unveiling the sources of the catastrophic 1456 multiple earthquake hints to an unexplored tectonic mechanism in southern italy we revisited data related to the 1456 seismic crisis the largest earthquake to have ever occurred in peninsular italy in search of its causative source s data about this earthquake consist solely of historical reports and their intensity assessment because of the age of this multiple earthquake the scarcity and sparseness of the data and the unusually large damage area no previous studies have attempted to attribute the 1456 events to specific faults existing analytical methods to identify a likely source from intensity data also proved inappropriate for such a sparse dataset since historical evidence suggests that the cumulative damage pattern contains at least three widely separated events we subdivided the 1456 damage pattern into three independent mesoseismal areas each of these areas falls onto east west tectonic trends previously identified and marked by deep 10 km right lateral slip earthquakes based on this evidence we propose 1 that the 1456 events were generated by individual segments of regional east west structures and are evidence of a seismogenic style that involves oblique dextral reactivation of east west lower crustal faults 2 that each event may have triggered subsequent but relatively distant events in a cascade fashion as suggested by historical accounts hence 3 that the 1456 sequence reveals a fundamental but unexplored mechanism of tectonic deformation and seismic release in southern italy this style dominates the region that lies between the northwest southeast system of large extensional faults straddling the crest of the southern apennines and the buried outer front of the chain although the quality of the available information concerning the 1456 earthquake is naturally limited we show that the overlap of the damage distribution the orientation and characteristics of regional tectonic structures the seismicity patterns and the focal mechanisms all concur with our interpretations and would be difficult to justify otherwise

reconstruction of past precipitation δ18o using tree ring cellulose δ18o and δ13c a calibration study near lac d annecy france abstract two sets of living oaks quercus r growing under different hydrological situations were sampled near lac d annecy france the stable isotope composition of the latewood cellulose was analysed in terms of oxygen and carbon isotopic composition for the period 1971 2001 and compared to the nearby monthly meteorological temperature relative humidity and isotopic composition of precipitation records a linear regression shows that 60 of the cellulose oxygen isotopic composition inter annual variations are due to changes in precipitation isotopic composition and relative humidity the small slope between cellulose versus precipitation oxygen isotopic composition suggests a significant contribution of local continental recycling and questions the common assumption that vapour oxygen isotopic composition is at equilibrium with precipitation isotopic composition in europe during the growing season finally the combined use of tree ring oxygen and carbon isotopic composition records enables to account for leaf water enrichment due to stomata stress and to provide a reconstruction r 2 0 64 of the summer precipitation isotopic composition

a magnetic model for deep plutonic bodies beneath the central taupo volcanic zone north island new zealand the central taupo volcanic zone tvz is a region of intense quaternary rhyolitic volcanism and geothermal activity in the north island of new zealand from which about 14 000 km3 of pyroclastics and lavas have been erupted during the last 1 6 ma analysis of aeromagnetic surveys over the tvz showed the presence of long wavelength 10 to 25 km magnetic anomalies which roughly follow the trend of the currently active eastern tvz from the north of lake taupo to the east of lake rotorua an interpretation of the long wavelength magnetic anomalies using 3 d magnetic modelling suggests that these anomalies are caused by the magnetic effects of 3 km thick sequence of volcanic rocks and deeper magnetised bodies within the non magnetic upper crust 4 7 km depth beneath the young age 0 7 ma currently active eastern tvz the deep magnetised bodies are interpreted as solidified rhyolitic sub volcanic plutons that have cooled down to below their curie temperature although the existence of plutonic bodies beneath the tvz has been postulated prior to this study this magnetic interpretation result appears to be the first geophysical model of such bodies

defining seismogenic sources from historical earthquake felt reports abstract we present a method that uses macroseismic intensity data to assess the location physical dimensions and orientation of the source of large historical earthquakes intensity data contain a great deal of information that can be used to constrain the essential characteristics of the seismic source in particular both the seismological theory and its practice suggest that the orientation of the source of significant earthquakes is reflected in the elongation of the associated damage pattern a plausible and easily manageable way of describing a seismic source is by representing it as an oriented rectangle the length and width of which are obtained from moment magnitude through empirical relationships this rectangle is meant to represent either the actual surface projection of the seismogenic fault or at least the projection of the portion of the earth crust where a given seismic source is likely to be located the systematic application of this method to all the m 5 5 earthquakes that occurred in the central and southern apennines italy in the past four centuries returned encouraging results that compare well with existing instrumental direct geological and geodynamic evidence the method is quite stable for different choices of the algorithm parameters and provides elongation directions that in most cases can be shown to be statistically significant in particular the resulting pattern of source orientations is rather homogeneous showing a consistent appennines parallel trend that agrees well with the ne sw extension style of deformation active in the central and southern portions of the italian peninsula

neoproterozoic tectonics of australia antarctica and laurentia and the 560 ma birth of the pacific ocean reflect the 400 m y pangean supercycle unequivocal evidence for the proterozoic reconstruction of australia antarctica and laurentia remains elusive although various authors have interpreted sedimentary and igneous events in terms of initial neoproterozoic rifting and final neoproterozoic cambrian drifting the synchronous rifting and drifting reflect the tectonics of a late neoproterozoic pangea east gondwanaland and laurentia that amalgamated along the mozambiquean belt 720 ma and broke up at 560 ma by growth of the paleo pacific and lapetus oceans in this paper these events are interpreted as part of a 400 m y supercycle comparable to the 320 ma amalgamation of pangea a and its 160 ma breakup during supercycle a 320 ma to present events near the end of the cambrian 500 ma in east gondwanaland included epeirogenic uplift of cratons shown by widespread k ar and apatite fission track dates and the inception of quartz turbidite fans intense deformation and intrusion by granite of the antarctic and south eastern australian mar

polyphase deformation in a fore arc back arc basin salin subbasin myanmar burma the salin subbasin of myanmar part of the larger central basin is a fore arc back arc basin couplet situated between an oblique subduction zone to the west and a major right lateral strike slip fault to the east surface and subsurface expressions of folds and faults suggest that the basin experienced north northwest directed extensional deformation in the miocene followed by east northeast directed pliocene pleistocene transpressional deformation resulting in a variety of structural styles including thrust faults oblique reverse faults strike slip faults and normal faults fault propagation folds cored by west dipping thrust faults in the basin center are located above steps in the top of basement surface most likely fault controlled unconformities at the base of and within the pliocene pleistocene synorogenic section indicate that the thrust faults were active during the pliocene pleistocene the southeastern region contains broad north northwest trending uplifts and east northeast striking normal faults associated with thickened miocene synorogenic deposits pliocene pleistocene sedimentary rocks lie unconformably above the miocene section and are folded above the uplifts reflecting pliocene pleistocene compression in the southern part of the basin miocene sedimentary rocks thicken dramatically over the 20 n uplift and the yedwet uplift suggesting that the north northwest striking faults that bound them represent pliocene pleistocene inversion of miocene normal faults during the miocene the burma plate acted as a fore arc sliver coupled with the india plate subducting obliquely underneath it and moved northward relative to asia along the sagaing fault normal faulting and local basin formation took place at this time when the northern part of the burma plate collided with eastern asia in the pliocene transpressional deformation predominated creating thrust and reverse faults positive flower structures and inverted basins

dike intrusion and displacement accumulation at the intersection of the okataina volcanic centre and paeroa fault zone taupo rift new zealand abstract we examine the relationship between dike emplacement and normal fault displacement along the south western margin of okataina volcanic centre new zealand at this location dikes including a basaltic dike up to 5 m wide at the ground surface intruded during the 1886 ad tarawera eruption formed over the last 22 kyr in the tarawera linear vent zone within a few kilometres of the paeroa fault zone displacement analysis and mapping of fault scarps indicate that fault and dike extension are complementary over time periods of tens of thousands of years extension that is primarily accommodated by faulting outside the volcanic complex is achieved by dike intrusion and faulting within it historical observations following the 1886 ad eruption and previously published active fault trenching collectively indicate however that dike intrusion generally does not induce slip within the paeroa fault zone close to the lateral dike tip we suggest that displacement in the paeroa fault zone outside the okataina volcanic centre is generally not triggered by eruptions and that this fault is principally tectonic in origin

complex evolution of volcanic arcs the lithofacies and palaeogeography of the cambrian stavely arc delamerian fold belt western victoria abstract the mount stavely volcanic complex is a cambrian greenstone belt in western victoria australia which formed as a continental arc during subduction of the proto pacific plate under gondwana while the msvc has been broadly described in literature its lithofacies and palaeogeography remains unconstrained the lithofacies that occur throughout the msvc were characterised using field work and diamond drill core from the geological survey of victoria the majority of the msvc consists of fragmental facies that were deposited in a deep marine environment these deposits were subsequently intruded by melts which formed the coherent facies some became either shallow intrusive or even extrusive the volcanic processes that formed the mount stavely volcanic complex are similar to those currently occurring in the present day kermadec arc furthermore the submarine nature of these volcanic facies is similar to the cambrian mount read volcanics in tasmania however in timing and cause of volcanic activity not all of these ancient volcanic terranes are related these findings help constrain the depositional environment in which the mount stavely volcanic complex was emplaced which in turn provides important constraints for the tectonic reconstruction of gondwana

waveform modeling of historical seismograms of the 1930 irpinia earthquake provides insight on blind faulting in southern apennines italy 1 the southern apennines chain is related to the west dipping subduction of the apulian lithosphere the strongest seismic events mostly occurred in correspondence of the chain axis along normal nw se striking faults parallel to the chain axis these structures are related to mantle wedge upwelling beneath the chain in the foreland faulting develops along e w strike slip to oblique slip faults related to the roll back of the foreland similarly to other historical events in southern apennines the i0 xi mcs intensity scale 23 july 1930 earthquake occurred between the chain axis and the thrust front without surface faulting this event produced more than 1400 casualties and extensive damage elongated approximately e w the analysis of the historical waveforms provides the chance to study the fault geometry of this anomalous event and allow us to clarify its geodynamic significance our results indicate that the ms 6 6 1930 event nucleated at 14 6 3 06 km depth and ruptured a north dipping n100 e striking plane with an oblique motion the fault propagated along the fault strike 32 km to the east at about 2 km s the eastern fault tip is located in proximity of the vulture volcano the 1930 hypocenter similarly to the 1990 mw 5 8 southern apennines event is within the mesozoic carbonates of the apulian foredeep and the rupture developed along a blind fault the 1930 fault kinematics significantly differs from that typical of large southern apennines earthquakes which occur in a distinct seismotectonic domain on late pleistocene to holocene outcropping faults these results stress the role played by pre existing blind faults in the apennines subduction setting

a geodynamic model of the southern apennines accretionary prism the apennines comprise a neogen quaternary accretionary prism that shows several anomalies with respect to classic alpine type mountain belts namely i low elevation ii a shallow new moho below the core of the belt iii high heat flow in the internal parts iv mainly sedimentary cover involved in the prism v a deep foredeep and vi a fully developed back arc basin the suction exerted by a relatively eastward migrating mantle can determine the eastward retreat of the subduction zone and an asthenospheric wedging at the retreating subduction hinge heat flow geochemical and seismological data support the presence of a hot mantle wedge underlying the western side of the apenninic accretionary prism a thermal model of the belt with foreland dipping isotherms fits with deepening of the seismicity toward the east mantle volatiles signatures are also widespread in springs along the apennines

