mesozoic radiolarian biostratigraphy of japan and collage tectonics along the eastern continental margin of asia abstract jurassic accretionary complexes mainly composed of carboniferous to permian limestone associated with greenstone triassic bedded chert jurassic siliceous shale and clastic rocks form the basement rocks of japan the stratigraphy of these complexes has recently been analysed utilizing radiolarian fossils resulting in the discovery that japan comprises a collage of disrupted terranes international co operative works reveal that lithologically and biostratigraphically similar terranes are distributed in northeast china nadanhada terrane and sikhote alin ussr khabarovsk terrane paleomagnetic studies demonstrate that prior to opening of the sea of japan the japanese islands were located much closer to the eastern margin of the asian continent where the nadanhada and khaborovsk terranes are now exposed features of the mino terrane in central japan are characteristic of these terranes which originally formed along the continental margin of east asia seamounts covered by fossiliferous limestone formed during the carboniferous to permian at low latitudes the seamounts drifted towards a continental margin together with upper paleozoic sediments triassic bedded chert and lower jurassic siliceous shale which accumulated around them upper paleozoic triassic and lower jurassic formations were accreted to the eastern continental margin which was a large tectonic collage developed as the chinese mainland during the late triassic enormous amounts of clastic detritus were deposited in sedimentary basins where jumbling and telescoping of pelagic sediments took place in a complicated fashion producing a melange the provenance of clastic detritus within the mino terrane is interpreted as a platform on which permian and carboniferous calcareous sediments containing diagenetic lutecite and orthoquartzite formations were widespread these formations covered a precambrian metamorphic and granodioritic basement similar to that seen in the south china region accretion culminated in the earliest cretaceous and the large disrupted terrane which had developed was transpressed northwards along the eastern margin of the continent during this period of dispersal the original terrane was sheared fragmented and separated into many smaller terranes some of which were transported to the sikhote alin region by the late cretaceous the most recent dispersal occurred during the opening of the sea of japan which is closely related to the latest movement of the pacific plate studies of radiolarian micropaleontology and the significance of these fossils to the resolution of the biostratigraphy and the tectonic history of japan are reviewed the results of biostratigraphic analyses are discussed in relation to the mesozoic tectonics of east asia

tectonic and sedimentary evolution of a cretaceous continental arc backarc system in the korean peninsula new view abstract this paper focuses on the tectonic and sedimentary evolution of the cretaceous volcanic rocks and nonmarine successions in the southeastern part of the korean peninsula which constitute an ancient continental arc system the arc system gyeongsang arc system comprising an arc platform gyeongsang volcanic arc and a backarc basin gyeongsang backarc basin was a southwestward extension of the japanese arc formed by oblique northward subduction of the proto pacific izanagi plate under the asian continent the backarc basin was initiated in the southeastern part of the korean peninsula in the early cretaceous as a narrow ns trending trough the basin was bounded by a major fault in the northern part of the basin from which sediments largely emanated sediments were deposited in streamflow dominated alluvial fans adjacent to the fault bounded basin margin in the north and low gradient fluvial systems of braided channels that extended southward and southeastward for tens of kilometers sediments were also derived from the western highland margin draining precambrian to jurassic basement rocks the initially narrow trough progressively expanded toward the east resulting in eastward migration of depocenters that eventually generated a broad fluvio lacustrine plain fringing the volcanic arc platform the arc platform played an important role for the derivation of volcanogenic materials and accreted sediments into the backarc basin via extensive fluvial network pyroclastic density currents and landslides which originated from the arc platform also entered the basin in addition extrusion of basaltic volcanic rocks was continual within the basin during basin expansion the resultant succession of mixed sedimentary and volcanogenic rocks is generally indicative of a temporal increase in volcanic activity in the arc platform and in subsidence rate of the basin in the late cretaceous andesitic to rhyolitic volcanism became climactic in the arc platform producing a number of calderas or volcanotectonic depressions volcaniclastic aprons fringing the arc platform encroached upon the basin fill intraarc basins produced by sinistral shearing of the arc platform received sediments from active volcanoes and footwalls of contemporaneous faults forming small scale streamflow dominated alluvial fans and floodplains with later development of a deep lake overall the gyeongsang arc system formed under an extensional or transtensional sinistral strike slip stress regime suggesting that the subducting and the overriding plates were not strongly coupled both the volcanic arc and the backarc basin ceased to develop as volcanic activities shifted progressively eastward in the paleogene accompanied with rollback of the subduction of the izanagi plate

