault length l and width w stress drop time characteristics and magnitudes and faulting type dip slip ds and strike slip ss are quantitatively analyzed using a dataset of 240 events m 5 the analysis is carried further toward an earthquake systematization by introducing earthquake classes the results are 1 1 l w 2 1 for ds l w 2 30 for ss and l w 3 7 for giant m0 1029 dyne cm earthquakes respectively 2 2 log m0 1 5 log s 22 2 s in km2 and tentatively log m0 2 45 log s 17 49 for ds and ss and giant earthquakes respectively 3 3 the large scatter of data in m0 s dependences is the result of the combined effect of the variation in and l w 4 4 the concept of constant is replaced by variable to explain the large variations in relations between m0 s l and w for both ds and ss earthquakes and partly between body and surface wave magnitudes low intermediate and high stress drop gd 30 30 60 and 60 bar respectively earthquakes are defined 5 5 a relation of reciprocity exists between seismic slip fault length and width and stress drop 6 6 a saturation of s for some very large earthquakes is suggested from the interpretation of actual data on m0 s l w etc 7 7 the total source duration tsd increases with m0 in relation with earthquake type and tentatively log m0 2 16 log tsd 24 50 holds for ds earthquakes 8 8 log m0 1 5 mm 16 1 holds for mm brune engen mantle wave magnitude 8 5 8 75 9 9 more magnitudes of shorter or longer period on both body and surface wave basis are useful in constraining significant earthquake features 10 10 low and high frequency earthquakes can be distinguished using the gutenberg richter relation ms mb as a reference relation or a relation between ms and mmaxb 11 11 aki s similarity conditions are extended by adding two more conditions as to express more specifically four basic features geometry deformation frequency and time of the earthquake source 12 12 a reference earthquake is defined by criteria consistent with the similarity conditions 13 13 on this basis and in view of nonsimilarity of earthquakes in their totality a scheme for earthquake classification is proposed

seismic and landslide source of the 1908 straits of messina tsunami sicily italy 1 one hundred years ago december 1908 a devastating tsunami associated with an earthquake struck the straits of messina area causing many casualties on the basis of seismic data and observed runups and arrival times we suggest that the tsunami was likely generated by coseismic seafloor displacement coupled with a small submarine landslide triggered by the earthquake backwards ray tracing using a depth dependent velocity field submarine slope analysis and inferences form the main drainage network allowed us to identify possible locations for the source of the submarine landslide we then performed direct simulations of tsunamis generated by the earthquake and landslides and identified the tsunami source earthquake plus landslide that best fits observational data in a small volume submarine landslide 1 5 km3 located offshore nizza sicily

active faulting and seismicity along the siculo calabrian rift zone southern italy abstract southern italy is dominated by extensional tectonics that in the calabrian arc and eastern sicily produced the development of the siculo calabrian rift zone scrz this zone is represented by a 370 km long fault belt consisting of 10 to 50 km long distinct fault segments which extend both offshore and on land being also responsible of the crustal seismicity of this region the geological and morphological observations indicate that the active normal faults of the scrz are characterized by throw rates ranging from 0 7 to 3 1 mm a they accommodate an almost uniform horizontal extension rate of about 3 0 mm a along a wnw ese regional extension direction based on our field observations and following empirical relationships between magnitude and surface rupture length connections between large crustal earthquakes and distinct fault segments of the scrz have been also tentatively tested our data indicate moreover that the magnitudes m of the historical and instrumental earthquakes are consistent with the estimated values and that the geometry and kinematics of the fault segments and the related different crustal features of the scrz control the different seismic behaviours of adjacent portions of the active rift zone

the response of drainage basins to the late quaternary tectonics in the sicilian side of the messina strait ne sicily abstract geomorphological analyses allow the study of modifications that affect hydrographic basins particularly modifications due to active tectonics and the quantitative description of landforms the evaluation of geomorphic indices may be used to appraise the influence of active faults on the hydrographic network a geomorphological analysis was carried out on drainage basins of the northern portion of the sicilian side of the messina strait this strait separates southern calabria from sicily and has a nne ssw orientation in its southern part passing to a ene wsw trend at its northern part this area has been subjected to disastrous earthquakes during the last centuries and considerable uplift during the late quaternary as testified by the presence of uplifted marine terraces the study has revealed the recent activity of some of the fault systems recognized in this area and has allowed reconstruction of the evolution of the fluvial network which develops initially with a ese trending drainage direction 90 100 ky later shifting to the sse toward the present day coast line finally this portion of the messina strait is controlled by ene wsw trending normal faults and nnw sse oblique dextral faults which are responsible of the recent deformation and the consequent modification of the hydrographic network

three dimensional controls on subsidence of a foreland basin associated with a thrust belt recess black warrior basin alabama and mississippi tectonic transport from different directions and convergence of separate thrust belts at structural recesses impart three dimensional variations to the pattern of foreland basin subsidence assuming approximately uniform flexural rigidity of the lithosphere subsidence is directly controlled by the geometry and density of the separate thrust loads and flexural deformations caused by the loads interfere within the recess for example the black warrior foreland basin which is located in mississippi and alabama within a recess in the appalachian ouachita orogen formed in response to two separate thrust loads 1 the ouachita accretionary prism along the southwest side of the basin and 2 thrust imbricated passive margin rocks in the appalachian thrust belt along the southeast side of the basin the subsidence history differs along two profiles each perpendicular to the appalachian and ouachita thrust fronts subsidence of the foreland basin began in middle mississippian meramecian time in response to northeast directed translation of the ouachita accretionary prism subsequently northwest directed appalachian thrusting began in middle early pennsylvanian morrowan time subsidence curves from the profile perpendicular to the ouachita prism show a clear progression of increasing subsidence rates and amounts toward the thrust front whereas curves from the profile perpendicular to the appalachian belt indicate out of plane effects from the ouachita thrust front and a later increase in subsidence toward the appalachian thrust front the major implication of this work is that the three dimensional geometry of a foreland basin within a thrust belt recess includes diachronous interfering elements

new simulations and understanding of the 1908 messina tsunami for a dual seismic and deep submarine mass failure source abstract over 100 years after the event the mechanism of the 1908 messina tsunami remains unresolved the up to 12 m runups observed along the coasts of sicily and calabria cannot be explained by the coseismic tsunami so recent studies have proposed a dual earthquake submarine mass failure smf mechanism here we propose a new dual source and use it to simulate tsunami generation with a three dimensional non hydrostatic model coupled to a two dimensional fully nonlinear and dispersive model to simulate tsunami propagation to shore we first reanalyze observations of tsunami arrival times from eyewitnesses acquired shortly after the 1908 event and a tsunami record at a tide gauge in malta similar to earlier work this data is used to locate the likeliest tsunami source area by inverse wave ray tracing but accounting for frequency dispersion effects on wave celerity uncertainty in reported arrival times and a time delay between the eq and smf triggering analyzing the seafloor morphology in this area we identify a new smf at the foot of the fiumefreddo valley northeast of mount etna the general location is consistent with earlier studies however our smf is much smaller 2 km3 than e g that of billi et al 2008 and is a fairly rigid block slump rather than a translational smf we model the block motion and simulate tsunami generation from a dual eq smf source and its propagation to shore in higher resolution grids and based on more accurate bathymetry and topography than in earlier work runups and travel times agree well with observations except for runups on either side of the messina straits north of the smf which are still underpredicted in the far field simulations reproduce well the arrival time and initial wave amplitudes at the malta tide gauge our newly parameterized smf and modeling improve tsunami runups simulated near the smf location and south of it however as with all previous modeling of this event additional sources are required to explain runups in the northern messina straits which we suggest might be smaller and shallower smfs located in this area these will be considered in future work