crustal velocity structure in italy from analysis of regional seismic waveforms abstract in this article we use regional seismic waveforms recorded by the recently installed istituto nazionale di geofisica e vulcanologia ingv national network and the mediterranean very broadband seismographic network mednet stations to develop 1d crustal velocity models for the italian peninsula about 55 000 p wave and 35 000 s wave arrival times from 4727 events are used to derive average seismic parameters in the crust and uppermost mantle we define four regions according to geological constraints and recent travel time tomography results based on the average seismic parameters we combine broadband seismic waveforms and travel times of regional phases to model crustal structures for the four regions by applying the genetic algorithm our results indicate smooth velocity gradients with a depth beneath the apennines and a deep moho beneath the central alps green s functions from the regionalized 1d velocity models are used to determine source depths and focal mechanisms for 37 events with a magnitude larger than 3 5 by a grid search technique our results show that normal and strike slip faulting source mechanisms dominate the apenninic belt and that most thrust faulting events occur in the adriatic sea and the outer margin of the northern apennines

active crustal deformation from the azores triple junction to the middle east the co seismic crustal deformation along the africa eurasia eurasia arabia plate boundary from the azores triple junction 30 w up to the karliova triple junction 41 e is examined based on the moment tensor summation of mainly post 1964 earthquakes with ms 5 0 strain rates range from 10 8 yr to 10 6 yr while values exceeding 10 7 yr were calculated for the back arc aegean area and for the north anatolian fault zone a remarkable stability in the azimuth of the component of compression and of extension is observed in the area that extends west of italy 17 e up to the azores triple junction along this region the deformation is taken up by compression along a mean direction of n140 with rates from 1 1 to 2 8 mm yr and by extension along a mean direction of n50 with rates from 2 4 to 12 0 mm yr at the gloria fault and in the surrounding area dextral strike slip motion occurs at a rate of 11 mm yr from sicily up to the eastern end of the hellenic arc the crust is compressed at azimuths in the range n20 n31 with an average value of 26 5 this compression is occurring at a rate of 1 21 mm yr with an average value of 9 8 mm yr in the back arc aegean area extension is occurring along a mean azimuth of n156 with a rate of 5 2 3 8 mm yr the average shortening rate along the convex side of the hellenic arc is 12 mm yr from the eastern end of the north anatolian fault 41 e up to the northern aegean trough extension along n68 n179 and compression along n158 n89 occurs which results in dextral strike slip motion the rate of extension reduces from east to west from 30 mm yr to 5 mm yr while the rate of compression reduces from 17 mm yr to 5 mm yr the northwards motion of arabia results in a n31 trending compression at a rate of 7 mm yr along the east anatolian fault zone

oroclines in the tasmanides abstract oroclines are features of orogenic belts that exhibit curvature in plan on a map scale with the additional requirement that this curvature resulted from relative rotation of the limbs around a vertical or near vertical axis much debate has centred on contrasts between thin skinned and thick skinned systems and on the question of whether the structural fabric was imposed prior to or synchronous with the development of curvature leading to a variety of inconsistent terminology a simple hierarchy in which all map scale curved orogenic features which pass a test for rotation are termed oroclines as distinct from primary arcs and in which these are then subdivided by timing into progressive synchronous fabric and curvature and secondary pre existing fabric is then rotated and by mechanism into thin or thick skinned is applied to a suite of curved orogenic features in the tasmanides of eastern australia this analysis includes the first formal application of the orocline test palaeomagnetic or palaeocurrent directions plotted against structural strike to the tasmanides the neoproterozoic to early mesozoic tasmanides comprise four orogens each of which contains curved orogenic features which are highlighted by extensive aeromagnetic datasets the delamerian orogen developed on the gondwana margin exhibits two curved structures in the neoproterozoic to cambrian adelaide fold belt termed the fleurieu and nackara arcs previous structural interpretations have indicated that the nackara arc is non rotational and hence not oroclinal re examination of existing palaeomagnetic data including a positive palaeomagnetic orocline test shows the nackara arc to in fact be a hinge of the adelaide orocline curvature in the adelaide orocline was dominantly progressive and thin skinned but may have been influenced by secondary rotation of the pre existing partly underlying curnamona craton mega kinks in a buried delamerian arc volcanic chain revealed in aeromagnetic images follow the curvature of the nackara arc suggesting an accompanying thick skinned secondary oroclinal deformation further from the continental margin orogenic curvature in the palaeozoic lachlan orogen has only been widely recognised since the advent of tilt filtered aeromagnetic images and a model of oroclinal folding with two hinges riverina and tambo and strike slip offset during the silurian bindian orogeny has recently been proposed to explain perplexing repetitions of sequence and inversions of structural vergence and directions of sediment provenance palaeomagnetic data indicates rotation of elements within the proposed orocline and a preliminary study indicates a positive palaeomagnetic orocline test for the riverina hinge palaeocurrent data around the tambo hinge provide a positive if scattered orocline test an independently conceived numeric model of the roll back response to congestion of a subduction zone has generated an oroclinal structure which shares many features with the proposed lachlan orocline and deep crustal ambient noise seismic data confirms that the major curved and strike slip features persist throughout the crust the lachlan orocline appears to be secondary and thick skinned orogenic curvature in the largely covered thomson orogen occurs along its southern border with the lachlan orogen the putative olepoloko orocline and around its geometrically complex boundary with the mossman orogen in northern queensland the charters towers orocline rotation of the olepoloko structure cannot be confirmed and competing models for its formation leave open the question of whether this is a primary arc a thin skinned progressive orocline or a thick skinned secondary orocline palaeomagnetic data from the charters towers orocline are limited to two poles but a change in declination between the silurian pole and the devonian pole matches the apparent rotation of the orocline which appears to have been thick skinned and secondary in contrast to the other orogens consensus that at least part of the curvature in the palaeozoic to triassic new england orogen is oroclinal has been broad although not universal there remains substantial debate over the number of hinges from two to four and mechanism palaeomagnetic poles have previously been cited as evidence of rotation of blocks within the orocline but this paper presents the first formal palaeomagnetic orocline test which is positive for the manning and texas hinges a palaeocurrent orocline test of the manning hinge in younger rocks than the palaeomagnetic sample is negative constraining rotation in the southern manning hinge to the carboniferous before 322 ma while rotation in the northern texas hinge appears to be latest carboniferous or permian the existence of a hastings hinge is questionable but if real its rotation also appears to be younger than that of the manning hinge thick skinned secondary rotation of the hinges of the new england orocline appears to have been diachronous

can climate variations be inferred from tree ring parameters and stable isotopes from larix decidua juvenile effects budmoth outbreaks and divergence issue abstract larch wood has been used for centuries as a building material hence the study of the tree ring width the latewood maximal density and the oxygen and carbon isotope composition of the cellulose of this tree provides potential and valuable insights when reconstructing past climate variability we explore the qualities and limitations of these proxies focusing on a forest standing the nevache valley french alps the analysis of 15 trees demonstrates a small intra tree variability in comparison with the inter tree variability of 13c and 18o and shows that 6 trees at least must be pooled to make a population representative sample our results show no juvenile effect for 13c unlike tree ring width and density 13c and 18o are not altered by budmouth outbreaks these two parameters therefore appear well suited for climate reconstructions and depict a strong correlation with july august temperature and relative humidity the 18o of larch cellulose is also strongly linked with the previous winter december march oxygen isotopic composition of the precipitation this is consistent with a winter water recharge of soil and ground the past variations of july august maximum temperature and relative humidity were established using two different combinations of the isotopic ratios uncertainties on the reconstructions are estimated respectively at 1 4 c and 3 6 inter annual variations of temperature and relative humidity are well reproduced however the reconstructed july august temperature series diverges from the instrumental one being lower after ca 1990 the effects of the variation through time of the depth of source water and of the ecophysiological response of trees to rising co2 on the isotope composition are discussed as possible causes of divergence this divergence problem strongly questions the possibility of producing appropriate isotope based temperature calibration the relationships between isotopes and the july august relative humidity are more stationary than those with temperature this may reflect the first order control of the relative humidity on 13c via the stomatal conductance and its influence on the evaporative enrichment of the oxygen of the leaf water our study suggests that past variations of relative humidity in the french alps can be accurately estimated using the stable isotope composition of larch cellulose

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

devonian crustal stretching in the northern tasmanides australia and implications for oroclinal bending the tasmanides in eastern australia exhibit a number of orogenic curvatures oroclines and possibly a continental scale bend that defines the continuation of the delamerian orogen with the thomson orogen we provide an insight into the geodynamic processes associated with the origin of this orocline we present interpretations of seismic reflection profiles and potential field data from the thomson orogen which provide information on the crustal architecture and unravel major structures and kinematic relationships results show that a large area in the northern tasmanides is underlain by thinned crust bounded in the north and south by e w trending geophysical features with apparent sinistral and dextral sense of kinematics respectively within the highly extended crust of the thomson orogen there is evidence for widespread devonian basins bounded by normal faults in stark contrast to the southern tasmanides where rocks show evidence for an earlier silurian episode of extension and devonian contractional deformation no evidence for silurian synrift sedimentation is observed in the thomson orogen evidence for e w trending sinistral and dextral crustal scale shear zones in the northern and southern boundaries of the thomson orogen respectively may represent tear faults which were active during the early devonian and were possibly accompanied by tear related magmatism we suggest that crustal stretching in the northern tasmanides was associated with devonian back arc extension in response to trench retreat bounded by zones of slab tearing and crustal segmentation that ultimately led to the development of the delamerian thomson orocline

tree ring δ2h values from lignin methoxyl groups indicate sensitivity to european scale temperature changes abstract stable hydrogen isotope ratios of lignin methoxyl groups 2hlm of wood have been shown to reflect climate sensitive 2h values of precipitation 2hprecip however a detailed calibration study between high resolution 2hlm and 2hprecip data has not been performed yet here we present annually resolved 2hlm values from nine tree ring series derived from four fagus sylvatica l trees collected near a station of the global isotope network of isotopes in precipitation gnip and the meteorological observatory at hohenpeisenberg germany 48 n 11 e the nine 2hlm tree ring series show highly significant inter series correlations rbar 0 52 over the common period of overlap 1916 2015 and no sign of a major juvenile trend affecting the first decades of growth when compared with local instrumental data the combined 2hlm chronology is most indicative for annually averaged 2hprecip values in line with this finding the 2hlm chronology shows similar climatic imprints as commonly observed for european stable water isotopes we find the highest correlation r 0 72 p

oxygen isotope ratios from tree rings containing compression wood abstract oxygen isotope determinations on the cellulose of tree rings cut from two leaning picea engelmannii revealed significant differences between results from normal and compression wood radii nine samples 10 year periods from the normal wood radius 1721 1953 in one tree showed good agreement with proxy climate information and maximum differences of 1 8 between the warmest and coolest decades sampled differences of equivalent magnitude were found between samples from the same decade from normal and compression wood radii these differences are strongly related to the amount and or density of compression wood present and suggest that sampling for paleoclimatic work should be restricted to complacent erect trees without compression wood rings

