systematic comparisons of earthquake source models determined using insar and seismic data abstract robust earthquake source parameters e g location seismic moment fault geometry are essential for reliable seismic hazard assessment and the investigation of large scale tectonics they are routinely estimated using a variety of data and techniques such as seismic data and more recently interferometric synthetic aperture radar insar comparisons between these two datasets are frequently made although not usually in a comprehensive way this review compares source parameters from global and regional seismic catalogues with those from a recent database of insar parameters which has been expanded with 18 additional source models for this study we show that moment magnitude mw estimates agree well between the two datasets with a trend for thrust events modelled using insar to have slightly larger mw estimates earthquake locations determined using insar agree well with those reported in regional catalogues with a median difference of 6 3 km between them which is smaller than for global seismic catalogues we also investigate the consistency of source parameters and source directivity by comparing isc hypocentres with gcmt and icmt centroid locations for earthquakes with mw 6 5 in some cases the source directivity is qualitatively comparable with previous studies especially when comparing isc and icmt locations the average difference between insar determined depths and those in the ehb catalogue is reduced if a layered half space is used in the inversion of insar data overall faulting geometry strike dip and rake angles remain in good agreement with values from the gcmt catalogue and any large discrepancies can be attributed to tradeoffs between parameters with continued investment in satellites for radar interferometry insar is a valuable technique for the estimation of earthquake source parameters the observed trends and discrepancies between insar and seismically determined source parameters are the result of issues with the data different inversion techniques and the assumed earth structure model

rupture directivity of the 2011 mw 5 2 lorca earthquake spain 1 on may 11th 2011 a rather small earthquake caused nine fatalities in the city of lorca se spain we analyze seismograms from a dense network to characterize the source of this earthquake we estimate an oblique reverse faulting mechanism moment magnitude of 5 2 and a shallow hypocenter 4 6 km at only 5 5 km epicentral distance from the city center double difference relocations yield a 5 km long ne sw trending distribution of aftershocks sw of the mainshock suggesting a sw propagating rupture along the alhama de murcia fault we use the mw 4 6 foreshock and an mw 3 9 aftershock as empirical greens functions to estimate apparent source time functions observing a clear directivity effect we model apparent durations with a unilateral and asymmetric bilateral rupture in both cases obtaining rupture directivity of n220 e towards lorca in addition to the near epicenter and shallow depth directivity may have contributed to the significant impact

finite faults and inverse theory with applications to the 1979 imperial valley earthquake abstract using a representation theorem from elastodynamics subsurface slip on a known fault is formulated as the solution to an inverse problem in which recorded surface ground motion is the data two methods of solution are presented the least squares method which minimizes the squared differences between theory and data and the constrained least squares method which simultaneously maintains a set of linear inequalities instabilities in the solution are effectively eliminated in both methods and the sensitivity of the solution to small changes in the data is quantitatively stated the inversion methodology is applied to 77 components of near field ground acceleration recorded during the 15 october 1979 imperial valley earthquake the faulting is constrained to propagate bilaterally away from the epicenter at an average velocity of 90 per cent of the shear wave speed on a vertical fault plane extending from the surface to 10 km depth inequality constraints are used to keep the faulting sequence physically reasonable by maintaining right lateral motion and positive slip velocity the preferred solution is stable and provides a good fit to the data it is also realistic and consistent with observed surface offsets and independent estimates of seismic moment

inversion of complex body waves we have developed a method that inverts seismic body waves to determine the mechanism and rupture pattern of earthquakes the rupture pattern is represented as a sequence of subevents distributed on the fault plane this method is an extension of our earlier method in which the subevent mechanisms were fixed in the new method the subevent mechanisms are determined from the data and are allowed to vary during the sequence when subevent mechanisms are allowed to vary however the inversion often becomes unstable because of the complex trade offs between the mechanism the timing and the location of the subevents many different subevent sequences can explain the same data equally well and it is important to determine the range of allowable solutions some constraints must be imposed on the solution to stabilize the inversion we have developed a procedure to explore the range of allowable solutions and appropriate constraints in this procedure a network of grid points is constructed on the i plane where and i are respectively the onset time and the distance from the epicenter of a subevent the best fit subevent is determined at all grid points then the correlation is computed between the synthetic waveform for each subevent and the observed waveform the correlation as a function of and i and the best fit mechanisms computed at each i grid point depict the character of allowable solutions and facilitate a decision on the appropriate constraints to be imposed on the solution the method is illustrated using the data for the 1976 guatemala earthquake

inversion of pack ice elastic wave data to obtain ice physical properties geophones mounted on floating ice sheets can potentially provide data for a robust method to monitor mechanical properties of the ice the technique relies on the measurement and inversion of low frequency elastic waves propagating in the ice to test this hypothesis several geophone systems were deployed on the arctic ice as part of the office of naval research sea ice mechanics initiative simi including a winter over system of 20 triaxial geophones at the fall 1993 simi camp an inversion technique is discussed here through references to the literature and by analysis of geophone data specifically those data collected on clean first year ice off resolute bay canada and on highly irregular multiyear ice found at the fall simi camp for undeformed first year ice the inversion technique gave an estimate of ice properties that agreed well with known values although extensive work remains to determine the effects of anisotropy and inhomogeneity the geophone data for the nonuniform ice at the simi camp were very complex and difficult to analyze the inversion yielded only trends in what can at best be termed effective ice thickness and bending rigidity it is uncertain how these relate to actual ice properties the simi geophone system demonstrated the feasibility of performing autonomous measurements of the characteristics of propagating waves in the arctic ice with continued study it seems evident that such systems can be used in clean first year ice to monitor ice properties however extensive research is required to make this technique useful in multiyear or complex first year ice

tectonics and topography for a lithosphere containing density heterogeneities the purpose of this paper is to clarify the dynamic role of lithospheric density heterogeneities in particular with respect to mountain building and other processes of intraplate deformation density anomalies within or just beneath the lithosphere constitute major sources for tectonic stress fields the product of their magnitude by their depth is shown to characterize their ability to induce deformation this rule of the density moment directly yields the lithospheric thickening or thinning rate when applied to structures of large lateral extent for anomalies of lateral extent that is small in comparison with their depth the deformation is vertically inhomogeneous and has been computed with the help of simple physical models of a stratified viscous newtonian lithosphere the analytical treatment is based on fourier transform continent continent collision thickens not only the crust but the entire lithosphere the cold root underlying a mountain chain induces strong regional compressive stresses able to sustain the mountain bulding process without further help from forces transmitted from far away thus the continental lithosphere is in a somewhat metastable mechanical state adiabatic i e rapid thickening or thinning tends to grow further once initiated tectonic phases of strong compression correspond to the climax of such instabilities the response of models with cold lithospheric roots of various intensities has been computed both in two and three dimensions they yield velocity distributions and stress fields instructive comparisons are made with earthquake focal mechanisms and in situ stress measurements in the alpine and appalachian regions in the presence of lateral variations of the mechanical properties of the lithosphere the tectonic style is not only function of the local topography and of the nature of its compensation deformations in neighbouring provinces are coupled as shown by 3 dimensional models for example thickening sustained by a cold lithospheric root may generate extension in peripheral zones of weakness these last results illustrate the point that the computation of regional tectonic stresses requires the knowledge of the density anomalies within the lithosphere on the one hand and of geometrical constraints related to lateral mechanical heterogeneities on the other

stability and uncertainty of finite fault slip inversions application to the 2004 parkfield california earthquake the 2004 parkfield california earthquake is used to investigate stability and uncertainty aspects of the finite fault slip inversion problem with different a priori model assumptions we utilize records from 54 strong ground motion stations and 13 continuous 1 hz sampled geodetic instruments two inversion procedures are compared a linear least squares subfault based methodology and a nonlinear global search algorithm these two methods encompass a wide range of the different approaches that have been used to solve the finite fault slip inversion problem for the parkfield earthquake and the inversion of velocity or displacement waveforms near surface related site response top 100 m frequencies above 1 hz is shown to not significantly affect the solution results are also insensitive to selection of slip rate functions with similar duration and to subfault size if proper stabilizing constraints are used the linear and nonlinear formulations yield consistent results when the same limitations in model parameters are in place and the same inversion norm is used however the solution is sensitive to the choice of inversion norm the bounds on model parameters such as rake and rupture velocity and the size of the model fault plane the geodetic data set for parkfield gives a slip distribution different from that of the strong motion data which may be due to the spatial limitation of the geodetic stations and the bandlimited nature of the strong motion data cross validation and the bootstrap method are used to set limits on the upper bound for rupture velocity and to derive mean slip models and standard deviations in model parameters this analysis shows that slip on the northwestern half of the parkfield rupture plane from the inversion of strong motion data is model dependent and has a greater uncertainty than slip near the hypocenter

indentation of a continent with a built in thickness change experiment and nature orogens oblique to the direction of plate convergence are currently attributed to obliquity between the margins of one or both of the sutured continents to their direction convergence we use a single analogue experiment and natural examples to illustrate a potential additional factor variations in strength of the indented continent at a high angle to the convergence direction the wavelengths of structures in laterally shortened lithosphere depend on the strength of the most competent layers lateral variations in crustal thickness must therefore lead to structures oblique to any applied lateral compression an analogue experiment was performed to explore this phenomenon a two layer indented continent was modelled by a brittle upper crust of sand above a lower crust of high viscosity polymer floating on a single layer of low viscosity syrup representing the mantle the well known strike slip structures allowing lateral escape to distant weak boundaries were hindered by lateral boundaries in front of the indenter this allowed us to focus on the effects of a thickness change built into the indented continent along a zone parallel to the direction in which a vertical rigid wall advancing at a steady rate represented the indenter vertical escape led to an orogenic belt oblique to the advancing wall this obliquity influences subsequent lateral escape model scaling and interpretations are based on extended thin sheet approximation etsa and standard theories of faulting four sectors of the alpine himalayan orogen iran tunisia the eastern alps and the himalaya are oblique to the continental convergence direction and we point to thickness changes at high angles to the suture that may account for this geometry as crustal thicknesses north of oblique sectors of the himalayas are not yet known we speculate on them we infer from the main difference between our experiment and all our examples chosen from nature that vertical orogenic escape was oblique to our model suture but can be parallel to natural sutures

