irregular recurrence of paleoearthquakes along the central garlock fault near el paso peaks california 1 new investigations at the el paso peaks paleoseismic site have refined and extended the record of paleoearthquakes for the central garlock fault event evidence in the form of buried fissures scarps folds and upward terminations has allowed us to identify six well resolved earthquakes designated as events w u r q k and f within the last 7000 years the exposures that we excavated did not reveal additional evidence for three poorly resolved events reported by mcgill and rockwell 1998 evidence for event y identified in the previous study was reexamined and found not to be a paleoearthquake radiocarbon dates of detrital charcoal combined with a method of interpolating the event ages with revised sedimentation rates provide our preferred constraints on the timing of faulting events the most recent surface rupturing earthquake event w occurred between a d 1450 and 1640 the penultimate event u occurred between a d 675 and 950 event r which was unrecognized in the previous study occurred between a d 250 and 475 event q occurred relatively shortly before event r between a d 25 and 275 event k occurred between 3340 and 2930 b c the oldest identified paleoearthquake event f occurred between 5300 and 4670 b c the event ages indicate that earthquake recurrence is highly irregular at the el paso peaks site with individual preferred intervals ranging from as little as 215 years to as many as 3300 years the irregular recurrence of surface rupturing earthquakes along the central garlock fault may be related to temporal and spatial clustering of earthquakes proposed for faults in the eastern california shear zone

neotectonics of the central parts of the balkan peninsula basic features and concepts the neotectonic movements on the balkan peninsula occurred after the last intense thrusting early miocene and after the early middle miocene planation they were controlled by extensional collapse of the late alpine orogen and by extension behind the aegean arc and were influenced by the complicated vertical and horizontal movements in the pannonian region the stara planina and dinarian hellenic linear neotectonic morphostructures inherited the alpine orogenic zones balkanides and dinarides hellenides and bounded the central balkan neotectonic region the linear morphostructures were tilted towards the pannonian and euxinian basins and the north aegean trough the central balkan neotectonic region has a complicated block structure horst and graben pattern dominated by the nnw sse struma and vardar lineaments the wnw ese sava and marica lineaments and the middle mesta and north anatolian fault zones the dominating serbo macedonian neotectonic swell was rifted and subsided along the struma and vardar lineaments the range of the vertical neotectonic displacements reached a maximum of 3 4 km and even up to 6 km at the edges of the pannonian and aegean basins the general doming of the region was controlled by the isostatic uplift of a thickened crustal lens rhodope massif in the southern margin of the eurasian plate the collapse of the complicated domal structure began along the main struma vardar and marica lineaments in the central parts of the dome and continued in the pliocene and quaternary along a more external contour bounded by the stara planina and dinarian hellenic linear morphostructures

block kinematics of the pacific north america plate boundary in the southwestern united states from inversion of gps seismological and geologic data 1 the active deformation of the southwestern united states 30 41 n is represented by a finite number of rotating elastic plastic spherical caps gps derived horizontal velocities geologic fault slip rates transform fault azimuths and earthquake derived fault slip vector azimuths are inverted for block angular velocities creep on block bounding faults permanent strain rates within the blocks and the rotations of 11 published gps velocity fields into to a common north american reference frame gps velocities are considered to be a combination of rigid block rotations recoverable elastic strain rates resulting from friction on block bounding faults and nonrecoverable strain rates resulting from slip on faults within the blocks the resulting pacific north america angular velocity is similar to some published estimates and satisfies transform azimuths and one spreading rate in the gulf of california earthquake slip vectors in the gulf of california and alaska and gps velocities along coastal california and within the pacific basin published fault slip rates are satisfied except in the southern mojave desert where the motion of the mohave block relative to north america is faster than can be explained by mapped faults the largest blocks the sierra nevada great valley and the eastern basin and range show permanent strain rates after removing elastic strain of only a few nanostrain per year demonstrating approximately rigid behavior observed horizontal strain rates correlate strongly with predicted strain rates from known faults suggesting that the short term strains evident in gps velocities are largely elastic in only about 20 of the region is distributed deformation needed to match the data indicating that a plate tectonic style description of the deformation of the western united states is plausible most blocks rotate about vertical axes at approximately the same rate as the pacific relative to north america suggesting that locally spin rates are communicated from block to block arguing against both floating block and ball bearing mechanisms of block rotation the similarities of the blocks spin rates to that of the pacific suggests that the pacific strongly influences their motions through edge tractions however it is shown that the blocks cannot rotate about the pacific north america pole without spinning counter to the sense of pacific north america shear unlike some other broad plate boundaries in the western united states vertical axis rotations take up very little of the slip rate budget across the region