genesis of a variscan batholith field petrological and mineralogical evidence from the corsica sardinia batholith abstract the genesis of the corsica sardinia batholith csb can be explained in a continental collision setting during the time of construction of the batholith which is dated at about 70 ma three magmatic associations were emplaced mg k calc alkaline u1 composite mafic silicic calc alkaline u2 and post collisional alkaline u3 in addition the level of intrusion became progressively shallower from 5 6 kbar for u1 to less than ikbar for u3 in a large scale uplift associations u1 and u2 exhibit non cogenetic mafic and felsic components the processes and products of interaction between mantle and crustal derived melts are however different and may be related to the thickness of the crust which controls both the parameters t pco2 ph2o andptot and the time of mingling of the products of anatexis and basaltic melts both u1 and u2 granitoids were formed by crystallization of a magma derived by fusion of a source of greywacke composition the melting occurred successively under granulitic u1 and amphibolite facies conditions u2 in association u1 basaltic melts displaying potassic lamprophyre like composition up to 8 k2o are of uncertain affinity furthermore crustal interaction with the basic magma precludes precise definition of the source in the u2 composite association the primary tholeiitic character of the mantle derived basic rocks is constrained by both mineralogical and geochemical data dry and hydrated subunits are distinguished among the basic rocks associated with the granitoids no hybridization processes have been identified in the core of the mafic complexes of the dry subunits but they are recognized at the level of emplacement at the margins at the contact with the granitoids contamination in the mafic hydrated subunit is due to the increase in water content of crustal origin in the magma during the ascent and emplacement of the basic complexes leading to the development of abundant green amphibole extensive hybridization is restricted to the base of the crust where it led to incomplete mixing yielding granodiorites and enclaves the genesis and emplacement of the composite calc alkaline u2 association took place in an extensional setting in an uplifting basement postdating a collisional event during the devonian an eastern austro alpine block was thrust onto the western ebro balearic continent the u1 mg k granitoids resulted from anatexis under conditions of pco2 ph2o this took place at the base of the austro alpine crust which was undergoing fusion due to its adiabatic ascent the u2 calc alkaline granitoid rocks were derived in a hydrated environment by fusion of the same austro alpine crust in corsica and of the ebro balearic crust on sardinia and in the pyrenees the conditions of interaction between mafic and felsic magmas may serve as a geodynamic marker providing information on the thickness of the crust in time and space and on the genesis of continental crust the persistence during the palaeozoic of dominantly tholeiitic mafic magmatism suggests that hot spot activity occurred in this area of southwestern europe during pre variscan and variscan times up to the time of opening of the liguro piedmontese ocean birthplace of the alpine orogen

structural control of volcanism and caldera development in the transtensional taupo volcanic zone new zealand abstract the taupo volcanic zone tvz new zealand comprises several segments with variable components of extension and is characterised by longitudinal segmentation into a central zone dominated by rhyolitic calderas and extremities with only andesitic composite volcanoes modern

seismotectonics of the calabrian arc abstract relocation of intermediate and deep earthquakes of tyrrhenian sea area through joint hypocenter determination for the period 1962 1979 has allowed a more detailed definition of the geometry of this peculiar benioff zone earthquakes dip along a quasi vertical plane to 250 km depth there is a 50 dip in the 250 340 km depth range and a low dip angle to 480 km depth the structure sketched from the hypocenters is almost continuous but most energy has been released in the 230 340 km depth interval an evaluation of fault plane solutions of intermediate earthquakes in this area indicates predominance of down dip compressions in the central part of the slab at the border strike slip motion occurs independent of depth some earthquakes that occurred at intermediate depth less than 100 km along the ionian margin of calabria show predominance of reverse faulting with the p axis oriented se nw however shallow earthquakes in the calabria sicily region indicate a more complex motion with predominance of normal faulting a possible interpretation of these features according to the available geological history which involves subduction of continental lithosphere is discussed

individual and pooled tree ring stable carbon isotope series in chinese pine from the nan wutai region china common signal and climate relationships abstract to investigate the differences in the climatic signals in stable carbon isotopic composition captured by averaging series from individual trees versus raw wood of trees pooled prior to analysis we analyzed two groups of chinese pine pinus tabulaeformis carr from the nan wutai region of the qinling mountains china one group included three trees that were analyzed separately and the other group comprised four other trees that were pooled prior to preparation and analysis all 13 c series were positively correlated r 0 50 0 58 p 13 c of atmospheric co 2 correlations between the meteorological data and all individual and pooled discrimination 13 c series revealed significant negative responses to temperature for several specific months and for mean january to september t j s temperature we used a numerical mix method nmm equivalent to unweighted mean by averaging individual 13 c series nps1 nps2 nps3 to generate a new series that more strongly correlated to climate series t j s r 0 67 p j s is significant for plant growth and is consistent with the tree physiology in this region our results suggest that the numerical mix method with tree ring stable isotope data from three trees provides a series quite satisfactory for climatic reconstruction the relationship of the numerical mix model 13 c with temperature was stronger than for the pooled series suggesting numerical mixing of series can be more effective than raw wood sample pooling at least according to the trees in this study

sr isotopic evidence for late neoproterozoic rifting in the adelaide geosyncline at 586 ma implications for a cu ore forming fluid flux abstract analyses of shales and basalts from all stratigraphic levels below the wonoka formation in the neoproterozoic adelaide geosyncline combine to define a 586 30 ma rb sr isochron with an initial 87sr 86sr value of 0 7180 the sr isotopic composition of most carbonate units deposited in this basin before this time are also altered and have sr isotopic compositions that fall between their primary contemporary seawater values and those of the clastic basin fill by contrast the neoproterozoic carbonates from strata including and younger than the late vendian wonoka formation conform to internationally correlated chemostratigraphic variations for both 87sr 86sr and 13c these data together with s and sr isotopic evidence from barite veins which cut late marinoan shales are interpreted to indicate that the adelaidean succession experienced a phase of intrabasinal fluid flow the fluid had an 87sr 86sr value of 0 7180 when convective circulation was terminated at 586 ma this timing is synchronous with down cutting of basin fill to form canyons beneath the wonoka formation and also coincides with the production of rift affiliated alkaline lavas to the east of the curnamona craton in western nsw the interpreted changed fluid flux regime together with the other geological features listed may indicate the onset of a new phase of extension and rifting of east gondwana s eastern margin at 586 30 ma contributing to a growing body of evidence that suggests that the main phase of proto pacific opening may have been vendian rather than sturtian in age the proposed basinal fluid flow event is of economic importance as it mobilised cu and other base metals and may have carried them to depositional sites in the thin platformal western marginal succession of the basin on the stuart shelf

do tree ring δ13c series from pinus sylvestris in northern fennoscandia contain long term non climatic trends abstract non climatic trends in tree ring 13 c series are investigated using highly replicated pinus sylvestris 13 c series from finnish lapland the declining trend in stable carbon isotopes over the industrial period reflecting changes in the isotopic ratio of atmospheric co 2 is removed mathematically without recourse to statistical de trending regional curve standardisation rcs is then used to identify and remove the juvenile phase during which 13 c values increase the chronologies all show approximately 1 depletion in the juvenile phase with an average rise of 0 029 year 1 lasting for about 50 years after which trees of very different cambial age capture common variance over the same chronological period there is no evidence of long term age related trends and rcs provides an alternative to simply omitting the juvenile portion of the stable carbon isotope series thus allowing greater sample depth to be retained

the source of the 30 october 1930 mw 5 8 senigallia central italy earthquake a convergent solution from instrumental macroseismic and geological data abstract on 30 october 1930 an m w 5 8 earthquake hit the northern marche coastal area central italy causing significant damage i 0 viii ix degree mercalli cancani sieberg along a 40 km stretch of the adriatic coast between pesaro and ancona centered on the town of senigallia this area is characterized by relatively infrequent and moderate sized earthquakes and by elusive active faults in spite of the presence of well known northwest southeast trending northeast verging fault propagation folds forming the outer thrusts of the apennines the current level of activity and the kinematics of these coastal structures are still controversial we present a multidisciplinary analysis of the source of the 30 october 1930 senigallia earthquake combining instrumental and macroseismic data and elaborations with available evidence from geological and tectonic investigations we determine the main seismic parameters of the source including the earthquake location its magnitude and for the first time its focal mechanism providing the first instrumental evidence for thrust faulting along the northern marche coastal belt our findings provide conclusive evidence for the current activity of the northern marche coastal thrusts as such they have significant implications for the seismic hazard of the area a densely populated region that hosts historical heritage tourism facilities industrial districts and key transportation infrastructures online material description of method used for moment tensor computation tables of focal mechanisms and recording stations and figures of seismic flux and uncertainty maps for macroseismic epicenters

structure of a growing accretionary prism hikurangi margin new zealand the hikurangi margin of eastern north island new zealand represents the feather edge of the indian plate at its convergent boundary with the subducting pacific plate a migrated seismic reflection profile across this margin clearly displays the structural evolution of an accretionary prism a 25 km wide band of protothrusts is delineated between the toe of the slope and a converging seamount this illustrates an early stage in the seaward propagation of a deformation front landward tilted trench slope basins are separated by ridges that have clearly defined thrusts which appear to sole out at a decollement the decollement continues at an angle of only 3 beneath the 150 km wide margin to a depth of 14 km near the coast where it coincides with an onshore zone of high seismicity

subduction evolution and mantle dynamics at a continental margin central north island new zealand 1 central north island new zealand provides an unusually complete geological and geophysical record of the onset and evolution of subduction at a continental margin whereas most subduction zones are innately two dimensional north island of new zealand displays a distinct three dimensional character in the back arc regions specifically we observe mariana type subduction in the back arc areas of central north island in the sense of back arc extension high heat flow prolific volcanism geothermal activity and active doming and exhumation of the solid surface evidence for emplacement of a significant percent of new lithosphere beneath the central north island comes from heat flux of 25 mw km of strike of volcanic zone and thinned crust underlain by rocks with a seismic wave speed consistent with underplated new crust seismic attenuation qp 1 is high 240 and rhyolitic and andesitic volcanism are widespread almost complete removal of mantle lithosphere is inferred here in pliocene times on the basis of the rock uplift history and upper mantle seismic velocities as low as 7 4 0 1 km s in contrast southwestern north island exhibits chilean type back arc activity in the sense of compressive tectonics reverse faulting low heat flow thickened lithosphere and strong coupling between the subducted and overriding plates this rapid switch from mariana type to chilean type subduction occurs despite the age of the subducted plate being constant under north island moreover stratigraphic evidence shows that processes that define the extensional back arc area the central volcanic region are advancing southward into the compressional system wanganui basin at about 10 mm yr we link the progression from one system to another to a gradual and viscous removal of thickened mantle lithosphere in the back arc regions thickening occurred during the miocene within the taranaki fault zone the process of thickening and convective removal is time and temperature dependent and has left an imprint in both the geological record and geophysical properties of central north island which we document and describe

australian antarctic breakup and seafloor spreading balancing geological and geophysical constraints abstract the motion of diverging tectonic plates is typically constrained by geophysical data from preserved ocean crust however constraining plate motions during continental rifting and the breakup process relies on balancing evidence from a diverse range of geological and geophysical observations often subject to differing interpretations reconstructing the evolution of rifting and breakup between australia and antarctica epitomizes the challenges involved in creating detailed models of pangea breakup in this example differing degrees of emphasis on and alternative interpretations of offshore geophysical data in particular magnetic anomalies and seismic reflection profiles and onshore geological data lead to starkly contrasting views of how the continents were configured at the onset of mesozoic rifting here we critically review reconstructions of rifting and breakup in the light of all available geological and geophysical data including magnetic anomalies fracture zones conjugate crustal domains amounts of continental extension continental geology plate boundary locations break up ages and stratigraphy we identify the most viable plate tectonic reconstructions both with and without the input of the oldest more controversial magnetic anomaly interpretations and discuss implications for reconstructions of other margin pairs our analysis highlights key discrepancies between reconstructions based solely on geological piercing points and those based on a range of constraints these insights provide a powerful framework for reducing the range of viable models for australian antarctic rifting and provide key lessons for future efforts aimed at constraining pre and syn rift plate tectonic reconstructions

