intermediate term predictions of earthquakes in italy algorithm m8 large earthquakes in italy are preceded by a specific seismic activation which could be diagnosed by a reproducible intermediate term earthquake prediction method a modification for lower seismic rate areas of the algorithm known as m8 keilis borok and kossobokov 1990 use has been made of the pfg ing catalog of earthquakes compiled on a regular basis to determine areas and times of increased probability for occurrences of m 6 earthquakes in retroactive simulation of forward prediction for the period 1972 1995 both the 1976 friuli m 6 1 and the 1980 irpinia m 6 5 earthquakes are predicted in the experiment where priority magnitude scale is used the times of increased probability for a strong earthquake to occur tips occupy less than a quarter of the total magnitude space time domain and are rather stable with respect to positioning of circles of investiga tion successful stability tests have been made considering a recently compiled catalog cci97 peresan et al 1997 in combination with the cn algorithm results costa et al 1996 the spatio temporal uncertainty of the prediction could be reduced to 5 the use of m8 for the forward prediction requires the computations to be repeated each half year using the updated catalog

diagnosis of time of increased probability of strong earthquakes in different regions of the world algorithm cn abstract an algorithm for intermediate term earthquake prediction is suggested which allows diagnosis of the times of increased probability of strong earthquakes tips tips are declared for the time period of one year and an area with linear dimensions of a few hundred kilometers and can be extended in time the algorithm is based on the following traits of an earthquake flow level of seismic activity its temporal variation clustering of earthquakes in space and time their concentration in space and their long range interaction the algorithm is normalized so that it can be applied in various regions without readaptation tips diagnosed by the algorithm precede 80 of strong earthquakes and take on average 24 of the total time

eddy zonal flow feedback in the southern hemisphere abstract the variability of the zonal mean zonal wind in the southern hemisphere is studied using eof analysis and momentum budget diagnostics of ncep reanalysis data 1978 97 the leading eof of the zonal mean zonal wind is well separated from the remaining eofs and represents the north south movement of the midlatitude jet analysis of the momentum budget shows that a positive feedback between the zonal mean wind anomalies and the eddy momentum fluxes accounts for the unusual persistence of eof1 and plays an important role in the selection of the leading eof of midlatitude variability further analysis also shows a propagating feedback common to both eof1 and eof2 which is responsible for the poleward drift of wind anomalies with time the observations support the following feedback mechanism anomalous baroclinic wave activity is generated at the latitude of anomalous temperature gradient that by thermal wind coincides with the latitude of the anomalous zonal jet the net propagation of baroclinic

climatic records over the past 30 ka from temperate australia a synthesis from the oz intimate workgroup temperate australia sits between the heat engine of the tropics and the cold southern ocean encompassing a range of rainfall regimes and falling under the influence of different climatic drivers despite this heterogeneity broad scale trends in climatic and environmental change are evident over the past 30 ka during the early glacial period 30 22 ka and the last glacial maximum 22 18 ka climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important murray darling basin the temperate region at this time appears to be dominated by expanded sea ice in the southern ocean forcing a northerly shift in the position of the oceanic fronts and a concomitant influx of cold water along the southeast including tasmania and southwest australian coasts the deglacial period 18 12 ka was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records while there is some evidence for climatic reversals e g the antarctic cold reversal in high resolution marine sediment cores through this period the high spatial density of holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after 12 ka presumably in response to increasing temperature while hydrological records reveal spatially heterogeneous hydro climatic trends patterns after 6 ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by the el nino southern oscillation

eddies and the annular modes of climate variability the dominant modes of month to month varia tion in the troposphere are realistically simulated in a gen eral circulation model whose lower boundary is prescribed with realistic topography and seasonally varying climato logical sea surface temperatures in both hemispheres these internal modes describe a nearly zonally symmetric north south shifting of the zonal jets as anomalous westerlies vac illate between high 50 60 a nd low 30 40 latitudes the eddy structures evolve with the jets and the corre sponding eddy momentum forcings support the shifts in jet position stationary synoptic wave variations mainly ac count for the total eddy forcings in the northern south ern hemisphere pronounced eddy variations occur over the north atlantic sector

intraseasonal oscillations in the global atmosphere part ii southern hemisphere abstract in part ii of this two part article we complete the systematic examination of oscillatory modes in the global atmosphere by studying 12 years of 500 mb geopotential heights in the southern hemisphere as in part i for the tropics and northern hemisphere extratropics the data were band pass filtered to focus on intraseasonal is phenomena and spatial eofs were obtained the leading principal components were subjected to singular spectrum analysis ssa in order to identify nonlinear is oscillations with high statistical confidence in the southern hemisphere the dominant mode has a period of 23 days with spatial patterns carried by the second and third winter eof of the is band it has a zonal wavenumber four structure the 40 day mode is second and dominated by wavenumbers three and four while a 16 day mode is too weak to separate its spatial behavior from the previous two the is dynamics in the southern hemisphere is more complex and dominated by shorter wavenumbers than the northern

streamline based simulation of solute transport we propose streamline based simulation as a possible alternative to particle tracking for modeling solute transport like particle tracking the pressure field is computed on an underlying grid using conventional techniques the flow velocity at cell edges is then computed using darcy s law and this information is used to trace streamlines throughout the domain in particle tracking mass is transported by moving particles along streamlines in the method we describe a one dimensional conservation equation is solved numerically along each streamline if the flow field changes the solute concentration is mapped onto the underlying grid and the streamlines are recomputed the concentration is then mapped back onto the new streamlines and the simulation proceeds as before the method is suited for modeling advectively dominated multispecies transport in heterogeneous aquifers we illustrate the streamline approach with synthetic example problems in fully saturated confined aquifers conservative sorbing and decaying tracer a four component radioactive decay chain and saltwater intrusion where the flow field changes with time where possible we compare the results with analytical solutions and results from particle tracking codes

