the bucobello 322 ka fossil bearing volcaniclastic flow deposit in the eastern vulsini volcanic district central italy mechanism of emplacement and insights on human activity during mis 9 abstract we present a multidisciplinary study of a fossiliferous site located in the vulsini volcanic district on the western side of the tiber river valley north of rome highlighting the peculiar geologic factors that contributed to the origin and preservation of an outstanding archaeological record testifying of the early human frequentation in this region mighty explosive eruptions since at least 500 ka affected the investigated area eventually culminating in the formation of the huge bolsena caldera tectonic deformation accompanying volcanic activity caused large fault displacements shaping the ground surface and contributing to route the path and possibly to trigger the catastrophic emplacement of volcaniclastic flows a sedimentary trap originated by fault scarp cutting through a streambed was likely the cause for the large accumulation of bones and stone artifacts ripped up and carried by a volcaniclastic flow at 322 ka the analysis of the fossil assemblage reveals both gnawing traces by carnivores and cut marks from the percussion tools employed by humans to butch the carcasses however the occurrence of retouched and unretouched blanks within the lithic assemblage also testifies for provenance from a wider area of human activity which included hunting and scavenging probably at a nearby butchering site

pulsed uplift estimated from terrace elevations in the coast of rome evidence for a new phase of volcanic activity abstract the most recent phase of activity from the roman volcanoes since 45 ka has been interpreted to be the waning stage of the older explosive activity that peaked between 550 and 250 ka yet substantial regional uplift from approximately 250 ka suggests that magma chambers beneath the area are growing rather than shrinking we have estimated the uplift history of the region using radioisotopically and paleomagnetically constrained coastal terrace elevation data that allow us to correlate these terraces with marine oxygen isotopic stages 1 22 elevations have been corrected for glacio eustatic sea level change our study shows that over the last million years regional uplift of coastal terraces occurred in pulses that preceded volcanic activity at roughly 800 ka in the monti sabatini and 600 ka in the alban hills the recent pulse of uplift since 250 ka occurred primarily during a period of relative volcanic dormancy that lasted from 250 to 45 ka we hypothesize that the most recent volcanic activity since 45 ka may reflect the completion of magma chamber recharge suggesting the start of a new volcanic epoch it is also possible that the local tectonic stress field changed recently from one dominated by transpression to one dominated by extension allowing magma to more easily reach the surface via normal faults

the 2006 2007 kuril islands great earthquake sequence the southwestern half of a 500 km long seismic gap in the central kuril island arc subduction zone experienced two great earthquakes with extensive preshock and aftershock sequences in late 2006 to early 2007 the nature of seismic coupling in the gap had been uncertain due to the limited historical record of prior large events and the presence of distinctive upper plate trench and outer rise structures relative to adjacent regions along the arc that have experienced repeated great interplate earthquakes in the last few centuries the intraplate region seaward of the seismic gap had several shallow compressional events during the preceding decades notably an m s 7 2 event on 16 march 1963 leading to speculation that the interplate fault was seismically coupled this issue was partly resolved by failure of the shallow portion of the interplate megathrust in an m w 8 3 thrust event on 15 november 2006 this event ruptured 250 km along the seismic gap just northeast of the great 1963 kuril island m w 8 5 earthquake rupture zone within minutes of the thrust event intense earthquake activity commenced beneath the outer wall of the trench seaward of the interplate rupture with the larger events having normal faulting mechanisms an unusual double band of interplate and intraplate aftershocks developed on 13 january 2007 an m w 8 1 extensional earthquake ruptured within the pacific plate beneath the seaward edge of the kuril trench this event is the third largest normal faulting earthquake seaward of a subduction zone on record and its rupture zone extended to at least 33 km depth and paralleled most of the length of the 2006 rupture the 13 january 2007 event produced stronger shaking in japan than the larger thrust event as a consequence of higher short period energy radiation from the source the great event aftershock sequences were dominated by the expected faulting geometries thrust faulting for the 2006 rupture zone and normal faulting for the 2007 rupture zone a large intraplate compressional event occurred on 15 january 2009 m w 7 4 near 45 km depth below the rupture zone of the 2007 event and in the vicinity of the 16 march 1963 compressional event the fault geometry rupture process and slip distributions of the two great events are estimated using very broadband teleseismic body and surface wave observations the occurrence of the thrust event in the shallowest portion of the interplate fault in a region with a paucity of large thrust events at greater depths suggests that the event removed most of the slip deficit on this portion of the interplate fault this great earthquake doublet demonstrates the heightened seismic hazard posed by induced intraplate faulting following large interplate thrust events future seismic failure of the remainder of the seismic gap appears viable with the northeastern region that has also experienced compressional activity seaward of the megathrust warranting particular attention

major explosive activity in the monti sabatini volcanic district central italy over the 800 390 ka interval geochronological geochemical overview and tephrostratigraphic implications abstract a review of the existing chronological stratigraphic and chemo petrologic data of the major eruptive units from the early phase of activity 800 390 ka in the monti sabatini volcanic district msvd belonging to the ultra potassic magmatic region of central italy is presented along with new radioisotopic age determinations and geochemical analyses through the combined use of electron microprobe glass compositions selected trace element compositions and single crystal 40ar 39ar age determinations we provide a new chrono and chemo stratigraphic classification of the products emplaced in the 800 390 ka time interval besides giving insights on the petrologic evolution of the roman comagmatic region the large dataset provides fundamental information that is applicable to tephrostratigraphic studies in the wide region encompassing the tyrrhenian sea margin to the adriatic sea basin distal tephras from this volcanic activity also act as important geochronologic markers for the coastal sedimentary successions deposited in response to glacio eustatic fluctuations as well as for successions in the quaternary tectonic basins of the central and southern apennines an innovative approach based on the use of discrimination diagrams of zr y vs nb y ratios for fingerprinting altered volcanic rocks recently developed and successfully employed in archaeometric studies is here combined to the glass compositions for classifying the msvd deposits and tested on two distal tephra layers showing its potentiality for tephrostratigraphic correlation

history of glacial terminations from the tiber river rome insights into glacial forcing mechanisms 1 we document the aggradational history of the tiber river delta through the last 17 000 years by means of 17 new 14c ages from peat or wood collected from the delta sediment an abrupt change in sediment clast size grading from gravel to clay occurred between 13 63 0 20 and 12 80 0 15 ka indicating that it was synchronous with the last glacial termination with no appreciable phase lag knowing this phase relationship enables us to reduce the magnitudes of age uncertainties for aggradational sections corresponding to glacial terminations ix through iii which we had dated previously by 40ar 39ar methods glacial terminations viii vi and iv precede beyond 95 confidence the ages predicted by northern hemisphere summer insolation maxima additionally we find that each of these seven glacial terminations follows particularly mild insolation minima which we suggest may be regarded as the preconditioning factor to trigger a glacial termination

studies of the arctic ice cover and upper ocean with a coupled ice ocean model an ice ocean model has been developed by coupling the hibler ice model to a three dimensional ocean model that consists of a turbulent mixed layer model and an inverse geostrophic model the coupled model has a horizontal grid spacing of 127 km and has 17 vertical levels extending to the ocean bottom the model is forced with 12 hourly general circulation model derived atmospheric fluxes for the year 1986 for which good quality ice edge analyses and buoy tracks were available for comparisons the results are presented for the fifth year of a repetitive simulation with the 1986 fluxes at which time the system has reached a statistical equilibrium the seasonal and geographical variations of the ice cover and the upper few hundred meters of the ocean have been examined including the heat and salt budgets the computed heat fluxes and mixed layer depths mlds fall in the observed seasonal ranges with winter heat fluxes ranging from 15 w m 2 in the central arctic to about 500 w m 2 in the barents sea area and summer fluxes from about 5 w m 2 under the ice to about 30 w m 2 in the various marginal ice zone miz edge areas the corresponding winter mlds are found to be about 25 75 m in the central arctic to a deep 800 m in the greenland sea typical summer mlds are between 5 and 30 m in all seasons the miz was found to be the center of flux activity for both heat and salt with the processes of advection diffusion atmospheric forcing and vertical oceanic fluxes having their largest values here and of comparable magnitudes values of the heat flux components in the miz exceed those found under the ice by an order of magnitude or more and those in the open water region by a factor of 2 for salt the situation is similar except in the summer june through september when a lot of salt flux activity takes place under the ice comparisons are made with naval polar oceanography center npoc analyses for ice concentration and ice edge and with observed arctic buoy tracks in the same 1986 time period the computed ice edge positions have comparable accuracy to previous three dimensional coupled ice ocean studies with too much ice growth during the winter in the barents sea and too little ice east of greenland the ice thickness distributions however are much better with a monotonic increase of the ice thickness from the siberian coast east toward the canadian archipelago with maximum winter values of about 5 6 m

