sedimentology and isotope geochemistry of carnian deep water marl limestone deposits from the sicani mountains sicily environmental implications and evidence for a planktonic source of lime mud abstract the upper triassic halobia bearing marl limestone deposits from the sicani mountains sicily record the sedimentary evolution of the sicanian basin through the middle and late carnian time dark marls and interbedded grey calcilutites of julian age are characterized by abundant pyrite sparse bioturbation and negative carbonate carbon 13c values they accumulated in a basin with dominantly anoxic to dysaerobic bottom waters lower tuvalian dark grey pyritic marls and calcilutites which contain carbonate minerals with relatively high mn contents and widely fluctuating 13c signatures were deposited under dysaerobic conditions middle and upper tuvalian cherty limestones show intense bioturbation and nearly invariable positive 13c values around 2 for calcite they form a thick and monotonous succession accumulated in a deeper and more oxygenated basin the halobia bearing deposits preserve some calcareous nannoplanktonic forms the nannofossils varying in size from 7 to 32 m are significantly abundant in the cherty limestones pointing to a notable role of the calcareous nannoplankton as a source of carbonate mud in the deep water basins of the southern tethys during the late triassic time

evidence for widespread nonlinear strong ground motion in the mw 6 9 loma prieta earthquake we exploit 55 repeating microearthquake sequences on the san andreas fault just south of the rupture zone of the 1989 m w 6 9 loma prieta earthquake to search for time dependent properties of the earth s crust using moving window waveform cross correlation we identify clear and systematic delays as large as 20 msec for the direct s wave and exceeding 50 msec in the early s wave coda following the loma prieta mainshock others have also identified phase delays velocity reductions associated with damaging earthquakes and they have suggested a myriad of possible causal mechanisms here we present new evidence for a mechanism to produce velocity reductions correlated in time and space with an earthquake a strong correlation between the spatial patterns of s delays and the intensity of strong ground motion in the loma prieta earthquake suggests that physical damage the formation or growth of cracks during strong ground motion to the earth s shallow crust is responsible for the observed velocity reductions the strong spatial variability in s delays over short distances and the strong correlation of the magnitude of delays with surface geology indicate that the phase delays accumulate primarily near the receiver the effect is stronger at stations on young soft rocks than at stations on old hard rock disproportionately larger s coda delays than p coda delays suggest that the cracks formed by the strong shaking are fluid filled in the 10 years after loma prieta the initial increase in travel times reduces logarithmically with respect to time often back to the premainshock levels we attribute this behavior to the same slow dynamic healing observed in laboratory studies of the recovery of materials from transient nonlinear strain manuscript received 14 january 2004

temporal changes of the crustal structure associated with the m6 1 earthquake on september 3 1998 and the volcanic activity of mount iwate japan we detected temporal changes of crustal structure by cross spectrum analyses of seismic waves excited by two artificial explosions that were carried out about one month before and two months after a m6 1 shallow earthquake phase spectrum analysis shows that seismic velocity of the upper crust around the focal area of the m6 1 earthquake and mount lwate decreased 0 3 1 0 during the three months since lager decreases of the seismic velocity were observed at the region close to the focal area and a volcanic pressure source we conclude that stress change in the upper crust is a most plausible candidate to cause the velocity changes among other candidates we further apply a coherence analysis to the observed seismic coda to locate regions where short wavelength heterogeneity temporally changed the result indicates a possibility of temporal changes of the heterogeneity beneath the volcano where a magmatic fluid intrusion is inferred

detecting seasonal variations in seismic velocities within los angeles basin from correlations of ambient seismic noise summary we analyse 3 yr of continuous seismic records from broad band stations of the caltech regional seismic network ci in vicinity of the los angeles basin using correlations of ambient seismic noise relative velocity variations in the order of 0 1 per cent can be measured between all interstation pairs it is the first time that such an extensive study between 861 interstation pairs over such a large area has been carried out we perform these measurements using the stretching technique assuming that one of the two waveforms is merely a stretched version of the other obviously this assumption is always violated and the two waveforms are generally decorrelated due to temporal changes in the earth crust due to different sources or simply because the cross correlations are not fully converged we investigate the stability of these measurements by repeating each measurement over various time windows of equal length on average between all interstation pairs in the los angeles basin a seasonal signal in the relative velocity variation is observed with peaks and troughs during winter and summer time respectively generally the observed signal decreases with increasing interstation distance and relative traveltime perturbations can only be measured up to an interstation distance of 60 km furthermore the traveltime perturbations do not depend on azimuth of station pairs suggesting that they are not related to seasonal variations of the noise sources performing a simple regionalization by laterally averaging measurements over a subset of stations we found the sedimentary basin showing the most consistent signal and conclude that the observed seasonality might be induced either by changes in the ground water aquifer or thermo elastic strain variations that persist down to a depth of 15 22 km