delineation of the north central italian upper mantle anomaly the italian peninsula is the focus of intense deformational tectonic activity it is underlain by mantle material whose inferred relatively anomalous properties1 2 are not inconsistent with the seismic volcanic and thermal activity that is manifested in this region the most effective geophysical tool for mapping the structure of the uppermost 200 300 km of the earth is the observation and analysis of seismic surface wave dispersion on a regional scale here we synthesize the interpretations of rayleigh wave dispersion measurements made by several authors each for different parts of north central italy3 8 to delineate the lateral extent of the upper mantle anomaly in this region

prediction of the occurrence of related strong earthquakes in italy in the seismic flow it is often observed that a strong earthquake se is followed by related strong earthquakes rses which occur near the epicenter of the se with origin time rather close to the origin time of the se the algorithm for the prediction of the occurrence of a rse has been developed and applied for the first time to the seismicity data of the california nevada region and has been successfully tested in several regions of the world the statistical significance of the result being 97 to date it has been possible to make five successful forward predictions with no false alarms or failures to predict

stochastic synthesis of earthquake catalogs a model of earthquake occurrence is proposed that is based on results of statistical studies of earthquake catalogs we assume that each earthquake generates additional a probability that depends on time as t 1 this assumption together with one regarding the independence of branching events on adjacent branches of the event tree is sufficient to permit the generation of complete catalogs of earthquakes that have the same time magnitude statistical properties as real earthquake catalogs if is about 0 5 the process generates sequences that have statistical properties similar to those for shallow earthquakes many well known relations are reproduced including the magnitude frequency law omori s law of the rate of aftershock and foreshock occurrence the duration of a recorded seismic event versus its magnitude the self similarity or lack of scale of rate of earthquake occurrence in different magnitude ranges etc a value of closer to 0 8 or 0 9 seems to simulate the statistical properties of intermediate and deep shocks a formula for seismic risk prediction is proposed and the implications of the model for risk evaluation are outlined the possibilities of the determination of long term risk from real or synthetic catalogs that have the property of self similarity are dim

southern hemisphere circulation features associated with el nino southern oscillation events abstract composite seasonal mean and anomaly fields prepared from operational numerical analyses have been used to describe the southern hemisphere sh circulation features associated with el nino southern oscillation enso events the period of analyses available 1972 83 has limited the composites to include only three enso events the reliability and stability of the composites has been tested using multiple permutation methods and by comparison with the results obtained using a longer period 1950 79 of sh rawinsonde station data in the sh winter a weak equivalent barotropic wavetrain pattern of anomalies extends over australia and the south pacific ocean to south america this wavetrain pattern is quite variable in amplitude and location between enso events although it is more stable over the subtropical pacific in the sh summer the circulation anomalies are more zonally symmetric with increased height at low and high latitudes and decreased height in middle latitudes the circulation anoma

on intermediate term earthquake prediction in central italy the time of increased probability tip for the occurrence of a strong earthquake is determined in central italy this is done with an algorithm that has been successfully applied in other regions of the world algorithm cn from the initials of california and nevada where the first diagnoses of tips were made the use of normalized functions allows direct application of the orginal algorithm to the new region being studied without anyad hoc adjustment of the parameters

forecasting strong aftershocks in earthquake clusters from northeastern italy and western slovenia abstract in this study we propose an analysis of the earthquake clusters that occurred in north eastern italy and western slovenia from 1977 to today given a mainshock generating alarm in the population we are interested in forecasting if a similar magnitude earthquake will follow we classify the earthquake clusters associated with mainshocks of magnitude mm into two classes if the strongest aftershock has a magnitude mm 1 swarms or large aftershock seismic sequences as type a otherwise smaller aftershocks seismic sequences as type b a large aftershock following a main shock can cause significant damages to already weakened buildings and infrastructures so a timely advisory information to the civil protection is of great interest for effective decision making for the first time we applied to a new catalogue a pattern recognition algorithm for cluster type forecasting that we developed for all italy gentili and di giovambattista 2017 thanks to the lower completeness magnitude of the local ogs catalogue compared to the national one and to a new version of the algorithm we were able to lower the threshold of the clusters mainshocks magnitude from 4 5 to 3 7 the method has been validated by rigorous statistical tests we tested the algorithm on the 1976 highly destructive earthquake cluster mainshock magnitude 6 5 the strongest in the last 80 years in the region and we retrospectively forecasted it as an a cluster successful results were obtained also on other three smaller earthquake clusters in 2019

intermediate term prediction of occurrence times of strong earthquakes pattern recognition procedures for infrequent events are adapted to the problem of identifying patterns of clustering of small and intermediate scale seismicity before large earthquakes identification procedures derived from analysis of large california and nevada earthquakes yield a high success rate when applied to other parts of the world

relationships between low frequency variability in the southern hemisphere and sea surface temperature anomalies abstract long term trends and interannual variations of circulation anomalies in the southern hemisphere are examined using the national centers for environmental prediction national center for atmospheric research reanalysis from 1949 to 1998 the changes in planetary circulation regimes are linked to global sea surface temperature anomalies sstas empirical orthogonal function eof analysis was performed on 500 hpa height anomalies the leading mode eof1 shows a strong zonal symmetry with a phase reversal between height anomalies in high and midlatitudes apart from zonal symmetry a zonal wavenumber 3 is evident with three centers located in three southern oceans in the low frequency band with fluctuations longer than 60 months eof1 is associated with the second rotated eof mode of sstas with positive loadings over three southern oceans and negative loadings in the north pacific and the north atlantic the next two modes are the pacific south american psa patterns they depict wave 3 patterns in