the mount wright arc a cambrian subduction system developed on the continental margin of east gondwana koonenberry belt eastern australia abstract the mount wright arc in the koonenberry belt in eastern australia is associated with two early to middle cambrian lithostratigraphic groups developed onto the late neoproterozoic volcanic passive margin of east gondwana the gnalta group includes a calc alkaline basalt andesite dacite suite mount wright volcanics interpreted to represent the volcanic component of the arc volcaniclastic gnalta group rocks now buried in the bancannia trough represent the continental back arc developed immediately behind the arc in a manner analogous to the modern taupo volcanic zone of new zealand east of the gnalta group is the ponto group a deep marine sedimentary package that includes tholeiitic lavas bittles tank volcanics and felsic tuffs interpreted as part of a fore arc sequence the configuration of these units suggests the mount wright arc developed on continental crust in response to west dipping subduction along the east gondwana margin in contrast with some models for cambrian convergence on other sections of the delamerian orogen which invoke east dipping subduction and arc accretion by arc continent collision this convergent margin was deformed by the middle cambrian delamerian orogeny which involved initial co axial shortening followed by sinistral transpression and oroclinal folding around the edge of the curnamona province

may september precipitation in the bhutan himalaya since 1743 as reconstructed from tree ring cellulose δ18o 1 we developed a 50 year tree ring 18o chronology for each of three tree species juniperus indica larix griffithii and picea spinulosa using a total of 12 trees four trees per species from the bhutan himalaya despite originating from different species sampled at two different altitudes the 18o chronologies are highly correlated with one another r 0 76 0 89 response analyses reveal that tree ring 18o values are controlled mainly by summer precipitation irrespective of species based on these results a robust 269 year 18o chronology was established to reconstruct the amount of may september precipitation based on data from four larch trees our tree ring 18o data show significant correlations with those from other regions of the himalaya and the tibetan plateau indicating that common signals related to monsoon activity are recorded in the data however at centennial timescales our data from bhutan show normal conditions during the 20th century whereas records from sites in western nepal and the southern eastern tibetan plateau show weakening trends in monsoon intensity during the last 100 200 years the weakening trends may be the result of a reduction in the meridional sea surface temperature gradient in the indian ocean during this time at continental scales the tree ring records show that areas more from ocean basins are particularly sensitive to reduced monsoon circulation correlation analyses suggest that the el nino southern oscillation enso plays an important role in modulating summer precipitation however the teleconnected relationship disappears during the period 1951 1970 coinciding with a negative phase of the pacific decadal oscillation pdo implying interdecadal modulation of the pdo on the influence of the enso on precipitation in bhutan

oxygen isotope ratios of oak in east england implications for reconstructing the isotopic composition of precipitation annual latewood 18o values from oak quercus robur l are presented for the period 1895 1994 for four trees growing in eastern england we demonstrate using the 18o values of precipitation from wallingford 1982 1994 and the longer time series from groningen 1965 1994 that the 18o values of winter precipitation had the strongest influence on the 18o values of tree ring cellulose the influence of winter precipitation on the spring summer formed latewood may be explained by several factors most soil water is replenished during the winter water may take several months to penetrate the unsaturated zone and oaks may sample water from lower in the profile during times of water stress the 18o values of oak latewood cellulose were also significantly p 0 01 correlated with summer relative humidity therefore although precipitation 18o values may be altered by partial isotopic exchange with xylem water and the influence of stomatal conductance upon evapotranspiration some of the original 18o signature remains

asymmetric rifting in a continental back arc environment north island new zealand marine seismic reflection data have been used to investigate the structure and evolution of the continental back arc basin forming the volcanic region of central north island new zealand the seismic reflection data defines two parts to the volcanic region in the west an older region showing narrow back tilted blocks and a younger rift basin delineated by the white island and tauranga fault zones to the east the younger rift coincides with the offshore trend of the active taupo volcanic zone tvz listric faulting of basement in the eastern part gives rise to about 80 extension for the basin which is consistent with the thinning of the crust from 25 km along the margins of the basin to 15 km under the basin basement in the region is interpreted to be highly extended greywacke the nature of the faulting and the seismic stratigraphy demonstrates that the extension has been asymmetric in nature being progressively younger towards the plate boundary in the east active faulting offsets the seafloor in the younger eastern part of the basin eight major sedimentary sequences delineated by unconformities are recognised in the basin these sequences based on correlation with major onshore rhyolitic eruptions are considered to be up to about 1 6 ma old a major unconformity within the sequences may coincide with a hiatus in volcanic activity from 0 7 0 4 ma ago a caldera structure is tentatively identified under the western part of the younger rift basin offshore tvz from seismic and other data its age is not well constrained but an age corresponding to the initiation of the younger extension episode 1 6 ma ago is preferred older volcanic sequences underlie the oldest tvz volcanic units to the west of the younger basin and probably correspond to the pliocene miocene volcanics onshore in the coromandel peninsula

sampling strategy and climatic implications of tree ring stable isotopes on the southeast tibetan plateau we explore the potential of tree ring cellulose d18o and d13c records for reconstructing climate variability in the southeast tibetan plateau our sampling strategy was designed to investigate intra and inter tree variability and the effects of the age of tree on d18o variation we show that intra tree d13c and d18o variability is negligible and inter tree coherence is sufficient to build robust tree ring d18o or d13c chronologies based on only four trees there is no evidence of an age effect regarding d18o in contrast with tree ring width in our warm and moist sampling site young tree d13c is not clearly correlated with monthly mean meteorological data tree ring d18o appears significantly anti correlated with summer precipitation amount regional cloud cover and relative humidity simulations conducted with the orchidee land surface model confirm the observed contribution of relative humidity to tree cellulose d18o and explain the weak correlation of d13c with climate by the non linear integration linked with photosynthesis altogether the tree ring cellulose d18o is shown to be a promising proxy to reconstruct regional summer moisture variability prior to the instrumental period 2010 elsevier b v

tree ring isotopic pooling without regard to mass no difference from averaging δ13c values of each tree abstract pooling of growth rings from several trees before subsequent isotopic analysis of the mixture may offer the advantage of obtaining representative isotopic values fairly rapidly in principle however unless equal masses are taken from the individuals to make the composite sample the measured isotope value will be biased by the relative mass contribution of the trees each of which likely has a different isotopic composition although biasing associated with direct pooling without regard to mass may happen this study provides evidence at least for stable carbon isotope composition from three sites in the u s midwest and southwest that the error probably more appropriately called difference is negligible with respect to error of preparation and analysis and variability of isotopic composition within and among trees at a site

seismic velocity structure of the central taupo volcanic zone new zealand from local earthquake tomography abstract the 3 d distribution of p wave velocity vp and the p wave s wave velocity ratio vp vs are derived for the crust in the central taupo volcanic zone tvz new zealand by tomographic inversion of p and s wave arrival time data from local earthquakes resolution in the seismogenic mid crust 4 6 km is good but poorer above and below these depths the 3 d velocity model has several vp anomalies as large as 5 in the mid lower crust 4 10 km and more than 10 in the upper crust 0 4 km the model achieves a 55 reduction in data variance from an initial 1 d model young caldera structures okataina rotorua and reporoa are characterised by low vp anomalies at a depth of about 4 km and these coincide with large negative residual gravity anomalies we attribute these anomalies to large volumes of low vp low density volcaniclastic sediments that have filled these caldera collapse structures although there are no vp anomalies which suggest the presence of molten or semi molten magma beneath the tvz a large high vp anomaly of more than 15 and a high vp vs anomaly are observed coincident with a diorite pluton beneath the ngatamariki geothermal field however vp anomalies cannot be seen beneath the largest geothermal fields waimangu waiotapu and reporoa and consequently if such anomalies exist they must be below the resolution of our data a prominent vp contrast of 5 10 occurs at a depth of about 6 km beneath the boundary between the taupo reporoa depression and the taupo fault belt tfb coincident with the eastern limit of the seismic activity beneath the tfb we interpret this velocity contrast as being caused by the presence of extensive non molten intrusives beneath the taupo reporoa depression we suggest that the high velocity material beneath the taupo reporoa depression is isolated from regional extension in the tvz and from the resulting faulting and seismicity which occurs preferentially within the weaker material of the tfb we are unable to determine whether greywacke which forms the basement beneath the eastern most part of the tvz continues further west or is replaced by a volcanic rock such as andesite which has similar vp and density vp vs anomalies are much smaller than vp anomalies and generally have little spatial relationship to the vp pattern there is a widespread decrease in vp vs from 1 76 to 1 70 1 73 between 4 and 6 km depth over much of the study area and vp vs is high southwest of the okataina caldera where vp is low hypocentres calculated using the 3 d velocity model differ little from those obtained using a 1 d model with station terms however some groups of earthquakes are more tightly clustered following relocation there is a slight decrease in the estimated thickness of the seismogenic zone with 73 of hypocentres between 4 and 7 km depth and a slight increase in the depth of the brittle ductile transition from 6 to 6 5 km

fossil seaward dipping reflector sequences preserved in southeastern australia a 600 ma volcanic passive margin in eastern gondwanaland evidence for a c 600 ma rifted passive margin in eastern australia exists in the form of multiple belts of mafic volcanic rocks preserved along the western margin of the tasman fold belt system and giving rise to elongate magnetic anomalies outcrop drillhole and geophysical evidence points to piles of lavas volcaniclastic and intrusive rocks up to 6 km thick extending for strike lengths of hundreds of kilometres in individual segments the distinctive unifying characteristics of these piles are apparent common formation ages 600 580 ma presence of early more landward transitional alkaline basalts and more seaward abundant rift tholeiites with high temperature picrites and olivine rich basalts at most localities despite later structural reorganization these belts have close geochemical geometric and lithological affinities with mesozoic seaward dipping reflector sequences along the north atlantic and northwestern australian volcanic passive margins and strongly imply the formation of a volcanic passive margin in eastern gondwanaland at the close of the neoproterozoic recognition of this event has implications for the position of an implied earlier rifted margin related to the break up of rodinia around 780 ma a rifting event at 600 ma in eastern gondwanaland helps explain both the lack of evidence for volcanism from rodinia break up and a widespread 600 ma population of inherited zircons within rocks of the lachlan orogen which developed outboard of the passive margin in earliest palaeozoic time

reducing uncertainties in δ13c analysis of tree rings pooling milling and cellulose extraction recent developments of on line methods have provided another boost to the determination of stable isotope ratios in organic material along with a significant increase in sample throughput the sample sizes decrease both of which are necessary conditions to acquire long time series from limited wood amounts in view of this new technique we reconsidered the most important factors influencing the measured isotopic signature which are 1 pooling 2 homogeneity and 3 cellulose extraction in most cases pooling i e mixing wood of the same year from different trees can be made in a simple way by mixing the whole wood available because mass weighted and unweighted isotope measurements were the same within the error more attention must be paid in homogenizing the sample theoretical considerations underpinned by experimental results suggest a fineness of 0 15 mm 115 mesh if cellulose is extracted and 0 1 mm 165 mesh for direct wood analysis many of previous studies did not achieve this fineness we find that wood is as good a climate proxy as cellulose this is shown by comparing correlations of wood and corresponding cellulose isotope values with meteorological data which are identical within the uncertainty