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

radiolarian bearing conglomerate from the hayang group the kyongsang supergroup southeastern korea abstract the non marine cretaceous kyongsang supergroup which is divided into the sindong the hayang and the yuchon groups is widely distributed in southeastern korea radiolarian bearing pebbles are collected from the conglomerates of the kumidong and the kisadong formations of the hayang group the age of radiolarian fossils range from late permian to middle jurassic in korea permian to middle jurassic marine chert beds are not exposed the directions of paleocurrents of the kumidong and the kisadong formations are mainly from the northeast to southwest during cretaceous time the mino tamba belt within which permian to middle jurassic chert beds are exposed is suggested to have been located northeast of the kyongsang basin the radiolarian faunas of the hayang group are similar to those of the mino tamba belt and other associated mesozoic accretionary belts in japan e g the ashio belt the provenance of the radiolarian bearing pebbles collected from the kumidong and the kisadong formations is interpreted to be the mino tamba belt and other associated mesozoic accretionary belts in japan

uniform california earthquake rupture forecast version 2 ucerf 2 the 2007 working group on california earthquake probabilities wgcep 2007 presents the uniform california earthquake rupture forecast version 2 ucerf 2 this model comprises a time independent poisson process earthquake rate model developed jointly with the national seismic hazard mapping program and a time dependent earthquake probability model based on recent earthquake rates and stress renewal statistics conditioned on the date of last event the models were developed from updated statewide earthquake catalogs and fault deformation databases using a uniform methodology across all regions and implemented in the modular extensible open seismic hazard analysis framework the rate model satisfies integrating measures of deformation across the plate boundary zone and is consistent with historical seismicity data an overprediction of earthquake rates found at intermediate magnitudes 6 5 m 7 0 in previous models has been reduced to within the 95 confidence bounds of the historical earthquake catalog a logic tree with 480 branches represents the epistemic uncertainties of the full time dependent model the mean ucerf 2 time dependent probability of one or more m 6 7 earthquakes in the california region during the next 30 yr is 99 7 this probability decreases to 46 for m 7 5 and to 4 5 for m 8 0 these probabilities do not include the cascadia subduction zone largely north of california for which the estimated 30 yr m 8 0 time dependent probability is 10 the m 6 7 probabilities on major strike slip faults are consistent with the wgcep 2003 study in the san francisco bay area and the wgcep 1995 study in southern california except for significantly lower estimates along the san jacinto and elsinore faults owing to provisions for larger multisegment ruptures important model limitations are discussed

computational tools for relaxing the fault segmentation in probabilistic seismic hazard modelling in complex fault systems use of faults in seismic hazard models allows us to capture the recurrence of large magnitude events and therefore improve the reliability of probabilistic seismic hazard assessment psha in the past decades fault segmentation provided an important framework for quantifying fault based psha recent complex coseismic ruptures e g 2010 mw 7 1 canterbury 2012 mw 8 6 sumatra 2016 mw 7 8 kaik ura 2016 mw 6 5 central italy have shown the need to consider different possible combinations of rupture scenarios in psha here we present two new methodologies that model rates of ruptures along complex fault systems one based on a floating rupture approach fresh and another one based on assumed rupture scenarios sunfish they represent alternatives to a recently proposed approach sherifs and further step to overcome the segmented and un segmented approaches commonly used in psha in europe differences among sherifs sunfish and fresh are related to the way slip rate rupture geometries and magnitude frequency distributions are modelled to quantify the differences between these three methodologies we compared psha results based on geometries and slip rates of a fault system located in northeastern italy assuming a given maximum magnitude and the same seismic moment rate target differences up to 20 30 in the peak ground acceleration at 2 and 10 in 50 years are observed finally we show that the three methodologies are able to solve for the long term rate of ruptures with resulting psha that reflect the fault system geometry and slip rates without any assumption on segment boundaries using fault based approaches in psha requires collecting as much local geological information as possible now that multi fault rupture approaches are available simplifying assumptions often made to model complex fault systems uniform slip rate segmentation hypothesis are no longer necessary on the other hand local data collection should be strongly encouraged to better characterize the actual fault slip rate variability and the complex 3d geometries