pi forecast for the sichuan yunnan region retrospective test after the may 12 2008 wenchuan earthquake the may 12 2008 wenchuan ms 8 0 mw 7 9 earthquake occurred in the middle part of the north south seismic zone in central west china being one of the greatest thrust events on land in recent years to explore whether there were some indications of the increase of strong earthquake probabilities before the wenchuan earthquake we conducted a retrospective forecast test applying the pattern informatics pi algorithm to the earthquakes in the sichuan yunnan region since 1992 a regional earthquake catalogue complete to ml 3 0 from 01 01 1977 to 15 06 2008 was used a 15 year long sliding time window was used in the pi calculation with anomaly training time window and forecast time window both set to 5 years with a forecast target magnitude of ms 5 5 the roc test shows that the pi forecast outperforms not only random guess but also the simple number counting approach based on the clustering hypothesis of earthquakes the ri forecast hotspots can be seen in the region of the northern longmenshan fault which is responsible for the wenchuan earthquake however when considering bigger grid size and higher cutoff magnitude such hotspots disappear and there is very little indication of an impending great earthquake

premonitory seismicity patterns in a platform region ardennes rhenish and brabant massifs lower rhine graben abstract this paper tests the similarity between premonitory seismicity patterns in active seismic belts and in a platform area of low seismicity this is of obvious theoretical interest as part of the general problem of similarity in geodynamic processes of different scales from a more practical point of view the prediction of earthquakes in platform areas such as the lower rhine graben is important as the possible damage from earthquakes in this area is rapidly increasing because of the construction of high risk objects such as dams and nuclear power plants and the increase of vulnerability of many common structures and lifelines

observed relationships between the el nino southern oscillation and the extratropical zonal mean circulation abstract there is increasing evidence indicating that the climate response to variations in the el nino southern oscillation enso includes not only thermally forced zonal wind anomalies in the subtropics but also eddy driven zonal wind anomalies that extend into the mid high latitudes of both hemispheres in this study new insights into the observed seasonally varying signature of enso in the extratropical zonal mean circulation are provided and the associated linkages with the dominant patterns of extratropical variability are examined the zonal mean extratropical atmospheric response to enso is characterized by two principal features an equivalent barotropic dipole in the southern hemisphere sh zonal mean zonal flow with centers of action located near 40 and 60 during austral summer and a weaker but analogous dipole in the northern hemisphere nh with centers of action located near 25 and 45 during early and late boreal winter both structures are accompanied by eddy momentum flux ano

annular modes in the extratropical circulation part i month to month variability the leading modes of variability of the extratropical circulation in both hemispheres are characterized by deep zonally symmetric or annular structures with geopotential height perturbations of opposing signs in the polar cap region and in the surrounding zonal ring centered near 458 latitude the structure and dynamics of the southern hemisphere sh annular mode have been extensively documented whereas the existence of a northern hemisphere nh mode herein referred to as the arctic oscillation ao has only recently been recognized like the sh mode the ao can be defined as the leading empirical orthogonal function of the sea level pressure field or of the zonally symmetric geopotential height or zonal wind fields in this paper the structure and seasonality of the nh and sh modes are compared based on data from the national centers for environmental prediction national center for atmospheric research reanalysis and supplementary datasets the structures of the nh and sh annular modes are shown to be remarkably similar not only in the zonally averaged geopotential height and zonal wind fields but in the mean meridional circulations as well both exist year round in the troposphere but they amplify with height upward into the stratosphere during those seasons in which the strength of the zonal flow is conducive to strong planetary wave mean flow interaction midwinter in the nh and late spring in the sh during these active seasons the annular modes modulate the strength of the lagrangian mean circulation in the lower stratosphere total column ozone and tropopause height over mid and high latitudes and the strength of the trade winds of their respective hemispheres the nh mode also contains an embedded planetary wave signature with expressions in surface air temperature precipitation total column ozone and tropopause height it is argued that the horizontal temperature advection by the perturbed zonal mean zonal wind field in the lower troposphere is instrumental in forcing this pattern a companion paper documents the striking resemblance between the structure of the annular modes and observed climate trends over the past few decades

diagnosis of time of increased probability tip for volcanic earthquakes at mt vesuvius the possibility of intermediate term earthquake prediction at mt vesuvius by means of the cn algorithm is explored cn was originally designed to identify the times of increased probability tips for the occurrence of strong tectonic earthquakes with magnitude m m0 within a region a priori delimited here the cn algorithm is applied for the first time to the analysis of volcanic seismicity the earthquakes recorded at mt vesuvius during the period from february 1972 to june 2004 are considered and the magnitude threshold m0 selecting the events to be predicted is varied within the range 3 0 3 3 satisfactory prediction results are obtained by retrospective analysis when a time scaling is introduced in particular when the length of the time windows is reduced by a factor 2 5 3 with respect to the standard version of cn algorithm more than 90 of the events with m m0 occur within the tip intervals with tips occupying about 30 of the total time considered the control experiment seismic history demonstrates the stability of the obtained results and indicates that the cn algorithm can be applied to monitor the preparation of impending earthquakes with m 3 0 at mt vesuvius