regional synthesis of mediterranean atmospheric circulation during the last glacial maximum atmospheric circulation leaves few direct traces in the geological record making reconstructions of this crucial element of the climate system inherently difficult we produced a regional mediterranean synthesis of paleo proxy data from the sea surface to alpine altitudes this provides a detailed observational context for change in the three dimensional structure of atmospheric circulation between the last glacial maximum lgm 23 000 to 19 000 years ago and the present the synthesis reveals evidence for frequent cold polar air incursions topographically channeled into the northwestern mediterranean anomalously steep vertical temperature gradients in the central mediterranean imply local convective precipitation we find the lgm patterns to be analogous though amplified to previously reconstructed phases of enhanced meridional winter circulation during the maunder minimum the little ice age

imaging the basement architecture across the cork fault in queensland using magnetic and gravity data abstract the basement rocks in central queensland are largely obscured by the phanerozoic sedimentary succession and direct information comes only from sparse geological data 2 5d forward modelling of regional aeromagnetic and bouguer gravity data has been undertaken to unveil the crustal architecture at the junction of the proterozoic mount isa terrane and the phanerozoic thomson orogen in queensland the most prominent geophysical character is represented by the abrupt termination of positive nnw trending geophysical anomalies of the mount isa terrane against ne trending low amplitude gravity and magnetic anomalies of the diamantina river domain of the thomson orogen potential field forward modelling indicates that the lower basement crust of the thomson orogen is petrophysically indistinguishable from the crust of the proterozoic mount isa terrane we interpret that the prominent gradients associated with the cork fault represent the displacement and burial of the mount isa terrane crust under the thomson orogen in this context the cork fault is inferred to represent a fundamental crustal discontinuity but does not represent the eastern margin of rodinia because the thomson orogen is floored by precambrian continental crust initiation of the cork fault might have occurred as early as the mesoproterozoic at that time the cork fault was a major structure that developed during the separation of the mount isa terrane and the curnamona province it is inferred that this break up occurred during initial n s to nnw sse extension the cork fault formed part of a network of major north and south dipping normal faults active at that time the cork fault was repeatedly reactivated during the neoproterozoic rodinia break up and during the phanerozoic evolution of the tasmanides we suggest that the segment of the inferred tasman line along the southern termination of the mount isa terrane should be regarded as a set of structures offsetting the proterozoic crust rather than a simple lineament dividing the proterozoic and the phanerozoic australian continent

constraining the vandieland microcontinent at the edge of east gondwana australia abstract using airborne magnetic and marine gravity data the geological subdivisions of western tasmania have been interpreted north across bass strait into victoria the three westernmost tasmanian zones the king island rocky cape and burnie zones are inferred to form the largely concealed selwyn block in victoria the eastern tasmania zone correlates with the victorian tabberabbera zone thus the tasmanian tamar fracture zone corresponds with the victorian governor fault the victorian ceres gabbro is correlated with magnetic rocks west of king island that are tentatively considered to be neoproterozoic most of the cambrian felsic volcanic rocks of the tasmanian mount read volcanics lie above the burnie zone as do the similar rocks exposed in the jamieson licola and glen creek windows in central victoria reinterpretation of a victorian deep seismic reflection line indicates burnie zone equivalent rocks were thrust south west over rocky cape zone equivalents a link between western tasmania and central victoria is evident from upper devonian granites intruded into the selwyn block region the eastern end of the upper devonian cobaw complex and the warburton granodiorite contain calcsilicate enclaves interpreted to be derived from a northern equivalent to the smithton basin the mount disappointment granodiorite has high ni and cr contents and pseudomorphs after orthopyroxenes consistent with having been partly sourced from the underlying basaltic rocks like those on the eastern margin of the king island zone the magnetic responses under the strathbogie complex the cerberean caldera and the lysterfield granodiorite are attributed to metamorphism of part of an extension of the smithton basin probably equivalents to the 580 ma spinks creek volcanics quartzite cobbles in a devonian conglomerate in the south eastern melbourne zone may be derived from rocky cape group equivalents when integrated with the geological interpretation of tasmania we provide a stratotectonic map of the vandieland micro continent

seismic response and construction of seaward dipping wedges of flood basalts voring volcanic margin geological and geophysical data from the 900 m of volcanic basement drilled at ocean drilling program site 642 provide the framework for studying seismic properties of huge extrusive constructions on volcanic margins the main part of the drilled section corresponding to a prominent seaward dipping reflector sequence consists of subaerially emplaced tholeiitic basalt flows and thin interbedded sediments the basalts exhibit a characteristic velocity and density lava flow distribution reflecting changing porosity pore aspect ratio distribution and alteration stacks of laterally continuous basalt flows appear to have thin layer transverse isotropic properties for typical wavelengths in multichannel seismic data vertical seismic profiling and average sonic log velocities are similar 3 77 km s and 3 88 km s respectively while comparable refraction velocities are 10 20 higher synthetic seismogram modeling based on downhole logs shows that basement reflectors originate from interference and tuning effects of numerous basalt flow and interbedded sediment interfaces though the most continuous reflectors are related to thick flows seismic models based on the characteristic velocity and density basalt flow distributions and site 642 stratigraphy show that reflector truncation and onlap may be caused by seismic interference phenomena in a sequence of landward thinning flows the base of the dipping reflector sequence reflector k correlates with flows in the lower part of upper series basalts while the transition from basaltic to underlying dacitic andesitic lavas correlates with a locally defined reflector a model for the breakup related volcanism includes 1 prebreakup dacitic andesitic volcanism 2 early breakup basaltic volcanism infilling the prebreakup relief 3 main breakup stage with intense focused volcanism large subsidence and lava pounding and 4 late breakup volcanism during a period of decreased subsidence and local off axis activity

the september 27 2012 ml 4 1 benevento earthquake a case of strike slip faulting in southern apennines italy abstract on september 27 2012 at 01 08 utc a m l 4 1 earthquake started a seismic sequence approximately 10 km east of the city of benevento in southern apennines italy during the following four days about 40 events with m l ranging between 1 3 and 4 1 were detected in the same area where the seismic hazard is one of the largest of the italian peninsula and where several historical and destructive events took place in order to investigate the seismicity spatio temporal pattern and to identify the seismogenic source geometry a detailed analysis was performed integrating data recorded at three different seismic networks the earthquakes were relocated using the double difference technique and focal mechanism solutions were obtained by the moment tensor inversion also to better understand the rupture process seismic source parameters were estimated and apparent source time functions were inverted to retrieve the slip distribution for the largest magnitude event our results show the existence in the study area of roughly e w striking fault plane with a right lateral strike slip kinematics seated at mid crustal depths 10 20 km revealing a characteristic seismicity quite different from that typically associated to the outcropping nw se striking active normal faults that are responsible of moderate to large earthquakes in the southern apennines axial sector in this work we address questions concerning i the presence in the benevento area of a mid crust seismogenic strike slip fault previously unrecognized ii its link to the regional seismotectonic setting and iii the existence of a strike slip tectonic regime that uniformly extends in the footwall of the apennines thrust at relevant depth not only in the apulian foreland as demonstrated to date but also under the mountain chain axial zone

structure and kinematics of the indo burmese wedge recent and fast growth of the outer wedge 1 the northern sunda subduction zone offshore burma and the associated indo burmese wedge mark the active eastern boundary of the burma platelet jammed between the india plate and the sunda plate the aim of this paper is to provide a structural and kinematics analysis of the indo burmese wedge based on seismic reflection geodetic and geological field data we found out that the indo burmese wedge is the place of diffuse strain partitioning right lateral shearing in the innermost part and e w shortening in the outermost part in the outer wedge thick skinned deformation overprints thin skinned deformation it can be explained by the required preservation of the critical taper after the fast westward propagation of the outer wedge above a very efficient clayey decollement layer the thick skinned deformation is here characterized by major right lateral strike slip faults the kaladan fault and the chittagong coastal fault and yet a typical internal deformation of the indo burmese wedge we suggest that the westward migration of internal right lateral shear deformation allows preservation of the strain partitioning ratios between internal n s trending right lateral shearing and external e w shortening some seismic lines show that the outer wedge deformation is not older than 2 ma its propagation could have been enhanced by the large amount of sediments filling up the sylhet flexural basin formed after the pliocene tectonic uplift of the shillong plateau

influence of detachment related passive margin geometry on subsequent active margin dynamics applied to the tasman fold belt system abstract the different upper and lower plate settings of detachment related geometries of passive margins controlled by different extensional geometries can strongly influence the geodynamics and resultant vergence of subsequent active convergent margins during contractional orogenic development the observed vergence along the tasman line and also the foreland directed vergence of the early tasmanides kanmantoo fold belt and the miogeoclinal belt adelaide fold belt support this concept the less frequently recognized mixed vergence like that in the lachlan fold belt has probably been caused by microcontinents and tectonically underplated terrane s which acted as structural backstops during the prolonged and complicated orogenic contraction the geometry of the orogenic float the mechanically separated surficial rock complexes and crustal units from the underlying continental and oceanic lithosphere was strongly influenced by the relative displacement of several individual basement domains some microcontinents separated by long lived i e reactivated sutures and or root zones

tree ring width and density data around the northern hemisphere part 2 spatio temporal variability and associated climate patterns patterns of summer temperature over the northern hemisphere obtained from a calibration of a treering network are presented for every year from 1600 to 1877 the network of tree ring density chronologies is shown to exhibit spatially coherent modes of variability these modes closely match summer half year tempera ture variations in terms of similar spatial patterns and similar temporal evolution during the instrumental period they can therefore be considered to be proxies for the temperature patterns and time series for the eight most dominant patterns are presented back to the late seventeenth century the first pattern represents spatially coherent warming or cooling and it appears to respond to climate forcings especially volcanic erup tions most other patterns appear to be related to atmospheric pressure anomalies and they can be partially explained by heat advection associated with anomalous atmospheric circulation this provides the potential for reconstructing past variations in atmospher

the database of individual seismogenic sources diss version 3 summarizing 20 years of research on italy s earthquake geology abstract this paper describes the main characteristics the evolution and the structure of the database of individual seismogenic sources diss and particularly of its release of early 2007 the database contains the results of the investigations of the active tectonics in italy during the past 20 years the first two sections of this paper document the recent evolution in mapping and archiving italian active fault data in relation to important achievements in the understanding of italian tectonics some of which were spurred by significant earthquakes the central sections describe the current structure of the database the reasons for its assumptions and data categories its current contents its evolution through several years of improvements the last section describes how the current contents of the database correspond with the existing strain and stress data available from focal mechanism borehole breakout and gps data for the whole of italy the database supplies a fresh and unified view of active and seismogenic processes in italy by building on basic physical constraints concerning rates of crustal deformation on the continuity of deformation belts and on the spatial relationships between adjacent faults both at the surface and at depth