recent advances in the cretaceous stratigraphy of korea abstract a subrounded accidental zircon grain from a rhyolite sample of the oknyobong formation has shown an u pb chime isochron age 187 ma implying its derivation from a jurassic felsic igneous rock such a lower limit of the geologic age of the oknyobong formation combined with its pre kyongsang upper limit constrains that the oknyobong formation belongs to the jasong synthem late jurassic early early cretaceous typified in north korea the jaeryonggang movement terminated the deposition of the jasong synthem and caused a shift of the depocenter from north korea to the kyongsang basin southeast korea the cretaceous paleocene kyongsang supergroup of the kyongsang basin is the stratotype of the kyongsang synthem an unconformity bounded unit in the korean peninsula the unconformity at the base of the yuchon volcanic group is a local expression of the interregionally recognizable mid albian tectonism it subdivides the kyongsang synthem into the lower kyongsang subsynthem barremian early albian and the upper kyongsang subsynthem late albian paleocene the latter is unconformably overlain by eocene and younger strata the late permian to early jurassic radiolarian fossils from the chert pebbles of the kumidong and the kisadong conglomerates of the aptian early albian hayang group of the kyongsang basin are equivalent with those of the cherts that constitute the jurassic accretionary prisms in japan the provenance of the chert pebbles in the kyongsang basin bimodal volcanisms throughout the history of the kyongsang basin is exemplified by the felsic kusandong tuff erupted abruptly and briefly in the late aptian when semi coeval volcanisms were of intermediate and mafic compositions the mean paleomagnetic direction shown by the kusandong tuff is in good agreement with the early cretaceous directions known from north china south china and siberia blocks

coseismic slip vectors of 24 august and 30 october 2016 earthquakes in central italy oblique slip and regional kinematic implications after 24 august and 30 october 2016 central italy earthquakes mw 6 0 and 6 5 respectively photogrammetry and geodetic survey were performed at various sites along a 6 km long portion of the rupturing monte vettore fault system providing very high resolution georeferenced 3 d point clouds and imagery of the 24 august rupture and a data set of bedrock fault scarp before after the 30 october earthquake the maximum coseismic displacement for both events occurs near scoglio dell aquila with an average normal dip slip of 22 4 and 184 6 cm respectively coseismic slip vectors and meter scale corrugation axis are oriented n280 10 on the n140 striking main vettore fault involving oblique normal slip with a right lateral component and n205 10 on n170 fault strands implying oblique normal slip with a left lateral component we quantify the near field coseismic displacements of the monte vettore fault for the 30 october event the footwall has been translated horizontally by 42 2 cm toward the ene and uplifted by 11 2 cm the hangingwall has moved horizontally by 26 2 cm toward the nw in a direction parallel to the fault plane and subsided by 116 2 cm the fault geometry and our determined surface coseismic slip vectors are mechanically compatible with a 3 n65 15 this stress regime is consistent with the 30 october 2016 focal mechanism and the relative motion between the adriatic microplate and the tyrrhenian coastal region the 30 october surface rupture results from seismic slip at depth and thus has a tectonic origin