velocity and deformation fields in the north aegean domain greece and implications for fault kinematics derived from gps data 1993 2009 abstract gps rates based on data of an extended continuous and campaign type gps network in the north aegean domain are presented the data processed for the time period 1993 2009 is used to analyze the complex kinematic and deformation fields in the north aegean sea and adjacent regions the presence of slowly deforming areas is investigated southern bulgaria eastern macedonia and thrace move uniformly southward relative to eurasia 1 5 3 5 mm yr western macedonia epirus thessaly and central greece rotate rather coherently clockwise the region comprising the islands of limnos agios efstratios and alonnisos moves like a counterclockwise rotating slowly deforming block the new gps rates allow a quantification of the spatial change of strike slip motion and locking depth along the north aegean trough dextral strike slip motion diminishes from east toward west amounting to 21 2 mm yr along the saros basin and 12 5 mm yr south of the chalkidiki peninsula less than 5 mm yr 50 nstrain yr shear strain rate is transferred from the sporades islands pelion toward northern evia the locking depth is shallow for the ganos fault and the western saros basin 5 6 8 9 km it is deeper between the sporades islands and pelion 17 7 km corresponding to a more diffuse shear zone an elementary finite element model is applied to derive slip rates of the three main ene wsw to ne sw trending dextral strike slip faults in the north aegean large scale n s to nne ssw extension in the north aegean domain is analyzed by employing finite element and gps based strain rate analyses pronounced extension 100 nstrain is associated with known tectonic structures e g mygdonian graben northern gulf of evia in offshore areas such as the sporades basin the correspondence between gps derived extension rates and active fault structures is not entirely evident however important constraints are provided for seismotectonic interpretations

crustal motion and strain accumulation in western bulgaria abstract global positioning system gps data acquired between 1996 and 2004 and fault plane solutions for four seismic zones are analyzed to obtain the velocity and strain rate fields for western bulgaria the gps derived velocities suggest that southwestern bulgaria moves to the s to sse at a rate of 1 mm year with respect to northern bulgaria and southern romania defining an approximately ese trending extensional boundary that marks the northernmost extent of the aegean extensional domain the boundary includes the e w trending sub balkan graben system of central bulgaria and its westward continuation into the sofia graben active faults within the boundary region trend ene to wnw and they have normal or oblique normal and strike slip displacements consistent with the velocity field within the western part of the boundary region extension is transferred to the north of the sofia graben across the westernmost part of the stara planina mountains and the ridges of the western sredna gora the geodetically derived n s extension is in agreement with the seismic data that show a variable pattern but with projections of the t axes mostly lying within the n s quadrant the predominant type of faulting is caused by sub horizontal extensional stresses in an approximate n s direction this is consistent with extension and oblique strike slip interpreted from geological studies that show numerous wnw ene to e w trending active normal faults in western bulgaria

the 1978 earthquake sequence near thessaloniki northern greece summary this paper presents a detailed study of teleseismically and locally recorded foreshocks and aftershocks of the 1978 thessaloniki earthquake sequence and discusses the relations between the locations and mechanisms of these shocks and the three dimensional geometry of faulting in the source region sixteen teleseismically recorded events were relocated using a relative relocation method and positioned geographically using the accurate locally determined location of the largest aftershock all these shocks had depths shallower than 15 km the spatial distribution of the foreshocks showed that the activity was initiated at the central part of the epicentral region progressed westwards and for about 20 days clustered in the region of the imminent mainshock no teleseismically recorded foreshock was located west of the mainshock location in less than 1 hr after the mainshock large aftershocks occurred west of it and in later stages spanned the entire western part of the epicentral region no teleseismically recorded aftershocks were located east of the mainshock locally recorded aftershocks were accurately located and provided a more detailed picture of the seismic deformation they occurred at depths between 3 and 12 km and in three distinct clusters separated by well defined gaps the largest foreshock on may 23 had a moment of 5 6 1024dyne cm and a mean displacement of 31cm the mainshock on june 20 had a moment of 5 2 1025dyne cm a strain drop of 4 0 10 5 static stress drop of 12 bar and a mean displacement of 64 cm these values are for one of the two possible interpretations of the aftershock distribution which suggests that the largest earthquakes of the sequence occurred on two different but adjacent fault segments the first event 1 on may 23 occurred along the central fault segment and was followed 28 days later by the second event 2 on june 20 along a western fault segment finally 61 days later another smaller earthquake event 3 occurred along another fault east of event 1