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

coseismic displacements and creeping along the pernicana fault etna italy in the last 17 years a detailed study of a tectonic structure on a volcano abstract the pernicana fault is a tectonic fault located on mt etna sicily movements across this structure have been monitored over the last 17 years by a levelling network operated by the osservatorio vesuviano during the monitoring period the network has recorded coseismic displacements associated with earthquakes of magnitude 4 5 as well as aseismic displacements we present a detailed analysis of the displacement data aimed at modelling the geometry and mechanism of this fault as well as the size and mechanisms of individual earthquakes we use for interpreting the displacement data two types of inverse methods the first is able to determine from ground deformation data the geometry mechanism and location of a system rectangular faults with homogeneous dislocation the second finds for a fixed fault system geometry the heterogeneous slip distribution giving the best fit to the data the total recorded displacements during the last 17 years are well described by a single homogeneous rectangular normal fault with dislocation and size corresponding to a magnitude 5 7 earthquake thus revealing intense dynamics along such a fault coseismic displacements for individual earthquakes of considerable magnitude account for about 30 of the total deformation when interpreted in terms of an homogenous slip fault as inferred from total deformation some aspects of the data are not well explained thus calling for heterogeneous slip models it is hence possible with a certain approximation to distinguish the slip distributions associated with individual earthquakes from the almost homogeneous slip resulting from the sum of coseismic and aseismic movements the inferred seismic moments for the two larger earthquakes that occurred along this fault are considerable higher than reported in seismic bulletins about 1 degree of magnitude the results obtained here support the important role of levelling data for the detailed study of a peculiar kind of tectonic structure on a volcano aimed at understanding the complex interaction between volcano dynamics and induced movements along well defined structures

paleoseismology along the cittanova fault implications for seismotectonics and earthquake recurrence in calabria southern italy 1 this paper focuses on the seismogenic structure responsible for the 5 february 1783 earthquake m 7 calabria southern italy in particular the slip rate and recurrence time along the cittanova fault thus giving new insights on the seismic hazards and seismotectonics of the region the 1783 earthquake one of the strongest earthquake of the mediterranean area caused more than 30 000 casualties and radically changed the physiography of the local landscape until now the cittanova fault or aspromonte fault has been generally identified as the surficial expression of the seismogenetic structure even though its youthful activity has never been demonstrated recently the shortage of geologic evidence of middle upper pleistocene activity on this fault led some authors to locate the 1783 fault elsewhere in our study we used a multidisciplinary approach paleoseismology geomorphology historical seismology archaeoseismology our analysis of contemporary literary sources strengthened our interpretation of the coseismic origin of many geological features and sometimes oriented our field research toward specific areas in particular we excavated trenches and pits at three different sites along the trace of the cittanova fault for paleoseismological analysis and 14 c dating our data document the holocene and present activity of the cittanova fault providing a minimum vertical slip rate of 0 44 mm yr and a possible return time of 1350 1800 years for earthquakes similar to 1783 the penultimate event has been dated to the 4th century a d a time when southern calabria and eastern sicily were devastated by an earthquake documented by archaeoseismic analyses

comment on are the source models of the m 7 1 1908 messina straits earthquake reliable insights from a novel inversion and sensitivity analysis of levelling data by m aloisi v bruno f cannavo l ferranti m mattia c monaco and m palano

the use of scenarios to evaluate the tsunami impact in southern italy this paper outlines the main contributions to the definition and evaluation of tsunami hazard and risk resulting from studies undertaken in italy in recent years and emphasises that adopting characteristic cases or scenarios is a very useful and advantageous technique three main cases are given as valuable examples that is the 1627 gargano tsunami the 1693 eastern sicily tsunami and the 1908 messina straits tsunami since 1 they characterise three distinct tsunamigenic regions 2 they are instances of destructive events and 3 they have been extensively studied in the last decade the paper elucidates the state of the art of the research on these events clarifies the chief points of agreement and disagreement among scientists and illustrates the main issues that are to be addressed by future research to provide reliable assessment of tsunami risk and to implement efficient countermeasures to defend the life of people coastal structures and the coastal environment against the attacks of tsunamis

comment on does specialization imply rare fossil records of some benthic foraminifera late palaeocene examples from the eastern neo tethys meghalaya ne india by suman sarkar palaeogeography palaeoclimatology palaeoecology 514 2019 124 134 abstract sarkar 2019 does specialization imply rare fossil records of some benthic foraminifera late palaeocene examples from the eastern neo tethys meghalaya ne india palaeogeogr palaeoclimatol palaeoecol 514 124 134 uses the first occurrences of two large benthic foraminifera lbf namely haymanella paleocenica sirel and keramosphaera iranica rahaghi in the upper lower paleogene thanetian lakadong limestone of ne india for far reaching speculations on autecology and specialization as well as paleobiogeography and migration patterns in the central and eastern neotethyan realm note the authors requested post submission that all instances of paleocenica made in the abstract and introduction be altered to elongata we believe that the true occurrences of such taxa in late paleocene shallow water carbonates from ne india are not only speculative but irrelevant because they are based on incorrect identifications on the basis of such documentation sar19 claimed that the sparse occurrences of both species can be correlated to their specialist behavior sar19 also added a more specific interpretation of the paleoecology of h elongata and k iranica relating them to the upper and lower parts of the upper photic zone respectively this conclusion is in our point of view not supported by the data and also conflicts with a bulk of publications supporting the opinion that the autecology of lbf must be interpreted by means of comparative anatomy with recent counterparts along with taphonomy and a comprehensive facies analysis of the host carbonates we will show that the taxon identified by sar19 as keramosphaera iranica instead is assigned to the orduella spherica sirel whereas the identification of haymanella paleocenica elongata from ne india remains unverified we will also show how contrary to what is claimed by sar19 the paleoecological model proposed is not substantiated by data finally we will argue that in the paleocene and lower eocene of central and eastern neo tethys the identification of a biogeographic region must be regarded with a focus on the faunal exchanges established within the so called lockhartia sea

palinspastic restoration of the anniston transverse zone in the appalachian thrust belt alabama abstract transverse zones are cross strike alignments of cross strike linking structures lateral ramps transverse faults and displacement transfer zones in foreland thrust belts cross strike links constitute one component of a three dimensional system of fault surfaces connecting strike parallel structures frontal ramps and detachment flats both geometrically and kinematically three dimensional palinspastic restoration provides the basis to consider causes of cross strike alignments of cross strike links into transverse zones as well as the role of transverse zones in kinematic history the anniston transverse zone in the appalachian thrust belt in alabama southeastern united states exemplifies the types and distribution of cross strike links within a transverse zone palinspastic reconstruction of the anniston transverse zone relies on matching hanging wall footwall pairs of frontal and lateral ramps for geometric balance in three dimensions in palinspastic map and cross section views cross strike links within the anniston transverse zone are systematically distributed across strike from hinterland to foreland as domains of lateral ramps transverse faults and displacement transfer zones in response to variations in depth to basement beneath the thrust belt and variations in thickness of decollement host weak rocks contrasting structural profiles characterize the thrust belt on opposite sides of the anniston transverse zone as a result of abrupt along strike changes at the cross strike alignment of cross strike links the anniston transverse zone is aligned with a northwest striking basement fault that offsets the boundary faults of the birmingham basement graben suggesting kinematic partitioning within the advancing thrust sheets at a stress concentrator the northwest striking basement fault separates domains of contrasting structural profiles of basement fault systems differing elevations of top of basement and differing thicknesses of the regional decollement host weak layer in the lower part of the sedimentary succession above basement rocks

effect of crustal layering upon dislocation modeling slip distribution at depth on a fault may be inferred from the deformation observed on the surface in inverting the surface deformation data to obtain the slip distribution the earth is generally approximated by an elastic half space slip distributions inferred from a half space model may contain artifacts including zones of reversed slip due solely to effects of layering in the real earth this effect is demonstrated for a vertical strike slip fault in an earth consisting of an elastic layer overlying an elastic half space slip on the fault is taken to be independent of the along strike coordinate i e antiplane strain is assumed for a given slip distribution in this model the slip distribution on a similar fault in an elastic half space is found that produces the identical surface deformation comparison of the two slip distributions reveals structure introduced into the half space equivalent slip profile by crustal layering the comparisons suggest that low resolution inversion schemes e g single screw dislocation models are not drastically affected by earth structure but attempts at detailed inversion are likely to produce profiles contaminated by artifacts of earth structure