temporal changes in the cumulative piecewise gradient of a variant of the gutenberg richter relationship and the imminence of extreme events abstract it is generally found that the relative frequencies of occurrence of earthquakes of different magnitudes in seismogenic zones have a power law distribution for a long term dataset the overall slope of this logarithmically transformed distribution is usually indicated by a best fit straight line and expressed as a b value this slope is stable and normally lies between 0 8 and 1 2 the actual value depending on the region examined and the threshold selected for data completeness the linearity of the distribution can be used to make statistical inferences about the potential for larger events over the long run and with appropriate reservations may even be extrapolated to magnitudes that are beyond recent experience we suggest the same information can also be viewed over shorter intervals in terms of an empirical piecewise distribution with relative frequencies of occurrence at adjacent magnitude steps controlling the local slope of the distribution an emergence through time of an excess number of lower magnitude earthquakes causes temporal changes to appear in the low end piecewise gradients of this distribution a marked excursion away from an overall uniform trend for the particular zone may be indicative of an imminent larger event on two separate occasions in 1982 and 1997 such temporal variations were seen in the magnitude distributions of sequences of events near tobago west indies and used to anticipate subsequent damaging mainshocks the recognition of temporal departures from overall linearity of the magnitude frequency relation in a suitable dataset may thus provide an evidential element that can contribute to earthquake forecasting this phenomenological approach was used in the analysis of the neic global dataset of earthquakes of magnitude 6 1 and bigger for the period 1973 2003 to explore its wider applicability trends in the piecewise gradients of the global data were interpreted as pointing to an imminent great earthquake perhaps exceeding magnitude 8 5 such an event did occur shortly afterwards in the form of the great sumatran earthquake of 2004 12 26 following that event global magnitude production continued to exhibit sharp imbalances in the lower magnitude bins indicating that another similar event was likely the second sumatran earthquake on 2005 03 28 satisfied that projection since that time a magnitude production imbalance persists in the global dataset suggesting the system could be poised to output an earthquake or earthquakes in the magnitude range 8 6 9 0 or even greater this contribution describes the piecewise gradient approach and examines its application to global earthquake data

construction of a seismotectonic model the case of italy procedures for constructing a seismotectonic model of italy designed to be used as a basis for hazard assessment are described the seismotectonic analysis has essentially been based on a gis aided cross correlation of three data sets concerning the 3 d structural model of italy and surrounding areas the space distribution of historical and present seismicity the kinematic model of the central mediterranean region referred to the last 6 ma and including the available information on the present day plate motion and stress field the seismicity pattern in the study area is controlled by a quite complex geodynamic framework which includes continent continent convergence alps and dinarides with development of a neutral arc bordering the plate margins plate divergence across margins characterized by passive slab sinking northern apennines and calabrian arc with development of backarc basins northern tyrrhenian sea and southern tyrrhenian sea flanked by forelandward migrating thrust belt foredeep systems plate divergence across a margin previously characterized by lithosphere sinking and afterwards discharged from the subducted slab southern apennines with development of quite peculiar rift processes within the inactive thrust belt transpression northern sicily due to the combined effect of plate convergence africa europe and high rate flexure hinge retreat of an intervening plate adria microplate with high angles between the respective slip vectors intraplate strain partition and fault activity mainly combined strike slip and thrust motions possibly in correspondence of inverted structures the results of the seismotectonic analysis are synthesized in a zonation of italy in which every delimited zone corresponds to the surface projection of a kinematically homogeneous segment of a seismogenic fault system in cornell type hazard evaluations every polygon should be considered as a homogeneous source zone seat of randomly distributed earthquakes a homogeneous mechanical behaviour of an entire zone and a random earthquake distribution within a single source zone obviously represent oversimplified assumptions since every zone includes one or more master fault segments responsible for the greatest events in the area and several second order associated faults responsible for the background minor seismicity therefore major faults and background seismicity should be treated separately nevertheless the oversimplified assumption of homogeneous seismic zones was the price the authors consciously paid to produce in a reasonably short time a homogeneous product relative to the entire national territory suitable for earthquake hazard evaluation and for decisions regarding risk mitigatiton

diagnosis of time of increased probability of strong earthquakes in the jordan dead sea rift zone abstract we have explored the possibility of intermediate term earthquake prediction in the jordan dead sea rift region using the cn algorithm keilis borok et al 1988 this algorithm is designed to identify the time of increased probability tip of the occurrence of strong earthquakes defined by the conditionm m0 where m is the earthquake magnitude and m0 is a numerical threshold chosen for the considered region the area under diagnosis includes israel most of lebanon and the eastern parts of jordan and syria three strong earthquakes defined by the condition m0 5 occurred in this area during the period july 1964 june 1990 by applying the cn algorithm with unchanged standard parameters we found that two of the strong earthquakes were within the range of corresponding tip intervals these intervals extend far beyond the time of the occurrence of the strong earthquakes and represent about 40 5 of the total time however the tip duration is considerably reduced to about 12 9 of the total time when the threshold of the tip termination rule is slightly changed although this a posteriori change violates the formal standard application of the cn algorithm the results seem to be encouraging since false alarms did not appear at random and the excessive tip duration has a simple and rather obvious explanation however it seems that the conditions for the determination of tips in the cn algorithm should be modified accordingly

reverse tracing of short term earthquake precursors abstract we introduce a new approach to short term earthquake prediction named reverse tracing of precursors rtp since it considers precursors in reverse order of their appearance first we detect the candidates for the short term precursors in our case these are newly introduced chains of earthquakes reflecting the rise of an earthquake correlation range then we consider each chain one by one checking whether it was preceded by an intermediate term precursor in its vicinity if yes we regard this chain as a precursor in prediction it would start a short term alarm the chain indicates the narrow area of possibly complex shape where an intermediate term precursor should be looked for this makes possible to detect precursors undetectable by the direct analysis rtp can best be described on an example of its application we describe retrospective prediction of two prominent californian earthquakes landers 1992 m 7 6 and hector mine 1999 m 7 3 and suggest a hypothetical prediction algorithm this paper descripes the rtp methodology which has potentially important applications to many other data and to prediction of other critical phenomena besides earthquakes in particular it might vindicate some short term precursors previously rejected as giving too many false alarms validation of the algorithm per se requires its application in different regions with a substantial number of strong earthquakes first and positive retrospective results are obtained for 21 more strong earthquakes in california m 6 4 japan m 7 0 and the eastern mediterranean m 6 5 these results are described elsewhere the final validation requires as always prediction in advance for which this study sets up a base we have the first case of a precursory chain reported in advance of a subsequent strong earthquake tokachi oki japan 25 september 2003 m 8 1 possible mechanisms underlying rtp are outlined