evolution of pangea paleomagnetic constraints from the southern alps italy abstract a new early late triassic paleopole for adria has been obtained from the val sabbia sandstone in the southern alps as early permian and jurassic cretaceous paleomagnetic data from para autochthonous regions of adria such as the southern alps are consistent with african apwps 1 2 paleomagnetic data from this region can be used to bolster the west gondwana apwp in the poorly known late permian triassic time interval the southern alpine paleopoles are integrated with the west gondwana and laurussia apwps of van der voo 1 and used to generate a tectonic model for the evolution of pangea the early permian overall mean paleopole for west gondwana and adria in conjunction with the coeval laurussia paleopole support pangea b of morel and irving 3 the late permian early triassic and the middle late triassic paleopoles from adria and laurussia support pangea a 2 of van der voo and french 4 the phase of transcurrent motion between laurasia and gondwana 5 that caused the pangea b to a 2 transition occurred essentially in the permian at the end of variscan orogeny with an average relative velocity of approximately 10 cm yr finally the late triassic early jurassic paleopoles from west gondwana and laurussia agree with pangea a 1 of bullard et al 6 the widely accepted pangea configuration at the time of the jurassic breakup

monitoring velocity variations in the crust using earthquake doublets an application to the calaveras fault california we present a technique that greatly improves the precision in measuring temporal variations of crustal velocities using an earthquake doublet or pair of microearthquakes that have nearly identical waveforms and the same hypocenter and magnitude but occur on different dates we compute differences in arrival times between seismograms recorded at the same station in the freqency domain by cross correlation of short windows of signal a moving window analysis of the entire seismograms including the coda gives t the difference in arrival times versus running time along the seismogram the time resolution of the method is an order of magnitude better than the digitization interval the t technique is illustrated with a pair of microearthquakes m 1 7 and 2 0 that occurred before and after the coyote lake california earthquake m 5 9 of august 6 1979 and on the same segment of the calaveras fault that ruptured during the earthquake the coda wave arrivals for some stations are progressively delayed for the second earthquake in the doublet so that its seismogram appears as a stretched version of the earlier event we interpret this systematic variation in t along the coda as a change in the average s velocity in the upper crust in the time interval between the two doublets s wave velocities appear to have decreased by 0 2 in an oblong region 5 10 km in radius at the south end of the aftershock zone

auto correlation analysis of coda waves from local earthquakes for detecting temporal changes in shallow subsurface structures the 2011 tohoku oki japan earthquake for monitoring temporal changes in subsurface structures i propose to use auto correlation functions of coda waves from local earthquakes recorded at surface receivers which probably contain more body waves than surface waves use of coda waves requires earthquakes resulting in decreased time resolution for monitoring nonetheless it may be possible to monitor subsurface structures in sufficient time resolutions in regions with high seismicity in studying the 2011 tohoku oki japan earthquake mw 9 0 for which velocity changes have been previously reported i try to validate the method kik net stations in northern honshu are used in this analysis for each moderate earthquake normalized auto correlation functions of surface records are stacked with respect to time windows in the s wave coda aligning the stacked normalized auto correlation functions with time i search for changes in phases arrival times the phases at lag times of 1 s are studied because changes at shallow depths are focused temporal variations in the arrival times are measured at the stations based on the stretching method clear phase delays are found to be associated with the mainshock and to gradually recover with time the amounts of the phase delays are 10 on average with the maximum of about 50 at some stations the deconvolution analysis using surface and subsurface records at the same stations is conducted for validation the results show the phase delays from the deconvolution analysis are slightly smaller than those from the auto correlation analysis which implies that the phases on the auto correlations are caused by larger velocity changes at shallower depths the auto correlation analysis seems to have an accuracy of about several percent which is much larger than methods using earthquake doublets and borehole array data so this analysis might be applicable in detecting larger changes in spite of these disadvantages this analysis is still attractive because it can be applied to many records on the surface in regions where no boreholes are available