fault based earthquake rupture forecast in central italy remarks after the l aquila mw 6 3 event abstract in 2006 we published an earthquake hazard model called lassci layered seismogenic source model in central italy in october 2008 we began to update the model for use in 5 and 10 year forecasts the lassci 2006 model is supported by good fault based definitions of seismogenic sources and simple physically motivated models of earthquake occurrence the lassci 2009 model has been improved by revision of the error propagation assumptions and increased accuracy of the earthquake probabilities the 6 april 2009 earthquake that struck l aquila occurred on the model fault having the highest probability of occurrence in the 2009 revised lassci forecast it is therefore consistent with our model assumptions furthermore peak ground accelerations were in reasonable agreement with the values having 90 probability of not being exceeded in 50 yr in the revised 2009 model the aggregate probability of having a maximum sized event in the next 5 yr on at least one of the neighboring sources less than 25 km distance away decreases in l aquila from 10 to 7 after the earthquake occurrence but still remains a maximum there along the central apennines the lassci models 2006 and 2009 featuring characteristic fault sources and time dependence seem to be suitable for guidance in reconstruction and seismic retrofit in the central appenines

weathering and damage 1 weathering of rock surfaces is often associated with a surface dissolution process chemical interactions occur on grain boundaries and diffusion is the controlling process a dissolution boundary layer rind develops adjacent to the weathering surface we quantify the extent of dissolution by introducing a damage variable f f 0 for pristine rock and when f f0 the rock disintegrates we assume that the variations of the damage variable are given by the diffusion equation we solve two problems the first is for the structure of the transient dissolution boundary layer prior to surface disintegration we find an incubation time ti before active weathering disintegration begins the second is the solution for steady state weathering with a constant weathering velocity vw our results are entirely consistent with weathering studies on carrera marble gravestones in the united kingdom

recurrent large earthquakes in a fault region what can be inferred from small and intermediate events we present a renewal model for the recurrence of large earthquakes in a fault zone consisting of a major fault and surrounding smaller faults with gutenberg richter type seismicity represented by seismic moment release drawn from a truncated power law distribution the recurrence times of characteristic earthquakes for the major fault are explored it is continuously loaded plate motion and undergoes positive and negative fluctuations due to adjacent smaller faults with a large number n eq of such changes between two major earthquakes because the distribution has a finite variance in the limit n eq the central limit theorem implies that the recurrence times follow a brownian passage time bpt distribution this allows us to calculate individual recurrence time distributions for specific fault zones without tuning free parameters the mean recurrence time can be estimated from geological or paleoseismic data and the standard deviation is determined from the frequency size distribution namely the richter b value of an earthquake catalog the approach is demonstrated for the parkfield segment of the san andreas fault in california as well as for a long simulation of a numerical fault model assuming power law distributed earthquake magnitudes up to the size of the recurrent parkfield event m 6 we find a coefficient of variation that is higher than the value obtained by a direct fit of the bpt distribution to seven large earthquakes we argue that the bpt distribution is a reasonable choice for seismic hazard assessment because it governs not only brownian motion with drift but also models with power law statistics for the recurrence of large earthquakes in an asymptotic limit finally we find that the condition b 1 separates two regimes in the first b 1 it is greater