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

distortion of magnetotelluric sounding curves by three dimensional structures distortions of magnetotelluric fields caused by three dimensional 3 d structures can be severe and are not predictable using one dimensional or two dimensional modeling i used a 3 d modeling algorithm based upon an extension of a generalized thin sheet analysis due to ranganayaki and madden 1980 to examine field distortions in crustal environments three major physical mechanisms cause these distortions these mechanisms are resistive coupling between the electrical mantle and upper crust resistive coupling between conductive features within the upper crust and local induction of current loops within good conductors each mechanism produces different spatial and frequency effects upon the background field so identification of the dominant mechanism can be used as an interpretational aid i finally use this analysis to identify distortion mechanisms seen in magnetotelluric data from beowawe nevada to aid in an interpretation of that area

discrepancy between geological and geodetic deformation rates in the ventura basin space geodesy provides a new tool for measuring neotectonic deformation which when combined with geological and geophysical observations and models can be used to infer rates and styles of deformation in the ventnra basin region of southern california the geodetically measured convergence rates of 7 10 mm yr 1 ref 1 are significantly lower than the 20 25 mm yr 1 estimated from geological data2 3 here we investigate the possible implications of this discrepancy it might be for example that temporal variations cause the short and long term convergence rates to differ but if this were the case we would expect to observe the long term rate by extending the geodetic measurements over a broader region yet only 11 3 mm yr 1 of regional convergence is observed4 our preferred explanation of the discrepancy is that the geological models require revision and to this end we present two deformation models that satisfy both the geological and geodetic constraints our modelling suggests that the faults bounding the basin are locked at the surface but are slipping at depths below 2 5 km

constraints on continued episodic inflation at long valley caldera based on seismic and geodetic observations 1 long valley caldera a large and potentially explosive silicic system has experienced highly anomalous continued inflation since late 1970s we characterize an episode of rapid episodic uplift occurring between 2002 and 2003 following similar episodes of 1979 1980 1983 1989 1990 and 1997 1998 this most recent episode was the first to be observed by a dense array of 13 continuous global positioning system gps stations similar to previously observed episodes of deformation uplift is quasi radially symmetric and is mostly explained by a compact pressure source located 3 km west of the resurgent dome the maximum uplift during the 2002 2003 episode is 35 8 mm about 1 3 the magnitude but with a similar time dependent behavior as the 1997 1998 episode the horizontal source location is well constrained at 118 930 37 678 for a small spherical source and indistinguishable from the location of a vertically dipping prolate spheroidal source a trade off between depth and volume change is observed for both spherical and prolate models with depth between 7 5 and 13 5 km and a volume change of 0 01 0 03 km3 at 95 confidence for prolate spheroidal models depth and volume change are additionally affected by the source axis ratio b a which is greater than 0 55 though the background seismicity remained low during the 2002 2003 episode we identified a significant spike in activity during the maximum rate of uplift similar to observations in both the much larger episodes in 1989 1990 and 1997 1998 more interestingly we additionally find that all three episodes begin immediately after a short period of seismic quiescence with background seismicity falling to levels below background levels following the prior uplift event with the dense gps coverage we also identify increased opening of the mono inyo volcanic chain after the 2002 2003 episode suggesting potential interaction of magmatic fluids between the two systems

the nature of the 660 kilometer discontinuity in earth s mantle from global seismic observations of pp precursors the 660 kilometer discontinuity which separates earth s upper and lower mantle has been detected routinely on a global scale in underside reflections of precursors to ss shear waves here we report observations of this discontinuity in many different regions using precursors to compressional pp waves the apparent absence of such precursors in previous studies had posed major problems for models of mantle composition we find a complicated structure showing single and double reflections ranging in depth from 640 to 720 kilometers that requires the existence of multiple phase transitions at the base of the transition zone the results are consistent with a pyrolite mantle composition