stepwise extinction of larger foraminifers at the cenomanian turonian boundary a shallow water perspective on nutrient fluctuations during oceanic anoxic event 2 bonarelli event a two step pattern in the extinction of larger foraminifers is recorded in the upper cenomanian shallow water carbonates of the southern apennines italy the first step eliminated the alveolinids the most extreme oligotrophs and reduced dramatically the diversity of larger foraminifers the second step wiped out the few survivors seemingly able to tolerate mesotrophic conditions leaving a disaster fauna dominated by small heterotrophs this pattern of extinction parallels the ecological succession of shallow water benthic foraminiferal assemblages along a gradient of increasing nutrient availability high resolution carbon isotope stratigraphy shows that the extinction of alveolinids was contemporaneous with the extinction of rotaliporid planktic foraminifers the drowning of certain tethyan carbonate platforms and an episode of thermal instability recorded in sea surface temperature in the open ocean ocean stratification during the first phase of oceanic anoxic event 2 would have promoted oligotrophic conditions in surface tropical waters and maximum diversity of larger foraminifers following this ocean overturning caused by surface water cooling is credited with delivering to shallow water environments the excess nutrient loads previously stored at depth triggering the environmental changes leading to stepwise extinction of larger foraminifers

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

source parameters of the 1908 messina straits italy earthquake from geodetic and seismic data 1 we carry out a nonlinear joint inversion of p wave first motion polarities and coseismic surface displacement data of the 1908 messina earthquake we model the earthquake using a single planar fault slip is at first assumed to be uniform across the whole fault then independent in a small set of coplanar subfaults and finally smoothly variable across the fault the first two steps are accomplished using a global minimization technique the main features of the retrieved model are very robust and independent of the seismic velocity profile of the presence of questionable bench marks and of the assumed residual distribution the along strike component of slip is about half the along dip component in agreement with the direction of the extensional stress axis retrieved from geological observations surface vertical displacement is consistent with tsunami data and with the morphology of the messina straits

tsunamigenic potential of a newly discovered active fault zone in the outer messina strait southern italy the 1908 messina tsunami was the most catastrophic tsunami hitting the coastline of southern italy in the younger past the source of this tsunami however is still heavily debated and both rupture along a fault and a slope failure have been postulated as potential origin of the tsunami here we report a newly discovered active fiumefreddo melito di porto salvo fault zone f mps fz which is located in the outer messina strait in a proposed landslide source area of the 1908 messina tsunami tsunami modeling showed that this fault zone would produce devastating tsunamis by assuming slip amounts of 5 m an assumed slip of up to 17 m could even generate a tsunami comparable to the 1908 messina tsunami but we do not consider the f mps fz as a source for the 1908 messina tsunami because its e w strike contradicts seismological observations of the 1908 messina earthquake future researches on the f mps fz however may contribute to the tsunami risk assessment in the messina strait

subduction zone geometry and stress patterns in the tyrrhenian sea joint hypocenter determination is performed for intermediate and deep earthquakes of the tyrrhenian sea region

the december 28 1908 messina straits southern italy earthquake waveform modeling of regional seismograms the 1908 messina straits earthquake is one of the most catastrophic events in history there were 60 000 to more than 100 000 deaths and the cities of messina and reggio calabria on the opposite sides of the straits were almost completely destroyed during the last decades only low magnitude events occurred in the area the 1908 earthquake is then crucial for understanding the mode of stress release in the area we collected and digitized several regional seismograms of this event recorded in central europe with the aim of studying the source characteristics in order to separate the path effects we analyzed recent events with simple and known sources owing to the small azimuth range spanned by the available stations we could not determine a fault plane solution for the messina straits event nor discriminate between the published focal mechanisms however the normal fault character of the rupture is confirmed by inverting the historical p waveforms we derived source time functions and obtained a seismic moment of 5 38 2 16 1019 n m mw 7 1 this is in good agreement with the results obtained by several authors from the inversion of the historical leveling data this value is confirmed by the sh wave modeling which also allowed the assessment of the unilateral northward character of the rupture propagation along an 43 km fault finally we applied a simple rupture model in order to derive the slip distribution along the fault the resulting function is in good correspondence with the geodetic inversions performed by boschi et al 1989 and de natale and pingue 1991 in particular a maximum slip of 4 m is located in proximity of the center of the slipped area the high dislocation patch beneath the messina harbor as depicted by de natale and pingue is not confirmed by our analysis and is probably connected to surface collapse of some of the bench marks

geodetic and seismologic evidence for slip variability along a blind normal fault in the umbria marche 1997 1998 earthquakes central italy summary we analysed elevation changes induced by the 1997 1998 umbria marche central apennines italy earthquakes we employed data from a first order geodetic levelling line measured in 1951 1992 and 1998 the line bears a record of pre seismic and coseismic strains associated with the causative fault of the 1997 september 26 09 40 mainshock mw 6 0 a first level analysis performed under the assumption of slip homogeneity of coseismic slip shows misfits that cannot be reduced simply by altering the fault size and geometry a more detailed analysis based on a distribution of coseismic slip obtained from broad band seismograms provides a better fit and is in agreement with 1951 1992 elevation changes interpreted as precursory slip by previous investigators the levelling data sets new constraints on the location extent dip and depth of the fault in full agreement with seismological evidence and images from sar interferometry the data show no evidence for slip in the uppermost 3 km of the crust suggesting that a major and widely recognized normal fault that exists in the area is no longer active and showing a tendency of present tectonic strains to revert the current topographic setting

a 125 kyr long geological record of seismic source repeatability the messina straits southern italy and the 1908 earthquake ms7 2 the occurrence of characteristic earthquakes along segments of major active belts has been described as early as the beginning of the century the large 1908 messina straits blind normal faulting earthquake provides an opportunity to investigate the repetition of characteristic earthquakes and the persistency of the main features of the fault zone over a time scale in the order of 100 kyr we have compared seismological and geodetic descriptions of the 1908 rupture process with long term crustal deformation recorded at different stratigraphic levels by marine terraces marine sedimentary units and landscape features the wealth of elevated coastal features in and around a region affected by large normal faulting earthquakes indicates that coseismic strain is superimposed on much faster uplift on a regional scale we investigated in detail the pattern of deformation of the 125 kyr old lowest emergent terrace and found that it mimics the pattern of elevation changes observed following the earthquake this suggests 1 that the 1908 earthquake is characteristic 2 that its segment boundaries have been stationary during the past 125 kyr and 3 that even the locations of the regions of largest coseismic release do not change through many seismic cycles based on a comparison between observed heights of the 125 kyr terrace and 1908 displacements we estimated an average repeat time of 1000 yr for a 1908 type earthquake we also investigated the height position age and state of deformation of older terraces and found 1 that uplift of the region started about 1 ma and has since continued rather uniformly at 0 9 1 4 mm yr 1 2 that during this time the straits have narrowed at a rate of 10 20 mm yr 1 and 3 that all the main geomorphic features of the messina straits result from the interaction of fast regional uplift 1908 type coseismic subsidence and global sea level fluctuations

acadian dextral transpression and synorogenic sedimentary successions in the appalachians the successive seboomook littleton northern appalachians and catskill pocono central appalachians clastic wedges suggest oblique convergence and southwestward migration of acadian orogeny beginning in early devonian and continuing into early mississippian wrench fault movement in maritime canada coincided with deposition of all but the earliest components of the catskill pocono clastic wedge and continued into the pennsylvanian contrasts between a thin lower to middle devonian shallow shelf facies in the alabama appalachian fold thrust belt and a time equivalent thick shallowing upward sedimentary to volcanic succession in the adjacent talladega slate belt are interpreted to reflect a wrench fault basin a wrench fault setting for devonian rocks in alabama integrated with manifestations of oblique convergence during the acadian orogeny in the central and northern appalachians can be accommodated in dextral transpression along the entire length of the acadian appalachian orogen