layered seismogenic source model and probabilistic seismic hazard analyses in central italy we defined a seismogenic model for central italy based on three layers of sources and computed the relative seismic hazard maps one layer is constituted by individual structures liable to generate major earthquakes m 5 5 we defined them as seismogenic boxes by using geological information in terms of plan projec tion of active faults the seismicity rates associated with an individual source are based on the geometry and kinematics of the fault the recurrence model is controlled by the earthquake source association and when possible we defined the occurrence time of the last major event using it in a time dependent approach another layer is given by the instrumental seismicity analysis of the past two decades which allows us to evaluate the background seismicity m 5 5 using a sliding window selec tion of events we defined a model of regular adjacent cells of variable a and b values of the gutenberg richter relation the last layer utilizes all the instrumental earth quakes and the historical events not correlated to known structures 4 5 m 6 by separating them into seismotectonic provinces shaped on a geological structural basis the seismic hazard computations first use this layered model in a traditional probabilistic scheme the results indicate a narrow belt of peak ground acceleration pga higher than 0 30g with standard deviation in attenuation functions in the axial part of the apennine chain with a maximum spot of pga 0 40g southeast of the area damaged by the 1997 1998 umbria marche sequence pga expected not to be exceeded in 50 years at 90 probability level the background seismicity gives a nonnegligible contribution to the hazard at least for first damage levels then a simplified time dependent hypothesis has been introduced for the individual sources alone computing the conditional probability of occurrence of characteristic earth quakes for each source by brownian passage time distributions adopting equivalent fictitious seismicity rates we obtained maps referring to the next 50 years by using traditional codes these results show that the contribution of the recently active sources vanishes and the most hazardous sites are now located south of l aquila and in the sulmona area we consider that the methodology and results obtained are useful for seismic risk reduction strategies

present activity and seismogenic potential of a low angle normal fault system citta di castello italy constraints from surface geology seismic reflection data and seismicity abstract we present new constraints on an active low angle normal fault system in the citta di castello sansepolcro basin csb of the northern apennines of italy new field data from the geological survey of the carta geologica d italia carg project define the surface geometry of the normal fault system and lead to an interpretation of the crop 03 deep crust seismic reflection profile castiglion fiorentino urbania segment with particular attention paid to the geometry of the plio quaternary extensional structures surface and sub surface geological data are integrated with instrumental and historical seismicity in order to define the seismotectonics of the area low angle east dipping reflectors are the seismic expression of the well known altotiberina fault af a regional extensional detachment on which both east and west dipping high angle faults bounding the csb sole out the af breakaway zone is located 10 km west of the csb within the extensional allochthon synthetic east dipping planes prevail displacement along the af is 4 5 km which agrees with the cumulative offset due to its synthetic splays the evolution of the csb has mainly been controlled by the east dipping fault system at least since early pleistocene time this system is still active and responsible for the seismicity of the area a low level of seismic activity was recorded instrumentally within the csb but several damaging earthquakes have occurred in historical times the instrumental seismicity and the intensity data points of the largest historical earthquakes 5 events with maximum mcs intensity of ix to ix x allow us to propose two main seismogenic structures the monte santa maria tiberina mmax 5 9 and citta di castello mmax up to 6 5 normal faults both are synthetic splays of the af detachment dipping to the ne at moderate 45 50 to low 25 30 angles and cutting the upper crust up to the surface this study suggests that low angle normal faults at least with dips of 25 30 may be seismogenic

uncertainty in strain rate from field measurements of the geometry rates and kinematics of active normal faults implications for seismic hazard assessment abstract multiple measurements of the geometry kinematics and rates of slip across the auletta fault campania italy are presented and we use these to determine 1 the spatial resolution of field measurements needed to accurately calculate a representative strain rate 2 what aspects of the geometry and kinematics would introduce uncertainty with regard to the strain rate if not measured in the field we find that the magnitude of the post last glacial maximum throw across the fault varies along strike if such variations are unnoticed different values for a representative strain rate hence different results in seismic hazard calculations would be produced to demonstrate this we progressively degrade our dataset calculating the implied strain rate at each step excluding measurements can alter strain rate results beyond 1 uncertainty thus we urge caution when using only one measurement of slip rate for calculating hazard we investigate the effect of approximating the throw profile along the fault with boxcar and triangular distributions and show that this can underestimate or overestimate the strain rate with results in the range of 72 237 of our most detailed strain rate calculation we discuss how improved understanding of the potential implied errors in strain rate calculations from field structural data should be implemented in seismic hazard calculations