tectonics of strike slip restraining and releasing bends restraining and releasing bends are common but enigmatic features of strike slip fault systems occurring in all crustal environments and at regional to microscopic scales of observation regional scale restraining bends are sites of mountain building transpressional deformation and basement exhumation whereas releasing bends are sites of topographic subsidence transtensional deformation basin sedimentation and possible volcanism and economic mineralization because restraining and releasing bends often occur as singular self contained domains of complex deformation they are appealing natural laboratories for earth scientists to study fault processes earthquake seismology active faulting and sedimentation fault and fluid flow relationships links between tectonics and topography tectonic and erosional controls on exhumation and tectonic geomorphology this volume addresses the tectonic complexity and diversity of strike slip restraining and releasing bends with 18 contributions divided into four thematic sections 1 a topical review of fault bends and their global distribution 2 bends sedimentary basins and earthquake hazards 3 restraining bends transpressional deformation and basement controls on development 4 releasing bends transtensional deformation and fluid flow

geodetic constraints on the fault pattern of the 1978 thessaloniki northern greece earthquake ms 6 4 summary repeated measurement of a 110 km long high precision spirit levelling traverse indicates that between 1958 and 1978 about 25 cm of subsidence occurred along a distance of 30 km in the mygdonian quaternary graben near thessaloniki northern greece observed displacements are significant against random and systematic errors and most are unrelated to near surface effects and can be assigned to the 1978 thessaloniki destructive earthquakes the available data do not permit a formal inversion but an elastic dislocation analysis indicates that the main shock of the seismic sequence ms 6 4 was probably associated with a ne dipping wnw trending blind normal fault marking the southwestern margin of the mygdonian graben in agreement with seismological and structural data there also exists evidence for incipient faulting in the central southern part of the mygdonian graben

bridging onshore and offshore present day kinematics of central and eastern mediterranean implications for crustal dynamics and mantle flow we present a new kinematic and strain model of an area encompassing the calabrian and hellenic subduction zones western anatolia and the balkans using haines and holt s 1993 method we derive continuous velocity and strain rate fields by interpolating geodetic velocities including recent gps data in the balkans relative motion between stable eurasia and the western aegean sea is gradually accommodated by distributed n s extension from southern balkans to the eastern corinth gulf so that the westward propagation of the north anatolian fault naf throughout continental greece or peloponnesus is not required we thus propose that the naf terminates in north aegean and that n s extension localized in the corinth gulf and distributed in southern balkans is due to the retreat of the hellenic slab the motion of the hyblean plateau apulia peninsula south adriatic sea ionian basin and sirte plain can be minimized by a single rigid rotation around a pole located in the sirte plain compatible with the opening the pelagian rifts 2 2 5 mm yr and seismotectonics in libya we interpret the trenchward ultraslow motion of the calabrian arc 2 2 5 mm yr as pure collapse the calabrian subduction being now inactive in the absolute plate motion reference frame our modeled velocity field depicts two toroidal crustal patterns located at both ends of the hellenic subduction zone clockwise in nw greece and counter clockwise in western anatolia we suggest the nw greece toroidal pattern is the surface expression of a slab tear and consequent toroidal asthenospheric flow

consistency of geologic and geodetic displacements during andean orogenesis displacement and convergence rates inferred from gps and marine magnetic data suggest that this trend may be continuing at present hence an increasing fraction of convergence is being absorbed by mountain building this change may reflect increased plate coupling due to decreased sediment supply younger subducting lithosphere or increased normal stress at the interface from the effects of uplift index terms 8102 tectonophysics continental contract orogenic belts 8157 evolution of the earth plate motions past 3040 8158 evolution of the earth plate motions present and recent 3040 8099 structural geology general or miscellaneous

the importance of microearthquakes in crustal extension of an active rift a case study from new zealand received 24 august 2012 revised 29 november 2012 accepted 19 december 2012 1 the amount of extension accommodated in active rifts by earthquakes that do not rupture the ground surface e g mw 5 5 is often poorly constrained the matata earthquake sequence mes a high quality dataset of 2563 relocated microearthquakes 1 mw 4 7 that ruptured the taupo rift in new zealand over a period of 49 months has been used to quantify the proportion of extension produced by small to moderate sized earthquakes analysis shows that the extension rate across the rift due to the mes is 2 4 0 7 mm yr at 1s standard deviation an average extension rate for small to moderate magnitude earthquakes which also prevailed during the preceding 28 years 1977 2004 and represents up to 30 of the total contemporary deformation recorded across the north taupo rift by gps 15 5 mm yr the bulk of the mes 94 occurred at depths of 1 5 to 6 5 km and may not be observed in geological datasets e g as displacements of the ground or near surface horizons small scale faulting associated with microseismicity may thus record strains not measured by geological datasets and constitute an important component of the 3 10 mm yr disparity between geological and gps rates of extension across the taupo rift