are the source models of the m 7 1 1908 messina straits earthquake reliable insights from a novel inversion and a sensitivity analysis of levelling data

role of the birmingham basement fault in thin skinned thrusting of the birmingham anticlinorium appalachian thrust belt in alabama the birmingham anticlinorium is a northeast striking northwest verging thrust related fold associated with the jones valley and opossum valley frontal thrust ramps in the southern appalachian thin skinned sedimentary thrust belt in alabama the amplitude of the southeastern trailing limb of the anticlinorium cahaba synclinorium is greater than that of the forelimb coalburg syncline the depth to the top of basement rocks beneath the decollement is greater beneath the cahaba synclinorium than beneath the coalburg syncline commensurate with vertical separation of the top of basement along the down to southeast birmingham basement fault at the northwest boundary of the birmingham basement graben the frontal ramp that controls the geometry of the birmingham anticlinorium rises northwestward over the down to southeast birmingham basement fault the geometry kinematics and mechanics of structure of the birmingham anticlinorium reflect stratigraphic variations in mechanical properties within the cambrian to pennsylvanian stratigraphic succession the stratigraphic variations record episodic synsedimentary movement on the birmingham basement fault the regional decollement at the birmingham anticlinorium is in the middle to lower upper cambrian conasauga formation which is dominantly a massive carbonate and less than 800 m thick northwest of the birmingham basement graben but is a succession of shale and thin bedded limestone more than 2 000 m thick within the graben ductile deformation of the thick shale dominated succession localized the palmerdale and bessemer mushwads ductile duplexes along strike beneath the birmingham anticlinorium the massive carbonate regional stiff layer the cambrian ordovician knox group forms the mushwad roof the upper part of the knox group was eroded as a consequence of inversion of the graben during flexural subsidence associated with taconic tectonic loading of the southeastern margin of laurentia small scale synsedimentary structures indicate minor structural reactivation from late ordovician through early mississippian thickness and facies variations in upper mississippian lower pennsylvanian synorogenic clastic wedge deposits document large scale reactivation of the down to southeast birmingham basement fault the birmingham basement fault localizes both the leading edge of the mushwads of shale dominated conasauga formation and frontal ramps of the regional decollement

sequence of deformation at the front of an orogen lublin basin case study poland abstract we provide a detailed description of a late carboniferous fold and thrust belt in the lublin basin based on seismic lines including new high resolution acquisitions and legacy borehole and gravimetric data a series of regional cross sections integrate results of the joint seismic borehole gravimetric interpretation cross section restoration provides estimates of the minimum incremental and total shortening and reveals its along strike variations the lublin basin straddles a leading edge of the variscan orogen and its undeformed foreland therefore it experienced only a minor deformation it preserves a fossilized record of early phases of shortening seismic scale divergent intra formational thrusts and folds in horizontal strata that were later passively rotated by subsequent folds developed above a regional decollement lateral variations of deformation styles from displacement of the entire basin with little internal deformation to dispersion of shortening by numerous contractional structures is attributed to along strike changes in lithology and thickness of the silurian detachment horizon lateral change of detachment strength is quantified using the critical wedge theory our observations deliver a new perspective on factors controlling the localization of incipient structures their differentiation as a function of detachment strength and interplay between folding and thrusting along a leading edge of an organic system

historical and pre historical tsunamis in the mediterranean and its connected seas geological signatures generation mechanisms and coastal impacts abstract the origin of tsunamis in the mediterranean region and its connected seas including the marmara sea the black sea and the sw iberian margin in the ne atlantic ocean is reviewed within the geological and seismotectonic settings of the region a variety of historical documentary sources combined with evidence from onshore and offshore geological signatures geomorphological imprints observations from selected coastal archeological sites as well as instrumental records eyewitnesses accounts and pictorial material clearly indicate that tsunami sources both seismic and non seismic e g volcanism landslides can be found in all the seas of the region with a variable tsunamigenic potential local regional and basin wide tsunamis have been documented an improved map of 22 main tsunamigenic zones and their relative potential for tsunami generation is presented from west to east the most important tsunamigenic zones are situated offshore sw iberia in the north algerian margin in the tyrrhenian calabria and messina straits in the western and eastern segments of the hellenic arc in the corinth gulf of central greece in the levantine sea offshore the dead sea transform fault and in the eastern side of the marmara sea important historical examples including destructive tsunamis associated with large earthquakes are presented the mean recurrence of strong tsunamis in the several basins varies greatly but the highest event frequency 1 96 years is observed in the east mediterranean basin for most of the historical events it is still unclear which was the causative seismic source and if the tsunami was caused by co seismic slip by earthquake triggered submarine landslides or by a combination of both mechanisms in pre historical times submarine volcanic eruptions i e caldera collapse massive pyroclastic flows volcanogenic landslides and large submarine landslides caused important tsunamis although little is known about their source mechanisms we conclude that further investigation of the tsunami generation mechanisms is of primary importance in the mediterranean region inputs from tsunami numerical modeling as well as from empirical discrimination criteria for characterizing tsunami sources have been proved particularly effective for recent well documented aseismic landslide tsunamis e g 1963 corinth gulf 1979 cote d azur 1999 izmit bay 2002 stromboli volcano since the tsunami generation mechanisms are controlled by a variety of factors and given that the knowledge of past tsunami activity is the cornerstone for undertaking tsunami risk mitigation action future interdisciplinary research efforts on past tsunamis are needed

recent deformations and the seismogenic source in the messina strait southern italy abstract the relationships between mechanisms and mode of faulting in pliocene and pleistocene times and seismic release are the basis for an interpretation of the growth of deformation energy in the messina strait the major fault systems trending in ne sw nw se and e w directions divide blocks subjected to high mobility in concurrence with greater uplifting of the calabrian side with respect to sicily across the two sides of the strait as revealed by structural analyses the tectonic features of the area are dominated by normal faulting many synsedimentary features seem to indicate repeated and intermittent pulses of high velocity fault slippage possibly related to seismic shaking when considering the seismic record it seems that the strongest shocks are generated by preferential strain accumulations along the nne ssw fault systems from a geological standpoint it seems clear that the largest events may be alternately related to either the nne ssw e w or nw se fault systems which dissect an extremely cataclastic upper crust the recent deformations of the messina strait can be related to the large scale processes induced by the overthrusting of the thinned tyrrhenian crust over the thickened african crust as suggested by seismic refraction profiles along the inner margin of the calabrian arc the deep deformation mechanisms are reflected by contrasting vertical movements between a stretched and downfaulted tyrrhenian domain and an uplifted chain with resulting large strain accumulations and seismic failure in the brittle upper crust

the interaction of tectonics climate and eustasy in controlling dolomitization a case study of cenomanian turonian shallow marine carbonates of the iberian basin

continental fault structure and the shallow earthquake source plate boundaries in continental crust are generally less sharply defined than in the oceans with seismicity spread over broad areas interplate displacements appear to be largely accommodated by networks of major fault zones a simple 2 level model for these important structures accounts for the depth distribution of most continental earthquakes and for the observed range of faulting styles and associated rock deformation textures the model consists of a seismogenic frictional slip regime overlying quasi plastic mylonite belts wherein shearing is largely accommodated aseismically due mainly to the changing response of quartz to deformation with increasing temperature shear resistance increases with depth to a peak value in the vicinity of the frictiona1 quasi plastic transition and then decreases rapidly the depth to which microseismic activity extends appears inversely related to regional heat flow and can be satisfactorily modelled as the frictional quasi plastic transition for different geotherms using laboratory determined flow laws for quartz bearing rocks larger earthquake ruptures m 5 5 tend to nucleate near the base of the seismogenic regime in the region inferred to have the highest shear resistance and concentration of distortional strain energy consideration is also given to the depression of isotherms and seismic activity in regions of thrusting and to the question of the downward continuation of major fault zones through the lithosphere decoupling of the upper crust on flat lying shear zones may accompany higher level dip slip and perhaps in some circumstances strike slip faulting being favoured by above average continental heat flow and a high quartz content in the middle or deep crust the average level of deviatoric stress within the seismogenic regime remains an outstanding problem