mantle dynamics uplift of the tibetan plateau and the indian monsoon convective removal of lower lithosphere beneath the tibetan plateau can account for a rapid increase in the mean elevation of the tibetan plateau of 1000 m or more in a few million years such uplift seems to be required by abrupt tectonic and environmental changes in asia and the indian ocean in late cenozoic time the composition of basaltic volcanism in northern tibet which apparently began at about 13 ma implies melting of lithosphere not asthenosphere the most plausible mechanism for rapid heat transfer to the midlithosphere is by convective removal of deeper lithosphere and its replacement by hotter asthenosphere the initiation of normal faulting in tibet at about 8 3 ma suggests that the plateau underwent an appreciable increase in elevation at that time an increase due solely to the isostatic response to crustal thickening caused by india s penetration into eurasia should have been slow and could not have triggered normal faulting another process such as removal of relatively cold dense lower lithosphere must have caused a supplemental uplift of the surface folding and faulting of the indo australian plate south of india the most prominent oceanic intraplate deformation on earth began between about 7 5 and 8 ma and indicates an increased north south compressional stress within the indo australian plate a tibetan uplift of only 1000 m if the result of removal of lower lithosphere should have increased the compressional stress that the plateau applies to india and that resists india s northward movement from an amount too small to fold oceanic lithosphere to one sufficient to do so the climate of the equatorial indian ocean and southern asia changed at about 6 9 ma monsoonal winds apparently strengthened northern pakistan became more arid but weathering of rock in the eastern himalaya apparently increased because of its high altitude and lateral extent the tibetan plateau provides a heat source at midlatitudes that should oppose classical symmetric hadley circulation between the equator and temperate latitudes and that should help to drive an essentially opposite circulation characteristic of summer monsoons for the simple case of axisymmetric heating no dependence on longitude of an atmosphere without dissipation theoretical analyses by hou lindzen and plumb show that an axisymmetric heat source displaced from the equator can drive a much stronger meridianal monsoonlike circulation than such a source centered on the equator but only if heating exceeds a threshold whose level increases with the latitude of the heat source because heating of the atmosphere over tibet should increase monotonically with elevation of the plateau a modest uplift 1000 2500 m of tibet already of substantial extent and height might have been sufficient to exceed a threshold necessary for a strong monsoon the virtual simultaneity of these phenomena suggests that uplift was rapid approximately 1000 m to 2500 m in a few million years moreover nearly simultaneously with the late miocene strengthening of the monsoon the calcite compensation depth in the oceans dropped plants using the relatively efficient c4 pathway for photosynthesis evolved rapidly and atmospheric co2 seems to have decreased suggesting causal relationships and positive feedbacks among these phenomena both a supplemental uplift of the himalaya the southern edge of tibet and a strengthened monsoon may have accelerated erosion and weathering of silicate rock in the himalaya that in turn enhanced extraction of co2 from the atmosphere thus these correlations offer some support for links between plateau uplift a downdrawing of co2 from the atmosphere and global climate change as proposed by raymo ruddiman and froehlich mantle dynamics beneath mountain belts not only may profoundly affect tectonic processes near and far from the belts but might also play an important role in altering regional and global climates

rupture directivity of small earthquakes at parkfield 1 theoretical modeling of strike slip ruptures along a bimaterial interface suggests that earthquakes initiating on the interface will have a preferred rupture direction we test this model with 450 small earthquakes 2 3 exhibiting southeast rupture characteristics some spatial and temporal variability in rupture directivity is also apparent we observe a higher proportion of northwest directivity ruptures following the 2004 m 6 parkfield earthquake which ruptured toward the northwest our results are generally consistent with the preferred southeast rupture directivity model but suggest that directivity is likely due to several contributing factors

arctic underwater noise transients from sea ice deformation characteristics annual time series and forcing in beaufort sea a 13 month time series of arctic ocean noise from the marginal ice zone of the eastern beaufort sea is analyzed to detect under ice acoustic transients isolated from ambient noise with a dedicated algorithm noise transients due to ice cracking fracturing shearing and ridging are sorted out into three categories broadband impulses frequency modulated fm tones and high frequency broadband noise their temporal and acoustic characteristics over the 8 month ice covered period from november 2005 to mid june 2006 are presented and their generation mechanisms are discussed correlations analyses showed that the occurrence of these ice transients responded to large scale ice motion and deformation rates forced by meteorological events often leading to opening of large scale leads at main discontinuities in the ice cover such a sequence resulting in the opening of a large lead hundreds by tens of kilometers in size along the margin of landfast ice and multiyear ice plume in the beaufort chukchi seas is detailed these ice transients largely contribute to the soundscape properties of the arctic ocean for both its ambient and total noise components some fm tonal transients can be confounded with marine mammal songs especially when they are repeated with periods similar to wind generated waves

under ice ambient noise in eastern beaufort sea canadian arctic and its relation to environmental forcing this paper analyzes an 8 month time series november 2005 to june 2006 of underwater noise recorded at the mouth of the amundsen gulf in the marginal ice zone of the western canadian arctic when the area was 90 ice covered the time series of the ambient noise component was computed using an algorithm that filtered out transient acoustic events from 7 min hourly recordings of total ocean noise over a 0 4 1 khz frequency band under ice ambient noise did not respond to thermal changes but showed consistent correlations with large scale regional ice drift wind speed and measured currents in upper water column the correlation of ambient noise with ice drift peaked for locations at ranges of 300 km off the mouth of the amundsen gulf these locations are within the multi year ice plume that extends westerly along the coast in the eastern beaufort sea due to the large beaufort gyre circulation these results reveal that ambient noise in eastern beaufort sea in winter is mainly controlled by the same meteorological and oceanographic forcing processes that drive the ice drift and the large scale circulation in this part of the arctic ocean

ocean surface wave evolvement in the arctic basin 1 recent basin scale changes to the compactness and thickness of arctic sea ice foreshadow that encroaching swells and locally generated waves will exert more influence there in the future indeed it is conceivable that waves may have already hastened the adjustments observed by breaking up ice floes yet waves advancing in sea ice attenuate due to being scattered from ice thickness variations and damped by ice inelasticity turbulence and friction while past research focuses on scattering by unnaturally perfect features in the ice the model reported herein assimilates realistic basin scale swathes of heterogeneous ice and parameterizes damping by way of example we show how an ocean wave train evolves during its passage in an 1670 km long arctic sea ice profile obtained from submarine

low frequency bursts of horizontally polarized waves in the arctic sea ice cover we report the detection of bursts of low frequency waves typically f 0 025 hz on horizontal channels of broadband seismometers deployed on the arctic sea ice cover during the damocles developing arctic modeling and observing capabilities for long term environmental studies experiment in spring 2007 these bursts have amplitudes well above the ambient ice swell and a lower frequency content their typical duration is of the order of minutes they occur at irregular times with periods of relative quietness alternating with periods of strong activity a significant correlation between the rate of burst occurrences and the ice cover deformation at the 400 km scale centered on the seismic network suggests that these bursts are caused by remote episodic deformation involving shearing across regional scale leads this observation opens the possibility of complementing satellite measurements of ice cover deformation by providing a much more precise temporal sampling hence a better characterization of the processes involved during these deformation events

the 2004 mw6 0 parkfield california earthquake inversion of near source ground motion using multiple data sets on 28 september 2004 the m w 6 0 parkfield earthquake became the most densely recorded earthquake for near source ground motion to infer the kinematic nature of this event we invert the strong motion data the non linear global inversion yields slip amplitude slip rake average rupture velocity and rise time over the fault by using subsets of the data we study the dependence of the kinematic solutions on data input the inversions reveal that the slip amplitude was less than 0 65 m and outline two major areas of slip one that laterally surrounds the hypocenter preferentially extending to its se the other 10 to 20 km nw of the hypocenter at a depth between 2 and 8 km the slip amplitude we obtain for each point on the fault varies less than 0 15 m depending on data set used the rake angle variability is less than 40 degrees

towards a mechanical model for the formation of the pannonian basin abstract new maps showing crustal and lithospheric thickness variations in the pannonian basin and the surrounding east alpine carpathian and dinaric mountains have been prepared on the basis of recent seismic seismologic and electromagnetic data a map presenting miocene faults of regional significance has been also constructed for the same region by using a wealth of recently available national and or more local studies it is suggested that observed crustal and lithospheric structural contrasts have been controlled primarily by neogene kinematic history of the region kinematic history is characterized by the following main patterns 1 1 indentation by adria and large scale backthrusting in the southern alps 2 2 eastward escape and extension of the eastern alps 3 3 extensional collapse in the pannonian basin area 4 4 formation of broad wrench fault systems along strike in the dinarides and southern carpathians and the western carpathians with dextral and sinistral shear respectively 5 5 compression and accretion of the external thrust and fold belt in the eastern carpathians these kinematic patterns are thought to be interrelated and all are manifestations of the late stage evolution of an overthickened orogenic wedge in order to arrive at a better understanding of the mechanism of extension which formed the pannonian basin deep crustal seismic profiles hydrocarbon exploration reflection lines and borehole data have been analyzed in the little hungarian plain this plain represents the transition zone between the alps and the pannonian lowlands and the results are illustrated by eight interpreted cross sections one result of regional importance is the clear recognition that the transdanubian central range at the southeastern flank of the little hungarian plain is composed of alpine pre senonian thrust sheets this finding marks the end of a century of debate the allochthony of the substrata of the pannonian basin can be now considered proven another result of more general interest is that these cross sections document the mode of lithospheric extension preexisting compressional detachment planes reactivate as low angle normal faults and lead to tectonic unroofing of deeply buried metamorphic terranes characterized by ductile flow along subhorizontal lineation