evidence for warming of atlantic water in the southern canadian basin of the arctic ocean results from the larsen 93 expedition potential temperature and salinity s data obtained along the perimeter of the southern canadian basin north of the east siberian sea in 1993 aboard the ccgs henry larsen show higher temperatures in waters of atlantic origin than in available climatological data for the canadian basin in particular a front is observed near the mendeleyev ridge which separates the cooler atlantic waters of the canada basin from the warmer atlantic waters observed in the makarov basin the front is further characterized by a change in the s slope of arctic thermocline water and by thermohaline intrusions and s reversals within the atlantic layer the idea that this warm variety of atlantic water has come recently from the eurasian basin is supported by its higher level of the tracer cfc 11

shumagin seismic gap alaska peninsula history of great earthquakes tectonic setting and evidence for high seismic potential the shumagin seismic gap a segment of the plate boundary along the eastern aleutian arc has not ruptured during a great earthquake since at least 1899 1903 because at least 77 years have elapsed since the shumagin gap last ruptured in a great earthquake and repeat times for the 1938 rupture zone and part of the shumagin gap are estimated to be 50 to 90 years a high probability exists for a great earthquake to occur within the shumagin gap during the next one to two decades reconsideration of the rupture zones of the aleutian earthquakes of 1938 1946 and 1948 suggests that those events did not break the interplate boundary beneath the shumagin islands thus the shumagin seismic gap extends from the western end of the 1938 rupture zone to the eastern end of that of 1946 these boundaries also coincide with transverse structural features at least the eastern half of the shumagin gap broke in great earthquakes in 1788 and 1847 and possibly in 1898 1903 the shumagin gap is probably not the result of aseismic slip rather plate motion is accommodated there seismically and episodically and can be expected to produce large earthquakes in the future although there is no definitive evidence of long term precursors of a possible future earthquake several observations suggest that the shumagin gap is in an advanced stage of the earthquake cycle both teleseismic and local network data indicate a near absence of seismic activity m 2 above a depth of 30 km along the main thrust zone within the gap this is in strong contrast to adjacent portions of the arc where seismic activity is scattered across most of the main thrust zone two earthquakes with high stress drops 600 900 bars which occurred at the base of the main thrust zone may indicate the accumulation of a considerable amount of strain energy within the gap a possible seismic gap at the eastern end of the aftershock zone of the aleutian earthquake of 1957 has been identified near unalaska island an earthquake that nucleates in the shumagin gap could also rupture the possible unalaska gap to the west the 1938 aftershock zone to the east or both with resultant magnitude up to mw 9 0 alternatively the shumagin gap alone or in one of the above combinations could rupture in a series of very large earthquakes instead of a single great shock past alaska aleutian earthquakes including those of 1788 1938 1946 1957 1964 and 1965 have generated very large tsunamis future large earthquakes in the shumagin islands region could generate wave heights of several tens of meters along shorelines near the rupture areas the shumagin gap is one of two major gaps along the united states portion of the alaska aleutian plate boundary and is one of the few areas in the united states where processes leading to a great earthquake are likely to be observed within a reasonable span of time

the olduvai buffalo pelorovis and the origin of bos the origin of the genus bos is a debated issue from 0 5 ma until historic times the genus is well known in the eurasian large mammal assemblages where it is represented by bos primigenius this species has a highly derived cranial anatomy that shows important morphological differences from other plio pleistocene eurasian genera of the tribe bovini such as leptobos bison proamphibos hemibos and bubalus the oldest clear evidence of bos is the skull fragment asb 198 1 from the middle pleistocene 0 6 0 8 ma site of asbole lower awash valley ethiopia the first appearance of bos in europe is at the site of venosa notarchirico italy 0 5 0 6 ma although the origin of bos has traditionally been connected with leptobos and bison after a detailed anatomical and morphometric study we propose here a different origin connecting the middle pleistocene eurasian forms of b primigenius with the african late pliocene and early pleistocene large size member of the tribe bovini pelorovis sensu stricto the dispersal of the bos lineage in western europe during middle pleistocene times seems to coincide with the arrival of the acheulean tool technology in this continent 2007 university of washington all rights reserved

new chronological framework mis 13 9 and depositional context for the lower palaeolithic sites north west of rome revisiting the early hominin in central italy abstract the paleolithic period in central italy is currently undergoing an extensive revision due to a significant chronological re examination of many archaeological sites recently several lower palaeolithic sites 20 km nw of rome previously dated within mis 9 335 300 ka i e la polledrara di cecanibbio torre in pietra castel di guido malagrotta and four sites along via aurelia have been geochronologically reassessed between 412 and 325 ka these sites in which abundant fauna artifacts and hominin remains have been found are remarkably well preserved a combination of geological factors and the peculiar geodynamic conditions of this region where tectonics volcanism and glacio eustatic forcing worked in concert allowed for the exceptional conservation of the remains in this paper we provide a review of these sites and analyze their depositional contexts showing that rapid filling of the fluvial incisions during glacial terminations combined with sudden emplacement of volcanic deposits caused the sealing of the archaeological materials accumulated at the bottom of the paleo valleys the aim of this paper is to contribute to a better understanding of these sites as well as to provide the archaeological implications of their new chronology and depositional contexts results allow to reconsider the hominin presence in central italy and highlight the importance to integrate archaeological investigations with modern geological studies combining sedimentological geochronological geomorphological and chronostratigraphical methods

a novel multidisciplinary bio and geo chronological approach for age determination of palaeolithic bone artifacts in volcanic settings an example from eastern sabatini latium italy in this study we provide combined biochronologic and chronostratigraphic constraints to the fluvial lacustrine succession cropping out near the village of rignano flaminio 35 km north of rome where two bone instruments have been recovered along with several vertebrate fossil remains the presence of bone tools is characteristic of the latium region whereas it is rare in the rest of italy but very few sites in which such artifacts occur have precise geochronological constraints in the investigated site the presence of cervus elaphus eostephanoceros among other taxa indicates a time interval limited to marine isotopic stage mis 13 and mis 11 the occurrence of the tufo rosso a scorie nere pyroclastic flow deposit dated 449 2 ka at the base of the sedimentary deposits hosting the faunal assemblage allows us at restricting the interval to mis 11 moreover applying a recently validated conceptual model accounting for an aggradational mechanism linked with sea level rise during glacial termination for the sedimentary successions of the tiber river and its tributaries in a relatively wider area around rome we further constrain the age to 430 405 ka following this approach we present a review of the archaeological sites of latium yielding bone instruments remarking that only other four sites have been recently provided with geochronological constraints through the application of the multidisciplinary methodology applied here

strike slip faulting and block rotation a possible triggering mechanism for lava flows in the alban hills abstract it is suggested in this paper that two distinct tectonic triggers tapping different depths of a magma reservoir may be the cause of nearly contemporaneous eruptions of lava flows and ignimbrites in the alban hills the area between the alban hills and rome underwent alternating regional extensional and strike slip faulting during the middle pleistocene the geometries of the main structural dislocations in quaternary strata combined with a statistical analysis of drainage network trends show a structural pattern that is consistent with local strain partitioning in transpressive zones at strike slip fault bends superimposed on regional extension based on this analysis it is suggested that local clockwise block rotation between parallel n s strike slip faults might have generated local crustal decompression allowing relatively volatile free magma to rise from deep reservoirs beneath the alban hills triggering peripheral fissure lava flows in contrast the main ignimbrite eruptions appear to tap shallow volatile rich magma reservoirs and are controlled by extensional processes

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

sea ice melting and floe geometry in a simple ice ocean model a coupled sea ice ocean numerical model has been developed that addresses the role of floe geometry during summertime melting the model contains a diagnostic equation for average floe diameter in addition to the usual prognostic equations for ice volume per unit area and ice concentration the partition between melting on the top bottom and lateral side surfaces of floes is examined using time dependent simulations with differing initial average floe diameters the different parameterizations for bottom and lateral melting in the literature are also compared and found to vary significantly the results show that lateral melting is important only for floes with diameters less than o 30 m given atmospheric thermal forcing typical of the central arctic in summer this means that the decrease in ice concentration over the summer is a strong function of floe diameter in keeping with simple geometrical arguments in all cases about 80 of the net thermal energy that enters the ocean through leads goes toward melting ice while the rest warms the ocean

re evaluation of the ages of 40ar 39ar sanidine standards and supereruptions in the western u s using a noblesse multi collector mass spectrometer abstract the rewards from resolving the tempo of magmatic paleobiologic paleoclimatic and tectonic processes at better than the per mil level of precision have spurred a quest within the geochronology community to improve the precision accuracy and calibration of several chronometers including the 40 ar 39 ar variant of the k ar clock a new generation of multi collector mass spectrometers for 40 ar 39 ar geochronology provides the means to address these issues as well as to evaluate the ages of 40 ar 39 ar standards and key marker horizons deposited by large volume caldera forming supereruptions in the western u s at unprecedented temporal resolution we highlight the utility of a 5 collector noblesse mass spectrometer that has a sufficiently high mass resolving power to distinguish 36 ar h 35 cl from a 36 ar h 35 cl 12 c 3 sum peak at m e 36 maintains a remarkably low and stable background and thus yields 40 ar 39 ar dates of exceptionally high precision we have calibrated a reference gas and developed a simple analytical routine involving one peak hop both of which are used to evaluate detector bias correction factors because the 40 ar 39 ar chronometer is a relative dating technique that relies on calibration against mineral standards of known age precise and accurate determination of the ages of these standards and verification of isotopic composition and homogeneity is essential we present results from both total fusion and incremental heating experiments on single crystals of the widely used alder creek acs and fish canyon fcs sanidine standards several recent independent measurements of acs using multi collector mass spectrometers including those presented herein favor an age of 1 1864 0 0003 0 0012 ma 95 confidence analytical full external uncertainty that is 1 younger than the widely used value obtained by nomade et al 2005 using a single collector mass spectrometer incremental heating experiments on single crystals of fcs most commonly do not yield plateau ages instead many crystals appear to be affected by ar loss or excess ar our findings obtained using ion counters independently confirm those recently obtained using a multiple faraday detectors or a combination of faraday and ion counting detectors thus careful consideration must be given to using fcs in future high precision 40 ar 39 ar calibrations of the geologic timescale notwithstanding 40 ar 39 ar dating of sanidine using the 5 collector noblesse can now provide leverage critical to interpreting the large range of u pb zircon dates commonly found in rhyolitic lavas and tuffs