westward propagation of the north anatolian fault into the northern aegean timing and kinematics we present new evidence for the propagation processes of the north anatolian fault folding in the dardanelles straits region allows us to document the timing of the deformation preceding and the finite displacement after the passage of the propagating tip of the fault the accuracy of the observations is due to interplay between deformation and the sea level changes in the mediterranean the well known messinian regression followed by the pliocene transgression the long term kinematics around the sea of marmara pull apart total displacement of about 85 km over the past 5 m y is similar to the present day kinematics deduced from space geodesy at a larger scale westward propagation of the north anatolian fault over nearly 2000 km in the past 10 m y appears to be associated with strain recovery suggesting that the continental lithosphere retains long term elasticity

thessaloniki gerakarou fault zone tgfz the western extension of the 1978 thessaloniki earthquake fault northern greece and seismic hazard assessment abstract active faulting and seismic properties are re investigated in the eastern precinct of the city of thessaloniki northern greece which was seriously affected by two large earthquakes during the 20th century and severe damage was done by the 1759 event it is suggested that the earthquake fault associated with the occurrence of the latest destructive 1978 thessaloniki earthquake continues westwards to the 20 km long thessaloniki gerakarou fault zone tgfz which extends from the gerakarou village to the city of thessaloniki this fault zone exhibits a constant dip to the n and is characterised by a complicated geometry comprised of inherited 100 trending faults that form multi level branching tree like fault geometry along with nne to ne trending faults the tgfz is compatible with the contemporary regional n s extensional stress field that tends to modify the pre existing nw se tectonic fabric prevailing in the mountainous region of thessaloniki both the 1978 earthquake fault and tgfz belong to a ca 65 km long e w trending rupture fault system that runs through the southern part of the mygdonia graben from the strymonikos gulf to thessaloniki this fault system here called thessaloniki rentina fault system trfs consists of two 17 20 km long left stepping 100 trending main fault strands that form underlapping steps bridged by 8 10 km long ene wsw faults the occurrence of large m 6 0 historical earthquakes in 620 677 and 700 a d demonstrates repeated activation and therefore the possible reactivation of the westernmost segment the tgfz could be a major threat to the city of thessaloniki changes in the coulomb failure function cff due to the occurrence of the 1978 earthquake calculated out in this paper indicate that the tgfz has been brought closer to failure a convincing argument for future seismic hazard along the tgfz

aseismic deformation in the alps gps vs seismic strain quantification neotectonics of the western and central alps is characterized by ongoing widespread extension in the highest zones of the chain and transcurrent compressive tectonics at the external limits of the belt the overall geodetically measured deformations also indicate extension across the western alps there is a good qualitative coherency between seismotectonic and geodetic approaches here we attempt to quantify the seismic part of the deformation the seismic strain is compared to the deformation derived from geodesy in sub areas of homogeneous seismic stress strain we computed the total seismic moment tensor and related strain tensor this study provides new quantitative elements about the ongoing geodynamic processes in the alpine belt the important discrepancies obtained between seismic strains and geodetically measured deformations raise the issue of aseismic deformation in the alps which could be related to elastic loading creeping and or a slower ductile style deformation

strain accommodation by slow slip and dyking in a youthful continental rift east africa continental rifts begin and develop through repeated episodes of faulting and magmatism but strain partitioning between faulting and magmatism during discrete rifting episodes remains poorly documented in highly evolved rifts tensile stresses from far field plate motions accumulate over decades before being released during relatively short time intervals by faulting and magmatic intrusions1 2 3 these rifting crises are rarely observed in thick lithosphere during the initial stages of rifting here we show that most of the strain during the july august 2007 seismic crisis in the weakly extended natron rift tanzania was released aseismically deformation was achieved by slow slip on a normal fault that promoted subsequent dyke intrusion by stress unclamping this event provides compelling evidence for strain accommodation by magma intrusion in addition to slip along normal faults during the initial stages of continental rifting and before significant crustal thinning