the seismotectonics of the po plain northern italy tectonic diversity in a blind faulting domain we present a systematic and updated overview of a seismotectonic model for the po plain northern italy this flat and apparently quiet tectonic domain is in fact rather active as it comprises the shortened foreland and foredeep of both the southern alps and the northern apennines assessing its seismic hazard is crucial due to the concentration of population industrial activities and critical infrastructures but it is also complicated because a the region is geologically very diverse and b nearly all potential seismogenic faults are buried beneath a thick blanket of pliocene pleistocene sediments and thus can be investigated only indirectly identifying and parameterizing the potential seismogenic faults of the po plain requires proper consideration of their depth geometry kinematics earthquake potential and location with respect to the two confronting orogens to this end we subdivided them into four main homogeneous groups over the past 15 years we developed new strategies for coping with this diversity resorting to different data and modeling approaches as required by each individual fault group the most significant faults occur beneath the thrust fronts of the ferrara romagna and emilia arcs which correspond to the most advanced and buried portions of the northern apennines and were the locus of the destructive may 2012 earthquake sequence the largest known po plain earthquake however occurred on an elusive reactivated fault cutting the alpine foreland south of verona significant earthquakes are expected to be generated also by a set of transverse structures segmenting the thrust system and by the deeper ramps of the apennines thrusts the new dataset is intended to be included in the next version of the database of individual seismogenic sources diss http diss rm ingv it diss version 3 2 0 developed and maintained by ingv to improve completeness of potential sources for seismic hazard assessment

lithospheric architecture of a phanerozoic orogen from magnetotellurics auslamp in the tasmanides southeast australia abstract we present a resistivity model of the southern tasmanides of southeastern australia using australian lithospheric architecture magnetotelluric project auslamp data modelled lower crustal conductivity anomalies resemble concentric geometries revealed in the upper crust by potential field and passive seismic data these geometries are a key part of crustal architecture predicted by the lachlan orocline model for the evolution of the southern tasmanides in which the proterozoic selwyn block drives oroclinal rotation against the eastern gondwana margin during the ordovician period for the first time we image these structures in three dimensions 3d and show they persist below the moho these include a lower crustal conductor largely following the northern selwyn block margin spatial association between lower crustal conductors and both paleozoic to cenozoic mafic to intermediate alkaline volcanism and gold deposits suggests a genetic association i e fluid flow into the lower crust resulting in the deposition of conductive phases such as hydrogen iron sulphides and or graphite the 3d model resolves a different pattern of conductors in the lithospheric mantle including northeast trending anomalies in the northern part of the model three of these conductors correspond to cenozoic leucitite volcanoes along the cosgrove mantle hotspot track which likely map the metasomatised mantle source region of these volcanoes the northeasterly alignment of the conductors correlates with variations in the lithosphere asthenosphere boundary lab and the direction of australian plate movement and may be related to movement of an irregular lab topography over the asthenosphere by revealing the tectonic architecture of a phanerozoic orogen and the overprint of more recent tectono magmatic events our resistivity model enhances our understanding of the lithospheric architecture and geodynamic processes in southeast australia demonstrating the ability of magnetotelluric data to image geological processes over time

age related trends in subfossil tree ring δ13c data abstract long stable isotope chronologies are increasingly constructed from tree rings averaging the mean chronologies necessitates that the contributing series contain no age related trends therefore any set of dendroisotope data needs to be tested for age dependency in isotope values before the chronology is compared with climate or other environmental records such age trends are common to tree ring width and density data but corresponding evidence on stable isotope records is yet relatively limited moreover there is contrasting evidence suggesting that while a number of dendroisotope datasets appear to portray no age related trends such trends may be found in different regions and tree species here we analyze a collection of 182 subfossil tree ring 13c series from a species pinus sylvestris and a region northern fennoscandia where previous investigations have found no support for age related trends beyond the juvenile effect in the tree ring 13c data our 13c dataset benefits from a large sample size of analysed tree rings representing a wide range of calendar years 5630 bc through ad 1930 formed under varying climate conditions our results indicate that the tree ring 13c series do contain age related trends throughout the trees lifespan this age dependence corresponded to an ascending linear change of ca 0 4 per 100 years illustrating the mean 13c curve as a function of trees biological age demonstrated that the age dependence may alternatively be modelled with non linear trends with varying curvature there were also time variant changes in the 13c trend curvature of subfossil tree ring data increasing and diminishing age trend curvatures coincided with palaeoecological indications of denser and thinner pine populations respectively over the study period overall our results highlight the hardships of detecting age related trends in dendroisotope data in comparison to records of tree ring widths and densities the possibility that age related trends are present in dendroisotope data in regions and tree species where such trends may not yet have been detected is underlined

evidence for long term diffuse deformation of the lithosphere of the equatorial indian ocean the presence of large earthquakes east west striking folds and thrust faults in sediments and east west striking undulations of wavelength 200 km in topography and gravity shows that the equatorial indian ocean is the locus of unusual deformation1 2 3 4 5 6 7 8 this deformation has been interpreted as a diffuse boundary between two tectonic plates9 10 11 12 13 seismic stratigraphy and deep sea drilling at two locations in the bengal fan indicate that the deformation began 7 5 8 0 myr ago3 14 15 here however we show using plate reconructions that motion across this diffuse oceanic plate boundary began more than 10 myr earlier than previously inferred and that the amount of north south convergence across the boundary through the central indian basin has been significantly greater than the convergence estimated from seismic profiles the relative plate velocity accommodated across the central indian basin has varied with time and has been as fast as 6 mm yr 1 about half the separation rate of earth s slowest spreading mid ocean ridge the earliest interval of measurable motion which began more than 18 myr ago may coincide with rapid denudation of the tibetan plateau from 21 myr to 15 17 myr ref 16 the present motion across the central indian basin began no earlier than 11 myr following an earlier interval of slower motion from 18 to 11 myr and may have begun at 8 myr when the tibetan plateau is thought to have attained its maximum elevation16 17

tertiary tectonics and sedimentation in the salin fore arc basin myanmar salin basin of central myanmar is a tertiary fore arc basin that extends over 10 000 mi sup 2 and contains 30 000 ft of siliciclastic rocks in the western salin basin tertiary deltaic and fluvial formations contain thousands of feet of lithic sandstones that alternate with transgressive shallow marine shales facies and paleocurrent studies indicate deposition by north to south prograding tidal deltas and associated fluvial systems in a semi restricted basin presence of serpentinite and volcanic clasts in tertiary sandstones may imply that the basin was bounded to the east by the volcanic arc and to the west by a fore arc accretionary ridge throughout much of the cenozoic salin basin is currently defined by a regional north south trending syncline with uplifts along the eastern and western margins elongate folds along the eastern basin margin verge to the east and lie above the reverse faults that dip west much of myanmar s present hydrocarbon production is from these structures analogous structures occur along the western margin but verge to the west and are associated with numerous hydrocarbon seeps and hand dug wells these basin bounding structures are the result of fault propagation folding in the western salin basin major detachments occur within the shaly tabyin and laungshe formations fault ramps propagatedmore through steep forelimbs on the western sides of the folds resulting in highly asymmetric footwall synclines stratigraphic and apatite fission track data are consistent with dominantly plio pleistocene uplift with limited uplift beginning approximately 10 ma paleostress analysis of fault slickenside data indicates that fold and thrust structures formed during regional east west compression and are not related in any simple way to regional transpression as suggested by plate kinematics less

trench investigations of the 1915 fucino earthquake fault scarps abruzzo central italy geological evidence of large historical events earthquake hazard analyses in italy are mainly based on historical seismic catalogs however the completeness of the italian catalog which spans more than 2000 years progressivcly decreases going back in time in the fucino basin historical research has not produced evidence of large earthquakes before the january 13 1915 event m s 7 0 33 000 people killed this event generated surface faulting along at least two parallel quaternary normal faults bounding the eastern side of the basin the celano gioia and parasano cerchio faults over an end to end length of about 23 km with a downthrow of 30 90 cm toward southwest to improve geological aspects of the seismic history of this area we trenched onc of the coseismic scarps along the celano gioia fault at a trench site near the village of san benedetto de marsi the fault traverses the area formerly covered by the fucino lake drained for farming in 1875 a d the evidence collected in the trenchcs suggests at least two large events in historical times before 1915 radiocarbon dates constrain the age of event b between the 6th and the 9th centuries a d possibly coinciding with the cvent felt in rome in 801 a d molin arid guidoboni 1989 event a probably occurred after the 10th ccntury a d and almost certainly before the 1349 a d earthquake because historical studies show 1 that event a was not produced during the earthquake sequence that occurred in central italy in 1349 a d molin and guidoboni 1989 and 2 that the post 1349 seismic catalog can be regarded as complete for surface faulting earthquakes surface displacements determined for events a and b compared to the 1915 surface faulting indicate that m 6 5 earthquakes were associated with each rupturc these obscrvations suggest that the return period for large earthquakes in the fucino basin is shorter than that indicated by the historical record alone the fucino example clearly shows that thc cxceptionally long historical record in italy is still inadequate for a comprehcnsive seismic hazard characterization

a transitional volume beneath the sannio irpinia border region southern apennines different tectonic styles at different depths abstract in this paper we investigate the border between the sannio and irpinia seismogenic regions a sector of the southern apennine chain considered among the most active seismic areas of the italian peninsula to shed further light on its complex seismotectonic setting we integrated recent seismicity with literature data a detailed analysis of the seismicity that occurred in the 2013 2016 time interval was performed the events were relocated after manual re picking using different approaches to retrieve information about the stress field active in the area inversion of fault plane solutions was also carried out hypocentral distribution of the relocated events ml 3 5 whose depth is included between 5 and 25 km with the deepest ones located in the nw sector of the study area shows a different pattern between the northern sector and the southern one the computed fault plane solutions can be grouped in three depth ranges 18 km dominated by strike slip kinematics stress field inversion across the whole area shows that we are dealing with an heterogeneous set of data apparently governed by distinct stress fields we built an upper crustal model profile through integration of geological data well logs and seismic tomographic profiles our results suggest the co existence of different tectonic styles at distinct crustal depths the upper crust seems to be affected mostly by normal faulting whereas strike slip faulting prevails in the intermediate and lower crust we infer about the existence of a transitional volume located between 12 and 18 km depth between the sannio and irpinia regions acting as a vertical transfer zone

new constraints shed light on strike slip faulting beneath the southern apennines italy the 21 august 1962 irpinia multiple earthquake abstract on 21 august 1962 an earthquake sequence set off near the city of benevento in italy s southern apennines three earthquakes the largest having mw 6 1 struck virtually the same area in less than 40 min at 18 09 18 19 and 18 44 utc respectively several historical earthquakes hit this region and its seismic hazard is accordingly among the highest countrywide although poorly understood in the past the seismotectonics of this region can be revealed by the 1962 sequence being the only significant earthquake in the area for which modern seismograms are available we determine location magnitude and nodal planes of the first event 18 09 utc of the sequence the focal mechanism exhibits dominant strike slip rupture along a north dipping e w striking plane or along a west dipping n s striking plane either of these solutions is significantly different from the kinematics of the typical large earthquakes occurring along the crest of the southern apennines such as the 23 november 1980 irpinia earthquake mw 6 9 caused by predominant normal faulting along nw se striking planes the epicentre of the 21 august 1962 18 09 event is located immediately east of the chain axis near one of the three north dipping e w striking oblique slip sources thought to have caused one of the three main events of the december 1456 sequence io xi mcs the most destructive events in the southern apennines known to date we maintain that the 21 august 1962 18 09 earthquake occurred along the e w striking fault system responsible for the southernmost event of the 1456 sequence and for two smaller but instrumentally documented events that occurred on 6 may 1971 mw 5 0 and 27 september 2012 mw 4 6 further suggesting that normal faulting is not the dominant tectonic style in this portion of the italian peninsula