the early middle pleistocene archeopaleontological site of wadi sarrat tunisia and the earliest record of bos primigenius abstract here we describe the new rich lacustrine paleontological and archeological site of wadi sarrat le kef northeastern tunisia dated to the beginning of the middle pleistocene 0 7 ma by a combination of paleomagnetism and biochronology this locality preserves the earliest record of auroch bos primigenius the ancestor of the worldwide extant domestic cattle species bos taurus which is represented by a nearly complete giant sized cranium specimen os1 both the cranial anatomy and the size of this specimen reflect the phylogenetic legacy inherited from its ancestor the late early pleistocene african bos buiaensis recorded in the eastern african paleoanthropological site of buia eritrea 1 0 ma given that the latter species is an evolved form of the classical early pleistocene african buffalo pelorovis oldowayensis the finding of b primigenius at wadi sarrat shows that the genus bos evolved in africa and dispersed into eurasia at the beginning of the middle pleistocene which coincides with the spread of the acheulian technocomplex in northern africa and europe therefore the lineage of pelorovis bos has been part of the human ecological landscape since the appearance of the genus homo in the african early pleistocene

chronostratigraphic constraints on middle pleistocene faunal assemblages and acheulian industries from the cretone lacustrine basin central italy integrated 40ar 39ar trace element stratigraphic palaeontological and palaethnological data provide geochronological and biochronological constraints for the sedimentary and tectonic history of a middle pleistocene fluvial lacustrine basin near rome cretone basin central italy which has yielded a significant record of mammal fossil remains and palaeolithic industry this work is a case study of the interplay between tectonics and glacio eustacy which strongly influenced the evolution of the tyrrhenian sea margin of central italy dating of tephra layers interbedded within the cretone basin lacustrine succession and reconstruction of relict terraced surfaces allow correlation with similar geochronologically constrained marine isotopic stages mis 15 5 terraced deposits along the coast coupled extensional tectonics and regional uplift over the last 600 ka caused the progressive uplifting and westward migration of the main fluvial lacustrine basin and the formation of a smaller satellite basin at its eastern margin here stable environmental conditions during mis 13 5 indicated continuous human and large mammal frequentation as testified by lithic industry and fossil remains ascribable to the acheulean and later early middle palaeolithic technocomplexes and galerian aurelian mammal faunas respectively in addition to providing independent age constraints to glacial sea level oscillations of this region the reconstructed chronostratigraphic setting for the cretone basin provides evidence for one of the oldest acheulean lithic assemblage of central italy as well as new biochronological and palaeobiogeographical data for some middle pleistocene mammal species of italy

plinian activity during the early eruptive history of the sabatini volcanic district central italy abstract the early activity of the sabatini volcanic district svd central italy was characterised by highly explosive eruptions that produced widespread subplinian and plinian fall deposits in this study four major eruptive units informally named as units a b c and d were recognised in the 514 449 ka age interval in particular unit d was emplaced during the early phase of the 449 ka tufo rosso a scorie nere pyroclastic flow forming eruption the most important event in the whole svd activity history estimates of relevant eruptive parameters indicate tephra fall volumes up to 4 km3 for individual units peak eruption column heights in the range of 14 29 km and corresponding mass eruption rates of 7 8 106 1 3 108 kg s isopach and isopleth maps of fallout deposits as well as the distribution of the proximal lag breccia of the tufo rosso a scorie nere consistently indicate a common vent area which does not correspond to any volcanic centre identified up to now in the svd this was located along ne sw trending tectonic lineaments that also controlled the location of the other major volcanic centres of the svd the characterisation by means of field aspects grain size componentry and density and chemical composition of juvenile clasts renders the studied fall deposits as valuable stratigraphic markers for the svd and well beyond it in fact their wide areal dispersals toward the e and se may allow correlations on a regional scale for the quaternary successions of intermountain basins of the central apennine and the adriatic sea basin successions finally the correct identification of distal tephra from plinian and co ignimbrite plumes and their attribution to specific explosive eruptions of the svd and the other volcanic districts of the roman province rather than to local intra apennine centres provides crucial implications for geodynamic reconstructions

on the deformation cycle of a strongly coupled plate interface the triple earthquakes of 16 march 1963 15 november 2006 and 13 january 2007 along the kurile subduction zone 1 the great plate interface kurile earthquake of 15 november 2006 mw 8 3 was immediately followed by normal aftershocks in the outer rise of the central kurile subduction zone two months later at a distance 50 km from this event the 13 january 2007 mw 8 1 earthquake with a pure normal mechanism occurred in the outer rise of the central kurile the 15 november 2006 earthquake ruptured an area of 280 150 km2 with maximum slip of almost 7 m while the 13 january 2007 earthquake ruptured an area of 240 40 km2 with a maximum slip of almost 14 m these two significant events were preceded by a major reverse earthquake on 16 march 1963 mw 7 7 that took place close to the location of the 13 january 2007 earthquake these very different earthquakes demonstrate the different stages of the deformation cycle along strongly coupled plates at the central kurile arc and present a rare case of stress regime reversal over a short time span in order to understand the details of these three earthquakes we inverted for the source rupture processes of the earthquakes and delineated the location and dimension of asperities the role of gravity and topography anomalies and their correlation to the asperity distribution as well as the long term seismicity is studied in detail using trench parallel bouguer anomaly we have identified the differences in the asperities and the location of larger normal outer rise aftershocks as well as the location of 13 january 2007 earthquake we also show that the long term seismicity of the central kurile arc is confined to the intraslab and not the plate interface the static stress transfer for these earthquakes showed that the stress on optimally oriented thrust faults is increased in the northeastern part of the rupture area of the 15 november 2006 earthquake absence of major and great earthquakes to the northeastern immediate vicinity of the rupture area of the 15 november 2006 earthquake supports the hypothesis that this area is mature for the next strong earthquake along the kurile arc

variable tsunami sources and seismic gaps in the southernmost kuril trench a review in the southernmost kuril trench the tsunami source regions vary their along trench extent even among earthquakes occurring within the same segment recent studies suggest that the tsunami source of the 1952 tokachi oki earthquake m 8 1 differs from but partially overlaps with that of the 2003 tokach oki earthquake m 8 0 furthermore the along trench extent among the earthquakes seems to differ between deep and shallow portions of the subduction interface a seismic gap has been recognized along the deep subduction interface between the sources of the 1952 and 1973 earthquakes we propose that the gap is now larger including both shallow to deep portions of the interface between the 1973 and 2003 earthquakes variability in spatial extent of large subduction earthquakes in both along trench direction and trench normal direction makes it difficult to forecast future earthquakes in the southernmost kuril trench

the aleutian earthquake of june 10 1996 mw 7 9 ruptured parts of both the andreanof and delarof segments the epicenter of the aleutian earthquake of june 10 1996 is located in the delarof segment where a large subduction earthquake is expected however the aftershock area of the earthquake is not only in the delarof segment but also in the andreanof segment where the 1986 andreanof earthquake occurred previously we estimate the fault parameters of the 1996 earthquake by numerically computing the tsunami and comparing the waveforms with that recorded at adak the fault width is 30 km or less and the average slip is about 4 m the observed far field tsunamis around the pacific are also explained by the synthetic tsunami computed using the above fault parameters the results indicate that the 1996 earthquake ruptured parts of both the delarof and andreanof segments however the 1996 earthquake did not rupture the region of the largest moment release by the 1986 earthquake

early italy and the colonization of western europe abstract the early phases of human occupation in italy are considered in the context of discussions on the chronology and patterns of hominid dispersal out of africa and into western europe this paper is therefore a synthesis and an evaluation of new data on three interrelated topics a the question of direct contacts between italy and north africa in the lower and middle pleistocene through the sicilian channel b the evidence for the successive dispersal in western europe of two different technical traditions and c the nature and chronology of the earliest human occupation of italy interpretations of bifaces and biface industries are discussed as they are an important aspect of out of africa models hominid presence in italy is documented at the beginning of the middle pleistocene their route of entry apparently not through sicily but from the north in contrast to the ubeidiya and gesher benot ya aqov assemblages in israel the earliest dated biface assemblages in italy with a preliminary date at about 640 70 ka show no specific characteristics that would tie them to the african acheulean evidence for a precedence of core and flake over handaxe industries is ambiguous their interpretation as designating different groups of hominids lacks a sound archaeological basis since faunal exchanges with continental europe are documented throughout the pleistocene the hypothesis of multiple episodes of human migration into italy should be considered however we can neither support it or refute it because the archaeological assemblages do not inform us on specific migration events