experimental characterization of elastic waves in a floating ice sheet frequency wave number analysis is applied to geophone data to study phase velocities of ice waves as a function of frequency previous measurements of phase velocities were based primarily on initial arrival time of individual waves which were valid only for the frequency components associated with the initial arrival by processing the geophone array data coherently this frequency wave number analysis measures the phase velocity as a function of frequency for a wide frequency band this processing is applied to geophone data collected on a line array of three axis geophones the data were generated by striking sledge hammers against a steel pipe frozen into the ice during an arctic experiment in 1988 as expected the longitudinal and horizontal shear waves travel with constant phase velocities below 100 hz applying this analysis to vertical axis geophone data we find two families of dispersion curves for the flexural waves only one dispersion curve is expected for the flexural wave for a uniform she

importance of bimaterial interfaces for earthquake dynamics and strong ground motion summary we perform a numerical investigation of dynamic ruptures on a bimaterial interface in 3 d with regularized slip weakening friction and a heterogeneous initial shear stress and discuss the resulting strong ground motion to isolate effects introduced by the material contrast we perform pairs of simulations with opposite material orientations we show that for many parameter sets the dynamics of rupture propagation are significantly influenced by the broken symmetry due to the material contrast during rupture propagation the resulting slip histories of two events with reversed orientations of the material contrast can deviate such that the emanating waves lead to large differences in peak ground motion peak ground velocity and peak ground acceleration even when slip distribution of the individual events are very similar and therefore their moment magnitudes are basically identical we also show that the wrinkle like slip pulse specific to the bimaterial mechanism can be nucleated naturally from an initially crack like mode of rupture when the initial stress allows for large propagation distances once such a pulse has been nucleated it travels at a dominant propagation speed close to the generalized rayleigh velocity the dynamic weakening of the fault due to the normal stress alteration during slip allows nucleating ruptures to overcome asperities of low initial shear stress in the preferred direction which is the direction of displacement on the seismically slower side of the fault in such situations the orientation of the material contrast determines rupture extent and therefore the size of the earthquake potentially by orders of magnitude

frictional constraints on crustal faulting we consider how variations in fault frictional properties affect the phenomenology of earthquake faulting in particular we propose that lateral variations in fault friction produce the marked heterogeneity of slip observed in large earthquakes we model these variations using a rate and state dependent friction law where we differentiate velocity weakening behavior into two fields the strong seismic field is very velocity weakening and the weak seismic field is slightly velocity weakening similarly we differentiate velocity strengthening behavior into two fields the compliant field is slightly velocity strengthening and the viscous field is very velocity strengthening the strong seismic field comprises the seismic slip concentrations or asperities the two intermediate fields weak seismic and compliant have frictional velocity dependences that are close to velocity neutral these fields modulate both the tectonic loading and the dynamic rupture process during the interseismic period the weak seismic and compliant regions slip aseismically while the strong seismic regions remain locked evolving into stress concentrations that fail only in main shocks the weak seismic areas exhibit most of the interseismic activity and aftershocks but can also creep seismically this mixed frictional behavior can be obtained from a sufficiently heterogeneous distribution of the critical slip distance the model also provides a mechanism for rupture arrest dynamic rupture fronts decelerate as they penetrate into unloaded complaint or weak seismic areas producing broad areas of accelerated afterslip aftershocks occur on both the weak seismic and compliant areas around a fault but most of the stress is diffused through aseismic slip rapid afterslip on these peripheral areas can also produce aftershocks within the main shock rupture area by reloading weak fault areas that slipped in the main shock and then healed we test this frictional model by comparing the seismicity and the coseismic slip for the 1966 parkfield 1979 coyote lake and 1984 morgan hill earthquakes the interevent seismicity and aftershocks appear to occur on fault areas outside the regions of significant slip these regions are interpreted as either weak seismic or compliant depending on whether or not they manifest interevent seismicity

neogene quaternary structures in the border zone between alps dinarides and pannonian basin hrvatsko zagorje and karlovac basins croatia analysis of neogene quaternary structures from seismic lines surface measurements and geological mapping is presented from the border zone between the alps dinarides and pannonian basin first early miocene extension was possibly characterised by ene directed extension it was partly synchronous with nw se shortening second middle miocene extension was possibly characterised by nw se to wnw ese directed extension again this event was followed by a new generation of thrusts related to end sarmatian shortening the last late miocene e w to wnw ese directed extension was followed by a final shortening that created major map scale folds basement pop ups and inverted former basins geometry onlap and thickness patterns of the youngest syn tectonic basin fill indicate that this last n s to nw se directed shortening started in late pontian and continued up to the present time when taking into account the wider surrounding area it seems that the structures related to this latest shortening are arranged in often perpendicular directions centred at the eastern end of the periadriatic lineament to explain this fan like pattern of synchronous shortenings a kinematic model is proposed combining counter clockwise rotation with north or northwestward shift of the dinaridic block with respect to the more stable alpine buttress

the alhama de murcia fault se spain a seismogenic fault in a diffuse plate boundary seismotectonic implications for the ibero magrebian region received 20 december 2002 revised 15 september 2003 accepted 26 september 2003 published 2 january 2004 1 the shortening between the african and the iberian plates is absorbed by a number of faults distributed over a very wide zone with very low slip rates and long periods of seismic loading thus a seismotectonic map based only on faults associated with seismicity or with expressive geomorphic features is incomplete it is possible to characterize seismogenic faults using paleoseismology first paleoseismological results based on trenching analysis in the eastern betics lorca totana segment of the alhama de murcia fault are presented the main paleoseismic parameters of this fault segment are 1 a minimum of two to three mw 6 5 7 earthquakes in the last 27 kyr shortly before 1650 a d between 830 and 2130 b c and shortly before 16 7 ka respectively with a mean recurrence period of 14 kyr and a very short elapsed time and 2 a net slip rate of 0 07 0 6 mm yr during the last 30 kyr these results were extrapolated to the rest of the known active faults in the eastern betics and were added to the slip rates of the active faults at the african margin the total slip rate of the transect which crosses de alhama de murcia fault in spain and reaches the cheliff basin algeria would represent 21 82 of the total shortening between africa and eurasia estimated from plate motion models and seismic moment summation a number of factors could account for this discrepancy 1 hidden seismogenic faults in the emerged areas 2 absence of correlation between current and late pleistocene slip rates 3 extensive small faults that are undetected and that absorb a significant amount of the deformation and 4 possible overestimation of the convergence rates index terms 7221 seismology paleoseismology 7230 seismology seismicity and seismotectonics 7215 seismology earthquake parameters 8150 tectonophysics plate boundary general 3040 keywords eastern betics alhama de murcia fault paleoseismology trenching seismotectonics plate boundary

a spatial random field model to characterize complexity in earthquake slip 1 finite fault source inversions reveal the spatial complexity of earthquake slip over the fault plane we develop a stochastic characterization of earthquake slip complexity based on published finite source rupture models in which we model the distribution of slip as a spatial random field the model most consistent with the data follows a von karman autocorrelation function acf for which the correlation lengths a increase with source dimension for earthquakes with large fault aspect ratios we observe substantial differences of the correlation length in the along strike a x and downdip a z directions increasing correlation length with increasing magnitude can be understood using concepts of dynamic rupture propagation the power spectrum of the slip distribution can also be well described with a power law decay i e a fractal distribution in which the fractal dimension d remains scale invariant with a median value d 2 29 0 23 while the comer wave number k c which is inversely proportional to source size decreases with earthquake magnitude accounting for larger slip patches for large magnitude events our stochastic slip model can be used to generate realizations of scenario earthquakes for near source ground motion simulations

directivity detection and source properties of the 11 may 2011 mw 5 2 lorca spain earthquake a kinematic finite source study of the 11 may 2011 m w 5 2 lorca spain earthquake has been performed using broadband data from the spanish national network the nodal plane ambiguity of the double couple solution was resolved from finite source analysis and a rupture velocity of 1 8 km s 1 and the northeast southwest striking northwest dipping plane was found to best fit the data this fault plane corresponds to the central sector of the alhama de murcia fault amf the resulting slip distribution has a maximum of 19 3 cm and a total seismic moment of 6 25 1016 n m a jackknife test has been performed to estimate the fault plane errors and their consequences in the slip distribution also synthetic tests have been performed to evaluate the errors in the finite source modeling from this model a prediction of the strong ground motion near the fault corrected for soil amplification is given in terms of peak ground velocity pgv which fits with the observed value at the accelerograph in the city of lorca we also compared the pgv converted to modified mercalli intensity at the surface with the intensity distribution also showing good agreement finally we extracted the directivity pulse from the strong ground motion record at lorca with 0 5 s period in the transverse component to the amf direction and 33 cm s 1 pgv to further analyze the directivity effect we estimate the duration and azimuthal amplitude distribution of the source time functions finding them to be shorter and of greater amplitude in the direction of rupture and longer and smaller in amplitude in the opposite direction