strontium isotopes age and tectonic setting of cambrian salinas along the rift and transform margins of the argentine precordillera and southern laurentia abstract the argentine precordillera generally is interpreted as a fragment of continental crust and sedimentary cover that was rifted from the ouachita embayment of southern laurentia in cambrian time synrift sedimentary successions in the northern part of the precordillera and in the birmingham graben of southern laurentia include thick evaporite deposits analyses of strontium isotopes indicate that the evaporites are of late early cambrian age consistent with biostratigraphic correlations variations in strontium ratios indicate that these early cambrian salinas had a persistent base of marine water and that contributions from meteoric runoff varied through time and with location the stratigraphic and isotopic data suggest a depositional setting of restricted circulation within a system of extensional fault blocks the salinas occupied graben blocks that were connected to marine circulation and that intermittently received meteoric runoff carrying fine detritus and radiogenic strontium from horst b

an elastic rebound model for normal fault earthquakes a viscoelastic finite element method is used to formulate an elastic rebound model for normal fault earthquake cycles model generated displacements correlate well with geodetic survey data collected before and after the 1954 m 7 1 fairview peak nevada and the 1959 m 7 1 hebgen lake montana earthquakes model coseismic deformation results in an uplift of the footwall block and a depression of the hanging wall block as has been reported by savage and hastie 1966 the interseismic phase of the deformation is characterized by a regional doming of the crust in the vicinity of the modeled normal faults doming observed before and after and adjacent to the faults which ruptured during the hebgen lake earthquake indicate that areas which are experiencing doming may be the future sites of normal fault earthquakes two areas which are presently experiencing crustal doming and are in the vicinity of a normal fault are the socorro new mexico and diablo plateau texas brown et al 1978 regions the interseismic doming will not occur if the modeled fault ruptures through the entire lithosphere if a single normal fault is active then model generated coseismic and interseismic deformations result in sum to a tilt block topography if two normal faults are active one master fault and a minor fault which dips toward the master fault then the resultant deformation is a horst and graben type of topography the rate at which the doming proceeds is primarily a function of the seismic stress drop and the effective viscosity of the asthenosphere doming rates following the hebgen lake earthquake indicate an asthenospheric viscosity of about 2 1021 p model recurrence intervals for the fairview peak and hebgen lake earthquakes are on the order of 103 yr

analysis of earthquake damage to ancient buildings on the san raineri peninsula messina sicily abstract a study aimed to shed some light on building collapse caused by the strongest earthquakes in the san raineri peninsula messina is here reported although a compilation of structurally damaged buildings is widely reported in historical sources the interpretation of seismic collapse has often been doubtful or ambiguous we therefore performed an exhaustive and detailed review of seismic effects caused by the 1783 and 1908 earthquakes on the peninsula buildings geological and geotechnical data were also collected on the peninsula the results of boring data reveal high seismic vulnerability for the peninsula in some areas the study shows that the ancient buildings were damaged by settlement due to soil liquefaction rather than by seismic shaking of the large walls the obtained results show that further investigations must be carried out in this area for a correct town planning of the peninsula

depositional model of a cenomanian turonian extensional basin sopeira basin ne spain interplay between tectonics eustasy and biological productivity abstract the sopeira basin is a small extensional basin with a continuous record of sedimentation from the late albian to the late turonian in its early stages late albian middle cenomanian it formed a half graben bounded to the south by a low angle normal fault during this time sedimentation was limited to the downfaulted block until the emerged footwall was flooded resulting in the deposition of shallow water limestones over a vast platform the platform was exposed during the middle late cenomanian by a relative sea level fall the sedimentation up to this point was controlled by local factors extensional tectonics and influenced by eustatic sea level change subsequently the entire area was flooded by the late cenomanian transgression during the cenomanian turonian boundary interval the basinal sedimentation was characterized by calcisphaerid limestones with black cherts and organic rich shales while on the platform a hiatus was produced these sedimentary features are interpreted as having been caused by global mechanisms changes in atmospheric co 2 and temperature along with an increased rate of precipitation that caused an intense primary productivity at the water surface in the basinal sea eutrophication led initially to an unusual development of calcisphaerids and later to the development of opportunistic planktonic foraminifera whereas in the platform it affected the life of carbonate producing organisms dramatically and sedimentation ceased eutrophication of marine water is thus interpreted to be the main cause of the extinction of k strategist foraminifera and associated fauna at the end of the cenomanian

tectonic eustatic and environmental controls on mid cretaceous carbonate platform deposition south central pyrenees spain cenomanian turonian strata of the south central pyrenees in northern spain contain three prograding carbonate sequences that record interactions among tectonics sea level environment and sediment fabric in controlling sequence development sequence uk 1 lower to upper cenomanian contains distinct lagoonal back margin margin slope and basin facies and was deposited on a broad flat shelf adjacent to a deep basin the lack of reef constructing organisms resulted in a gently dipping ramp morphology for the margin and slope sequence uk 2 upper cenomanian contains similar shallow water facies belts but syndepositional tectonic modification of the margin resulted in a steep slope and deposition of carbonate megabreccias sequence uk 3 lower to middle turonian records a shift from benthic to pelagic deposition as the shallow platform was drowned in response to a eustatic sea level rise coupled with increased organic productivity sequences uk 1 to uk 3 are subdivided into lowstand transgressive and highstand systems tracts based on stratal geometries and facies distribution patterns the same lithologies e g megabreccias commonly occur in more than one systems tract indicating that 1 the depositional system responded to more than just sea level fluctuations and 2 similar processes occurred during different times throughout sequence development these sequences illustrate the complexity of carbonate platform dynamics that influence sequence architecture rift tectonics and flexural subsidence played a major role in controlling the location of the platform margin maintaining a steep slope gradient through syndepositional faulting enhancing slope instability and erosion and influencing depositional processes stratal relationships and lithofacies distribution on the slope sea level variations eustatic and relative strongly influenced the timing of sequence and parasequence boundary formation controlled changes in accommodation and promoted platform drowning in conjunction with other factors physico chemical and climatic conditions were responsible for reducing carbonate production rates and inducing platform drowning finally a mud rich sediment fabric affected platform morphology growth geometries aggradation vs progradation and facies distribution patterns

organic geochemistry stable isotopes and facies analysis of the early aptian oae new records from spain western tethys abstract the early aptian oceanic anoxic event oae1a is a time interval characterized by increased organic carbon accumulation in marine sediments notable sedimentary and biotic changes and abrupt carbon isotope excursions indicative of significant major palaeoenvironmental changes linked to a perturbation in the global carbon cycle here we present the study of four sections recording the oae1a early aptian in spain which are located in two broad basins respectively located in the south and the north of iberia the southern iberian palaeomargin carbonero la frontera and cau sections and the basque cantabrian basin puentenansa section which represent depositional settings ranging from shallow marine distal ramp cau and drowned platform puentenansa to pelagic environments carbonero la frontera biomarker compositions c isotope profiles biostratigraphic data and facies analysis from the four sections are correlated and integrated the c isotope curves all present a clear negative excursion followed by a positive shift the integration of the c isotope curves with the biostratigraphic data has been used to correlate the studied sections and to tentatively identify the eight segments formerly proposed from the alpine domain and subsequently identified in sections worldwide four main groups of compounds are present in all sections n alkanes isoprenoids hopanes and steranes n alkanes and acyclic isoprenoids pristane and phytane are dominant in most samples the hopanes are represented by a range of c 27 to c 35 components with the specific isomers varying amongst the sections due to differences in thermal maturity steranes occur as a range of c 27 c 28 and c 29 isomers whereas diasteranes only occur in the most thermally mature section carbonero other compounds of interest include gammacerane and dinosterane differences in thermal maturity appear to be the first order control on different biomarker assemblages amongst the studied sections the carbonero section is thermally mature whereas the nearby la frontera and cau sections are immature puentenansa has intermediate values organic matter is derived from a range of terrestrial marine and bacterial sources the dominance of the c 29 sterane isomers in all sections suggests a strong contribution from higher plants the presence of gammacerane indicates water column stratification and high c 29 c 30 hopane ratios suggest anoxia at the water sediment interface respectively sedimentologic analysis also suggests anoxic conditions during sedimentation but evidence for strong and persistent water column anoxia is equivocal the correlation of the sections reveals that sedimentation of organic rich facies started earlier in pelagic and later in the shallow marine settings which can be related to an expansion of the favorable conditions for organic matter accumulation and preservation from deep marine waters to shallower platform environments during the development of oae1a