transtensional origin of the ne sw simitli basin along the strouma strymon lineament sw bulgaria several depocentres have developed along the nnw sse striking strouma strymon lineament since the miocene forming the strouma strymon graben system some of these basins including the dzherman and simitli strike at high angles to the lineament the rhomboid shaped simitli basin is limited in the south by the ne sw striking seismically active kroupnik fault and contains terrestrial clastic sediments which have been deposited since the sarmatian its formation is attributed to wrench dominated transtension d b event which activated the basin9s ne sw striking boundary faults as left lateral strike slip structures during the early middle miocene this deformation was associated with nne ssw contraction and wnw ese extension and succeeded the nne ssw contraction caused by pure shear dominated transpression d a event which governed the region in late oligocene early miocene times during the middle late miocene the d b event was followed by wnw ese pure shear dominated extension d 1 event which caused further widening of the basin the transtensional origin of the simitli basin is explained by lateral extrusion of the crustal mass squeezed between the apulian adriatic microplate and the european foreland towards the north aegean sea the subduction retreat of the hellenic orogen possibly enhanced this lateral extrusion and from the late miocene onwards the ne sw oriented back arc extension balanced the continuing retreat

energetic rupture coseismic and post seismic response of the 2008 mw 6 4 achaia elia earthquake in northwestern peloponnese greece an indicator of an immature transform fault zone summary the 2008 june 8 moment magnitude mw 6 4 crustal earthquake in northwestern peloponnese greece was a strong shaking dextral strike slip event with teleseismic broad band and high frequency energy magnitudes me of 6 8 and 7 2 respectively a high stress drop 5 10 times the global average is associated with excessive high frequency energy the ne sw trending fault plane shown by the aftershock distribution and focal mechanism is not associated with previously mapped faults and no obvious coseismic surface rupture was discovered contrasting the enhanced rupture energy the event created no substantial coseismic or post seismic surface deformation likely due to a fault buried below a detached thick and compositionally weak flysch layer comparative spatial analysis including over 30 regional strike slip events between 1965 and 2009 reveals a ne sw striking diffuse transform fault zone subparallel to the cephalonia transform fault the dextral sense of motion along the transform zone is consistent with the ongoing global positioning system gps derived deformation along the west hellenic arc and the motion on the cephalonia transform fault characterizing this system is important to constraining the seismic hazard near patras a major port city immediately ne of the 2008 event

geodetic evidence for tectonic activity on the strymon fault system northeast greece abstract the current kinematic patterns of northeast greece remain largely unknown this is mainly because this region is characterised by low seismicity rates and is poorly covered by gps stations here we analyse new homogeneous gps data collected over a period of 5 5 years from the first permanent network in northeast greece hepos to shed light in the kinematics of this region we find that gps displacement vectors that derive from either side of the natural depression of the strymon valley differ significantly in orientation and magnitude specifically we find that across a distance of ca 30 km the gps displacement vectors change orientation by 130 from nnw to ssw producing a mean horizontal strain rate of 3 3 0 3 mm yr we attribute this kinematic translation to result from movement along the strymon fault system sfs a 200 km long structure that strikes nw se and extends from sw bulgaria to north aegean where possibly abuts against the north anatolian fault up to date the sfs was considered to be a major alpine and neogene geotectonic boundary of unclear holocene activity if the interseismic strain stored currently across the fault system is released seismically large earthquakes m 7 and associated coseismic lateral displacements should be expected in the area these results call for a better assessment of the earthquake risk in northeast greece which is currently evaluated as a low seismic hazard region

structural characteristics of two strong earthquakes in the north aegean ierissos 1932 and agios efstratios 1968 abstract structural analysis has been carried out on the volcanics of the island of agios efstratios and along the highly faulted zone of se chalkidiki south and north of the north aegean trough respectively northern greece the areas have been affected by strong earthquakes and a comparison is made between the available structural and seismological data together with new seismotectonic information at agios efstratios the earthquake of 1968 m7 1 occurred on a principal displacement zone with dextral strike slip movement while the fault geometry of the whole area supports the view of transtensional deformation the strong m7 0 earthquake of 1932 at ierissos was directly connected with an e w trending normal fault striations on the seismic fault surfaces and the corresponding fault mechanism indicate a n s direction of active extension the hangingwall is also affected by smaller antithetic e w and nw se trending structures