tertiary to recent oblique convergence and wrenching of the central dinarides constraints from a palaeostress study the late eocene to neogene tectonic evolution of the dinarides is characterised by shortening and orogen parallel wrenching superposed on the late cretaceous and eocene double vergent orogenic system the central dinarides exposes nw trending tectonic units which were transported towards the adria apulian microcontinent during late cretaceous palaeogene times these units were also affected by subsequent processes of late palaeogene to neogene shortening neogene extension and subsidence of intramontane sedimentary basins and pliocene quaternary surface uplift and denudation the intramontane basins likely relate to formation of the pannonian basin major dextral se trending strike slip faults are mostly parallel to boundaries of major tectonic units and suggest dextral orogen parallel wrenching of the whole central dinarides during the neogene indentation of the apulian microplate into the alps and back arc type extension in the pannonian basin these fault systems have been evaluated with the standard palaeostress techniques we report four palaeostress tensor groups which are tentatively ordered in a succession from oldest to youngest 1 palaeostress tensor group 1 d1 of likely late eocene age indicates e w shortening accommodated by reverse and strike slip faults 2 palaeostress tensor group 2 d2 comprises n nw trending dextral and w wsw trending sinistral strike slip faults as well as wnw striking reverse faults these indicate ne sw contraction and subordinate nw se extension related to oligocene to early miocene shortening of the dinaric orogenic wedge 3 palaeostress tensor group 3a d3a comprises mainly nw trending normal faults which indicate early middle miocene ne sw extension related to syn rift extension in the pannonian basin the subsequent palaeostress tensor group 3b d3b includes ne trending se dipping normal faults indicating nw se extension which is likely related to further extension in the pannonian basin 4 palaeostress tensor group 4 d4 i s characterised by mainly nw trending dextral and ne trending sinistral strike slip faults together with some e trending reverse faults they indicate roughly n s shortening and dextral wrenching during late miocene to quaternary this is partly consistent with the present day kinematics with motion of the adriatic microplate constrained by gps data and earthquake focal mechanisms the north north westward motion and counterclockwise rotation of the adriatic microplate significantly contribute the shortening and present day wrenching in the central dinarides d 2005 elsevier b v all rights reserved

the november 2017 mw 5 5 pohang earthquake a possible case of induced seismicity in south korea the moment magnitude mw 5 5 earthquake that struck south korea in november 2017 was one of the largest and most damaging events in that country over the past century its proximity to an enhanced geothermal system site where high pressure hydraulic injection had been performed during the previous 2 years raises the possibility that this earthquake was anthropogenic we have combined seismological and geodetic analyses to characterize the mainshock and its largest aftershocks constrain the geometry of this seismic sequence and shed light on its causal factors according to our analysis it seems plausible that the occurrence of this earthquake was influenced by the aforementioned industrial activities finally we found that the earthquake transferred static stress to larger nearby faults potentially increasing the seismic hazard in the area

accurate estimations of sea ice thickness and elastic properties from seismic noise recorded with a minimal number of geophones from thin landfast ice to thick pack ice despite their high potential for accurate sea ice properties estimation seismic methods are still limited by the difficulty of access and the challenging logistics of polar environments conventional seismic methods generally require tens of geophones together with active seismic sources for monitoring applications while this is not an issue for mainland environment it is restrictive for sea ice and prevents long term monitoring we introduce a method to estimate sea ice thickness and elastic properties from passive recordings of the ambient seismic field with a minimal number of geophones in comparison with our previous work moreau et al 2020 where about 50 sensors were used the number of geophones is reduced by one order of magnitude thanks to a new strategy of inversion of the passive seismic data the method combines noise interferometry for estimating the elastic properties with a bayesian inversion of the dispersion in the waveforms of icequakes for inferring ice thickness based on passive recordings from only 3 to 5 geophones depending on the signal to noise ratio we demonstrate its potential both on data recorded on thin landfast ice in svalbard and on data recorded on thick pack ice in the arctic ocean

earthquake rupture propagation inferred from the spatial distribution of fault rock frictional properties abstract the frictional properties of fault rocks that rupture during earthquakes are expected to affect the nucleation and propagation of seismic slip but these properties and their variation under in situ earthquake conditions are typically unknown here we present experimental results on the variation of frictional properties of fault rocks from the alhama de murcia fault amf in se spain which ruptured in the 2011 lorca earthquake in the epicentral area the fault zone is characterized by the presence of abundant phyllosilicate rich gouges that surround more competent fractured lenses of the phyllitic basement measurements of lineaments and orientations of r shears in the gouges are consistent with cmt solutions of the 2011 lorca earthquake suggesting that the bulk of displacement on the amf was accommodated within similar gouges at depth in order to evaluate the frictional properties of the fault rocks of the amf we performed rotary shear experiments under hydrothermal conditions of samples obtained from surface outcrops of the amf zone progressively simulating deeper levels in the crust by stepping temperature effective normal stress and fluid pressure a negative velocity dependence of friction expressed as a negative value of the rate and state friction rsf parameter a b and which is a prerequisite for the nucleation of an instability was observed only for samples derived from competent lenses under hydrothermal conditions gouge derived samples exhibited only velocity strengthening properties i e positive values of a b which increase with deeper conditions in particular with increasing effective normal stress combined with our outcrop observation of the anastomosing nature of gouges surrounding more competent lenses of fractured protolith our results suggest that the 2011 lorca earthquake nucleated in the competent lenses followed by propagation of slip into the frictionally weaker gouges the inferred upward propagation direction of the 2011 lorca earthquake is consistent with propagation of the rupture into the velocity strengthening gouges which at shallower levels provide a smaller barrier to seismic slip due to lower values of effective normal stress and a b our results suggest that the spatial variation of the frictional properties along the amf was an important factor controlling the nucleation and propagation of seismic slip which together with the shallow hypocenter close to the city of lorca led to serious damage we infer that understanding of such variations in frictional properties may significantly improve seismic hazard evaluations in tectonically active regions

analysis of the ground accelerations radiated by the 1980 livermore valley earthquakes for directivity and dynamic source characteristics the strong motion accelerograph recordings of the 24 january 1980 main shock and the 27 january 1980 aftershock of the livermore valley earthquake sequence are analyzed for systematic variations with azimuth or station location the variation of the peak accelerations with epicentral azimuth is apparently reversed for the two events the main shock accelerations are larger to the south and the aftershock accelerations are larger to the northwest we eliminate the site effects by forming the ratio of the peak accelerations recorded at the same station after correcting for the epicentral distance this analysis indicates that source directivity caused a total variation of a factor of 10 in the peak accelerations comparison of this variation with the spatial extent of the aftershock sequences suggests that the strong directivity in the radiated accelerations is the result of unilateral ruptures in both events the accelerograms recorded at 10 stations within 35 km of the events were digitized to analyze the azimuthal variation of the rms acceleration the peak velocity and the radiated energy flux the variation of rms acceleration correlates almost exactly with the variation of the peak accelerations this correlation is analyzed using both deterministic and stochastic models for the acceleration waveforms the peak velocities corrected for epicentral distance vary with azimuth by a factor of 5 for both events while the radiated energy flux varies by a factor of 30 for the main shock and 15 for the aftershock the peak velocities are strongly correlated with the radiated energy flux the radiated seismic energies are estimated to be 2 6 0 9 1020 dyne cm for the main shock and 1 5 0 3 1020 dyne cm for the aftershock

sea ice thickness measurement based on the dispersion of ice swell the dispersion of flexural waves propagating in the arctic sea ice cover is exploited in order to locally measure the ice thickness the observed dispersion for waves filtered in the 4 20 s period interval at up to 4 broad band seismometers deployed in spring 2007 near the north pole is compared to a parameterized model that accounts for a complex wavefield made of a superposition of independent plane waves with different amplitudes and back azimuth angles the parameterization that includes finding the best modeled ice thickness is performed by using the cross correlation functions between the seismometers the ice thickness is estimated to 2 5 0 2 m for the 1 km large floe the seismic stations were deployed on which is coherent with other independent measurements at this site this study thus demonstrates the feasibility of using broad band seismometers deployed on the sea ice in order to passively measure the ice thickness without requiring active sources nor human intervention