arc segmentation and seismicity in the solomon islands arc sw pacific abstract this paper evaluates neotectonic segmentation in the solomon islands forearc and considers how it relates to regional tectonic evolution and the extent of ruptures of large megathrust earthquakes we first consider regional geomorphology and quaternary vertical displacements especially uplifted coral reef terraces then we consider geographic seismicity patterns aftershock areas and vertical displacements for large earthquakes focal mechanisms and along arc variations in seismic moment release to evaluate the relationship between neotectonically defined segments and seismicity notably one major limitation of using seismicity to evaluate arc segmentation is the matter of accurately defining earthquake rupture zones for example shoreline uplifts associated with the 1 april 2007 mw 8 1 western solomons earthquake indicate that the along arc extent of rupture was about 50 km smaller than the aftershock area thus if we had relied on aftershocks alone to identify the 2007 rupture zone as we do for most historical earthquakes we would have missed the rupture s relationship to a major morphologic feature in many cases the imprecision of defining rupture zones without surface deformation data may be largely responsible for the poor mismatches to neotectonic boundaries however when a precise paleoseismic vertical deformation history is absent aftershocks are often the best available tool for inferring rupture geometries altogether we identify 16 segments in the solomon islands these comprise three major tectonic regimes or supersegments that correspond respectively to the forearc areas of guadalcanal makira the new georgia island group and bougainville islands subduction of the young and relatively shallow and buoyant woodlark basin and spreading system distinguishes the central new georgia supersegment from the two neighboring supersegments the physiographic expression of the san cristobal trench is largely absent but bathymetric mapping of the surface trace of the interplate thrust zone defines it adequately the new georgia supersegment has smaller arc segments and more islands due to general late quaternary forearc uplift very close to the trench where vertical displacement rates tend to be faster prior to the 2007 earthquake it had much lower rates of seismic activity than the neighboring supersegments generally the mean along arc lateral extent of solomon arc segments is about 75 km somewhat smaller than the segments reported in some other island arcs such as japan 100 260 km but larger than those of the tonga 30 80 km and central new hebrides arcs 30 110 km these differences may be real but it may occur simply because the coral friendly tropical environment of the south pacific arcs numerous emerged forearc islands and high seismicity rates provide an unusually favorable situation for observing variations in vertical tectonic activity and thus for identifying segment boundaries over the past century seismic slip in the solomons as indicated by seismic moment release has corresponded to about half the plate convergence rate however there are notable variations along the arc even with the 2007 earthquake the long term moment release rate in the new georgia supersegment is relatively low and this may indicate that large earthquakes are imminent

scaling relations of earthquake source parameter estimates with special focus on subduction environment abstract earthquake rupture length and width estimates are in demand in many seismological applications earthquake magnitude estimates are often available whereas the geometrical extensions of the rupture fault mostly are lacking therefore scaling relations are needed to derive length and width from magnitude most frequently used are the relationships of wells and coppersmith 1994 derived on the basis of a large dataset including all slip types with the exception of thrust faulting events in subduction environments however there are many applications dealing with earthquakes in subduction zones because of their high seismic and tsunamigenic potential there are no well established scaling relations for moment magnitude and length width for subduction events within this study we compiled a large database of source parameter estimates of 283 earthquakes all focal mechanisms are represented but special focus is set on large subduction zone events in particular scaling relations were fitted with linear least square as well as orthogonal regression and analyzed regarding the difference between continental and subduction zone oceanic relationships additionally the effect of technical progress in earthquake parameter estimation on scaling relations was tested as well as the influence of different fault mechanisms for a given moment magnitude we found shorter but wider rupture areas of thrust events compared to wells and coppersmith 1994 the thrust event relationships for pure continental and pure subduction zone rupture areas were found to be almost identical the scaling relations differ significantly for slip types the exclusion of events prior to 1964 when the worldwide standard seismic network was established resulted in a remarkable effect on strike slip scaling relations the data do not show any saturation of rupture width of strike slip earthquakes generally rupture area seems to scale with mean slip independent of magnitude the aspect ratio l w however depends on moment and differs for each slip type

spatially linked asperities of the 2006 2007 great kuril earthquakes revealed by gps 1 in 2006 2007 two great earthquakes ruptured the center of the kuril subduction zone first the interplate thrust event then the intraplate extensional event on the outer rise the affected region was a seismic gap since 1915 published patterns of slip differ for various seismic and tsunami inversions the surface offsets that we measured with gps on the kuril islands are sensitive to the total slip including slow components beyond the seismic and tsunami band we invert coseismic offsets and show that the asperities or regions of high slip are spatially linked for both earthquakes this pattern suggests although does not prove that the first event triggered the second for the 2006 earthquake the asperity is very shallow probably because of the absence of an accretionary prism for the 2007 earthquake our modeling suggests that the rupture occurred in the bent pacific lithosphere to a depth of 50 km

predictions and studies with a one dimensional ice ocean model abstract a coupled one dimensional ice ocean model is developed in differential form the ice snow system is represented by the simplified thermodynamic model of semtner and a dynamic approximation that neglects the internal stresses the ocean is represented by the mellor yamada level 2 turbulence mixed layer model the thermodynamic coupling considers a moving ice ocean interface and salinity flux generated by the freezing or melting of ice the dynamic coupling occurs via the turbulent stress that exists in the mixed layer beneath the ice the test cases are used for model validation and scientific studies one is the standard climatological test used by semtner and others the other test case is with the aidjex data the ice ocean model is compared to semtner s ice model to determine the effect of a variable depth mixed layer as opposed to an isothermal fixed depth mixed layer the sensitivity of the ice ocean model to changes in certain parameters and forcing is also examined finally the ability of the model simulate arctic conditions is shown by comparison of model results of data obtained during aidjex keywords ocean models sea ice arctic regions oceanographic data marine climatology diurnal variations heat flux solar radiation marine mixed layers

field survey and geological effects of the 15 november 2006 kuril tsunami in the middle kuril islands the near field expression of the tsunami produced by the 15 november 2006 kuril earthquake mw 8 1 8 4 in the middle kuril islands russia including runup of up to 20 m remained unknown until we conducted a post tsunami survey in the summer of 2007 because the earthquake occurred between summer field expeditions in 2006 and 2007 we have observations topographic profiles and photographs from three months before and nine months after the tsunami we thoroughly surveyed portions of the islands of simushir and matua and also did surveys on parts of ketoi yankicha ryponkicha and rasshua tsunami runup in the near field of the middle kuril islands over a distance of about 200 km averaged 10 m over 130 locations surveyed and was typically between 5 and 15 m local topography strongly affected inundation and somewhat affected runup higher runup generally occurred along steep protruding headlands whereas longer inundation distances occurred on lower flatter coastal plains sediment transport was ubiquitous where sediment was available deposit grain size was typically sand but ranged from mud to large boulders wherever there were sandy beaches a more or less continuous sand sheet was present on the coastal plain erosion was extensive often more extensive than deposition in both space and volume especially in areas with runup of more than 10 m the tsunami eroded the beach landward stripped vegetation created scours and trim lines cut through ridges and plucked rocks out of the coastal plain

structure of the kuril trench from seismic reflection records three multichannel seismic reflection records across the kuril convergent margin provide the first deep data in this area the records are located across the southern tip of kamchatka the central kuril arc and the northern extension of hokkaido island platform which show three distinct tectonic regimes the lower slope contains a wedge shaped buttress surrounded by low velocity sediments underplating sediment uplifts the buttress as indicated by faults that displace its upper surface the middle slope is a block of acoustic basement which has a rough surface with significant arcward dipping faults the middle slope is separated from the upper slope along a steep arcward dipping reflection the middle slope boundary the upper slope structure off kamchatka is different from that off hokkaido off kamchatka a regular stratified sediment section has been uplifted tilted and dips seaward off hokkaido stronger uplift has tilted regional blocks seaward and arcward along the southern line north of hokkaido well studied nonthrust earthquakes with lateral motions occur beneath the middle slope boundary and on the boundary of the subducting plate thrust earthquakes occur under the middle and upper slope whereas tsunami earthquakes occur under the lower slope high amplitude reflections along the lower boundary of the wedge shaped buttress and along the active decollement indicate high fluid concentrations which reduce the friction along the tectonic units so that through the weak coupling slow rupture may extend up to the seafloor from a tsunami earthquake