new insights on the messina 1908 seismic source from post seismic sea level change the identification of a source model for the catastrophic 1908 december 28 messina earthquake m w 7 2 has been the subject of many papers in the last decades several authors proposed different models on the basis of seismological macroseismic and geodetic data sets among these models remarkable differences exist with regard to almost all parameters we selected a subset of six models among those most cited in literature and used them to model the post seismic sea level variation recorded at the tide gauge station of messina until 1923 to attempt an independent discrimination among them for each model we assumed a simple rheological structure and carried out a direct search inversion of upper crust thickness and lower crust viscosity to fit the post seismic sea level signal this approach enabled us to identify a class of fault geometries which is consistent with the post seismic signal at the messina tide gauge and with the known structural and rheological features of the messina strait

evolution of the concept and structure of a mushwad abstract a mushwad forms as a result of bulk ductile deformation and large scale tectonic thickening of depositionally thick weak decollement host strata a mushwad has floor and roof thrusts like a conventional brittle duplex but the internal structure of a mushwad which includes disharmonic small scale folds and faults differs from the large scale imbricate horses in a conventional duplex the concept of mushwad structure has evolved as more subsurface data from deep drill holes and seismic reflection profiles have become available the formation of a mushwad requires an anomalously thick shale dominated succession at the level of the decollement and a structural buttress generally a basement fault to deflect the decollement upward in a frontal ramp tectonic thickening of the mushwad elevates and distorts the roof producing a complex antiformal structure that differs from conventional frontal thrust ramps

sequence stratigraphy of mixed carbonate siliciclastic platforms developed in a tectonically active setting upper cretaceous betic continental margin spain abstract the late cretaceous platforms in the betic continental margin record a prolonged interval 30 m y in which eustasy and tectonics operated simultaneously but with well differentiated frequencies this resulted in development of two types of unconformity bounded units sequence sets which are tectonically controlled and depositional sequences which are the result of variations in relative sea level unconformities bounding sequence sets are the result of tectonic episodes that induced great changes in basin geometry and basin subsidence they operated without apparent rhythmicity at intervals ranging from i to 12 m y regional tectonics was related to variations in the intraplate stress regime associated with 1 the mid atlantic spreading 2 the tectonic regime in the africa iberia boundary still poorly documented 3 the opening of the bay of biscay between the aptian and the early campanian and 4 the oblique convergence between iberia and europe in the pyrenees which started in the early campanian during periods of relative tectonic quiescence eustasy and subsidence controlled development of depositional sequences these resulted from relative sea level oscillations most of them interpreted as third order eustatic cycles however the correlation between our depositional sequences and the global cycles of the exxon chart is not always easy mainly because subsidence can mask or enhance the eustatic signal

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

mode of strain release of three graben associated earthquakes the nature of graben associated earthquakes has been investigated through a study of three earthquake sequences using various seismological geophysical and geological data the three earthquake sequences are the hsingtai china earthquakes maximum magnitude ms 7 2 of march 1966 the nevada earthquakes maximum m 7 1 of 1954 and the new madrid earthquakes maximum ms 8 8 of 1811 1812 these earthquake sequences represent a unique mode of strain release away from plate margins and have bearings on earthquake hazard evaluation a number of similarities have been observed during these earthquake sequences for instance all the three sequences are characterized by large multiple shocks or swarms which last from several weeks to several months among the large multiple shocks in each sequence the largest one usually is not the first one migrations of epicenters were observed during the hsingtai and the new madrid earthquakes significant amount of strike slip motion was associated or inferred with all these three sequences in particular for the hsingtai earthquakes the swarm of multiple shock activities is probably due to induced instability or strong coupling and interactions among a series of adjacent faults in a heterogeneous graben the strike slip motion can be explained by a change or a rotation of stress orientation after the formation of a graben the graben events are similar to the earthquake swarms associated with spreading oceanic ridges but with significant differences available data indicate that the recurrence intervals for the three graben earthquake sequences studied are of the order of thousands of years

a model for the 1908 messina straits italy earthquake by inversion of levelling data abstract the 28 december 1908 messina earthquake was a normal faulting event which produced considerable vertical displacements three levelling surveys having an overall extension of 125 km in calabria and sicily were performed by the igmi italian military geographical institute shortly before the occurrence of the main event and during the first months of 1909 vertical subsidence up to 70 cm was measured at bench marks located close of messina the inversion of the observed displacements has been performed by using a model consisting of uniform dislocation on one or more rectangular faults and the mathematical formalism developed by matsu9ura and hirata 1982 results indicate that the observed displacements are well modeled by a normal fault oriented about ns with a dislocation of 1 5 m dipping 39 e this fault is located beneath the messina straits with the upper end at 1 km depth and crossing to the city of messina this model gives a seismic moment m o 4 9 0 8 10 26 dyne cm and shows a good agreement with the fault plane solution derived from the long period p wave first arrivals

reconciling deep seismogenic and shallow active faults through analogue modelling the case of the messina straits southern italy abstract the catastrophic 28 december 1908 m w 7 1 messina straits earthquake was generated by a large low angle se dipping blind normal fault a number of shallow high angle normal faults arranged in a graben like fashion occur in the same area both on land and offshore reaching the surface and in some instances affecting recent deposits these faults are normally interpreted as active and have often been considered potentially seismogenic we used an analogue modelling approach to simulate the evolution of a large low angle normal fault and investigate its relationships with the overlying secondary faults we find that these faults represent the brittle surface expression of the long term activity of the underlying master fault and that all faults mapped by previous workers in the messina straits are compatible with sustained slip along the fault responsible for the 1908 earthquake our results confirm that analogue modelling provides a useful tool to investigate the evolution and the hierarchical relationships of fault systems suggesting that this approach is effective in the investigation of complex seismogenic areas

gigantic gaseous mushwads in cambrian shale conasauga formation southern appalachians usa giant duplexes called mushwads in the southern appalachian thrust belt are estimated to contain a natural gas resource base of about 17 7 tcm 625 tcf early development efforts in mushwads of the cambrian age conasauga formation encountered significant challenges and highlight the need for an integrated multidisciplinary approach to shale gas exploration to facilitate development of this gigantic resource an integrated geological analysis of stratigraphy sedimentation structural geology basin hydrodynamics petrology geochemistry gas storage and mobility and reservoir volumetrics was conducted the results of this analysis demonstrate the myriad geological factors that need to be considered when developing shale gas resources and suggest that the greatest reservoir potential lies deep in the mushwads where free gas is concentrated meeting the challenges posed by deformed shale masses in thrust belts is a major frontier for hydrocarbon exploration that could result in a major expansion of natural gas reserves

mushwad ductile duplex in the appalachian thrust belt in alabama structural style in thin skinned thrust belts is controlled substan tially by the stratigraphic succession and relative thicknesses of lith otectonic units stiff layers and weak layers in contrast to the rela tively predictable geometry of fault related folds fault bend folds fault propagation folds and detachment folds ductile deformation of a stratigraphically thick weak layer generates a ductile duplex that elevates and distorts the overlying stiff layer a ductile duplex is herein termed a mushwad malleable unctuous shale weak layer accretion in a ductile duplex in the appalachian thrust belt in alabama mushwads nucleated in a thick shale dominated suc cession of weak rocks in association with basement faults beneath the regional decollement the stiff layer roof is deformed by folds and faults and is elevated by tectonic accretion of weak rocks in a mushwad shortening within the mushwad may drive translation of the stiff layer from the roof over the foreland lateral termina tions range from plunge of the stiff layer roof over a laterally thin ning mushwad to a transverse fault the examples in the appala chian thrust belt suggest a style of structure that may be more common than presently recognized the structural geometry of a mushwad as well as the potential for concentration of fractures in the distorted stiff layer suggests important applications in petro leum exploration and reservoir development