recent tectonic stress and crustal deformation in and around the pannonian basin data and models this paper is part of the special publication no 156 the mediterranean basins tertiary extension within the alpine orogen eds b durand l jolivet f horvath and m seranne recent active tectonics of the pannonian basin and its surrounding has been investigated using data from over 900 earthquake focal mechanism solutions 200 borehole breakout analyses some in situ stress measurements and by applying finite element modelling technique we have established a database for indicators of recent stress and analysed the stress state of the region by the methods of the world stress map project the alignments of the largest horizontal stresses have been mapped and the tectonic regimes were also determined we present a map of seismoactive faults and seismic energy release combining historical and modern seismicity data and results of local seismotectonic studies the pattern of earthquake slip vectors and the style of faulting are summarised in order to characterise the active deformations our results show that the alignment of the largest horizontal stress exhibits a radial pattern around the adriatic sea in the southern alps and northwestern dinarides the largest horizontal stress sh is aligned n s and thrust faulting is dominant along the southern dinarides and the dalmatian coast thrusting with strike slip component can be observed here the trajectories of sh are aligned ne sw e w aligned sh trajectories and normal faulting are characteristic of the rhodope massif thrust faulting of the vrancea region seems to be distinct from the compressive regime around the adriatic sea in the pannonian basin borehole breakout analyses show that the direction of largest horizontal stress is changing from n s in the western part to ne sw in the east most of focal mechanisms and available hydraulic fracturing measurements indicate strike slip and thrust faulting inside the basin the lack of normal faulting mechanisms indicates that the extension of the basin has been terminated and a new compressive stress regime prevails the crustal deformation of the area is controlled by the counterclockwise rotation of adria with respect to europe around a pole at the 45 n latitude and 6 10 e longitudes which is inferred from satellite geodesy and supported by earthquake slip vectors this movement can explain the shortening of the southern alps and squeezing eastward the region between the adriatic sea and the mur murz line rotation of adria generates thrusts along the dalmatian coast and this compressive deformation extends into the land far from the coastline and leads to squeezing of the pannonian basin from the southwest the seismicity pattern in the pannonian basin shows that earthquakes are restricted to the crust and the control by pre existing mostly miocene fault zones is strongly masked by random activity due to general weakness of the lithosphere although earthquakes are of small to medium magnitude m 6 the cummulative energy release is remarkably higher than in the surrounding carpathian arc the vrancea zone is the only exception where high energy release in the crust and down to 200 km depth is associated with a relict subducted slab finite element stress modelling has been performed in order to simulate the observed stress pattern and hence to understand the importance of different possible stress sources in and around the pannonian basin the observed radial stress pattern of the region can be well explained by the counterclockwise rotation of the adriatic microplate as a first order stress source additional boundary conditions such as the active deformation at the vranceas zone and the role of rigid crustal blocks at the bohemian massif and the moesian platform can significantly effect the style of deformation and the alignment of the largest horizontal stress furthermore our calculations show that differences in the crustal thickness and the presence of large scale fault zones in the pannonian region have only local influence on the model results

interpretation of earthquake epicenter and cmt centroid locations in terms of rupture length and direction abstract a comparison is made between hypocenter and centroid estimates of shallow earthquakes to investigate whether the difference between these two quantities contains useful information on fault rupture length and direction an initial comparison of international seismological centre isc and harvard centroid moment tensor cmt catalog locations suggests that for earthquakes below mw 6 5 the difference in location is dominated by location errors whilst larger earthquakes appear to show the effect of increasing spatial rupture however for this data set combined location errors greater than 25 km are observed for a majority of earthquakes imposing a limit on interpretation we use these constraints to investigate this approach using a consistent earth model in the re analysis of eight previously well studied events new hypocenter estimates based on teleseismic p wave arrivals from the isc bulletin and a 3 d velocity model of the mantle s p12 wm13 are compared with new centroid locations obtained using the same 3 d model and waveform data from international deployment of accelerometers ida global digital seismic network gdsn and re calibrated high gain long period hglp stations the distance between our new hypocenter and centroid locations is shown to provide reliable information on both the rupture length and direction the rupture lengths and azimuths generally agree with the most recent previous results from other methods and provide an absolute estimate of the location of the rupture

modelling recent deformation of the pannonian lithosphere lithospheric folding and tectonic topography article i nfo we investigated the role of lithospheric folding in the quaternary inversion of the pannonian basin by a series of analogue models to this aim build up of stresses due to intraplate compression in the hot and weak pannonian lithosphere changes in the style of deformation and related surface processes were modelled the primary response of the lithosphere to compression appears to be deformation in the form of large scale folding as a consequence of the folding differential crustal motions occur affecting present day surface morphology and landscape processes the analogue experiments examined folding mechanisms of the hot pannonian lithosphere characterised by extremely low strengths except for a thin layer of brittle upper crust modelling results confirmed the existence of a large wavelength 350 400 km component of deformation accounting for large scale vertical crustal motions the amplitude of folding is sufficient to generate the amount of observed uplift and subsidence our analogue models supported by the results of stress analyses suggest that despite the low rate of convergence between the adriatic microplate adria push and the european plate the weak pannonian lithosphere has been an efficient transmitter of compression during the basin inversion crustal thickness variations are of key importance in governing regional deformation pattern and influence the timing and extent of the basin inversion effects of alternating strong and weak units in the brittle crust were also examined by means of two series of conceptual models in which the order of thin and thick crustal blocks was opposite strain localisation in the brittle crust was strongly controlled by the moderate initial thickness variations the concept gives a plausible explanation for the presence of anomalous rates of uplift and subsidence and multi wavelength folding inside the basin models taking into account horizontal movements due to lateral extrusion were constructed with an oblique face of the indenter this kinematic boundary condition resulted in a complex internal structure of the folded layers the presented analogue experiments together with previous numerical modelling studies demonstrate the link between large scale lithospheric folding and topography evolution in the pannonian basin system

milankovitch scale multi proxy records from fluvial sediments of the last 2 6 ma pannonian basin hungary abstract the continuous cores of two nearly 500 m deep boreholes cutting pleistocene fluvial sequences in the eastern part of the pannonian basin hungary have been studied magnetostratigraphy indicates that the sediment sequences span the last 2 6 ma without significant hiatuses comparison of systematic variations in magnetic susceptibility with changes in grain size distribution revealed milankovitch scale cyclicity in sedimentation of 40 and 100 kyr cyclicity which also shows a correspondence with the 18o variations of the odp 677 site comparison of pollen and gastropod paleoecological data with the magnetic susceptibility proxies suggests that climate was a major allogenic control on the cyclicity zones of high magnetic susceptibility correspond closely with sandy and coarse silty parts of the borehole successions which largely coincide with pollen and molluscs indicating a warm climate on the contrary zones with low magnetic susceptibility correspond to silts and clays and in most cases coincide with cold climate indicator pollen and molluscs heavy mineral and xrd studies revealed that magnetic susceptibility reflects the absolute amount of detrital fe oxide minerals mostly magnetite variations in the amount of magnetite are related to changes in heavy mineral content which arise primarily from changes in sediment supply to the basin by rivers the depositional model for the pleistocene fluvial sediments suggests that sediment flux increased towards the basin during interglacials due to the increased discharge and transport capacity of the rivers while a decreased sediment supply to the distal parts of the basin occurred during glacials a delay between erosion and storage of weathering products near to the source area and subsequent transportation and re deposition of sediments in the basin interior setting is an important cause of this effect

magnitude scaling of the near fault rupture directivity pulse abstract current ground motion models all assume monotonically increasing spectral amplitude at all periods with increasing magnitude however near fault recordings from recent earthquakes confirm that the near fault fault normal forward rupture directivity velocity pulse is a narrow band pulse whose period increases with magnitude this magnitude dependence of the period of the near fault pulse is expected from theory because the period of the pulse is related to source parameters such as the rise time duration of slip at a point on the fault and the fault dimensions which generally increase with magnitude this magnitude dependence of the pulse period causes the response spectrum to have a peak whose period increases with magnitude such that the near fault ground motions from smaller earthquakes may exceed those of larger earthquakes at intermediate periods around 1 s this paper presents preliminary equations relating the period of the fault normal component of the forward rupture directivity velocity pulse to the earthquake magnitude and a preliminary model for the acceleration response spectra of near fault fault normal ground motions that includes the magnitude dependence of the period of the response spectral peak

high frequency directivity effect for an mw 4 1 earthquake widely felt by the population in southeastern france abstract we document a moderate earthquake in the french alps 26 february 2012 m w 4 1 that has been much more distinctly felt south of the event than north of it this discrepancy was especially clear in the two large cities of nice and grenoble both situated at 100 km from the epicenter this observation was confirmed by ground motion measurements that were eight times larger in one city than in the other one for the same site conditions using a time domain deconvolution between the broadband recordings of the mainshock and an aftershock used as empirical green s functions we show that the rupture process of this event had a strong directivity effect toward a direction of n155 5 on an 2 km long fault detectable only at frequencies higher than 1 hz the fault size and direction are in good accordance with the location of the aftershocks despite the various possible contributions leading to high frequency amplification we show here that this simple directivity effect controlled the intensity felt by the population and the acceleration measured in the cities

predominance of unilateral rupture for a global catalog of large earthquakes the manner in which an earthquake rupture propagates across a fault reflects both the initial properties of the fault and the dynamical stresses produced by the rupture we quantify the propagation of an earthquake rupture using the second moments of the earthquake space time distribution in particular the second moments provide a simple way to differentiate between approximately bilateral and predominantly unilateral ruptures we determined the second moments for a catalog of m w 7 earthquakes that have occurred since 1994 the results show that approximately 80 of large shallow ruptures are predominantly unilateral our result agrees well with strong motion inversions from previous studies on moderate and large earthquakes the predominance of unilateral propagation in large earthquakes is explained by a simple characteristic earthquake model in which large events rupture an entire structurally defined fault segment and nucleation points are uniformly distributed along the fault the predominance of unilateral rupture may also be enhanced by the dynamic stress field produced by contrasts in the elastic properties between the two sides of plate boundary faults manuscript received 16 november 2001

monitoring ice thickness and elastic properties from the measurement of leaky guided waves a laboratory experiment the decline of arctic sea ice extent is one of the most spectacular signatures of global warming and studies converge to show that this decline has been accelerating over the last four decades with a rate that is not reproduced by climate models to improve these models relying on comprehensive and accurate field data is essential while sea ice extent and concentration are accurately monitored from microwave imagery an accurate measure of its thickness is still lacking moreover measuring observables related to the mechanical behavior of the ice such as young s modulus poisson s ratio etc could provide better insights in the understanding of sea ice decline by completing current knowledge so far acquired mostly from radar and sonar data this paper aims at demonstrating on the laboratory scale that these can all be estimated simultaneously by measuring seismic waves guided in the ice layer the experiment consisted of leaving a water tank in a cold room in order to grow an ice layer at its sur