mesozoic terrane accretion in northeast china sikhote alin and japan regions abstract the nadanhada range in northeast china is composed of upper paleozoic limestone greenstone middle to late triassic bedded chert and middle jurassic siliceous shale these rocks are enclosed in post middle jurassic clastic rocks the lithologic association ages radiolarian assemblages and geologic structure of the nadanhada range are very similar to those of the tamba mino ashio terrane in southwest japan this indicates that the nadanhada range is the northern extension of the tamba mino ashio terrane mesozoic tectonostratigraphic terranes identified in northeast china sikhote alin and southwest japan are the khanka terrane a micro continent composed of precambrian metamorhic rocks and paleozoic to mesozoic sedimentary and volcanic covers the nadanhada western sikhote alin terrane a disrupted terrane composed of upper paleozoic to jurassic sedimentary rocks the eastern sikhote alin terrane a terrane composed mainly of early cretaceous clastics the tetyukhe terrane a disrupted terrane composed of upper paleozoic to early cretaceous sedimentary rocks the hida terrane a continent type stratigraphic terrane composed of precambrian and upper paleozoic basement covered with jurassic to cretaceous coarse clastics and the tamba mino ashio terrane a disrupted terrane composed of upper paleozoic to earliest cretaceous sedimentary rocks accretionary history of these terranes is discussed on the basis of paleomagnetic and paleobiogeographic data

the role of viscoelastic stress transfer in long term earthquake cascades insights after the central italy 2016 2017 seismic sequence central italy is characterized by a network of active faults that interact in a complex manner coseismic coulomb stress changes have been invoked by several authors to explain the concentration of moderate to strong earthquakes in this region but none has considered the time dependent viscoelastic relaxation of the lower crust and upper mantle as a possible additional source of stress changes at a regional scale here starting from the 1915 m w 6 9 0 2 fucino earthquake we calculated the coseismic plus postseismic coulomb failure stress changes cfs due to eight moderate to strong earthquakes that have struck central italy in the last century and culminated with the 2016 2017 sequence results from this modeling coupled with some synthetic tests simulating normal fault earthquakes with different magnitudes allowed us to highlight the importance of postseismic processes in particular the viscoelastic stress transfer due to events of m w 6 5 can modify the spatial distribution of cfs on a centennial timescale and therefore trigger events at larger distances in addition using these results we identified other earthquake clusters in the historical catalogue last 618 years which like the 1915 2017 series were potentially modulated by both coseismic and postseismic processes finally considering our calculations combined with historical and paleoseismological data we suggest that several faults in central italy may be at present close to failure

the magnitude distribution of declustered earthquakes in southern california abstract the binned distribution densities of magnitudes in both the complete and the declustered catalogs of earthquakes in the southern california region have two significantly different branches with crossover magnitude near m 4 8 in the case of declustered earthquakes the b values on the two branches differ significantly from each other by a factor of about two the absence of self similarity across a broad range of magnitudes in the distribution of declustered earthquakes is an argument against the application of an assumption of scale independence to models of main shock earthquake occurrence and in turn to the use of such models to justify the assertion that earthquakes are unpredictable the presumption of scale independence for complete local earthquake catalogs is attributable not to a universal process of self organization leading to future large earthquakes but to the universality of the process that produces aftershocks which dominate complete catalogs

do static stress changes of a moderate magnitude earthquake significantly modify the regional seismic hazard hints from the l aquila 2009 normal faulting earthquake mw 6 3 central italy we investigated the coulomb stress changes in the active faults surrounding a moderate magnitude normal faulting earthquake 2009 l aquila mw 6 3 and the associated variations in the expected ground motion on regional probabilistic seismic hazard maps we show that the static stress variations can locally increase the seismic hazard by modifying the expected mean recurrence time on neighbouring faults by up to 290 years with associated variations in the probability of occurrence of the maximum expected earthquake of up to 2 our findings suggest that the increase in seismic hazard on neighbouring faults following moderate magnitude earthquakes is probably not sufficient to necessitate systematic upgrades of regional probabilistic seismic hazard maps but must be considered to better address and schedule strategies for local scale mitigation of seismic risk