joint inversion of strong motion teleseismic geodetic and tsunami datasets for the rupture process of the 2011 tohoku earthquake 1 the 2011 tohoku earthquake was observed by dense strong motion teleseismic geodetic and tsunami networks we first inverted each of the datasets obtained by the networks separately for the rupture process of the earthquake we then performed checkerboard resolution tests for assessing the resolving power of these datasets in order to overcome the limited resolutions of the separate inversions and differences in their results we performed a quadruple joint inversion of all these data to determine a source model most suitable for explaining all the datasets in the obtained source model the maximum coseismic slip was approximately 35 m and the total seismic moment was calculated to be 4 2 1022 nm which yielded mw 9 0 the main rupture propagated not only in the strike direction but also in the dip direction and included both the deep area called the miyagi oki region and the compact shallow area near the japan trench

norian magnetostratigraphy from the scheiblkogel section austria constraint on the origin of the antalya nappes turkey abstract late triassic magnetostratigraphic investigations in southwestern turkey have suggested that parts of the antalya nappes are constituted of a melange of blocks originally deposited either in the vicinity of the northern tip of arabia or more surprisingly directly north of india in the southern hemisphere in order to ascertain this result more clearly we have correlated the turkish series with austrian sections of corresponding age from the northern calcareous alps for which the hemisphere of deposition is beyond doubt the new magnetostratigraphic results obtained from the scheiblkogel section austria confirm the previously suggested middle to late norian magnetic polarity sequence and support the heterogeneous character of the antalya nappes

magnetostratigraphy of the kavur tepe section southwestern turkey a magnetic polarity time scale for the norian we present the magnetostratigraphy of the late triassic pelagic kavur tepe section from the taurides southwestern turkey the section investigated is about 30 m thick and consists of fine grained whitish limestones the biostratigraphy based on the conodont zonation gives an age from the lacian 2 zone lower norian to the sevatian 2 zone upper norian the paleomagnetic analyses indicate very favourable behaviour with two magnetic components which can be isolated both by thermal and af demagnetization the magnetization is carried by magnetite and goethite which are clearly evident in irm experiments the first component of normal magnetic polarity has roughly the direction of the present day field the high unblocking temperature component shows directions of both polarities in total fifteen magnetic polarity intervals are observed within the kavur tepe section the characteristic calculated fisherian mean direction is particularly tightly grouped d 220 2 and i 32 1 with k 40 9 95 1 7 and nsamp 179 after bedding correction polarity correlations with two other sections in turkey and in austria northern calcareous alps show that the kavur tepe sediments were deposited in the southern hemisphere by combining the magnetostratigraphic results from the bolucektasi tepe 1 and the kavur tepe sections an almost complete norian magnetic polarity sequence is established showing 30 magnetic intervals that are well calibrated with the conodont and ammonoid zonations a magnetic reversal frequency close to about 2 7 reversals myr is derived for the norian this medium frequency is in agreement with the hypothesis of a long time constant 150 200 myr in the changes of the magnetic reversal frequency since the kiaman reversed superchron

seismic evidence of nonlinear crustal deformation during a large slow slip event in mexico repeated cross correlations of ambient seismic noise indicate a long term seismic velocity change associated with the 2006 m7 5 slow slip event sse in the guerrero region mexico because the sse does not radiate seismic waves the measured velocity change cannot be associated with the response of superficial soil layers to strong shaking as observed for regular earthquakes the perturbation observed maximized at periods between 7 s and 17 s which correspond to surface waves with sensitivity to the upper and middle crust the amplitude of the relative velocity change 10 3 was much larger than the volumetric deformation 10 6 at the depths probed 5 20 km moreover the time dependence of the velocity perturbation indicated that it was related to the strain rate rather than the strain itself this suggests that during strong slow slip events the deformation of the overlying crust shows significant nonlinear elastic behavior

contemporaneous thrusting and large scale rotations in the western sicilian fold and thrust belt in the western sicilian fold and thrust belt large clockwise rotations of allochthons occurred during late cenozoic contraction of part of the southern tethyan margin the magnitude of rotation decreases stepwise from over 120 in the upper sheets lying on the north coast of sicily to no appreciable rotation in the frontal portion of the belt flanking the southern coast of the island the allochthons are composed of imbricate thrust sheets derived primarily from individual basin and platform assemblages of the old tethyan margin paleomagnetic and structural data indicate that the rotation of the allochthons was accommodated by coherent torsional displacements on relatively low angle detachment surfaces timing relations for the imbrication history of the sicilian fold and thrust belt are derived from stratigraphic overlap and local involvement of sediments deposited in a series of foreland and piggyback basins the locus of deposition within successive foreland basins first migrated easterly then southerly during progressive deformation in the orogen imbrication began in the early miocene burdigalian langhian and continued at least through the early pleistocene and appears to be continuing today rotation is related to thrusting and accompanies a 70 change in the tectonic transport direction from easterly to southerly easterly striking right oblique transpressional faults and associated northeasterly trending folds postdate thrust sheet rotation in the interior of the thrust belt and were active contemporaneously with south directed thrusting in the foreland region pleistocene and possibly older late pliocene extension strongly modified the older thrust morphology along the tyrrhenian coast of northwestern sicily with the development of down to the north listric normal faults the extensional structures apparently are related to the opening and subsequent deformation of the tyrrhenian sea to the north