a back arc basin formed within continental lithosphere the central volcanic region of new zealand abstract the central volcanic region is an area of quaternary volcanism and tensional tectonics within the north island of new zealand that appears to be a direct continuation of a young oceanic back arc basin the havre trough into the continental structure of new zealand volcanism is predominantly rhyolitic yet the region possesses many of the geophysical characteristics often associated with oceanic back arc basins upper mantle seismic velocities are low pn and sn velocities of 7 4 and 3 95 km s respectively the crust is anomalously thin for its continental setting and the heat flow almost all of which is expressed in the discharge of hot water through geothermal systems is about 700 mw m2 i e some twelve times greater than normal continental heat flow in order to account for such a high heat flow a large scale mass transfer of heat is required it is proposed therefore that the central volcanic region represents a site of active back arc spreading within a continental lithosphere

geological evolution of the wonominta block abstract the wonominta block in western new south wales is an area of over 20 000 km2 of poorly to moderately exposed palaeozoic and older rocks the block is surrounded by mesozoic or younger sediments and is separated from the broken hill and euriowie blocks by the bancannia trough the wonominta block can be divided into a number of lithostratigraphic units the oldest unit is a fault bounded sequence of multiply deformed low to medium grade metasediments basic volcanics and silicic tuffs that may be correlated with the middle proterozoic willyama supergroup of the broken hill block the second unit is an extensive sequence of carbonaceous slates containing several clean quartzite beds with some dolomitic limestones and rare polymictic conglomerates in its upper section this unit is equated with the upper proterozoic adelaidean sequence overlying the broken hill block but differs in having a sequence of alkalic basaltic pillow lavas and tuffs interbedded with quartz rich rocks at one level within the unit a thin slate bed at the top of this unit marks a transitional stratigraphie contact with a thick overlying sequence of graded lithic and quartzofeldspathic sandstones with thin slate interbeds this thick turbidite sequence forming the third unit is widespread within the wonominta block becomes less oxidised to the east contains rare trace fossils and sponge spicule shale horizons and is isoclinally folded along with the two older units this unit equates with the kanmantoo group in south australia the more fossiliferous lower to middle cambrian gnalta group exposed near mount arrowsmith and near mount wright on the western edge of the wonominta block may represent a shallow water near shore sequence equivalent to this deeper water turbidite unit to the east the fossiliferous upper cambrian to lower ordovician mootwingee group in the west and the kayrunnera group in the east overlie the older units with a pronounced unconformity this unconformity represents the delamerian orogeny in western new south wales and the overlying units define the near shore facies at the western edge of an extensive sedimentary depository that was destined to become the lachlan fold belt

accordion vs quantum tectonics insights into continental growth processes from the paleozoic of eastern gondwana the early paleozoic lachlan fold belt of eastern australia is widely regarded as an ancient convergent plate margin beneath which paleo pacific panthalassic oceanic lithosphere was continuously subducted it is cited as the type example of a retreating accretionary orogeny however sandstone compositions the sedimentological nature and timing of chert accumulation and overall stratigraphic architecture are not necessarily consistent with this model we suggest an alternative explanation for growth of gondwanan continental margin oceanic lithosphere outboard of the passive gondwana continental margin was subducted beneath an extensive intra oceanic island arc that now crops out as an allochthonous element macquarie arc within the fold belt once intervening oceanic lithosphere was eliminated this arc collided with and was emplaced upon the gondwana margin recognition of four such events along this margin through the phanerozoic suggests it is a significant mechanism for continental growth

tree ring stable carbon isotope based may july temperature reconstruction over nanwutai china for the past century and its record of 20th century warming growth anomaly of trees in some regions was detected under current episode of rapid warming thisraises a dilemma for temperature reconstructions by using tree ring width which is believed to be themost important proxy on inter annual temperature reconstruction during the past millenniums here weemployed the tree ring d13c to reconstruct temperature variations for exploring their potential oncapturing signals of rapid warming and to test how its difference with the tree ring width basedreconstruction in this study the mean mayejuly temperature tmej was reconstructed over the pastcentury by tree ring d13c of chinese pine trees growing in the nanwutai region the explained varianceof the reconstruction was 43 3 42 1 after adjusting the degrees of freedom compared to a ring widthtemperature reconstruction mayejuly from the same site the tree ring d13c based temperaturereconstruction offered two distinct advantages 1 it captured a wider range of temperature variability i e at least mayejuly even over a longer part of the year januaryeseptember and 2 the reconstructionpreserved more low frequency climate information than that of ring width did the 20th century warming was well represented in the nanwutai tree ring d13c temperature reconstruction which implied that stable carbon isotope of tree rings potentially represents temperaturevariations during historical episodes of rapid warming a spatial correlation analysis showed that ourtemperature reconstruction represented climate variations over the entire loess plateau in north centralchina significant positive correlations p 0 1 were found between the temperature reconstruction andenso as well as ssts in the pacific and indian oceans the reconstruction showed the periodicities of22 78 4 16 3 45e3 97 and 2 04e2 83 year quasi cycles at a 95 confidence level our results suggestedthat temperature variability in the nanwutai region may be linked to pacific and indian ocean sstvariations and solar activity less

subsurface andesite lavas and plutonic rocks in the rotokawa and ngatamariki geothermal systems taupo volcanic zone new zealand abstract deep 2 km drillholes into the rotokawa and ngatamariki geothermal systems taupo volcanic zone tvz new zealand penetrate a sequence of silicic volcanic rocks and andesite lavas the latter being locally more than 1100 m thick one drillhole at ngatamariki bottoms in diorite 2200 m the first plutonic rocks reached by any well drilled into the taupo volcanic zone the rotokawa andesite lavas which occur below 1400 m depth are older than 330 ka and locally rest upon mesozoic metasedimentary basement rocks of the torlesse terrane they are typically dense jointed and where fresh contain phenocrysts of andesine labradorite augite hypersthene titanomagnetite and in places hornblende geochemically these rocks are medium k calc alkaline orogenic andesites their major and trace element contents and sr isotopic ratios show them to be chemically coherent with little lateral or vertical variation hydrothermal alteration has typically added volatiles but has been largely isochemical on a hand specimen scale mineralogical geochemical and stratigraphic evidence indicates that the rotokawa andesites are not genetically or temporally related to andesite lavas exposed at rolles peak 5 km east of rotokawa nor to andesite or diorite penetrated at ngatamariki but they have closer chemical affinities with the plagioclase pyroxene phyric lavas of the tongariro volcanic centre at the south end of the tvz the ngatamariki andesites have distinctive trace element compositions particularly ti and zr and are chemically and petrographically different from most other tvz lavas the occurrence of thick subsurface andesite sequences in the rotokawa ngatamariki area suggests that early eruptives here were of intermediate composition rather than the more silicic volcanics now so widespread both at the surface and in the shallow levels of several nearby geothermal systems

the location and sizing of historical earthquakes using the attenuation of macroseismic intensity with distance we herein describe new methods for computing the quantitative parameters of earthquakes using macroseismic data and the uncertainties associated with these parameters the methods allow for the location of epicenters that are offshore or that have no intensities assigned to any points in the epicentral region by maximizing the likelihood function of an attenuation equation with observed intensity data in the most favorable cases such an approach also allows the estimation of the source depth and the local attenuation coefficients we compute the parameter uncertainties in two ways 1 using formal methods such as the inversion of the hessian of the log likelihood function at its maximum and 2 by using bootstrap simulations we tested the performance of our methods by comparison with reliable instrumental hypocenters of onshore earthquakes and found a reasonable agreement with the epicentral locations within 10 15 km for more than 70 of cases but not with the hypocentral depths for which our results are generally underestimated by a factor of 2 or more and are poorly related to instrumental estimates this finding indicates that the use of macroseismic depths in seismic hazard and seismotectonic investigations should be treated with caution we nevertheless found good agreement within 10 15 between the fault trace orientations that were computed using the macroseismic data and the associated focal mechanisms of earthquakes with m w 5 7 the surprising accuracy of the macroseismic orientations obtained using this method could in some cases allow the true fault to be inferred between the two conjugate planes of a given focal mechanism

imposition of a proterozoic salient on a palaeozoic orogen at the eastern margin of gondwana abstract regional analysis of the distribution of metamorphic fabrics and shear zones in the palaeo mesoproterozoic curnamona province has enabled the deconstruction of a cambrian fold arc that defines part of the eastern margin of gondwana we suggest a tectonic model whereby the arc formed at ca 500 ma during accretion of phanerozoic terranes to the eastern margin of precambrian australia the regional fold arc is interpreted to have formed along an irregular plate margin comprising a se convex rigid promontory of precambrian basement during initial accretion of the phanerozoic terranes during the cambrian an early phase of dextral oblique slip along shear zones in the south and west of the province indicates an initial wnw transport direction as the arc was folded a slightly later phase of sinistral oblique slip shearing was initiated along shear zones in the east in response to deflection of the arc around the rigid promontory

are pooled tree ring δ13c and δ18o series reliable climate archives a case study of pinus nigra spp laricio corsica france abstract stable carbon and oxygen isotopes in tree rings are considered as reliable climate archives as they provide past environmental information with high resolution however recent studies have shown that isotope chronologies may reveal a long term age trend and be influenced by non climatic factors as other tree ring parameters as well these trends can only be identified in chronologies measured on individual trees but not on pooled sample chronologies consisting of several trees in order to test whether pooled chronologies from pine trees from the island of corsica mediterranean france can be used for climatic reconstructions we compared calculated mean values from 5 individual trees with pooled chronologies from the same 5 individuals carbon and oxygen isotope chronologies for a 50 year interval with annual resolution and 400 years with decadal resolution were analysed in order to document secular changes in inter tree variability and to test for age related trends in the isotope ratios pooled carbon and oxygen isotope series correspond well to chronologies based on mean values calculated from analyses of individual trees inter tree variability in oxygen isotope ratios is higher than in carbon isotope ratios but remains relatively constant over time similarities between the isotope series of individual trees are stronger over the 400 year time scale documenting a common long term signal in the isotope values no long term age related trends are observed oxygen isotope values of the juvenile phase are characterised by a remarkable decrease over 40 50 years interpreted to be related to the less developed root system of the young trees this age effect can be avoided by not considering the first 50 years from the chronologies our results confirm that pooled carbon and oxygen isotope chronologies from pinus nigra can be used for environmental reconstructions without statistical detrending

orogen perpendicular structures in the central tasmanides and implications for the paleozoic tectonic evolution of eastern australia the curvilinear e w structures of the southern thomson orogen are approximately orthogonal to the general n s structural trend of the tasmanides of eastern australia the origin of these orogen perpendicular structures and their implications to tectonic reconstructions of eastern gondwana are not fully understood here we use geophysical data to unravel the geometry kinematics and possible timing of major structures along the boundary between the thomson orogen and the southern tasmanides delamerian and lachlan orogens aeromagnetic data from the southern thomson orogen show wnw e w and or ene trending structural grains corresponding to relatively long wavelength linear geophysical anomalies kinematic analyses indicate strike slip and transpressional deformation along these geophysically defined faults structural relationships indicate that faulting took place during the benambran late ordovician to middle silurian and tabberabberan late early to middle devonian orogenies however some of the described crustal scale structures may have developed in the cambrian during the delamerian orogeny interpretation of deep seismic data shows that the crust of the southern thomson orogen is substantially thicker than the lachlan orogen crust which is separated from the thomson orogen by the north dipping olepoloko fault a major lithospheric scale change across this boundary is also indicated by a contrast in seismic velocities together with evidence for the occurrence of delamerian deformation in both the koonenberry belt and northeastern thomson orogen and a significant contrast in the width of the northern tasmanides versus the southern tasmanides it appears that the southern thomson orogen may represent the locus of orogen perpendicular segmentation which may have occurred in response to along strike plate boundary variations