the great 2006 and 2007 kuril earthquakes forearc segmentation and seismic activity of the central kuril islands region we present a structural study of the central kuril islands forearc region where the great megathrust tsunamigenic earthquake m w 8 3 occurred on november 15 2006 based on new bathymetry and seismic profiles obtained during two research cruises of r v akademik lavrentiev in 2005 and 2006 ten crustal segments with along arc length ranging from 30 to 100 km separated by ns and nw trending transcurrent faults were identified within the forearc region the transcurrent faults may serve as barriers impeding stress transfer between the neighboring segments so that stress accumulated within separate forearc segments is usually released by earthquakes of moderate to strong magnitudes however the great november 15 2006 earthquake ruptured seven of the crustal segments probably following a 226 year gap since the last great earthquake in 1780 the geographic extent of earthquake rupture zones aftershock areas and earthquake clusters correlate well with forearc crustal segments identified using the geophysical data based on segmented structure of the central kuril islands forearc region we consider and discuss three scenarios of a great earthquake occurrence within this area although the margin is segmented we suggest that a rupture could occupy the entire seismic gap with a total length of about 500 km in such a case the earthquake magnitude m w might exceed 8 5 and such an event might generate tsunami waves significantly exceeding in height to those produced by the great 2006 2007 kuril earthquakes

a 560 440 ka tephra record from the mercure basin southern italy volcanological and tephrostratigraphic implications integrated electron microprobe analyses empas on glass and sr nd isotope analyses have been performed on 17 tephras from the middle pleistocene mercure lacustrine succession southern apennines two 40ar 39ar ages and the recognition of four relevant tephras from colli albani sabatini and possibly roccamonfina volcanoes allowed us to ascribe the investigated succession to the late marine isotope stage mis 15 12 interval 560 440 ka the sr nd isotopes and major element glass compositions allowed us to attribute 10 out of the other 13 tephras to a poorly known activity of the roccamofina volcano whereas two layers were tentatively attributed to previously unknown middle pleistocene activity of ponza island or campanian volcanoes and one to salina island the tephrostratigraphic correlation of the mercure tephras with the acerno lacustrine pollen record campania also allowed us to evaluate the climatostratigraphic position of the tephras within the framework of the mis 15 12 climatic variability these results were obtained by combining the sr nd isotope ratio with empa and 40ar 39ar geochronological data this confirms the notable consistency of this approach for studying the mediterranean middle pleistocene tephrostratigraphy which despite its great potential for both volcanology and quaternary studies has been hitherto barely explored

age intercalibration of 40ar 39ar sanidine and chemically distinct u pb zircon populations from the alder creek rhyolite quaternary geochronology standard abstract we report results from a 40 ar 39 ar sanidine and ca tims 238 u 206 pb zircon dating study of eruption and crystal residence timescales of the alder creek rhyolite acr california extruded during the cobb mountain normal polarity subchron c1r 2n a 40 ar 39 ar acr sanidine date of 1 1850 0 0016 ma 2 external uncertainty determined relative to the astronomically dated a1 tephra sanidine is interpreted as the acr eruption age this age is supported by ca tims u pb zircon dating guided by la icpms trace element analyses titanium in zircon tizr thermometry and cathodoluminescence cl imaging using these data two compositionally distinct zircon populations were revealed pre acr group b zircon exhibit oscillatory zoning large positive ce and negative eu anomalies high incompatible trace element contents tizr temperatures of 650 c 750 c and th u disequilibrium corrected 238 u 206 pb dates of 1 38 1 24 ma these crystals are interpreted as antecrysts inherited from earlier intrusives in the geysers cobb mountain magma source region acr related group a zircon present as discrete grains and overgrowths on group b zircon display less intense cl with diffuse zoning and have less pronounced positive ce and negative eu anomalies lower incompatible trace element contents higher tizr temperatures that range up to 840 c and significantly younger dates the youngest group a dates yield a weighted mean of 1 1978 0 0046 ma 2 including systematic uncertainties that is interpreted as the mean age of zircon crystallization prior to eruption the 13 5 ka offset between the 40 ar 39 ar and 238 u 206 pb dates can be attributed to zircon magma residence time recognition of a young population of acr zircon is consistent with the 40 ar 39 ar eruption age which coincides with the astronomical age estimate for the cobb mountain subchron determined by correlating the oxygen isotope record of the giant piston core md972143 to the la93 1 1 orbital solution on the basis of independent radio isotopic and orbital forcing results we propose the refined age of 1 1850 0 0016 ma 2 external uncertainty for the quaternary acr 40 ar 39 ar sanidine standard

radioisotopic age constraints for glacial terminations ix and vii from aggradational sections of the tiber river delta in rome italy abstract buried sedimentary aggradational sections deposited between 800 ka and 600 ka in the tiber river coastal alluvial plain have been studied using borecores from around rome 40ar 39ar ages on sanidine and or leucite from intercalated tephra layers and paleomagnetic investigation of clay sections provide geochronologic constraints on the timing of aggradation of two alluvial sections demonstrating that they were deposited in response to glacio eustatic sea level rise caused by glacial terminations ix and vii 40ar 39ar age data indicate ages of 802 8 ka 1 full errors and 649 3 ka 1 full errors for glacial terminations ix and vii respectively providing a rare test beyond the range of u series dating for corals and speleothems 500 ka of the astronomically calibrated timescale developed for oxygen isotope records from deep sea cores

geochronology of the most recent activity in the sabatini volcanic district roman province central italy abstract the presence of young highly explosive volcanoes in the densely populated roman area central italy makes the evaluation of the long term volcanic hazard a crucial point the sabatini volcanic district svd part of the potassic quaternary roman province extends over an area of 1800 km2 including the city of rome here we report twenty six new 40ar 39ar age analyses of pyroclastic and lava units in order to put time constraints on the most recent svd eruptive activity i e post dating 400 ka as a groundwork for a detailed reconstruction of the whole volcano tectonic evolution integrated geochronological and field evidence shows that svd volcanism maintained a typical areal character through the whole history both effusive and explosive activity phases from different source areas and volcano tectonic settings overlapped in time and space while climactic phases migrated repeatedly through time in particular new geochronological data better constrain a climactic phase of activity at around 300 ka related to the bracciano volcano tectonic depression and the sacrofano caldera and point out that the most recent eruptive activity in the svd took place from time space clustered hydromagmatic centres at least up to 90 ka in addition we remark some parallelism among major activity phases in the svd and the nearby districts of the roman province with possible implications on quaternary regional tectonics finally new age data put constraints on tephrostratigraphic correlations through the apennine chain and the adriatic sea

bridging great earthquake doublets through silent slip on and off fault aftershocks of the 2006 kuril island subduction earthquake toggled by a slow slip on the outer rise normal fault of the 2007 great earthquake 1 the november 2006 great thrust earthquake of moment magnitude m w 8 3 on the plate boundary in the kuril chishima islands triggered as many vigorous normal faulting aftershocks in the outer rise region seaward of the trench as on fault aftershocks here we show that the aftershocks for a 40 day period preceding the january 2007 m w 8 1 event in the outer rise were less frequently observed than the rate expected by both the omori utsu formula and the epidemic type aftershock sequence etas model while at the same time were more frequent along the plate boundary we discuss whether such simultaneous quiescence and activation in the pervasive 2006 aftershocks might have been initiated by the onset of aseismic slip on the 2007 rupture plane the stable fault sliding in an elastic half space demonstrates progressive stress shadowing in the outer rise and stress loading along the plate boundary furthermore the rate and state dependent friction of dieterich quantitatively simulates temporal changes in seismic behavior the same trends of the anomalous activities last in both zones after the 2007 rupture which suggests that the slips continuously take place in the similar region on the fault throughout the period before and after the rupture the kuril case implies that temporal seismic quiescence in an aftershock sequence is useful in evaluating the possibility of the subsequent triggered event thus suggesting itself as a potential earthquake forecasting model together with pervasive earthquake clustering models

slip distribution of the 1963 great kurile earthquake estimated from tsunami waveforms the 1963 great kurile earthquake was an underthrust earthquake occurred in the kurile kamchatka subduction zone the slip distribution of the 1963 earthquake was estimated using 21 tsunami waveforms recorded at tide gauges along the pacific and okhotsk sea coasts the extended rupture area was divided into 24 subfaults and the slip on each subfault was determined by the tsunami waveform inversion the result shows that the largest slip amount of 2 8 m was found at the shallow part and intermediate depth of the rupture area large slip amounts were found at the shallow part of the rupture area the total seismic moment was estimated to be 3 9 1021 nm mw 8 3 the 2006 kurile earthquake occurred right next to the location of the 1963 earthquake and no seismic gap exists between the source areas of the 1963 and 2006 earthquakes