coseismic and postseismic velocity changes measured by repeating earthquakes 1 repeating earthquakes that rupture approximately the same fault patch and have nearly identical waveforms are a useful tool for measuring temporal changes in wave propagation in the earth s crust since source and path effects are common to all earthquakes in a repeating earthquake sequence multiplet differences in their waveforms can be attributed to changes in the characteristics of the medium we have identified over 20 multiplets containing between 5 and 40 repeating events in the aftershock zones of the 1989 loma prieta and 1984 morgan hill california earthquakes postmain shock events reveal delays of phases in the early s wave coda of as much as 0 2 s relative to premain shock events the delay amounts to a path averaged coseismic velocity decrease of about 1 5 for p waves and 3 5 for s waves since most of the multiplets are aftershocks and follow omori s law we have excellent temporal sampling in the immediate postmain shock period we find that the amplitude of the velocity decrease decays logarithmically in time following the main shock in some cases it returns to the premain shock values while in others it does not similar results are obtained for the morgan hill main shock because the fractional change in s wave velocity is greater than the fractional change in p wave velocity it suggests that the opening or connection of fluid filled fractures is the underlying cause the magnitude of the velocity change implies that low effective pressures are present in the source region of the velocity change our results suggest that the changes are predominantly near the stations and shallow but we cannot exclude the possibility that changes occur at greater depth as well if the variations are shallow we may be detecting the lingering effects of nonlinearity during main shock strong ground motion if the variations are deep it suggests that pore pressures at seismogenic depths are high which would likely play a key role in the earthquake process

seismic velocity reductions caused by the 2003 tokachi oki earthquake 1 we use four repeating earthquake sequences located near hokkaido to identify velocity changes caused by the mw 8 0 2003 tokachi oki earthquake using a moving window cross correlation technique we identify delays in the arrival time of seismic waves that accumulate linearly with time into the seismogram this behavior is indicative of multiple scattering within a medium where the seismic velocity has been reduced for all of our earthquake receiver geometries we find evidence of significant velocity reductions close to the receiver the correlation of the size of the velocity reductions with both strong shaking and site characteristics suggests that these velocity reductions are caused by damage to near surface materials created by nonlinear strong ground motion for earthquake receiver geometries where the seismic waves cross the tokachi oki rupture zone we identify particularly large reductions in velocity as a result of the earthquake for these geometries we believe that the rupture zone of the tokachi oki earthquake or the shallow crust above it represents a second region where seismic velocities are reduced as a result of the main shock

seismic velocity changes strain rate and non volcanic tremors during the 2009 2010 slow slip event in guerrero mexico summary we use ambient noise cross correlations to monitor small but reliable changes in seismic velocities and to analyse non volcanic tremor nvt intensities during the slow slip event sse that occurred in 2009 and 2010 in guerrero we test the sensitivity of the seismic velocity to strain variations in absence of strong motions the 2009 2010 sse presents a complex slip sequence with two subevents occurring in two different portions of the fault from a seismic array of 59 seismometers installed in small antennas we detect a velocity drop with maximum amplitude at the time of thefirst subevent we analyse the velocity change at different period bands and observe that the velocity perturbation associated with the sse maximizes for periods longer than 12 s then a linearized inversion of the velocity change measured at different period bands is applied in order to determine the depth of the portion of the crust affected by this perturbation no velocity change in the first 10km is detected below the velocity perturbation increases with depth affecting the middle and lower crust finally we compute the transient deformation produced by the sse in an elastic model using the slip evolution recovered from the inversion of continuous gps the comparison between the velocity changes and the deformation suggests that the velocity change is correlated with the strain rate rather than with the strain this result is similar to what was observed during the 2006 sse in the same region and suggests a non linear behaviour of the crust the velocity changes can be interpreted together with other observables such as nvts during the 2009 2010 sse we measure nvt activity using continuous seismic records filtered between 2 and 8 hz we observe a correlation between velocity changes for period band greater than 14 s and tremor activity whereas no correlation exists between velocity changes and seismic noise energy measured at long periods these observations suggest that both seismic velocity change and nvt can be used as indication of transient deformation at depth