rates of geodetic deformation across active faults in southern italy abstract active deformation in southern italy is accommodated by a distributed number of faults with low moderate slip rates outcropping extensional faults and mostly blind transcurrent faults are mapped within a western or axial and an eastern domain respectively we use a combination of continuous 2001 00 2011 84 and episodic 1995 68 2010 79 gnss observations to firstly estimate the geodetic deformation rate on 32 faults geodetic results were successively compared with geological displacement estimates in agreement with seismological and geological information a net spatial segregation emerges between the extensional axial belt and the eastern domain where strike slip faults are geodetically active although uncertainties are at times large average displacement rates show broadly consistent patterns within both domains a longitudinal gradient in extension rate is observed for the axial fault array with two sectors of higher magnitude 0 8 1 7 mm yr for individual faults this result is consistent with geological observations and supports the notion that extension occurs in discrete patches faults of the eastern domain have lower few 0 1 to 1 2 mm yr strike slip rates and an eastward decreasing extensional component but significant geodetic displacement is detected in areas lacking clear evidence of activity few faults with 1 2 mm yr extension rate are locally found in the eastern domain but based on their limited length and on inconsistency with seismology and geology they are considered as due to deep seated gravitational spreading for crustal faults although geodetic slip and moment rates are larger than geological rates the broad trend of long to short term rates is similar indicating the feasibility of geodetic analysis to contribute estimating fault slip rate and testing tectonic models in the region whereas the western domain extension is thought to be controlled by potential energy related to the tyrrhenian moho uplift beneath the apennines strike slip in the east is related to shear on inherited faults within the adriatic crust

a mutually consistent seismic hazard source model for southern california abstract a previous attempt to integrate geological geodetic and observed seismicity data into a probabilistic hazard source model predicted a rate of magnitude 6 to 7 earthquakes significantly greater than that observed historically one explanation was that the discrepancy or apparent earthquake deficit is an artifact of the upper magnitude limit built into the model this was controversial however because removing the discrepancy required earthquakes larger than are seen in the geological record and larger than implied from empirical relationships between fault dimension and magnitude although several articles have addressed this issue an alternative integrated source model without an apparent deficit has not yet appeared we present a simple geologically based approach for constructing such a model that agrees well with the historical record and does not invoke any unsubstantiated phenomena the following factors are found to be influential the b value and minimum magnitude applied to gutenberg richter seismicity the percentage of moment released in characteristic earthquakes a round off error in the moment magnitude definition bias due to historical catalog incompleteness careful adherence to the conservation of seismic moment rate uncertainty in magnitude estimates obtained from empirical regressions allowing multi segment ruptures cascades and the time dependence of recurrence rates the previous apparent deficit is shown to have resulted from a combination of these factors none alone caused the problem nor solves it the model presented here is relatively robust with respect to these factors

seismic slip history of the pizzalto fault central apennines italy using in situ produced 36cl cosmic ray exposure dating and rare earth element concentrations morphological and geological observations reveal that most apenninic faults are highly segmented and that the majority of the fault segments are less than 10 km long although these faults have undergone numerous paleoseismological investigations quantitative data remain crucially lacking for a large number of fault segments because such data are essential to understanding how these faults have ruptured and interacted in the past and how they might behave in the future we investigated the holocene seismic history of the pizzalto normal fault a 13 km long fault segment belonging to the pizzalto rotella aremogna fault system in the apennines we collected 44 samples from the pizzalto fault plane exhumed during the holocene and analyzed the 36cl and rare earth element ree contents together the 36cl and ree concentrations show that at least six events have exhumed 4 4 m of the fault scarp between 3 and 1 ka with slip per event values ranging from 0 3 to 1 2 m no major events have been detected over the last 1 kyr the rotella aremogna pizzalto fault system has a clustered earthquake behavior with a mean recurrence time of 1 2 kyr and a low to moderate probability ranging from 4 to 26 of earthquake occurrence over the next 50 years