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

aeromagnetic investigation of southern calabria and the messina straits italy tracking seismogenic sources of 1783 and 1908 earthquakes southern calabria and the ne corner of sicily italy were struck in 1783 and 1908 a d by two of the most catastrophic earthquakes ever in european history although it is generally acknowledged that the seisms were yielded by normal faults rupturing the upper crust of the calabria peloritani terrane no consensus exists on seismogenic source location and orientation here we report on a high resolution low altitude aeromagnetic survey of southern calabria and messina straits in southern calabria we document a broad weakly positive 5 10 nt anomaly zone interrupted by three en echelon sw ne null to negative magnetic anomaly corridors euler deconvolution and magnetic modeling show that the anomaly pattern is produced by a 1 1 5 km thick crustal layer located within 3 km depth this layer is offset by a 25 km long ne trending fault that corresponds to the armo normal fault recently inferred to be the source for the 1908 earthquake few kilometers to the south we also document a subparallel and previously unrecognized fault entering the messina straits and likely joining the armo fault at depth further east we model a 40 km long normal fault probably extending northeastward for additional 40 km running along the south calabria axis from aspromonte to the serre mountains and partly following the 18 km long surface rupture witnessed by deodat de dolomieu after the 1783 earthquake thus aeromagnetic data suggest that the sources of the 1783 and 1908 earthquakes are en echelon faults belonging to the same nw dipping normal fault system straddling the whole southern calabria

some seismological features from an analysis of the recent seismic activity in the messina strait an analysis of the recent seismic activity at the strait of messina during the last 30 yr made on the basis of collected observation data is reported for about 2 yr this activity has been better observed since a short period seismic network messina strait network msn has been installed on both sides of the strait the use of a compatible crustal model and of the hypostre program elaborated to determine the hypocentral parameters of local events gives results which can be correlated with the structural characteristics of the graben of the strait besides some elements arising from a previous seismological analysis made in the same area before the msn had been activated are confirmed in particular the existence of a microearthquake source having its epicenter situated a little south of messina is here reproposed furthermore the increase in the number of stations on both sides of the reveals that the absorption of the seismic energy propagating parallel to the graben structures is different from that observed when the energy travels orthogonally to them this fact together with the results obtained using hypostre for calculating the focal depth of some local events suggest the existence of an energy trap affecting the more superficial crustal layers this is correlated with the existence of the dynamic discontinuity of the strait

mid cenomanian separation of atlantic and tethyan domains in iberia by a land bridge the origin of larger foraminifera provinces abstract the middle and late cretaceous shallow water carbonate platforms widely exposed across the eastern half of the iberian peninsula including the betic cordillera the iberian ranges and the pyrenees provides an excellent material for analyzing the origin of two iberian late cretaceous larger foraminifera provinces the betic and the pyrenean the former corresponds to the tethyan domain the latter to the atlantic domain the spatiotemporal distribution in the three studied areas of the larger foraminifera k strategists the alveolinaceans from the latest albian cenomanian time interval suggests that separation of the two faunal provinces started during early cenomanian mid cretaceous global community maturation cycle and the shelves of the iberian seaway formed the boundaries of the corresponding bioprovinces this occurred before the betic pyrenean communication near the middle late cenomanian transition was interrupted by a land bridge therefore the separation of the two bioprovinces cannot be due to the physical barrier created by the opening or closure of the shallow seaway across the iberia here it is attributed to the differences in the ecological gradients at the end of the cenomanian the cenomanian turonian eutrophication event eliminated all the k strategist larger foraminifera to such a degree that all their essential k strategy information was lost the newly arising k strategist foraminifera needed a considerable time 8 10 m y to recover their lost genetic complexity this occurred during the coniacian in the following gcm cycle

kinematic evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic abstract we present an updated series of kinematic reconstructions of the major plates around the tethys from the atlantic ocean to the pamirs between the early jurassic and the present this set is used elsewhere as a basis for paleogeographic maps of the entire region the problems related to the positions of the continents in the lower triassic are also discussed no direct analyses of magnetic anomalies and fracture zones in the atlantic have been made rather all available poles and rotations have been tested in order to eliminate or minimize possible kinematic errors the reconstructions are shown for nine key geological periods which correspond to well recognized magnetic anomalies except for the jurassic cretaceous boundary and the cretaceous tertiary boundary which correspond to interpolated positions paleolatitudes have been drawn using the study of westphal et al 1986 an attempt has been made to take into account the displacements caused by formation of the continental margins and basins by stretching the resulting relative vector of motions along the northern boundary of the tethys shows a significant change 80 m y ago left lateral motion with compression dominates before whereas right lateral motion with compression dominates after to the east rates of motion vary by a factor of three with time and four maxima can be clearly related to tectonic events in the late jurassic late cretaceous eocene and post middle miocene to the west north of apulia on the contrary the motion rate has not changed significantly since the early cretaceous and is close to 1 cm yr as an average these rather complex adjustments in rates and directions of relative motion are produced in great part through a complex migration of the africa eurasia pole of rotation and seem to be mostly governed by the tectonics of the tethys plate boundary

inversion of source parameters from near and far field observations an application to the 1915 fucino earthquake central apennines italy we use a nonlinear inversion approach for determining source parameters of the fucino m s 6 9 earthquake that occurred along central apennines italy in 1915 taking into account both near field surface deformations and far field first motion polarities this event was one of the most destructive in italy this century causing over 30 000 casualties altitude and leveling measurements were performed before 1862 and after 1917 the event along a circular route consisting of 18 benchmarks polarities of first arrivals do not constrain a unique fault plane solution while the one obtained by inverting geodetic data with relevant constraints provided by neotectonic data disagrees with p wave polarities our joint inversion based on a robust fitting technique has resulted in only one well defined solution satisfying geophysical data as well as surface faulting distribution and paleoseismological information

high resolution morpho bathymetric imaging of the messina strait southern italy new insights on the 1908 earthquake and tsunami the 28 december 1908 reggio calabria and messina earthquake named after the two most damaged cities on the coasts of messina strait was one of the strongest mw 7 1 ever to occur in italy and was also followed by a tsunami that severely impacted the coasts of the strait although there is general agreement that its epicentre is located offshore in the messina strait the source fault has never been detected a century long question is therefore pending on the source of both the 1908 earthquake and tsunami within the ongoing debate on this subject little attention has been given so far to morphological insights from high resolution bathymetric multibeam data particularly as regarding the evidence of faults affecting the seafloor and the question of whether a submarine landslide may had been the cause of the tsunami we aim to address this issue by presenting the results of a morpho bathymetric study in the messina strait and surroundings investigated by means of high resolution swath bathymetry the primary morpho structural feature in this area is the axial channel of the messina canyon towards which flow several tributary canyons that incise the steep continental slope on the calabrian and sicilian margins these canyons carve deeply into a very narrow almost lacking continental shelf and merge laterally forming a continuous erosional margin rimming the messina strait this giant composite canyon environment is the locus of intense erosional and depositional processes that superimpose on active tectonic deformation resulting in a complex geomorphology that hinders the distinction between tectonic and sedimentary features seafloor ruptures that may be linked to fault systems compatible with the source of the 1908 earthquake and tsunami could not be identified based from our morpho bathymetric analysis however we provide evidence of several geomorphic features indicative of tectonic deformation in the messina strait define the presence and distribution of submarine landslides and evaluate their possible role as tsunami sources