seismic velocity changes of p and s waves associated with the 2011 tohoku oki earthquake mw 9 0 as inferred from analyses of repeating earthquakes

magnetostratigraphy and biostratigraphy of the carnian norian boundary interval from the pizzo mondello section sicani mountains sicily the 146 5 m thick upper triassic limestone section at pizzo mondello in the sicani mountains of western sicily is characterized by high quality of exposure accessibility and stratigraphic continuity magnetostratigraphic results delineate 12 normal and reverse polarity magnetozones labelled successively from the base upwards as pm1n pm1r pm6n pm6r the carnian norian boundary based on conodont biostratigraphy falls somewhere in the pm3n to pm5n interval which corresponds to the e14n to e16n magnetozone interval in the newark reference sequence of polarity reversals comparison of magnetobiostratigraphic data from the newark basin pizzo mondello and other late triassic marine sections available from the literature suggests the existence of a reduction in sedimentation rate in the tethyan marine domain at around the carnian norian boundary although the newark and the expanded pizzo mondello sections correlate well with each other correlation with the condensed kavur tepe and scheiblkogel sections is unsatisfactory a re interpretation of the kavur tepe results suggests that the section is younger than its previous correlation with the newark section and that it was deposited in the northern instead of the southern hemisphere most of the condensed tethyan marine sections are seen to be highly discontinuous as evidenced by concantenated conodont total range zones q 2001 elsevier science b v all rights reserved

a unified source model for the 2011 tohoku earthquake abstract the devastating 2011 tohoku earthquake was observed by dense networks of geophysical instruments a unified source model was constructed through joint inversion of teleseismic strong motion and geodetic datasets the result indicates that the earthquake consists of three main ruptures after small rupture in the initial 50 s the first rupture expanded at a slow speed of 1 8 km s to the northeast and east the second rupture began 20 s later at the slowest speed of 1 5 km s and became dominant with the largest slip of 36 m the third rupture then played the leading role propagating southward at a speed of 2 5 km s only the tsunami inversion requires an extension of the source fault to a shallow part between the first rupture area and the japan trench recovering tsunamigenic slips larger than 40 m the slow rupture speed and tsunamigenic slips can explain the features of the disaster by the earthquake

a u pb and 40ar 39ar time scale for the jurassic published time scales provide discrepant age estimates for jurassic stage boundaries and carry large uncer tainties the u pb or 40 ar 39 ar dating of volcaniclastic rocks with precisely known stratigraphic age is the preferred method to improve the calibration a radiometric age database consisting of fifty u pb and 40 ar 39 ar ages was com piled to construct a revised jurassic time scale accepted ages have a precision of 5 ma 2 or better and are con fined to no more than two adjacent stages the majority of these calibration points result from integrated bio and geochronologic dating in the western north american cordillera and have not been previously used in time scales di rect dates are available only for the triassic jurassic boundary and the initial boundary of the crassicosta chron and the callovian stage the chronogram method was used to estimate all early and early middle jurassic zone boundaries attempted here for the first time late middle jurassic substage boundaries and late jurassic stage boundaries signif icant improvement is achieved for the pliensbachian and toarcian where six consecutive zone boundaries are deter mined the derived zonal durations are disparate varying between 0 4 and 1 6 ma the latest jurassic isotopic database remains too sparse therefore chronogram estimates are improved using interpolation based on magnetochronology the initial boundaries of jurassic stages are proposed as follows berriasian jurassic cretaceous 1418 18

conodont biostratigraphy of uppermost triassic deep water calcilutites from pizzo mondello sicani mountains evidence for rhaetian pelagites in sicily abstract rhaetian pelagites are described for the first time from western sicily in the pizzo mondello area sosio valley sicani mountains where a thick pile of upper triassic cherty calcilutites outcrops the upper triassic pelagic calcilutites of pizzo mondello are divided into three lithostratigraphic units the lower unit consists of a few meters of dark gray marls and clay marlstones equivalent to the mufara fm of carnian age followed by halobia bearing cherty limestones about 300 m thick of late carnian late norian age the upper unit consists of white calcilutites and grey greenish marls containing the conodonts misikella posthernsteini and zieglericonus rhaeticus of rhaetian age these rhaetian deposits are here informally named as portella gebbia limestone in the pizzo mondello succession the norian rhaetian boundary sensu kozur and mock 1991 can be approximated along the lowermost calcilutite bed of portella gebbia limestone containing the first occurrence of m posthernsteini