earthquake potential of the sichuan yunnan region western china abstract we estimate the seismic hazard potential in the sichuan yunnan region western china using three different approaches our first approach based on the assumption that the earthquake probability is proportional to the past seismicity rate uses a regional earthquake catalog to constrain the probability model a retrospective test shows that the forecasts have some predictive power for strong events occurred on fault segments with shorter earthquake recurrence time but not for that with longer recurrence time such as the longmenshan fault our second approach based on the assumption that the earthquake probability is proportional to crustal strain rate uses secular geodetic strain rate deduced from gps velocity data to constrain the probability model a retrospective test of the model with earthquake occurrence of the past 30 years shows that the model forecasted poorly however the model seems to forecast spatial intensity of earthquakes for the past 500 years reasonably well suggesting that the geodetic strain rate obtained at the decadal scale may still be a good indicator of long term earthquake activity in the region but only at a time scale of hundreds of years our third approach uses gps velocity data to determine the seismic moment accumulation rates on major faults and a historical earthquake catalog to estimate seismic moments released in the past comparison of the two yields estimates of present day seismic moments cumulated on major faults and a retrospective test shows some predictive power of the method our result suggests that numerous faults in the sichuan yunnan region have cumulated seismic moments capable of producing m 7 5 earthquakes including the xiaojiang jiali northern nujiang nandinghe and red river puer faults and the junction fault between the xianshuihe and ganzi yushu faults

stability of premonitory seismicity pattern and intermediate term earthquake prediction in central italy the algorithm cn makes use of normalized functions therefore the original algorithm developed for the california nevada region can be directly applied without adjustment of the parameters to the determination of the time of increased probability tip of strong earthquakes for central italy the prediction is applied to the events with magnitudem m0 5 6 which in central italy have a return period of about six years the routinely available digital earthquake bulletins of the istituto nazionale di geofisica ing rome permits continuous monitoring here we extend to november 1994 the first study made by keilis boroket al 1990b on the basis of the combined analysis of seismicity and seismotectonic we formulate a new regionalization which reduces the total alarm time and the failures to predict and narrows the spatial uncertainty of the prediction with respect to the results ofkeilis boroket al 1990b

catalog errors and the m8 earthquake prediction algorithm the goal of earthquake prediction algorithm research efforts is to identify patterns in data that characteristically occur prior to large earthquakes most of these algorithms implicitly assume that variations in the data they examine are related to actual changes in physical processes occurring in the earth in the case of seismicity data most of the observed variations are in fact related to changes in the system for detecting and reporting earthquakes and not to actual changes in the earth we have tested the earthquake prediction algorithm m8 using five different seismicity data sets for the southwest pacific we demonstrate that the alarms identified by m8 are strongly dependent on the seismicity catalog used the alarms occur preferentially during times when magnitudes are relatively high because of systematic errors these alarms cannot be reasonably interpreted as precursors to earthquakes or any other real change in the earth without first understanding and correcting the errors in the seismicity catalogs this study highlights the need for improving the quality of geophysical data which is presently unsuitable for many studies related to earthquake prediction

pattern informatics and its application for optimal forecasting of large earthquakes in japan pattern informatics pi technique can be used to detect precursory seismic activation or quiescence and make an earthquake forecast here we apply the pi method for optimal forecasting of large earthquakes in japan using the data catalogue maintained by the japan meteorological agency the pi method is tested to forecast large magnitude m 5 earthquakes spanning the time period 1995 2004 in the kobe region visual inspection and statistical testing show that the optimized pi method has forecasting skill relative to the seismic intensity data often used as a standard null hypothesis moreover we find in a retrospective forecast that the 1995 kobe earthquake m 7 2 falls in a seismically anomalous area another approach to test the forecasting algorithm is to create a future potential map for large m 5 earthquake events this is illustrated using the kobe and tokyo regions for the forecast period 2000 2009 based on the resulting kobe map we point out several forecasted areas the epicentral area of the 1995 kobe earthquake the wakayama area the mie area and the aichi area the tokyo forecast map was created prior to the occurrence of the oct 23 2004 niigata earthquake m 6 8 and the principal aftershocks with 5 0 m we find that these events were close to in a forecasted area on the tokyo map the pi technique for regional seismicity observation substantiates an example showing considerable promise as an intermediate term earthquake forecasting in japan

seismotectonic models and cn algorithm the case of italy the cn algorithm is utilized here both for the intermediate term earthquake prediction and to validate the seismotectonic model of the italian territory using the results of the analysis made through the cn algorithm and taking into account the seismotectonic model three main areas one for northern italy one for central italy and one for southern italy are defined two transition areas between the three main areas are delineated the earthquakes which occurred in these two areas contribute to the precursor phenomena identified by the cn algorithm in each main area