tephrostratigraphy of grotta del cavallo southern italy insights on the chronology of middle to upper palaeolithic transition in the mediterranean abstract the grotta del cavallo contains one of the most important stratification of mousterian uluzzian and final epigravettian tecnocomplexes its chronology is of paramount importance for understanding the timing of the transition between middle and upper palaeolithic in the mediterranean region as well as the demise of the neanderthal and the dispersal of the first anatomically modern humans through europe within the stratigraphy of the cave three different volcanic ash layers occur layer g fa and c ii they are located in the middle section of the mousterian layer g in between the mousterian and uluzzian layers layer fa and on top of the uluzzian horizons layer c ii the three tephra layers were chemically fingerprinted and correlated to well known and precisely dated widespread late pleistocene tephra markers specifically layer g fa and c ii were correlated to the x 6 108 7 0 9 ka y 6 45 5 1 0 ka and campanian ignimbrite 39 85 0 14 ka respectively these findings provide robust chronological points allowing to conclude that i the mousterian occupation of the cave took place after the fall of the sea level following the mis 5e high stand ii the mousterian uluzzian boundary can be dated to 45 5 1 0 ka and climatostratigraphically firmly placed at the transition between the greenland interstadial 12 gi12 greenland stadial 12 gs12 iii the uluzzian lasted for at least five millennial spanning the gs12 gi9 period and ended at beginning of the heinrich event 4

spatial relation between main earthquake slip and its aftershock distribution 1 we examine where aftershocks occur relative to the spatial distribution of the main shock slip using data from several recent large earthquakes no universal relation between high and low moment regions and high or low aftershock occurrence or vice versa is found we generally find that few and usually the smaller aftershocks occur in the high slip regions of the fault a notable exception to this being the great 1996 biak indonesia subduction zone earthquake in all cases aftershocks occur on favorably oriented planes of weakness in regions of increased postseismic stress generally they are clustered at both ends of faults but examples where aftershocks occur only at one end or where there is no clustering at the ends are found aftershock clusters are also found at the edge of unbroken barriers and regions of rapid transition from high to low slip within the main fault area we identify examples of geometrical and inhomogeneous barriers and sharp and dull stress concentrations rupture in the main shock is generally found to nucleate in the region of low slip or at the edge of high slip regions the 1996 biak earthquake again being the only exception nucleating in a very high slip region off fault aftershocks are found for all earthquakes in this study and they sometimes rupture the nodal plane conjugate to the main shock fault plane

the high resolution sequence stratigraphy and the mammal fossil record a test in the middle upper pleistocene deposits of the roman basin latium italy abstract in the campagna romana area pleistocene vertebrate fossil remains are preserved both in continental and marine sedimentary successions this fact favoured the identification of faunal complexes in agreement with the biochronologic setting proposed for the plio pleistocene large mammal faunas of the italian peninsula at the same time the detailed facies and sequence stratigraphic analyses carried out in the last years on such deposits have allowed establishment of a regional and local chronostratigraphic framework which sets some physical and temporal limits to the occurrence of faunal complexes in this light the study of the pleistocene deposits of the roman basin based on sequence stratigraphy and mammal biochronology approach can constitute a significant tool to test the relationships among physical stratigraphic units faunal complexes and faunal units in the examined area the fossiliferous levels are essentially found in transgressive fluvial and fluvio palustrine deposits filling incised valleys tst and in highstand barrier island lagoon deposits hst excluding some cases where bones show a probable exhumation process whole discovered mammal remains are mostly coeval with deposits containing them based on taphonomic considerations and on depositional and physical stratigraphic settings a correlation scheme among roman pleistocene sequence stratigraphic units local faunal complexes and italian mammal biochrons is proposed nevertheless many problems remain to be clarified before either the correlation between events and the geochronological framework or the significance and the biochronological value of each faunal assemblage can be considered as definitive

the history of the monti sabatini and alban hills volcanoes groundwork for assessing volcanic tectonic hazards for rome abstract the volcanic rocks of rome provide chronostratigraphic constraint that is of use to geologists archaeologists and paleontologists identifying the areal distribution of these rocks their mode of emplacement and a detailed chronology of the eruptive events also is crucial for assessing local natural hazards in a volcanic tectonic context and for recognizing whether the volcanoes may erupt again in the future we have identified and dated many of the volumetrically significant eruptive units from the monti sabatini and alban hills colli albani and propose a formalized volcanic stratigraphy for rome it is probable that seismic events triggered some eruptions as several ignimbrites from the two volcanoes have statistically indistinguishable ages following a 200 kyr period of dormancy that was coincident with a pulse of regional uplift the alban hills appears to have begun recently circa 45 ka a new eruptive cycle therefore accurate assessment of volcanic tectonic hazards and estimation of possible future volcanic activity is necessary for the safety of the five million people living near these volcanoes

paleomagnetism and geochronology of early middle pleistocene depositional sequences near rome comparison with the deep sea δ18o record abstract a sequence stratigraphic analysis was carried out on clastic coastal deposits ponte galeria formation pgf of the tiber river delta cropping out to the southwest of rome in order to correlate these sequences to pleistocene eustasy tectonic subsidence affected sedimentation but is distinguished from the glacio eustatic signal showing that the pgf consists of four depositional sequences that correlate to two fourth order cycles a paleomagnetic investigation of clay horizons deposited before and after the brunhes matuyama reversal combined with 40 ar 39 ar ages from a tuff horizon within the pgf constrain the timing of the relative sea level changes and allow us to tie it to the astronomically calibrated deep sea 18 o record the brunhes matuyama boundary in the pgf postdates a set of highstand systems tract sediments suggesting that the reversal occurs late in 18 o stage 19 this position is consistent with the recent study of deep sea cores by bassinot et al earth planet sci lett 126 1994 91 108 the assumption of a common continental stage marking the start of the middle pleistocene 18 o stage 22 in the mediterranean region is not supported by the tiber river sections which in our interpretation begin at stage 20

are rupture zone limits of great subduction earthquakes controlled by upper plate structures evidence from multichannel seismic reflection data acquired across the northern ecuador southwest colombia margin 1 subduction of the nazca plate beneath the ecuador colombia margin has produced four megathrust earthquakes during the last century the 500 km long rupture zone of the 1906 mw 8 8 event was partially reactivated by three thrust events in 1942 mw 7 8 1958 mw 7 7 and 1979 mw 8 2 whose rupture zones abut one another multichannel seismic reflection and bathymetric data acquired during the sisteur cruise show evidence that the margin wedge is segmented by transverse crustal faults that potentially correlate with the limits of the earthquake coseismic slip zones the paleogene neogene jama quininde and esmeraldas crustal faults define a 200 km long margin crustal block that coincides with the 1942 earthquake rupture zone subduction of the buoyant carnegie ridge is inferred to partially lock the plate interface along central ecuador however coseismic slip during the 1942 and 1906 earthquakes may have terminated against the subducted northern flank of the ridge we report on a newly identified manglares crustal fault that cuts transversally through the margin wedge and correlates with the limit between the 1958 and 1979 rupture zones during the earthquake cycle the fault is associated with high stress concentration on the plate interface an outer basement high which bounds the margin seaward of the 1958 rupture zone may act as a deformable buttress to seaward propagation of coseismic slip along a megathrust splay fault coseismic uplift of the basement high is interpreted as the cause for the 1958 tsunami we propose a model of weak transverse faults which reduce coupling between adjacent margin segments together with a splay fault and an asperity along the plate interface as controlling the seismogenic rupture of the 1958 earthquake

a great earthquake doublet and seismic stress transfer cycle in the central kuril islands temporal variations of the frictional resistance on subduction zone plate boundary faults associated with the stick slip cycle of large interplate earthquakes are thought to modulate the stress regime and earthquake activity within the subducting oceanic plate here we report on two great earthquakes that occurred near the kuril islands which shed light on this process and demonstrate the enhanced seismic hazard accompanying triggered faulting on 15 november 2006 an event of moment magnitude 8 3 ruptured the shallow dipping plate boundary along which the pacific plate descends beneath the central kuril arc the thrust ruptured a seismic gap that previously had uncertain seismogenic potential although the earlier occurrence of outer rise compressional events had suggested the presence of frictional resistance within minutes of this large underthrusting event intraplate extensional earthquakes commenced in the outer rise region seaward of the kuril trench and on 13 january 2007 an event of moment magnitude 8 1 ruptured a normal fault extending through the upper portion of the pacific plate producing one of the largest recorded shallow extensional earthquakes this energetic earthquake sequence demonstrates the stress transfer process within the subducting lithosphere and the distinct rupture characteristics of these great earthquakes illuminate differences in seismogenic properties and seismic hazard of such interplate and intraplate faults

the isc gem global instrumental earthquake catalogue 1900 2009 introduction abstract in this introductory article we give a general description of the isc gem global instrumental earthquake catalogue 1900 2009 we also provide the background for four further articles that describe the effort in collecting and digitizing parametric earthquake bulletin data as well as the methodologies developed to compute homogeneous earthquake parameters the result of the two and a half year project is a catalogue of approximately 20 000 large earthquakes covering 110 years with hypocentres and uncertainties computed using the same technique and velocity model we show that the overall homogeneity of the main earthquake parameters in the catalogue was achieved despite changes in instrumentation and routine measurement practices concurrent with developments in instrumental seismology from almost a ground level to its current state for each earthquake mw magnitude values and uncertainties were computed either based on available estimates of seismic moment or using new empirical relationships between mw ms and mb further important results of this project include the electronic availability of a considerable volume of seismic wave arrival time and amplitude measurements from early instrumental printed station bulletins these newly recovered amplitude measurements provided a basis for computation of many previously unavailable ms magnitudes with uncertainties in this article we describe why such a catalogue is required for a comprehensive assessment of global and regional seismic hazard we also describe other potential uses of the catalogue in many other fields of earth sciences we discuss the catalogue availability and lay out the plans of further development