preceding coseismic and postseismic slips of the 2011 tohoku earthquake japan 1 we estimated the spatial and temporal evolution of the preceding aseismic slip from january 2003 to january 2011 the coseismic slip of the tohoku earthquake and the postseismic slip after the earthquake based on global positioning system gps data time dependent analysis indicates aseismic slip offshore of miyagi and fukushima prefectures from 2004 associated with a series of subduction earthquakes that overlap the aseismic slip area these preceding aseismic and coseismic slip areas are centered between the centers of the coseismic and afterslip areas of the tohoku earthquake offshore of miyagi prefecture while they overlap the coseismic and afterslip areas of the tohoku earthquake off fukushima prefecture the timing of moment magnitude nine mw9 class earthquakes appears to be controlled by multiple preceding slip events smaller earthquakes and their afterslip the preceding aseismic and coseismic slip decreased the coupling rate off the tohoku coast suggesting the possibility that the preceding slip represented a precursive stage of the tohoku earthquake the afterslip of the tohoku earthquake occurred in an area where the coseismic slip was not large complementing the large coseismic slip zone the afterslip along iwate miyagi extends up to 80 km in depth and is currently the sole mechanism of strain release in this depth range the source region of the anticipated miyagi oki earthquake shows small postseismic slip after the tohoku earthquake reflecting the energy release at the time of the earthquake aftershock activity is roughly governed by an afterslip process

estimating near surface shear wave velocities in japan by applying seismic interferometry to kik net data 1 we estimate shear wave velocities in the shallow subsurface throughout japan by applying seismic interferometry to the data recorded with kik net a strong motion network in japan each kik net station has two receivers one receiver on the surface and the other in a borehole by using seismic interferometry we extract the shear wave that propagates between these two receivers applying this method to earthquake recorded data at all kik net stations from 2000 to 2010 and measuring the arrival time of these shear waves we analyze monthly and annual averages of the near surface shear wave velocity all over japan shear wave velocities estimated by seismic interferometry agree well with the velocities obtained from logging data the estimated shear wave velocities of each year are stable for the niigata region we observe a velocity reduction caused by major earthquakes for stations on soft rock the measured shear wave velocity varies with the seasons and we show negative correlation between the shear wave velocities and precipitation we also analyze shear wave splitting by rotating the horizontal components of the surface sensors and borehole sensors and measuring the dependence on the shear wave polarization this allows us to estimate the polarization with the fast shear wave velocity throughout japan for the data recorded at the stations built on hard rock sites the fast shear wave polarization directions correlate with the direction of the plate motion

the cuyama strike slip basin california u s a an exemplar of contrasting syntectonic and post tectonic strata abstract miocene strata in the cuyama basin of southern california exemplify syntectonic and post tectonic stratigraphic development in a strike slip basin integrated seismic well log and outcrop data provide a detailed portrayal of the seismic stratigraphy and sedimentary facies in the previously unstudied middle and upper miocene sequences results show sharp contrast among syntectonic and post tectonic strata from composition and texture of sediments to lateral distribution and thickness of facies seven post tectonic sequences were mapped across the basin sequences contain eolian to fluvial terrestrial facies wave and tide dominated nearshore facies biosiliceous dolomitic and phosphatic outer shelf and slope mudstones and shale rich submarine fans in basinal environments authigenic dolomites and phosphates are pervasive in outer shelf and slope facies and indicate the possibility of restricted sediment supply post tectonic sequences are thin but laterally continuous and they exhibit little depositional asymmetry minor erosion is distributed equally among regressive and transgressive relative sea level changes asynchronous changes in tectonism sediment supply and eustatic sea level change created dramatic differences among syntectonic and post tectonic sequences interbasinal tectonic quiescence led to the abrupt end of stratigraphic mismatches and the accumulation of sediment during brief episodic periods multiple points of progradation persisted through several million years of post tectonic basin development and highlight the importance of extrabasinal sediment supply to the development of all sequences the eventual loss of most accommodation space promoted the importance of eustatic sea level change and reduced the prominence of asymmetric facies and abrupt lateral facies changes

mapping pressurized volcanic fluids from induced crustal seismic velocity drops volcanic eruptions are caused by the release of pressure that has accumulated due to hot volcanic fluids at depth here we show that the extent of the regions affected by pressurized fluids can be imaged through the measurement of their response to transient stress perturbations we used records of seismic noise from the japanese hi net seismic network to measure the crustal seismic velocity changes below volcanic regions caused by the 2011 moment magnitude m w 9 0 tohoku oki earthquake we interpret coseismic crustal seismic velocity reductions as related to the mechanical weakening of the pressurized crust by the dynamic stress associated with the seismic waves we suggest therefore that mapping seismic velocity susceptibility to dynamic stress perturbations can be used for the imaging and characterization of volcanic systems