neo deterministic seismic hazard and pattern recognition techniques time dependent scenarios for north eastern italy an integrated neo deterministic approach to seismic hazard assessment has been developed that combines different pattern recognition techniques designed for the space time identification of impending strong earthquakes with algorithms for the realistic modeling of seismic ground motion the integrated approach allows for a time dependent definition of the seismic input through the routine updating of earthquake predictions the scenarios of expected ground motion associated with the alarmed areas are defined by means of full waveform modeling a set of neo deterministic scenarios of ground motion is defined at regional and local scales thus providing a prioritization tool for timely preparedness and mitigation actions constraints about the space and time of occurrence of the impending strong earthquakes are provided by three formally defined and globally tested algorithms which have been developed according to a pattern recognition scheme two algorithms namely cn and m8 are routinely used for intermediate term middle range earthquake predictions while a third algorithm allows for the identification of the areas prone to large events these independent procedures have been combined to better constrain the alarmed area the pattern recognition of earthquake prone areas does not belong to the family of earthquake prediction algorithms since it does not provide any information about the time of occurrence of the expected earthquakes nevertheless it can be considered as the termless zero approximation which restrains the alerted areas e g defined by cn or m8 to the more precise potential location of large events italy is the only region of moderate seismic activity where the two different prediction algorithms cn and m8s i e a spatially stabilized variant of m8 are applied simultaneously and a real time test of predictions for earthquakes with magnitude larger than a given threshold namely 5 4 and 5 6 for cn algorithm and 5 5 for m8s algorithm has been ongoing since 2003 the application of the cn to the adriatic region which is relevant for seismic hazard assessment in the northeastern part of the italian territory is also discussed examples of neo deterministic scenarios are provided at regional and local scale and for the cities of trieste and nimis friuli venezia giulia region where the knowledge of the local geological conditions permitted a detailed evaluation of the expected ground motion

premonitory spreading of seismicity over the faults network in southern california precursor accord 1 we establish a connection between geometry of the faults network in a region and seismicity preceding the strong earthquakes in the intermediate term timescale of years previous studies of observed and computer simulated seismicity demonstrated that strong earthquakes are preceded in that timescale by the rise of seismic activity in a lower magnitude range here we explore a complementary phenomenon spreading of activity over the fault network this phenomenon is depicted by the seismicity pattern accord defined as a simultaneous rise of seismicity in a sufficiently large number of fault zones hence its name pattern accord has been found recently in synthetic seismicity generated by the colliding cascades cc model the present study demonstrates this pattern in observed seismicity of southern california we applied to observations a prediction algorithm based on the pattern accord scaled to the target magnitude 7 5 the pattern accord emerges within a few years before each of the three largest earthquakes in southern california kern county 1952 landers 1992 and hector mine 1999 and at no other time scaled to the target magnitude interval from 6 5 to 7 4 the pattern accord precedes six out of nine earthquakes the duration of alarms in both cases is about 30 of the time considered we repeated prediction with different combinations of adjustable numerical parameters of the algorithm summing up the success and error scores on an error diagram this numerical experiment shows that the prediction results are stable under moderate variations of adjustable parameters the final test would be as always an advance prediction the pattern accord has a simple physical explanation connected with equilibrium of the crustal blocks system under the impact of tectonic driving forces at the same time accord is a manifestation of a broader phenomenon premonitory increase of earthquakes correlation range the latter phenomenon was found for the first time in the cc model although it was hypothesized by one of the authors much earlier

cn algorithm and long lasting changes in reported magnitudes the case of italy summary prediction methods based on seismic precursors and hence assuming that catalogues contain the necessary information to predict earthquakes are sometimes criticised for their sensitivity to the unavoidable catalogue errors and possible undeclared variations in the evaluation of reported magnitudes we consider a real example and we discuss the evect on cn predictions of a long lasting underestimation of the reported magnitudes starting approximately in 1988 the cn functions in central italy evidence an anomalous behaviour not associated with tips that indicates an unusual absence of moderate events to investigate this phenomenon the magnitudes given in the catalogue used which since 1980 is defined by the ing bulletins are compared to the magnitudes reported by the global catalogue neic national earthquake information centre usgs usa and by the regional ldg bulletins issued at the laboratoire de detection et de geophysique bruyeres le chatel france the comparison is performed between the ing bulletins and the neic catalogue considering the local m l and duration m d magnitudes first within the central region and then extended to the whole italian territory to check the consistency of the conclusions drawn from ing and neic data the comparison of local magnitudes is extended to a third data set the ldg bulletins the diverences between duration magnitudes m d that are reported by ing and neic since 1983 appear quite constant with time starting in 1987 an average underestimation of about 0 5 can be attributed to m l reported by ing for the central region this diverence decreases to about 0 2 when the whole italian territory is considered the anomalous behaviour of the cn functions disappears if a magnitude correction of 0 5 is applied to m l reported in the ing bulletins however such a simple magnitude shift cannot restore the real features of the seismic flow and ing bulletins are not suitable for cn algorithm application

premonitory raise of the earthquakes correlation range lesser antilles abstract we apply to the observed seismicity of lesser antilles a short term earthquake precursor which has been recently found by analysis of synthetic seismicity the latter was generated by a lattice type colliding cascades model of interacting elements precursor named roc depicted premonitory increase of the earthquakes correlation range here this precursor is used as a second approximation to the intermediate term prediction as a first approximation we use the alarms determined in the previous publication by the algorithm seismic reversal sr it depicts premonitory reversal of territorial distribution of seismicity we consider combined performance of both algorithms in prediction of earthquakes with magnitude 5 5 or above four such earthquakes occurred in the territory considered during 1984 1998 the alarms occupy 0 5 of the total time space three alarms happened to be correct two alarms were false and one earthquake was missed by prediction the alarms are very stable to variation of adjustable parameters of prediction method in view of this stability such a prediction is unusually good even for retrospective analysis we present this prediction method as a hypothesis to be tested on advance prediction