rupture directivity of the 18 april 2008 mt carmel illinois earthquake from modeling of local seismic waveforms the 2008 m w 5 2 mt carmel earthquake is the largest earthquake in the last 50 yrs in southeastern illinois near the north termination of the north northeast trending wabash valley fault system wvfs the earthquake shows almost pure strike slip focal mechanism but it is still uncertain which nodal plane np is the ruptured fault plane to resolve the fault plane we determine rupture directivity of the earthquake via the relative centroid method we begin with inverting the point source solution strike 297 dip 84 rake 1 for np1 strike 206 dip 89 rake 173 for np2 and centroid depth 16 km and then determine the relative location between the centroid and hypocenter via regional waveform fitting two m 4 aftershocks are used as reference events and the waveform time shifts of reference events with respect to the 1d velocity model are used to calibrate the path effects the results show that the illinois mainshock ruptured to east southeast along the 297 np for about 2 3 km consistent with relocated aftershock distribution and we infer that the sinistral causative fault connects the north northwest trending la salle anticlinal belt and the north northeast trending wvfs

tectonic activity in the croatian part of the pannonian basin abstract three main stages in structural development of the sw pannonian basin are differentiated the onset of extensional tectonics between the oligocene and the early miocene main extensional processes in the early and middle miocene and prevailing transpression in the pliocene and quaternary the neotectonic phase is given special attention in this paper structural fabrics allow to subdivide the area into three large structural zones corresponding to the western southern and central marginal part of the pannonian basin in croatia these zones are bounded by important faults the periadriatic drava fault the medvednica fault zone and the southern marginal fault of the pannonian basin the recent displacements within the dinarides and the eastern alps form the boundary conditions for active transpressional deformation in the western marginal part of the pannonian basin dextral transcurrent displacement is evident in the zone of the periadriatic drava wrench fault the formation of the new types of structures is observed especially in zones of compression along the faults narrowing of the area between the sava and drava rivers causes structural changes in the marginal parts of the corresponding basins i e in the areas close to the slavonian mts recent tectonic activity is marked by the occurrence of earthquakes which are most common in the northwestern part of croatia the spatial distribution of hypocentres and of seismotectonically active zones is used to reconstruct probable displacements and the structural style of deformation in depth the earthquake sources in the vicinity of the medvednica fault and the periadriatic drava fault are given special attention

present day lithospheric strength of the eastern alps and its relationship to neotectonics 1 we calculate the present day lithospheric strength of the eastern alps along the new reflection seismic profile transalp to examine vertical and lateral strength variations and their implications on neotectonic activity of the eastern alps the large scale geometry of the eastern alps and the spatial distribution of upper and lower crustal layers and the lithospheric mantle is constrained by the deep seismic line two rheological models coupled to a kinematic thermal model that accounts for the thermal evolution of the eastern alps for the last 30 myr are investigated for the present day lithospheric configuration in the eastern alps models with strong model a and weak model b crustal rheologies predict the european and the adriatic plates to be stronger than the central zone of the orogen comprising the region between the inntal fault and the periadriatic fault model a is characterized by a brittle ductile boundary between 14 and 9 km depth and strong coupling of the mechanically strong lower crust to the upper mantle whereas model b suggests the presence of a thick decoupling zone between the upper crust and the upper mantle and a shallower brittle ductile boundary 7 10 km of these end member scenarios model a is in better agreement with neotectonic data including seismicity down to the upper lower crust boundary within the adriatic plate uplift of the central zone of the eastern alps and the southern alps and eastward escape of fault bound blocks such deformation pattern is best explained by lateral extrusion upon north south compression supporting a strong weak strong configuration of tectonic units along the transalp line

quantification of quaternary vertical movements in the central pannonian basin a review of chronologic data along the danube river hungary abstract this study aims at a new quantification of neotectonic deformation of the central part of the pannonian basin we use terrace levels and associated travertine as well as speleothem data along the danube river to quantify its incision rate and thus estimate the amount and rate of uplift at the axis of the hungarian mountain range hmr several terrace levels and other geomorphic features along the danube river are indicative for quaternary uplift of the axial part of the emerging hungarian mountain range while the correlative terraces are at considerable height at the axis of the hmr the terraces are gradually dipping below the basin fill of the adjacent lowlands the correlation of the terrace segments is difficult because of their poor preservation small size and variable height the geomorphologic horizons indicate gradual incision of the river throughout the quaternary during simultaneous deformation however no reliable chronological data have been available so far to quantify landscape forming processes such as uplift incision or erosion rates a reconsideration of existing published data for three consecutive segments of the danube valley yields incision rates between 0 14 and 0 41 mm year for the last 360 ky with the highest value for the area of the danube bend accordingly the middle to late quaternary uplift rate of the axial zone of the hmr exceeded significantly that of the marginal areas these rates represent an approximation as some quantitative data are still controversial our results suggest that formation of the danube terraces is result of river incision triggered by the uplift of the hmr and modified by periodic climate changes

estimation of rupture propagation direction and strong motion generation area from azimuth and distance dependence of source amplitude spectra strong motion generation areas which reproduce ground motions in 0 2 to 10hz were estimated using the empirical green s function method this strong motion generation area was somewhat smaller than the total rupture area and coincident with the area of asperities derived from heterogeneous slip distributions estimated by waveform inversions using lower frequencies 1hz we confirmed that the azimuth and distance dependence of observed source amplitude spectra in the near source area i e rupture directivity effects were controlled by rupture propagation style and size of the strong motion generation area we found that the source displacement spectra at stations in forward rupture propagation directions had higher corner frequencies and steeper high frequency decays compared with stations in sideways directions stations in backward directions had opposite tendencies different relationships between size and average corner frequencies of the strong motion generation area were proposed for unilateral and bilateral ruptures with radial propagation

ambient seismic hydroacoustic and flexural gravity wave noise on a tabular iceberg cross correlation of ambient seismic noise between four seismographs on tabular iceberg c16 ross sea antarctica reveals both the source and the propagation characteristics of signals associated with icebergs we find that noise correlation functions computed from station data are asymmetric about zero time lag and this indicates that noise observed on the iceberg originates primarily from a compact localized source associated with iceberg collisions between c16 and a neighboring iceberg b15a we additionally find two and possibly more distinct phases of noise propagation we believe that flexural gravity wave propagation dominates the low frequency noise 10 s period and that hydroacoustic wave propagation in the water column between the ice and seabed appears to dominate high frequency noise 10 hz faster seismic propagation dominates the intermediate band 2 6 hz however we do not have sufficient data to characterize the wave mechanisms more precisely e g by identifying distinct longitudinal and shear body waves and or surface waves secular changes in the amplitude and timing of ambient noise correlations e g a diurnal cycle and an apparent shift in the noise correlation of fast seismic modes between two periods of the deployment allow us to speculate that ambient noise correlation analysis may be helpful in understanding the sources and environmental controls on iceberg generated ocean noise as well as geometric properties such as water column thickness of subglacial lakes

stress field variation related to fault interaction in a reverse oblique slip fault the alhama de murcia fault betic cordillera spain abstract the interpretation of kinematic data from microstructural observations has led many authors to propose a complex dynamic development for the eastern betic cordillera from the late miocene to the present in which different and sometimes contradictory stress fields explain the generation of the same structures the main aim of this work is to determine whether the dynamic variability of the study area observed during the neotectonic period is coherent with a single regional stress field the structure of the area was analysed through the detailed mapping of the alhama de murcia fault amf and the associated structures further microtectonic data from shear veins in an interaction zone between the main and secondary faults were studied by the stress inversion method of reches tectonics 6 1987 849 a hierarchy is proposed for stress fields and their interpretation with respect to the interaction between structures of different scales relative movements of fault bounded blocks with different sizes produce this hierarchy these movements depend on boundary conditions of blocks and their position relative to the alhama fault zone the study shows that adequate cartography and understanding the context of micro and mesotectonic data is necessary for determining the dynamic significance of microtectonic data the use of stress inversion methods without taking the local tectonic context into consideration can give rise to incorrect interpretations incorrect processing of previous data and extrapolations inappropriate at other scales

comparison of seasonal sea ice thickness change in the transpolar drift observed by local ice mass balance observations and floe scale em surveys local and transect ice thickness measurements were performed between may and november 2007 on an ice floe in the transpolar drift of the arctic ocean using an ice mass balance buoy and electromagnetic induction em sounding repeated em surveys along an originally 2160 m long profile including level and deformed ice showed that between june and september modal and mean thicknesses decreased by 0 6 and 0 86 m respectively the modal thickness decrease is in good agreement with the thinning of 0 6 m observed by the ice mass balance buoy at one location on unponded ice during the same period although the local observations do not capture the different melt rates on level and rough ice the paper discusses methodological and operational challenges in sustaining both measurements over periods of several months and concludes that more work needs to be done to better understand their representativeness

indentation model of the eastern alps and the origin of the tauern window a lithospheric model scaled for density and viscosity was shortened obliquely in front of an indenter whose shape and orientation match those of the south alpine indenter deformation was initially localized into subparallel sets of conjugate transpressive thrusts these structures evolved into folds which were strongly amplified and converged closer together during ongoing shortening finally forming a series of tight antiforms at the same time this tightly folded structure locally accommodated significant orogen parallel extension attaining 100 in front of the leading edge of the indenter but only 15 on the scale of the entire model the internal architecture and fault pattern of the model in map view are very similar to those of the tauern window in the eastern alps emphasizing the importance of localization of folding and shortening rather than orogen parallel extension for its formation