thermal evolution of cretaceous tethyan marine waters inferred from oxygen isotope composition of fish tooth enamels 1 the evolution of subtropical 30 35 n upper ocean temperatures through the cretaceous is inferred from the oxygen isotope compositions of 64 fish teeth enamel coming from the western tethyan platform mean 18o values of 22 at the berriasian valanginian boundary decrease with oscillations to 18 5 around the cenomanian turonian boundary and progressively increase to 21 5 by the end of the cretaceous the similarity of this oxygen isotope curve for bioapatites from platform environments with those for foraminifera and bulk carbonates that were deposited in deeper waters and at other paleolatitudes indicates that they record global climatic signals major cooling events at the million year scale can be distinguished 1 at the berriasian valanginian boundary and 2 during the earliest late valanginian a third cooling event is detected during the earliest aptian these events already proposed as icehouse interludes during the lower cretaceous are also recorded at subtropical latitudes a progressive warming is identified from the aptian to the cenomanian turonian interval that corresponds to a thermal optimum and then upper ocean temperatures decreased to the maastrichtian minimum isotopic temperatures range from 15 c to 28 c assuming a 18oseawater of 1 for an ice free world taking more realistic 18oseawater values of 0 for tropical waters during glacial periods within the berriasian valanginian interval and earliest aptian or with above average salinities possibly the maastrichtian temperatures are increased by 4 5 c temperature differences between climatic extremes of the valanginian and cenomanian turonian are estimated to have been 10 c latitudinal thermal gradients for the albian cenomanian turonian and maastrichtian were 0 2 0 3 c latitude and thus weaker than modern oceanic values at about 0 4 c latitude

late cretaceous subsidence history of the betic continental margin jumilla yecla region se spain abstract a combined approach of subsidence and tectono stratigraphic analyses is presented to document the vertical tectonic motions of the crust in the betic margin se part of the iberian plate during the late cretaceous late albian late maastrichtian when the basin was evoling from a passive margin into a convergent one the overall patterns of tectonic subsidence and paleogeography are characterized by the following phases 1 middle late albian regional tectonic pulse 98 ma major basin reorganization 2 latest albian early middle cenomanian relatively rapid subsidence wide carbonate platform development 3 late middle cenomanian early coniacian regional uplift and related tectonic pulses at 94 5 and 93 5 ma followed by a prolonged low subsidence phase 4 intra coniacian extensional tectonic event 88 5 ma 5 late coniacian late santonian interval relative tectonic quiescence and moderate subsidence rates wide carbonate platform development 6 latest santonian earliest campanian compressional tectonic event 83 5 ma restructuring of the betic margin 7 early campanian early maastrichtian low subsidence narrow mixed carbonate siliciclastic platforms 8 mid maastrichtian tectonic event 71 ma abrupt paleographic changes 9 late maastrichtian overall moderate subsidence high terrigenous influx and 10 latest maastrichtian regional tectonic event major basinal reorganization characterization of these periods which include the first compressional or transpressional tectonic phases of the alpine orogeny in the betic margin permits the integration of the late cretaceous tectono sedimentary evolution of the betic margin into the geodynamic evolution of iberia on the basis of this integration tectonic pulses and related changes in subsidence are interpreted as the result of variations on intraplate stresses which are superimposed on the general longer term subsidence of the passive margin these intraplate stresses were governed by 1 the north atlantic spreading and the consequent decrease in the sinistral relative motion between iberia and africa 2 the progressive opening of the bay of biscay between the late aptian and the early campanian and 3 the onset of the oblique convergence between africa and europe in the late cretaceous

runup distribution for the 1908 messina tsunami in italy observed data versus expected curves the source of the catastrophic 1908 messina tsunami southern italy is studied by best fitting the available datasets of observed runup with a previously published empirical function i e the expected runup distribution the maximum runup is 12 m and was measured 30 40 km to the south of the area where the maximum coseismic dislocation and mercalli cancani sieberg mcs intensities were recorded the observed runup drops from 12 m to less than 1 m in a few tens of kilometers the comparison between observed and expected runup distributions suggests that the main cause of the 1908 tsunami was a mass failure thus supporting previously published evidence including tsunami arrival times bathymetric maps and chronicles reporting the interruption of submarine cables this article adds a significant case history to the very limited database of thoroughly documented runup for landslide tsunamis

recent and active tectonics in the calabrian arc southern italy normal faulting which has developed since the middle pleistocene with an overall ese wnw extension is the dominant mode of deformation which has characterized the calabrian arc up to the present quaternary normal faults extend for a total length of about 180 km along the inner side of the arc the different normal fault segments which during the pleistocene controlled the evolution of the main marine sedimentary basins are varying in length from 10 to 20 km and have fault escarpments showing a very young morphology which define the fronts of the major mountain ranges of the arc the morphological features of the fault escarpments suggest slip rates of 0 8 1 1 mm yr for the last 700 k y and values of 0 6 0 9 mm yr for the last 120 k y indicating a uniform rate of faulting since the middle pleistocene crustal seismicity and the mesoseismic areas of historical large events 6 5 m 7 1 which occurred in the calabrian arc are located within a narrow belt along the hanging walls of the quaternary normal fault segments this suggests that the normal faults which dissect the inner side of the calabrian arc may be seismically active

a variable slip fault model for the 1908 messina straits italy earthquake by inversion of levelling data summary a variable slip fault model is presented for the 1908 december 28 messina italy earthquake it has been obtained by inversion of levelling data using a gradient method fault location and mechanism are consistent with an approximately n s orientation and normal faulting on a low angle plane dipping 39 with about 45 of strike slip component the main difference from a homogeneous slip model is represented by a higher slip area up to 3 m located close to the city of reggio calabria it is interpretable as a major asperity which is related to the main fracture episode this is in agreement with some macroseismic evidence and the same structure could be responsible for the nearby recent seismic activity the area which effectively slipped is all confined within the messina straits this result differs from the homogeneous slip model recently proposed by capuano et al 1988

geophysical and geodetic observations in the messina straits abstract the present note is intended as a contribution to the clarification of the collision process generally assumed to be active between the african and the eurasian plates in the area of the messina straits for this purpose detailed analyses are made of the surveys carried out in the straits of messina in order to investigate the 1908 earthquake the magnitude and intensity are established limits are set for the linear dimension of the fault and of the dislocation that gave rise to the earthquake and an estimate is then given of these parameters the results are then set out of the investigation into the focal mechanism of the earthquake of 1908 the results are also studied of geodetic surveys carried out at the time for the purpose of measuring the variations in height that occurred during the earthquake a study is also made of the results of geodetic surveys some of which are still under way designed to measure the horizontal movements of sicily with respect to calabria in order to study locally the continental collision process in the area of the messina straits it is found that the old and recent geodetic measurements as well as the fault plane solution of the old and recent earthquakes of that area and the slips associated with those earthquakes indicate a motion towards the north of sicily with respect to calabria

character of the stress field in the calabrian arc and southern apennines italy as deduced by geological seismological and volcanological information abstract three crustal sections located in key zones of the calabrian arc and southern apennines have been drawn on the basis of the available geological geophysical seismological and volcanological data the purpose is to gather information on the state of stress at different crustal levels and to test to which extent data sampled at different time intervals may be consistently compared the analysis allows for the individualization of the following sectors 1 1 peri tyrrhenian belt marked by a tensional state of stress down to the moho depth 2 2 apenninic chain subjected to tension only in its shallow portions and to a compressive regime at depth 3 3 external chain internal foretrough characterized by a deep compressive regime which is expressed at the surface in its outermost zone only 4 4 external foretrough foreland with tensional processes in the whole crust compressional processes are linked to the activity of a deep shear zone which causes the thrusting of the tyrrhenian crust over the adriatic crust and which seems to control the present distortion of the calabrian arc the analysis suggests a change in the stress field and deformation mechanisms from the uppermost to the lowermost levels of the crust and an eastward migration with time of the compressional events these facts would explain the contrasting evidence sometimes given by stress constraints derived from geological seismological and volcanological data