the subsurface geology of rome sedimentary processes sea level changes and astronomical forcing abstract in this paper we present a reconstruction of the stratigraphic setting of the continental sedimentary sequences that were deposited by the paleo tiber river within the greater area of rome between 0 9 and 0 6 ma carried out through analyses of a large number of borehole data through palinspastic restoration of several cross sections we depict the original geometry of the sedimentary record that has been dislocated by intense tectonic activity linked to volcanism and we reconstruct the geologic and paleogeographic evolution of this area moreover we provide a complete review of the chronostratigraphic and magnetostratigraphic data reported in previous work and we extend paleomagnetic analyses to three new clay sections these geochronological constraints allow us to compare aggradation of the paleo tiber sedimentary successions with the 18o record evidencing a strict link between sedimentation and sea level changes in the rome area by doing so we provide a direct test on the timing of the sea level rise for mis 19 through mis 15 a record of data for which no equivalent exists in the literature

rupture process of the february 4 1965 rat islands earthquake the great rat islands underthrusting earthquake mw 8 7 of february 4 1965 represents subduction of the pacific plate beneath the north american plate along a 600 km segment of the western end of the aleutian islands body wave inversion techniques are used to determine the spatial and temporal heterogeneities associated with the rat islands earthquake we have deconvolved world wide standard seismograph network long period teleseismic p wave seismograms to obtain source time functions directivity associated with the three major pulses of moment release in the source time functions indicates a total source duration of 160 s unilateral rupture in the direction 300 fault length of 420 km and average rupture velocity of 2 5 km s the three pulses of moment release are located along the fault and these regions of high moment release are interpreted as asperities the first asperity extends from the epicenter to 100 km to the wnw this is the largest asperity and corresponds to a smooth pulse of moment release in the source time function with a duration of 50 s the second pulse of moment release is very jagged is less coherent between stations and is centered 200 km wnw of the epicenter the third pulse of moment release extends from 360 to 420 km wnw of the epicenter although the aftershock area is 600 km in length we can not resolve any moment release from the p waves beyond 420 km wnw of the epicenter the rat islands event was closely followed by a large tensional outer rise event on march 30 1965 ms 7 5 which is located oceanward of the largest moment release associated with the rat islands mainshock rupture detailed analysis of the p waves for this large outer rise event confine the depth extent to the upper 30 5 km of the crust the spatial and temporal association between the february 4 mainshock and the march 30 tensional outer rise event suggests the tensional event may have been triggered by the large displacement near the mainshock epicenter the overriding plate along the western aleutian subduction zone is laterally segmented into a series of rigid tectonic blocks separated by fault controlled canyons and extensional basins geist et al 1988 we suggest that the central undeformed parts of the blocks have the strongest coupling with the down going plate and hence are the sites of the largest moment release during an underthrusting earthquake the three asperities determined from the p waves correspond to the rat buldir and near tectonic blocks respectively hence the p wave seismic moment release of the rat islands earthquake is controlled by the lateral segmentation of the overriding plate

circum pacific seismic potential 1989 1999 the seismic potential for 96 segments of simple plate boundaries around the circum pacific region is presented in terms of the conditional probability for the occurrence of either large or great interplate earthquakes during the next 5 10 and 20 years i e 1989 1994 1989 1999 and 1989 2009 this study represents the first probabilistic summary of seismic potential on this scale and involves the comparison of plate boundary segments that exhibit varying recurrence times magnitudes and tectonic regimes presenting these data in a probabilistic framework provides a basis for the uniform comparison of seismic hazard between these differing fault segments as well as accounting for individual variations in recurrence time along a specific fault segment and uncertainties in the determination of the average recurrence time

paleoshoreline record of relative holocene sea levels on pacific islands abstract understanding the history of relative holocene sea levels on pacific islands is important for constraining fundamental geodynamic theories interpreting the environments of early human occupation sites and forecasting future environmental conditions on the islands an observational paleoshoreline record is provided by emergent paleoshoreline indicators formed at higher relative sea levels hence standing at higher elevations than modern counterparts emergent paleoshoreline notches in limestone seacliffs record paleo high tide levels and emergent paleoreef flats record paleo low tide levels whereas emergent paleobeachrock locally records paleo intertidal levels both paleonotches and paleoreefs occur along the coasts of high standing islands exposing volcanic bedrock and uplifted reef complexes but low lying coralline atolls lack sufficient relief to preserve paleonotches controls on relative holocene sea level include global eustatic and regional hydro isostatic changes in ambient sea level relative to island landmasses and shifts in the elevations of islands relative to sea level caused by thermal subsidence of the oceanic lithosphere or thermally rejuvenated loci of hotspot volcanism by flexure of the lithosphere under the load of growing volcanic edifices hawaii samoa society islands by arching of the lithosphere over trench forebulges loyalty islands niue bellona rennell and by tectonism within forearc belts between active volcanic chains and trenches mariana islands tonga vanuatu the dominant pattern of relative sea level change where not overprinted by local tectonism or lithospheric flexure was a uniform early holocene rise in eustatic sea level followed by a regionally variable late holocene hydro isostatic drawdown in sea level the resultant was a mid holocene highstand in relative sea level that affected the development of shoreline morphology throughout the tropical pacific ocean the earliest human migrations into intra oceanic island groups of both the northwestern and southwestern pacific ocean followed close on the heels of the mid holocene sea level highstand and took advantage of newly attractive coastal environments engendered by sea level drawdown the effects of the mid holocene highstand were modified to varying degrees in different island groups by geodynamic uplift or subsidence

reassessing the sedimentary deposits and vertebrate assemblages from ponte galeria area rome central italy an archive for the middle pleistocene faunas of europe abstract the ponte galeria area is part of the larger campagna romana and hosted the inner delta of the tiber river since the beginning of the middle pleistocene allowing the deposition of a series of glacio eustatically controlled fluvial lacustrine sedimentary successions very rich in fossil mammal remains due to its richness of fossiliferous sites this area represents an exceptional archive for the study and understanding of the biochronological paleobiogeographical and paleoenvironmental evolution during the middle pleistocene in europe a series of recent studies using the 40 ar 39 ar ages of tephra intercalated within the sedimentary deposits provided a large amount of geochronological data linking these aggradational successions to the different marine isotopic stages in the present paper we present a complete review of the faunal assemblages identified so far in the ponte galeria area and we constrain the ages of the faunal units by placing them within the new chronostratigraphic scheme by means of this interdisciplinary approach we re calibrate the mammal assemblages collected in this area and reconstruct a new biochronological and paleobiogeographic framework for the italian peninsula during the middle pleistocene in particular we distinguish six well defined biochronological units slivia ponte galeria isernia fontana ranuccio torre in pietra and vitinia in the studied area covering a time span of ca 0 6 myr from the early to middle pleistocene transition to at least marine isotope stage 7 this period is characterized in europe by the mid pleistocene revolution global climate change and by the transition at first between villafranchian and galerian taxa and later between the galerian and aurelian ones according to the reviewed data the persistence of villafranchian taxa is recorded in italy at the beginning of the middle pleistocene probably due to favorable climatic conditions or delay in dispersal of competitive species while the faunal turnover between the villafranchian and galerian species was completed around 0 6 0 5 ma during this time bos primigenius and other temperate warm taxa were widespread in the peninsula earlier than in western europe in contrast typical aurelian taxa usually related with temperate cold climatic conditions ursus spelaeus megaloceros giganteus occurred later in italy than in other western european areas

space time variation of mixed layer properties heat and salt fluxes and ice melt in the newfoundland marginal ice zone oceanographic data collected in the newfoundland marginal ice zone in march 1992 are analyzed to study the variation of mixed layer properties across the ice zone the mixed layer depth decreases from 80 m in the interior of the pack ice to 25 m at the eastern ice edge over a distance of 120 km in the open ocean without ice cover the depth is considerably greater 150 200 m the temperature under the pack ice is near freezing a sharp increase in both the temperature and salinity occurs across the ice edge the variation of the mixed layer properties is simulated by integrating a one dimensional bulk mixed layer model coupled to sea ice from november 1991 to march 1992 the initial ocean conditions are obtained from an objective analysis of archived data of november 1991 the forcings are 6 hourly meteorological data from the european centre for medium range weather forecasts ice concentration and thickness are treated as prescribed functions of time extracted from daily ice maps since ice in the area is not locally formed the model simulation is in good agreement with the observations from the model results a detailed analysis of the roles of wind stress ice melt surface cooling and shortwave radiation in the water mass transformation of the upper ocean is carried out there are large differences in the melt rate and water ice heat flux between the times when ice enters the shelf and after the water has been cooled by the ice to near freezing 15 20 cm d 1 and 500 700 wm 2 and 0 2 cm a 1 and 20 50 wm 2 respectively a large portion of the heat in the water column is expended for ice melting from january to march calculations that use surface data such as surface wind and sea surface temperature without considering ice melt can underestimate the net ocean to air heat flux especially at the eastern ice edge in march