rupture directivity of microearthquake sequences near parkfield california 1 the direction of propagation is an important factor that affects the pattern of ground motion generated by an earthquake characterizing factors favoring a potential rupture propagation direction is thus an important task here we analyze the earthquake directivity of repeating earthquake sequences located on the san andreas fault near parkfield california all earthquakes of a sequence have very similar waveforms and have overlapping surface ruptures we show that subtle variations of the transfer function between earthquakes of a common sequence can be interpreted as a change of apparent rupture duration relative apparent rupture durations are computed for all pairs of events at all available stations and for each sequence we invert these measurements to obtain an estimation of the apparent rupture duration for each individual event of the sequence relative to a reference event variation of apparent rupture duration with azimuth attests for the rupture directivity we show that the majority of analyzed microearthquakes presents a rupture in the south east direction we also show that on a given repeating sequence most earthquakes tend to show the same rupture direction

late quaternary dynamics of the tisza river evidence of climatic and tectonic controls abstract the focus of this study is to understand a dramatic avulsion event on the tisza river during the late pleistocene the river course switched by about 80 km from the east to west of the great hungarian plain ghp through the zahony bend to its present meander belt the aim of this study is to date this zahony avulsion based upon radiocarbon and pollen samples from six cores in the polgar study area situated in the west of the ghp at the middle course of the tisza river in addition a grain size composition and heavy mineral analysis has been performed the results of these analyses reveal a sequence of paleochannels and have been plotted on a high resolution digital elevation model illustrating the paleochannel form and age relationships the study suggests that the age of this major avulsion event is significantly older than it was previously supposed instead of 10 to 11 ka it is according to our new data 16 18 ka and definitely predates the last glacial maximum lgm the river cut into the previous contiguous surface and formed at least one climatic terrace then drifted gradually westward as a response to a tilt or the differential subsidence of tectonic origin

lithospheric folding in iberia integration of stress indicator data gravity data crustal kinematics data and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large scale alpine to recent intraplate deformation in iberia the inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the surface support the existence of a close coupling with plate boundary processes operating at the margins of iberia patterns of lithosphere and upper crustal folds are oriented perpendicular to the main axis of present day intraplate compression in iberia inferred from structural analysis of stress indicator data and focal mechanism solutions these findings suggest the presence of lithospheric folds with wavelengths compatible with theoretical predictions of folding wavelengths of variscan lithosphere stress induced intraplate deformation set up by plate interactions is compatible with indications for the absence of present day deep mantle lithosphere interactions inferred from seismic tomography

extended fault inversion with random slipmaps a resolution test for the 2012 mw 7 6 nicoya costa rica earthquake inversions for the full slip distribution of earthquakes provide detailed models of earthquake sources but stability and non uniqueness of the inversions is a major concern the problem is underdetermined in any realistic setting and significantly different slip distributions may translate to fairly similar seismograms in such circumstances inverting for a single best model may become overly dependent on the details of the procedure instead we propose to perform extended fault inversion trough falsification we generate a representative set of heterogeneous slipmaps compute their forward predictions and falsify inappropriate trial models that do not reproduce the data within a reasonable level of mismodelling the remainder of surviving trial models forms our set of coequal solutions the solution set may contain only members with similar slip distributions or else uncover some fundamental ambiguity such as for example different patterns of main slip patches for a feasibility study we use teleseismic body wave recordings from the 2012 september 5 nicoya costa rica earthquake although the inversion strategy can be applied to any type of seismic geodetic or tsunami data for which we can handle the forward problem we generate 10 000 pseudo random heterogeneous slip distributions assuming a von karman autocorrelation function keeping the rake angle rupture velocity and slip velocity function fixed the slip distribution of the 2012 nicoya earthquake turns out to be relatively well constrained from 50 teleseismic waveforms two hundred fifty two slip models with normalized l1 fit within 5 per cent from the global minimum from our solution set they consistently show a single dominant slip patch around the hypocentre uncertainties are related to the details of the slip maximum including the amount of peak slip 2 3 5 m as well as the characteristics of peripheral slip below 1 m synthetic tests suggest that slip patterns such as nicoya may be a fortunate case while it may be more difficult to unambiguously reconstruct more distributed slip from teleseismic data

rupture directivity of the strongest 2016 2017 central italy earthquakes the along strike rupture directivity of 16 of the strongest earthquakes 4 4 mw 6 5 within the 2016 2017 central italy seismic sequence is estimated by investigating high frequency s wave amplitude variations versus source azimuths with an empirical green s function deconvolution approach the results confirm that an along strike rupture directivity is a persistent feature of normal faulting earthquakes in the apennines the preferred rupture directions of the 2016 2017 earthquakes and of similar magnitude events from the 1997 umbria marche and 2009 l aquila campotosto seismic sequences show a significant spatial consistency different sectors of the apennines show an alternating trend of preferential along strike rupture propagation directions with significant spatial and temporal stabilities independent of the magnitude these results if confirmed by further data could lead to more refined hazard assessments of the investigated region

surface wave tomography from microseisms in southern california received 5 april 2005 revised 23 may 2005 accepted 9 june 2005 published 26 july 2005 1 since it has already been demonstrated that point topoint seismic propagation green functions can be extracted from seismic noise it should be possible to image earth structure using the ambient noise field seismic noise data from 148 broadband seismic stations in southern california were used to extract the surface wave arrival times between all station pairs in the network the seismic data were then used in a simple but densely sampled tomographic procedure to estimate the surface wave velocity structure within the frequency range of 0 1 0 2 hz for a region in southern california the result compares favorably with previous estimates obtained using more conventional and elaborate inversion procedures this demonstrates that coherent noise field between station pairs can be used for seismic imaging purposes citation sabra k g p gerstoft p roux w a kuperman and m c fehler 2005 surface wave tomography from microseisms in southern california geophys res lett 32 l14311 doi 10 1029 2005gl023155

comment on basin inversion and fault reactivation in laboratory experiments a recent paper describing laboratory experiments on fault reactivation misinterprets the principles of scale models of physical systems by using inconsistent dimensionless ratios that determine the correspondence between model and nature for example the dimensionless stress ratio is not consistent with the dimensionless time ratio moreover consistent independent fundamental ratios of mass length and time cannot be derived from the values of the variables and constants known in both the model and nature consequently little information about the natural system can be derived from the model

gravity anomalies over the ferghana valley central asia and intracontinental deformation gravity anomalies over the ferghana valley a deep sedimentary basin in the western tien shan differ from those expected for local airy isostatic equilibrium by 120 mgal and imply a deficit of mass beneath the basin equivalent to a moho deeper by 10 km than prevails where isostasy holds although the ferghana valley is underlain by thick mesozoic and cenozoic sediment measurements of density show that this material cannot account for the deficit of mass gravity anomalies over both the surrounding mountain belts and the kazakh platform farther north imply that local airy isostatic equilibrium is approached flexure of a relatively thin effectively elastic plate thickness 10 15 km loaded by the present topography can account for the range of bouguer anomalies of 50 to 450 mgal over these regions we infer that approximately north south shortening of the relatively thin lithosphere has created mountains north and south of the basin has warped the basement of the immediate surroundings of the basin up by folding the mantle lithosphere and has forced the basin floor down beneath the ferghana valley it appears that the preexisting thermal structure and variations in crustal thickness have dictated the styles and distribution of deformation in this region

lunar subsurface investigated from correlation of seismic noise by correlating seismic noise recorded by four sensors placed on the moon during the apollo 17 mission we have retrieved a well defined dispersed rayleigh wave pulse inversion of its group velocity provides new constraints on the lunar subsurface structure the estimated signal to noise ratio snr of the retrieved rayleigh wavetrain is strongly dependent on solar illumination effectively making solar heating a source of seismic noise on the moon this result suggests that in future planetary missions it is feasible to extract information on the internal structure of extraterrestrial objects by correlating seismic noise even when natural quakes are absent

systematic determination of earthquake rupture directivity and fault planes from analysis of long period p wave spectra summary if an earthquake has a primarily unilateral rupture the pulse width observed on seismograms will vary depending on the angle between the rupture direction and the takeoff vector to the station we have developed a method to estimate the amount of pulse broadening from the spectrum and apply it to a long period database of large globally distributed earthquakes that occurred between 1988 and 2000 we select vertical component p waves at epicentral distances of 20 98 w ecompute the spectrum from a 64 s long window around each p wave arrival each spectrum is the product of source receiver and propagation response functions as well as local source and receiver side effects since there are multiple receivers for each source and multiple sources for each receiver we can estimate and remove the source and receiverside terms by stacking the appropriate p log spectra for earthquakes deeper than 200 km source effects dominate the residual spectra we use our pulse width estimates to determine the best rupture direction and to identify which nodal plane of the harvard centroid moment tensor cmt solution is most consistent with this rupture direction for 66 events in about 30 per cent of the cases one of the two nodal planes produces a much better fit to the data and can be identified as the true fault plane when results from previous studies are available for comparison our rupture directions are usually consistent with their results particularly for earthquakes with simple rupture histories

inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 imperial valley california earthquake a least squares point by point inversion of strong ground motion and teleseismic body waves is used to infer the fault rupture history of the 1979 imperial valley california earthquake the imperial fault is represented by a plane embedded in a half space where the elastic properties vary with depth the inversion yields both the spatial and temporal variations in dislocation on the fault plane for both right lateral strike slip and normal dip slip components of motion inversions are run for different fault dips and for both constant and variable rupture velocity models effects of different data sets are also investigated inversions are compared which use the strong ground motions alone the teleseismic body waves alone and simultaneously the strong ground motion and teleseismic records the inversions are stabilized by adding both smoothing and positivity constraints the moment is estimated to be 5 0 10 25 dyne cm and the fault dip 90 5 dislocation in the hypocentral region south of the united states mexican border is relatively small and almost dies out near the border dislocation then increases sharply north of the border to a maximum of about 2 m under interstate 8 dipslip motion is minor compared to strike slip motion and is concentrated in the sediments the best fitting constant rupture velocity is 80 per cent of the local shear wave velocity however there is a suggestion that the rupture front accelerated from the hypocenter northward the 1979 imperial valley earthquake can be characterized as a magnitude 5 earthquake at the hypocenter which then grew into or triggered a magnitude 6 earthquake north of the border

a new view of the underside of arctic sea ice the autosub ii autonomous underwater vehicle auv operating off ne greenland in august 2004 obtained the first successful swath sonar measurements under sea ice showing in unprecedented detail the three dimensional nature of the under ice surface the vehicle operated from rrs james clark ross obtained more than 450 track km of under ice multibeam data we show imagery from first and multiyear ice including young ridges old hummocks and undeformed melting ice in addition we show how the combination of other on board sensors enabled the vehicle to obtain detailed information about seabed topography water structure and current fields in an exploratory mode within a region which is seldom visited because of difficult year round ice conditions this included identification of a new current regime in the norske trough

the equivalent elastic thickness te seismicity and the long term rheology of continental lithosphere time to burn out creme brulee insights from large scale geodynamic modeling abstract depending on the conditions and time scale the lithosphere exhibits elastic brittle plastic or viscous ductile properties as suggested by rock mechanics experiments a large part of the long term lithospheric strength is supported in the ductile regime unfortunately these data validated for strain rates 10 6 s 1 small scales few cm and simplified conditions cannot be univocally interpolated to geological time and spatial scales strain rates 10 17 10 13 s 1 100 1000 km spatial scales complex conditions without additional parameterization an adequate parameterization has to be based on real time observations of large scale deformation indeed for the oceanic lithosphere the goetze and evan s brittle elastic ductile yield strength envelopes derived from data of experimental rock mechanics were successfully validated by a number of geodynamic scale observations such as the observations of plate flexure and the associated t e equivalent elastic thickness estimates yet for continents the uncertainties of flexural models and of the other data sources are much stronger due to the complex structure and history of continental plates for example in one continental rheology model dubbed jelly sandwich the strength mainly resides in the crust and mantle while in another dubbed creme brulee the mantle is weak and the strength is limited to the upper crust these models have arisen because of conflicting results from distributed earthquake elastic thickness t e and rheology data we address these problems by examining the plausibility of each rheological model from general physical considerations we review the elastic thickness t e estimates and their relationship to the seismogenic layer thickness t s to show that these two quantities have no direct physical relation we also show that some of small t e must be artifacts of inconsistent formulation of the mechanical problem in some free air anomaly admittance models we point out that this does not necessarily detract from the admittance method itself but refers to its incorrect application in the continental domain we then explore by analytical and numerical thermo mechanical modeling the implications of a weak and strong mantle for tectonic structural styles we conclude that rheological models such as creme brulee which invoke a weak lithosphere mantle are generally incompatible with observations the jelly sandwich is in better agreement and we believe provides a useful first order explanation for the long term support of the earth s main surface features

resolution of rupture directivity in weak events 1 d versus 2 d source parameterizations for the 2011 mw 4 6 and 5 2 lorca earthquakes spain resolving robustly source parameters of small moderate magnitude earthquakes is still a challenge in seismology we infer directivity from apparent source time functions astfs at regional distance and quantify the associated uncertainties astfs are used for i modeling a propagating 1d line source from the duration data and ii inverting the 2d slip distribution from the full signals slip inversion is performed through a popperian scheme where random trial models are either falsified on account of large misfit or else become members of the solution set of the inverse problem we assess the resolution of rupture directivity representing centroid shifts from the solution set in a rose diagram using as example an event with well studied rupture directivity the 2011 mw 5 2 lorca spain earthquake 1d and 2d parameterizations yield similar estimates for direction n213 e and n220 e respectively and asymmetry 67 33 65 35 of rupture propagation as well as rupture length 2 1 km 2 7 km and speed 3 5 km s 3 25 km s the high rupture velocity 90 vs may be held primarily responsible for the strong directivity effect of this earthquake we show that inversion of apparent source durations is intrinsically unable to resolve highly asymmetric bilateral ruptures while inversion of full astfs misses part of the signal s complexity suggesting the presence of deconvolution artifacts we extend the analysis to the mw 4 6 foreshock of the lorca earthquake inferring similar directivity parameters and slip pattern as for the mainshock the rupture towards sw of both earthquakes suggests that this direction could be inherent to the fault segment

on the mechanics of basin formation in the pannonian basin inferences from analogue and numerical modelling abstract we present the results of a thrust fault reactivation study that has been carried out using analogue sandbox and numerical modelling techniques the basement of the pannonian basin is built up of cretaceous nappe piles reactivation of these compressional structures and connected weakness zones is one of the prime agents governing miocene formation and quaternary deformation of the basin system however reactivation on thrust fault planes average dip of ca 30 in normal or transtensional stress regimes is a problematic process in terms of rock mechanics the aim of the investigation was to analyse how the different stress regimes extension or strike slip and the geometrical as well as the mechanical parameters dip and strike of the faults frictional coefficients effect the reactivation potential of pre existing faults results of analogue modelling predict that thrust fault reactivation under pure extension is possible for fault dip angle larger than 45 with normal friction value sand on sand of the fault plane by making the fault plane weaker reactivation is possible down to 35 dip angle these values are confirmed by the results of numerical modelling reactivation in transtensional manner can occur in a broad range of fault dip angle from 35 to 20 and strike angle from 30 to 5 with respect to the direction of compression when keeping the maximum horizontal stress magnitude approximately three times bigger than the vertical or the minimum horizontal stress values our research focussed on two selected study areas in the pannonian basin system the danube basin and the derecske trough in its western and eastern part respectively their miocene tectonic evolution and their fault reactivation pattern show considerable differences the dominance of pure extension in the danube basin vs strike slip faulting transtension in the derecske trough is interpreted as a consequence of their different geodynamic position in the evolving pannonian basin system in addition orientation of the pre existing thrust fault systems with respect to the early to middle miocene paleostress fields had a major influence on reactivation kinematics as part of the collapsing east alpine orogen the area of the danube basin was characterised by elevated topography and increased crustal thickness during the onset of rifting in the pannonian basin consequently an excess of gravitational potential energy resulted in extension v h during early miocene basin formation by the time topography and related crustal thickness variation relaxed middle miocene the stress field had rotated and the minimum horizontal stress axes h became perpendicular to the main strike of the thrusts the high topography and the rotation of h could induce nearly pure extension dip slip faulting along the pre existing low angle thrusts on the contrary the derecske trough was situated near the carpathian subduction belt with lower crustal thickness and no pronounced topography this resulted in much lower v value than in the danube basin moreover the proximity of the retreating subduction slab provided low values of h and the oblique orientation of the paleostress fields with respect to the master faults of the trough this led to the dominance of strike slip faulting in combination with extension and basin subsidence transtension

rupture directivity of moderate earthquakes in northern california we invert peak ground velocity and acceleration pgv and pga to estimate rupture direction and rupture velocity for 47 moderate earthquakes 3 5 m 5 4 in northern california we correct sets of pgas and pgvs recorded at stations less than 55 125 km depending on source depth for site amplification and source receiver distance then fit the residual peak motions to the unilateral directivity function of ben menahem 1961 we independently invert pga and pgv the rupture direction can be determined using as few as seven peak motions if the station distribution is sufficient the rupture velocity is unstable however if there are no takeoff angles within 30 of the rupture direction rupture velocities are generally subsonic 0 5 0 9 for stability we limit the rupture velocity at v 0 92 the rayleigh wave speed for 73 of 94 inversions the rupture direction clearly identifies one of the nodal planes as the fault plane the 35 strike slip earthquakes have rupture directions that range from nearly horizontal 6 events to directly updip 5 events the other 24 rupture partly along strike and partly updip two strike slip earthquakes rupture updip in one inversion and downdip in the other all but 1 of the 11 thrust earthquakes rupture predominantly updip we compare the rupture directions for 10 m 4 0 earthquakes to the relative location of the mainshock and the first two weeks of aftershocks spatial distributions of 8 of 10 aftershock sequences agree well with the rupture directivity calculated for the mainshock

tectonic and seismic implications of an intersegment rupture the damaging may 11th 2011 mw 5 2 lorca spain earthquake on may 11th 2011 a mw 5 2 earthquake stroke the city of lorca in the se spain this event caused 9 fatalities 300 injuries and serious damage on the city and the surrounding areas the lorca earthquake occurred in the vicinity of a region bounding two well known segments of a large active fault the alhama de murcia fault amf the lorca earthquake offers a unique opportunity to study how strain is accommodated in an intersegment region of a large strike slip fault we map recent tectonic structures in the epicentral region and we use radar interferometry to analyze the coseismic deformation combining these data with seismological observations of lorca seismic sequence we first model the source of the earthquake then we analyze the influence of our preferred model in the adjacent segments by coulomb failure stress modeling the proposed earthquake source model suggests that this event ruptured an area of 4 3 km within the complex structure that limits the gonar lorca and lorca totana segments of the amf the induced static stress change on the adjacent segments of the fault represents a seismic cycle advance equivalent to 200 to 1000 years of tectonic loading