prediction of strong earthquakes in vrancea romania using the cn algorithm the application of the cn algorithm to a new earthquake catalogue for the period from 1932 to 1993 obtained by merging romanian and u s s r data allows us to monitor on the intermediate time scale the preparation of strong intermediate depth earthquakes in the vrancea region four of the five strong earthquakes with a magnitude above 6 4 are predicted the total duration of the time of increased probability of the occurrence of an earthquake tip occupies 21 7 of the time interval under consideration i e about 2 5 years for each strong earthquake

application of a modified pattern informatics method to forecasting the locations of future large earthquakes in the central japan we propose a modification of the pattern informatics pi method that has been developed for forecasting the locations of future large earthquakes this forecast is based on analyzing the space time patterns of past earthquakes to find possible locations where future large earthquakes are expected to occur a characteristic of our modification is that the effect of errors in the locations of past earthquakes on the output forecast is reduced we apply the modified and original methods to seismicity in the central part of japan and compared the forecast performances we also invoke the relative intensity ri of seismic activity and randomized catalogs to constitute null hypotheses we do statistical tests using the molchan and relative operating characteristic roc diagrams and the log likelihoods and show that the forecast for using the modified pi method is generally better than the competing original pi forecast and the forecasts from the null hypotheses using the bootstrap technique with monte carlo simulations we further confirm that earthquake sequences simulated based on the modified pi forecast can be statistically the same as the real earthquake sequence so that the forecast is acceptable the main and innovative science in this paper is the modification of the pi method and the demonstration of its applicability showing a considerable promise as an intermediate term earthquake forecasting tool

interannual extremes in new zealand precipitation linked to modes of southern hemisphere climate variability abstract interannual extremes in new zealand rainfall and their modulation by modes of southern hemisphere climate variability are examined in observations and a coupled climate model north island extreme dry wet years are characterized by locally increased reduced sea level pressure slp cold warm sea surface temperature sst anomalies in the southern tasman sea and to the north of the island and coinciding reduced enhanced evaporation upstream of the mean southwesterly airflow during extreme dry wet years in south island precipitation an enhanced reduced meridional slp gradient occurs with circumpolar strengthened weakened subpolar westerlies and an easterly westerly anomaly in zonal wind in the subtropics as a result via ekman transport anomalously cold warm sst appears under the subpolar westerlies while anomalies of the opposite sign occur farther north the phase and magnitude of the resulting sst and evaporation anomalies cannot account for the rainfall extremes over t

coupled ocean atmosphere ice response to variations in the southern annular mode abstract the coupled ocean atmosphere ice response to variations in the southern annular mode sam is examined in the national center for atmospheric research ncar community coupled climate model version 2 the model shows considerable skill in capturing the predominantly zonally symmetric sam while regional deviations between model and observation sam winds go a long way in explaining the generally small differences between simulated and observed sam responses in the ocean and sea ice systems vacillations in the position and strength of the circumpolar winds and the ensuing variations in advection of heat and moisture result in a dynamic and thermodynamic forcing of the ocean and sea ice both meridional and zonal components of ocean circulation are modified through ekman transport which in turn leads to anomalous surface convergences and divergences that strongly affect the meridional overturning circulation and potentially the pathways of intermediate water ventilation a heat budget analysis de

gps monitoring and earthquake prediction a success story towards a useful integration abstract we describe a success story at the junction between south eastern alps and external dinarides that has led to an early deployment of gps stations prior to the predicted july 12th 2004 moderate size slovenia krn mountain earthquake the success story consisted in a straightforward integration between a long lasting lithosphere scale rock mechanics experiment along with gps monitoring leading to a physical model of stress evolution and tested earthquake prediction experiment using m8s cn and rtp algorithms to point out the area of the impending earthquake within the alarmed area by the prediction algorithms the lithosphere scale rock mechanics experiment revealed that the location of the 2004 event falls within an area of stress shadow due to the recent 1998 bovec earthquake but is also very close to an area of increased stress due to the long lasting effect of the 1511 event the pre and post 2004 earthquake gps data provided the following results 1 the krn mountain earthquake magnitude has to be increased from mw 5 2 to 5 5 therefore doubling the fault slip in order to provide a better fit to the near field displacements accordingly the rtp 2004 alarm in northern dinarides can be considered a successful prediction now that the magnitude is inside the prediction range 2 the existence of an important amount of aseismic deformation related to such a moderate size earthquake and the feasibility of monitoring these transients 3 the evidence of a resolved acceleration of the strain rates one year prior to the earthquake 4 the robustness of the bayesian approach in detecting discontinuities in the times series their magnitude and statistical significance the discontinuities or jumps in the time series can correspond to coseismic deformation or time dependent deformation such as creeping slow motion strain acceleration and transients in general 5 when integrated with tested earthquake prediction algorithms the capability to forecast earthquakes can be extended to the scale of the active fault systems

techniques and parameters to analyze seismicity patterns associated with large earthquakes a pattern recognition algorithm is developed to provide potential improvements over existing earthquake prediction practices the parameters employed in the analysis include degree of spatial nonrandomness in two distance ranges spatial correlation dimension spatial repetitiveness of earthquakes with a similar size average depth of events time interval for the occurrence of a constant number of events and ratio of the numbers of events in two magnitude intervals the parameter temporal variations are compared quantitatively with the time series of large events using a technique of association in time the significance of the association frequencies is evaluated by comparison with chance associations estimated from corresponding simulated random time series the developed techniques differ from existing approaches in the following aspects the parameters here emphasize the spatial distribution of earthquakes possible correlations among the parameters are evaluated to determine the final set of parameters to be monitored threshold values for the assumed anomalies are chosen with consideration of properties of the available earthquake catalogs such as the number of large events to be retrospectively predicted equal weight is given to both locally high and locally low parameter values care is taken to distinguish between anomalies preceding large events and those following previous events it is shown that the relationship between precursory local extrema and precursory trends is nonunique with precursory local extrema of the same type frequently associated with opposite observable precursory trends the application of the seismicity parameters and pattern recognition techniques is demonstrated using synthetic earthquake catalogs generated by models of segmented fault systems in a three dimensional elastic solid ben zion 1996