time lapse changes of p and s wave velocities and shear wave splitting in the first year after the 2011 tohoku earthquake japan shallow subsurface

magnetostratigraphy of the mayerling section austria and erenkolu mezarlik turkey section improvement of the carnian late triassic magnetic polarity time scale abstract we present a magnetostratigraphic study of two carnian late triassic pelagic limestone sections from the northern calcareous alps mayerling section and southwestern turkey erenkolu mezarlik section biostratigraphic control is based on conodont zonation for the mayerling section and both on conodonts and ammonoids for the erenkolu mezarlik section in both sections the characteristic magnetization is essentially carried by a mineral of the magnetite family eight magnetic intervals are obtained from the mayerling section and fourteen from erenkolu mezarlik when these results are compared to the carnian magnetostratigraphic sequence obtained from the bolucektasi tepe section satisfactory correlations are observed and a composite carnian magnetic polarity time scale containing 24 intervals can be proposed by combining all these results the lower part of the upper carnian is however missing tuvalian 1 zone and lower part of the tuvalian 2 zone no clear correlation is observed between our composite sequence and the other published magnetostratigraphic data of carnian age the satisfactory correlation observed between the mayerling and the bolucektasi tepe sections indicates that both sections were deposited in the northern hemisphere thus providing constraints on the origin of the antalya nappes

monitoring seismic velocity change caused by the 2011 tohoku oki earthquake using ambient noise records 1 we estimated the changes in seismic velocity in the southern tohoku district of japan during the six month period centered on the 11 march 2011 tohoku oki earthquake using scattered waves retrieved by autocorrelation of ambient seismic noise the estimated velocity decrease after the earthquake and after two large aftershocks in the study area was as great as 1 5 in the area nearest to the mainshock the velocity changes displayed gradual healing the spatial distribution of the velocity change showed a correlation with both the changes in static strain derived from gps records and the peak particle velocity experienced during the three earthquakes derived from strong motion records therefore our results show that velocity changes possibly contain information from deep in the crust bearing on coseismic stress release in addition to shallower effects due to strong ground motion

coseismic and postseismic elastic wave velocity variations caused by the 2008 iwate miyagi nairiku earthquake japan 1 we analyze coseismic and postseismic velocity variations caused by the june 13 2008 iwate miyagi nairiku earthquake mw 6 9 using passive image interferometry pii seismic noise is correlated in order to reconstruct the green s function between two sensors shear wave velocity changes are determined by relating the coda parts of the daily green s functions to a long term reference green s function our study extends from january 2008 to august 2010 and includes the correlations for 190 station pairs in three different frequency ranges from 0 125 to 1 0 hz we show that combining the 9 different component cross correlation functions stabilizes the velocity change estimation and increases analysis resolution the observed velocity change curves can be fitted by model time series consisting of a coseismic velocity drop followed by logarithmic postseismic recovery and seasonal velocity variations the coseismic velocity drops are stronger at higher frequencies and are concentrated in the southern part of the fault zone a tomography algorithm was developed to reproject the observed velocity variations of the different sensor pairs onto the single sensors the depth distribution of coseismic changes was modeled for the three stations with the largest velocity drops at two stations the coseismic velocity changes are located in the upper several hundred meters the third station shows indications for deeper changes in the order of kilometers postseismic recovery takes significantly longer than the analyzed two year period seasonal velocity variations with periods of one year are observed at all analyzed frequencies for most station pairs

joint hypocentral location in media with lateral velocity variations and interpretation of the station corrections abstract the application of a new implementation of the joint determination of hypocenters origin times and station correction terms jhd technique to data from the arkansas swarm usa the campi flegrei italy and the nazca plate argentina throws new light onto the problem of earthquake location in all these cases good quality p and s wave arrival times were available the main results are as follows 1 large lateral velocity variations llvv are generally associated with relatively large station corrections these corrections in turn are usually much larger than the average of the station residuals determined when the same set of events is located using a single event location sel method 2 the locations determined by the jhd and sel methods may be substantially different 3 since the effect of llvv on jhd locations is not well established simple 3 d velocity models are constructed so that the jhd technique applied to synthetic data generated using these models produce station corrections similar to those observed 4 the analysis of the synthetic data also shows that the locations determined by the jhd method are much closer to the true locations than the locations determined with the sel method the use of the weighted average of the sel station residuals as station corrections does not give better located events although there is a large decrease in the r m s residual computed for each event therefore the use of r m s residuals to estimate the quality of event locations is not always warranted in view of these results it is possible to conclude that the jhd station corrections can be used to detect lateral velocity variations and to produce locations substantially less affected by these variations than the locations determined by the sel method furthermore under appropriate conditions the jhd station corrections can also be used in a forward modeling scheme to get a semiquantitative velocity model such a model may be the only information that can be obtained from a data set when the station and event distributions are not adequate for 3 d velocity inversion