evidence for deformation in the cambrian ordovician warburton basin and implications for the evolution of the tasmanides eastern australia the paleozoic tectonic history of the tasmanides in eastern australia was dominated by subduction related processes along the margin of eastern gondwana the earliest deformation event delamerian orogeny took place in the middle late cambrian and is recorded in rocks within the delamerian and thomson orogens the cambrian ordovician warburton basin covers the boundary between the delamerian and thomson orogens but very little is known about its origin and deformation history here we interpret geophysical data including 2 d seismic reflection transects bouguer gravity and aeromagnetic data that provide new insights into the deformation in the eastern warburton basin and the kinematics of major faults our results show that curvilinear ne trending faults in the eastern warburton basin are basement reverse faults that experienced multiple phases of contractional deformation evidence for a syn kinematic cambrian package kalladeina formation suggests that faulting commenced in response to the delamerian orogeny a subsequent early devonian deformation in the eastern warburton basin is evident from k ar geochronology of low grade subgreenschist metasedimentary rocks we suggest that the ne trending cambrian fold thrust belt within the eastern warburton basin marks the continuation of the curved delamerian orogen into the thomson orogen this oroclinal structure may have developed in the early devonian in response to dextral transpression along the northern boundary of the delamerian orogen our results provide a demonstration for the complex interactions that can take place during the evolution of convergent plate boundaries involving deformation in the fold thrust belt development of sedimentary basins and oroclinal bending

insights on the seismotectonics of the western part of northern calabria southern italy by integrated geological and geophysical data coexistence of shallow extensional and deep strike slip kinematics abstract we assess the seismotectonics of the western part of the border area between the southern apennines and calabrian arc centered on the mercure extensional basin by integrating recent seismicity with a reconstruction of the structural frame from surface to deep crust the analysis of low magnitude m l 3 5 events occurred in the area during 2013 2017 when evaluated in the context of the structural model has revealed an unexpected complexity of seismotectonics processes hypocentral distribution and kinematics allow separating these events into three groups focal mechanisms of the shallower

a reappraisal of the 1978 ferruzzano earthquake southern italy from new estimates of hypocenter location and moment tensor inversion abstract the march 11th 1978 ferruzzano earthquake is the most recent moderate to major earthquake occurred in the southern calabrian region southern italy one among the highest seismic risk areas of the whole mediterranean previous information available from the literature on the 1978 earthquake is quite contrasting and not well framed in the regional seismotectonic scenario in the present study we selected and digitized analog seismograms coming from stations of the euro mediterranean region to invert for the deviatoric seismic moment tensor through a time domain algorithm properly implemented to analyze data recorded before the advent of the digital era moreover we estimated a new hypocentral location by using original bulletin data and a non linear probabilistic earthquake location technique working with 3d velocity models the quality and stability of the obtained results both for hypocenter location and moment tensor inversion were accurately checked by several inversion tests our results indicate that the 1978 earthquake i occurred westward and at a shallower depth respect to previous hypocenter locations ii is characterized by a ca n s trending normal faulting mechanism and iii has a moment magnitude of 4 7 thus suggesting an overestimate of previous evaluations this study furnishes new information on the 1978 ferruzzano earthquake allowing to better frame it in the regional seismotectonic scenario and also proves that the time domain waveform inversion algorithm applied to digitized old seismograms is capable to successfully invert also mw

stable carbon isotope ratios of pinus sylvestris from northern finland and the potential for extracting a climate signal from long fennoscandian chronologies stable carbon isotope ratios were measured on the latewood cellulose of 36 scots pine trees from four sites in northern finland 13c values were corrected for changes in the 13c of air and de trended to remove the effect of tree age simple linear and multivariate correlations were used to determine the nature and strength of any climate signal at three sites the dominant controls are in descending order summer sunshine temperature and antecedent precipitation at the fourth site the dominant controls are antecedent precipitation and air relative humidity while summer sunshine and temperature appear unimportant 13c values record changes in the concentration of co2 in the stomatal chambers which reflects the balance between stomatal conductance and photosynthetic rate photosynthetic rate is controlled primarily by photon flux sunshine and temperature suggesting that this dominates at three of the sites whereas stomatal conductance is controlled by air humidity and soil moisture status ant

surface faulting in the southern italian campania basilicata earthquake of 23 november 1980 the campania basilicata earthquake of 23 november 1980 was the largest ms 6 9 and most destructive earthquake that has occurred in this region of southern italy for over 100 years killing more than 3 000 people the consensus among seismologists geologists and earthquake engineers who have studied1 10 this event is in keeping with previous italian earthquakes that it did not produce faulting at the surface this has led to the establishment of a number of models2 3 11 13 requiring an unusual tectonic setting for the southern apennines however on a recent visit to the epicentral region of the earthquake may 1984 we discovered more than 10 km of surface faulting that is consistent with focal mechanisms for this event based on first motion polarities2 4 5 12 and long period waveform studies14 16 which show that it involved normal faulting with one nodal plane dipping at 60 towards the north east our observations of this the first well documented earthquake fault break to be reported in italy suggest that the deformation associated with earthquakes in the southern apennines takes place in the upper 10 15 km of the earth s crust on steep planar normal faults which break the surface as is widely observed in other areas of active extension outside italy

the structure and kinematics of the southeastern zagros fold thrust belt iran from thin skinned to thick skinned tectonics 1 we present the first complete balanced cross section across the southeastern zagros fold thrust belt zftb the following main structural features emerge from this section 1 in the south of the zftb the proterozoic to recent sedimentary sequence has been decoupled from its panafrican basement along the ductile basal evaporites and folded into a series of large detachment anticlines ongoing shortening of these structures has resulted in migration of the basal salt layers into the cores of the anticlines and propagation of forelimb thrusts 2 in the north of the zftb deep seated ramps have folded the hanging wall rocks and produced imbrications and duplex structures within the higher levels of the sedimentary sequence 3 out of sequence thrusts linked to major seismogenic basement faults have cut through the structures in the cover of the zftb a three step incremental restoration of the section shows that two main phases of deformation can be separated in the tectonic evolution of the zftb a mio pliocene thin skinned phase in the course of which most of the structures in the cover were generated followed by a pliocene to recent thick skinned phase expressed as out of sequence faulting in the cover which is currently underlined by the seismicity within the basement in plan view the initial structures of the southeastern zftb developed with a curved shape essentially controlled by the shape and thickness of the underlying proterozoic salt basin i e the jura style in the following basement involved phase out of sequence thrusts cut at oblique angles through the preexisting structures of the cover the total shortening absorbed in the cover amounts to at least 45 km corresponding to a ratio of 22

seismic studies of the crust under the hydrothermal areas of the taupo volcanic zone new zealand abstract observations of relative p wave travel time residuals for local mantle earthquakes and p s amplitude ratios for more distant events have been used to investigate the nature of the crust under the hydrothermal areas of the central taupo volcanic zone in contrast to some other regions of similar activity such as the yellowstone and geysers geothermal areas u s a there is no evidence in the data for an extensive region of semi molten or molten rock in the crust thus the large amounts of mafic intrusive rock and associated crustal melt inferred to be present on geological grounds must be now largely at temperatures below the appropriate solidus the data do provide further evidence for previously suspected lateral inhomogeneity in the underlying mantle

a reanalysis of the hypocentral location and related observations for the great 1906 california earthquake we determine probabilistic hypocentral locations for the foreshock and mainshock of the great 1906 california earthquake through reanalysis of arrival time observations in conjunction with modern velocity models and advanced event location techniques we obtain two additional observations for the mainshock and one for the foreshock that were not used in previous location studies using a robust likelihood function for event location we generate a usable subset of the predominantly unreliable teleseismic readings and determine new wave type identifications for some of the local and teleseismic readings our locations are much better constrained than those of earlier studies even though we do not assume that the epicenter lies on the san andreas fault as did previous authors we confirm the conclusions of earlier studies that the local and teleseismic arrival time observations can be explained by a single foreshock focus and a single mainshock focus on the san andreas fault and that there is no single unique hypocenter that satisfies all available local observations the maximum likelihood point latitude 37 78 n longitude 122 51 w for our preferred mainshock location indicates a hypocenter to the west of san francisco close to the san andreas fault zone this hypocenter has a 68 confidence error of about 8 km parallel to the san andreas fault and about 24 km perpendicular to the fault and a depth in the midcrust of about 12 7 km the closest point on the san andreas fault to this hypocenter lies about 10 km to the northwest of the widely accepted mainshock epicenter of bolt 1968 our mainshock location is consistent with the association of initial rupture of the 1906 mainshock with a dilatational right bend or step over in the submerged san andreas fault system offshore of the golden gate our foreshock location is less well constrained than our mainshock location but is consistent with the foreshock hypocenter being at the same location as the mainshock hypocenter online material visualization of 3d probabilistic hypocentral locations associated with the 1906 earthquake

stable isotope coherence in the earlywood and latewood of tree line conifers abstract annually resolved and replicated tree ring stable isotope series have the potential to reconstruct growing season environmental parameters over multi millennial timescales as this archive may require only minimal statistical detrending it has the potential to preserve a large portion of low frequency climate signals to date many studies have utilised only the latewood portion of the tree ring in an attempt to minimize carry over effects from previous year reserves and maximise the annual nature of the climate signal preserved however the old trees from tree line locations necessary to build long chronologies often display narrow ring widths

seismic moment from regional surface wave amplitudes applications to digital and analog seismograms accurate consistent earthquake size estimates are fundamental for seismic hazard evaluation in central europe seismic activity is low and long term seismicity available as intensities from written historical records has to be included for meaningful assessments we determined seismic moments m 0 of 25 stronger twentieth century events in switzerland from surface wave amplitude measurements these m 0 can be used to calibrate intensity moment relations applicable to preinstrumental data we derived the amplitude moment relation using digital data from 18 earthquakes in and near switzerland where independent m 0 estimates exist the surface wave amplitudes were measured at empirically determined distance varying reference periods t for amplitudes measured at t the distance attenuation term of the surface wave magnitude relation s log a t max 1 66 log is independent of distance for log m 0 m s c e we get log m 0 s 14 90 uncertainties of 0 3 for the 14 90 constant correspond to a factor of 2 m 0 uncertainty which was verified with independent data our relation allows fast direct m 0 determination for current earthquakes and after recalibration of the constant the relation can be applied anywhere we applied our relation to analog seismograms from early instrumental earthquakes in switzerland that were collected from several european observatories amplitude measurements from scans were performed at large amplifications and corrected for differences between t and actual measurement periods the resulting magnitudes range from m w 4 6 to 5 8 for the largest earthquake in switzerland during the twentieth century uncertainties for the early instrumental events are on the order of 0 4 magnitude units online material moment tensor analysis of 14 recent earthquakes