the 1957 great aleutian earthquake the 9 march 1957 aleutian earthquake has been estimated as the third largest earthquake this century and has the longest aftershock zone of any earthquake ever recorded 1200 km however due to a lack of high quality seismic data the actual source parameters for this earthquake have been poorly determined we have examined all the available waveform data to determine the seismic moment rupture area and slip distribution these data include body surface and tsunami waves using body waves we have estimated the duration of significant moment release as 4 min from surface wave analysis we have determined that significant moment release occurred only in the western half of the aftershock zone and that the best estimate for the seismic moment is 50 100 1020 nm using the tsunami waveforms we estimated the source area of the 1957 tsunami by backward propagation the tsunami source area is smaller than the aftershock zone and is about 850 km long this does not include the unalaska island area in the eastern end of the aftershock zone making this area a possible seismic gap and a possible site of a future large or great earthquake we also inverted the tsunami waveforms for the slip distribution slip on the 1957 rupture zone was highest in the western half near the epicenter little slip occurred in the eastern half the moment is estimated as 88 1020 nm or m w 8 6 making it the seventh largest earthquake during the period 1900 to 1993 we also compare the 1957 earthquake to the 1986 andreanof islands earthquake which occurred within a segment of the 1957 rupture area the 1986 earthquake represents a rerupturing of the major 1957 asperity

multi segment earthquakes and tsunami potential of the aleutian megathrust abstract large to great earthquakes and related tsunamis generated on the aleutian megathrust produce major hazards for both the area of rupture and heavily populated coastlines around much of the pacific ocean here we use paleoseismic records preserved in coastal sediments to investigate whether segment boundaries control the largest ruptures or whether in some seismic cycles segments combine to produce earthquakes greater than any observed since instrumented records began virtually the entire megathrust has ruptured since ad1900 with four different segments generating earthquakes m8 0 the largest was the m9 2 great alaska earthquake of march 1964 that ruptured 800 km of the eastern segment of the megathrust the tsunami generated caused fatalities in alaska and along the coast as far south as california east of the 1964 zone of deformation the yakutat microplate experienced two m8 0 earthquakes separated by a week in september 1899 for the first time we present evidence that earthquakes 900 and 1500 years ago simultaneously ruptured adjacent segments of the aleutian megathrust and the yakutat microplate with a combined area 15 greater than 1964 giving an earthquake of greater magnitude and increased tsunamigenic potential

a new age within mis 7 for the homo neanderthalensis of saccopastore in the glacio eustatically forced sedimentary successions of the aniene river valley rome abstract field observations as well as borehole sedimentological and geochronologic data allow us to reconstruct the geologic setting of the aniene river valley in northern rome framing it within the recently recognized picture of temporally constrained glacio eustatically forced aggradational successions of this region the sedimentary successions cropping out in this area include those described in the literature of the early 20th century in saccopastore where two skulls of homo neanderthalensis were recovered based on the geometry elevation and sedimentologic features of the investigated sedimentary deposits the stratigraphic record of saccopastore is correlated with the aggradational succession deposited in response to sea level rise during glacial termination iii at the onset of mis 7 i e 250 ka corresponding to the local vitinia formation as opposed to previous correlation with the mis 5 interglacial and a locally defined tyrrhenian stage 130 ka this previous attribution was based on the interpretation of the sedimentary succession of saccopastore occurring between 15 and 21 m a s l as a fluvial terrace formed around 130 ka during the riss wurm interglacial ca 6 m above the present day alluvial plain of the aniene river in contrast to this interpretation a 40ar 39ar age of 129 2 ka determined for this study on a pyroclastic flow deposit intercalated in a fluvial lacustrine sequence forming a terrace 37 m a s l near the coast of rome constrains the aggradational succession in this area to mis 5 precluding the occurrence of an equivalent fluvial terrace at lower elevation in the inland sector of saccopastore we therefore interpret the stratigraphic record of saccopastore as the basal portion of the aggradational succession deposited in response to sea level rise during mis 7 whose equivalent fluvial terrace occurs around 55 m a s l in this region we also review the published paleontological and paleoethnological records recovered in saccopastore and demonstrate their compatibility with the faunal assemblages and lithic industries occurring in the sedimentary deposits of the vitinia formation while we show the lack of any unequivocal late pleistocene mis 5 affinity we therefore propose that the chronostratigraphic position of the saccopastore deposits containing the two skulls should be around 250 000 years as opposed to a previously preferred age of 130 000 years the revised age makes these skulls the oldest italian occurrences of h neanderthalensis and provides evidence for a substantially coeval appearance and evolutionary path with respect to central northern europe

tephro stratigraphy and the age of ancient southern italian acheulean settlements the sites of loreto and notarchirico venosa basilicata italy the stratigraphic and chronological positions of the palaeolithic sites of loreto and notarchirico have been revised by adopting a litho tephro stratigraphic approach applied to the deposits of the venosa basin relating them to the evolution of volcanic eruptions of mount vulture the notarchirico tephra dated to around 640 ka is a geological marker of paramount importance in the study of ancient southern italia settlements and identifies the assemblage from level f at notarchirico as one of the oldest acheulean in europe

analysis of seismotectonic processes in subduction zones from the standpoint of a keyboard model of great earthquakes abstract the block like structure of the frontal part of the overriding plate in the subduction zones of the aleutian and kurile trenches is described both block interaction with a subducted plate and reciprocal interblock actions are considered these interactions are reflected 1 1 in the seismic regime 2 2 in the distribution of the sources of great earthquakes 3 3 in the focal mechanisms of shallow earthquakes the mechanical keyboard model proposed incorporates these interactions this model is the basis of a mathematical description of the subsequent slow accumulation of strain and fast seismic release in ajacent blocks in the course of their seismotectonic evolution some results of numerical simulations are given they are in good agreement with the main features of distribution of great earthquakes in space and time for the kuriles japan and central and south america keyboard analysis of seismic cycles can be considered as a mechanical basis for long term prediction of great earthquakes which allows the distinguishing of a number of new earthquake precursors

correlation of fluviodeltaic aggradational sections with glacial climate history a revision of the pleistocene stratigraphy of rome volcanic horizons interbedded with fluviodeltaic clastic sediments of the tiber and fosso galeria river valleys near rome provide a unique opportunity to date five middle pleistocene fining upward aggradational sections 40 ar 39 ar ages from the interbedded volcanic beds illustrate that aggradation occurred on an approximate 100 k y cycle and was initiated by sea level rise associated with glacial melting the age constraint additionally shows that aggradation occurs rapidly in response to sea level change and thus ages from volcanic strata within the aggradational sections provide high resolution constraint on the timing of relative sea level rise the established chronology is consistent with other glacial proxies and their radioisotopically or orbitally based time scales for the timing of glacial terminations vi and v but is significantly older than most records for the timing of termination iii ultimately the age of each termination should be determined by radioisotopic means and to that end the work here shows that fluviodeltaic sedimentology provides valuable information for middle pleistocene time scale calibration

a flying start then a slow slip the human tragedy caused by the sumatra andaman earthquake moment magnitude 9 3 on 26 december 2004 and its companion nias earthquake moment magnitude 8 7 on 28 march 2005 is difficult to comprehend these earthquakes the largest in 40 years have also left seismologists searching for the words and tools to describe the enormity of the geological processes involved four papers in this issue discuss aspects of a rupture process of surprising complexity the first such event to test the sensitivity and range of many new technologies a surprising feature of the earthquake is that after the initial rapid rupture subsequent slip of the plate interface occurred with decreasing speed toward the north

modeling the thermodynamics of a sea ice thickness distribution 2 sea ice ocean interactions in this paper we examine the coupling of an ice thickness distribution model with an ocean mixed layer model the annual cycle of the modeled mixed layer temperature salinity and depth are compared to observations from the drifting ice stations of the arctic ice dynamics joint experiment aidjex the role of the ice thickness distribution in determining the ice ocean coupling is examined we find that the ice thickness distribution is important for the exchange of heat salt and fresh water between the ice and the ocean especially with regard to the effects of thin first year ice several different parameterizations of the ice ocean turbulent heat exchange are compared the results indicate that the storage of heat in the ocean mixed layer is an important physical process for determining the annual average ice thickness double diffusion and the stabilizing effects of meltwater also impact the exchange of heat between the ocean and ice cover questions remain as to the relative importance of these processes and their accurate parameterization in ice ocean coupled models

oblique subduction and collision forearc tectonics of the kuril arc the tectonics of the southwestern kuril arc are a result of the oblique subduction of the pacific plate at the kuril trench in association with forearc sliver migration caused by the oblique subduction collision tectonics occur at the leading margin of the sliver and tensional tectonics take place at the tapering margin as a result of the collision a deep crustal section of island arc is observed at the leading margin of the forearc sliver tectonics of the kuril arc related to oblique subduction are different from those of the western sunda arc where backarc spreading occurs at the leading margin this difference is due to margin morphology of the oblique subduction zone