near surface weakening in japan after the 2011 tohoku oki earthquake 1 the magnitude mw 9 0 tohoku oki earthquake on 11 march 2011 was one of the largest in recent history ground motion caused by the seismicity around the time of the main shock was recorded by kik net the strong motion network that covers most of japan by deconvolving waveforms generated by earthquakes that are recorded at the surface and in a borehole at kik net station fksh18 we detect a reduction of shear wave velocity in the upper 100 m of about 10 and a subsequent healing that varies logarithmically with time using all available borehole and surface records of more than 300 earthquakes that occurred between 1 january 2011 and 26 may 2011 we observe a reduction in the shear wave velocity of about 5 in the upper few hundred meters after the tohoku oki earthquake throughout northeastern japan the area of the velocity reduction is about 1 200 km wide which is much wider than earlier studies reporting velocity reductions following other larger earthquakes the reduction of the shear wave velocity is an indication that the shear modulus and hence the shear strength is reduced over a large part of japan

paleomagnetically determined rotations in the western sicilian fold and thrust belt new paleomagnetic data from the west sicilian fold and thrust belt indicate large scale clockwise rotations during tectonic transport for the platform and seamount paleogeographic units of the fold and thrust belt panormide and trapanese units there is a general consistency in the magnitude of rotation along strike suggesting the existence of large coherent structural units for the panormide platform clockwise rotations in the range of 90 to 140 relative to the underlying iblean parautochthon are recorded along 125 km of outcrop strike in the case of the trapanese unit clockwise rotations in the range of 47 to 70 relative to iblei are recorded along about 90 km of outcrop strike intervening basinal paleogeographic units imerese and sicanian units show clockwise rotations of similar magnitude although few reliable data are available from these units palinspastic reconstruction of the thrust belt incorporating the rotations and arguments for the present orientation of the margins of the paleogeographic units implies that the panormide platform and trapanese seamounts were originally elongated more or less north south relative to the present orientation of iblei the two units apparently coalesced to the south and were discontinuous to the north they and their intervening basins were part of a passive continental margin which occupied a large part of the area that was subsequently rifted to form the tyrrhenian sea

temporal change in shear velocity and polarization anisotropy related to the 2011 m9 0 tohoku oki earthquake examined using kik net vertical array data 1 the m9 0 tohoku oki earthquake took place off ne japan which is covered by a dense seismic network in particular kik net observed the strong motions of the main shock and numerous aftershocks both on the ground and at the bottom of boreholes at a depth of a few hundred meters we applied cross correlation analysis to the coda part of a seismogram observed by kik net and estimated not only the temporal change in shear velocity but also the change in polarization anisotropy between the bottom of the borehole and the ground the shear velocity was suddenly reduced by 5 to 10 after the tohoku oki earthquake over a wide area of ne japan which is consistent with the results of a previous study although some stations also reveal a change in polarization anisotropy the polarization anisotropy change is smaller than the velocity change which may suggest that the static stress change due to the coseismic slip on the pacific plate is not large enough to change the direction of polarization anisotropy and or deviatoric stress in the land area of ne japan

real time monitoring of relative velocity changes using ambient seismic noise at the piton de la fournaise volcano la reunion from january 2006 to june 2007 we present the results of a real time method based on coda wave interferometry from seismic noise cross correlation functions for relative seismic velocity variations monitoring on a volcanic edifice the ambient seismic noise at the piton de la fournaise volcano on la reunion island is analyzed from january 2006 to june 2007 during this period five eruptions occurred showing a great diversity in eruption duration intensity and eruptive fissure location two different methods are used to compute the velocity variations in order to compare their stability in quasi real time routine we compare the obtained velocity variations with the surface deformation observed by gps and extensometers networks this allows us to identify and quantify three major processes at the origin of seismic wave velocity variations in the edifice firstly the observed pre eruptive summit inflation is accompanied by a decrease in seismic velocity secondly the edifice deflation following the opening of an eruptive fissure is characterized by an increase of the velocity finally the summit caldera collapse generates a strong velocity drop coda wave interferometry from seismic noise cross correlation functions in quasi real time may allow us to forecast eruption and constrain the processes taking place in the volcanic plumbing system