provenance of the hayang group early cretaceous in the yeongyang subbasin se korea and its bearing on the cretaceous palaeogeography of sw japan abstract the lower cretaceous hayang group in the yeongyang subbasin se korea was deposited in a forearc basin formed by the subduction of the palaeo pacific izanagi plate underneath the east asian continent it is characterized by an alternating sequence of reddish sandstones and mudstones deposited in fluvial plain environments sandstone compositions upsequence reveal that the tectonic regimes of source terrains evolved successively from basement uplift to recycled orogen to magmatic arc and back to recycled orogen characteristically sandstones contain abundant plagioclases but rare k feldspars except for sandstones derived from basement sources sandstones derived from recycled orogens are rich in sedimentary rock fragments especially chert fragments which contain radiolarian faunas similar to those of the jurassic accretionary complex located in southwest japan minor continental arc volcanism contributed volcanic materials to the basin during the middle stage of the basin filling during the deposition of the hayang group strike slip fault movements were active due to the oblique subduction of the izanagi plate and caused strong pulsed uplift of the trench slope break areas resulting in supply of accretionary complex derived sediments considering a direct drainage connection between the uplifted accretionary complex in southwest japan and the yeongyang subbasin current cretaceous palaeogeographic reconstructions of the east asian continental margin need to be reconsidered and it is suggested that the collage of tectonic blocks in southwest japan assembled in post early cretaceous time

effect of time dependence on probabilistic seismic hazard maps and deaggregation for the central apennines italy abstract we produce probabilistic seismic hazard assessments for the central apennines italy using time dependent models that are characterized using a brownian passage time recurrence model using aperiodicity parameters of 0 3 0 5 and 0 7 we examine the sensitivity of the probabilistic ground motion and its deaggregation to these parameters for the seismic source model we incorporate both smoothed historical seismicity over the area and geological information on faults we use the maximum magnitude model for the fault sources together with a uniform probability of rupture along the fault floating fault model to model fictitious faults to account for earthquakes that cannot be correlated with known geologic structural segmentation we show maps for peak ground acceleration pga and 1 0 hz spectral acceleration sa 1 on rock having 10 probability of exceedence in 50 yr we produce maps to compare the separate contributions of smoothed seismicity and fault components in addition we construct maps that show sensitivity of the hazard for different parameters and the poisson model for the poisson model the addition of fault sources to the smoothed seismicity raises the hazard by 50 at locations where the smoothed seismicity contributes the highest hazard and up to 100 at locations where the hazard from smoothed seismicity is low for the strongest aperiodicity parameter smallest the hazard may further increase 60 80 or more or may decrease by as much as 20 depending on the recency of the last event on the fault that dominates the hazard at a given site in order to present the most likely earthquake magnitude and or the most likely source site distance for scenario studies we deaggregate the seismic hazard for sa 1 and pga for two important cities rome and l aquila for pga both locations show the predominance of local sources having magnitudes of about 5 3 and 6 5 respectively for sa 1 at a site in rome there is significant contribution from local smoothed seismicity and an additional contribution from the more distant apennine faults having magnitude around 6 8 for l aquila the predominant sources remain local in order to show the variety of impact of different values we also obtained deaggregations for another three sites in general as decreases periodicity increases the deaggregation indicates that the hazard is highest near faults with the highest earthquakes rates this effect is strongest for the long period 1 sec ground motions

the 2009 l aquila earthquake central italy a source mechanism and implications for seismic hazard an edited version of this paper was published by agu copyright 2009 american geophysical union

reply to comment on layered seismogenic source model and probabilistic seismic hazard analyses in central italy by b pace l peruzza g lavecchia and p boncio by w marzocchi we greatly appreciate the interest in and feedback onour article we will address the comments in the next par agraphs following the comment points our article is not a novel or new approach toquantifyingthe recurrence behavior and seismic hazard of faults in italy fault recurrence behavior has been addressed previously innortheastern italy e g papoulia and slejko 1992 slejkoand rebez 2000 southern italy peruzza