precursory seismic activation and critical point phenomena in this paper we relate the behavior of seismicity prior to a characteristic earthquake to the excitation in proximity to a spinodal instability we illustrate the spinodal instability as the upper limit of superheated water prior to a steam explosion we draw an analogy between the steam explosion and a characteristic earthquake and show that the power law activation associated with the spinodal instability is essentially identical to the power law increase in benioff strain observed prior to characteristic earthquakes we find that theory and actual data give very similar results

seismotectonic model and cn earthquake prediction in italy the choice of the regions is essential in the application of the algorithm cn therefore a seismotectonic criterion for their definition is tested in order to take into account the geodynamic complexity characterising the italian peninsula we established to strictly follow the seismotectonic zones including in each region only zones with similar seismogenic behaviour and the transitional zones connected to them three regions have been successfully defined in this way corresponding approximately to the north centre and south of italy the reduction of the space time uncertainty and the increase of the stability of prediction results obtained with this regionalisation with respect to the previous applications of cn in italy keilis borok et al 1990 costa et al 1995 1996 can be interpreted as a validation of the seismotectonic model

annular modes in global daily surface pressure annular modes are patterns characterized by synchronous fluctuations in surface pressure of one sign over the polar caps and the opposite sign at lower latitudes the southern annular mode sam and northern annular mode nam also called the arctic oscillation patterns are the leading empirical orthogonal functions eofs of slowly varying hemispheric cold season sea level pressure anomalies deviations from climatology daily indices of the sam and nam are a measure of the similarity between surface pressure anomaly patterns and the annular modes here it is shown that the first two eof time series of daily global year round zonally averaged surface pressure are nearly identical to the sam and nam indices together they account for more than 57 of the daily variance of zonally averaged surface pressure the sam and nam patterns extend through the tropics well into the opposite hemispheres fluctuations of the sam and nam indices are accompanied by interhemispheric transfer of mass

long term earthquake clustering summary we analyse statistically the long term properties of several instrumental earthquake catalogues complete catalogues exhibit both short and long term clustering for earthquakes of all depth ranges after accounting for the effect of short term clustering we find that in residual declustered catalogues long term clustering not periodicity characterizes the occurrence of all earthquakes shallow intermediate and deep the degree of clustering in residual catalogues is the same for earthquakes in different depth ranges circumstantial evidence indicates that the long term v ariation of seismicity is governed by a power law temporal distribution as in short term clustering it is scale invariant the fractal dimension of an earthquake set on the time axis is of the order of 0 8 0 9 therefore mainshock occurrence is closer to a stationary poisson process than standard aftershock sequences of shallow earthquakes

mapping seismic quiescence in california the decrease of microearthquake activity is a controversial possible precursor for mainshock prediction the calculation of seismic quiescence is a convenient tool to quantify this decrease however the actual size of an anomaly significantly depends on the calculation parameters the necessary averaging over space and time acts as 3d lowpass filter the sliding statistics windows introduce highpass behavior and the magnitude threshold shall ensure catalog completeness but also biases the data selection to argue on any claimed anomaly the only conclusive solution would be an exhaustive search over all parameters over an area significantly larger than just the epicenter region and against a test of the null hypothesis qmap is a new mapping approach to process full catalogs that is some twenty years of data for areas of one million km 2 with one fixed set of parameters it utilizes fractil statistics to avoid errors otherwise induced by clusters of aftershock series qmap features two different scaling modes one to display absolute decrease and a second for weighted anomalies by erosion filtering applied to california one can recognize quiescence anomalies of regional scale prior to the coalinga and loma prieta earthquakes but there are more and greater anomalies distributed all along the san andreas fault system without further criteria to understand these patterns the additional anomalies degrade seismic quiescence to an observation with high false alarm rate for earthquake prediction

application of the cn intermediate term earthquake prediction algorithm to the area of the southern external dinarides the paper presents the results of application of the cn algorithm to the area of the southern external dinarides two cases are considered one for the knowledge gained throughout the considered period of time 1936 1996 and the other when learning ceased in 1986 in the first case 8 out of 9 strong earthquakes could have been predicted three false alarms are declared covering 7 of the total time considered and tips occupy 32 of the total time there is no clear relation between the tips duration and the size of the related earthquake the second case when the cn functions are defined on the basis of a shorter learning period produces even slightly better results only two false alarms are declared in both cases current alarm exists in the region all attempts to reduce the area of the regional polygon resulted in poorer prediction results

statistical physics approach to understanding the multiscale dynamics of earthquake fault systems 1 earthquakes and the faults upon which they occur interact over a wide range of spatial and temporal scales in addition many aspects of regional seismicity appear to be stochastic both in space and time however within this complexity there is considerable self organization we argue that the occurrence of earthquakes is a problem that can be attacked using the fundamentals of statistical physics concepts of statistical physics associated with phase changes and critical points have been successfully applied to a variety of cellular automata models examples include sandpile models forest fire models and particularly slider block models these models exhibit avalanche behavior very similar to observed seismicity a fundamental question is whether variations in seismicity can be used to successfully forecast the occurrence of earthquakes several attempts have been made to utilize precursory seismic activation and quiescence to make earthquake forecasts some of which show promise

atmospheric teleconnections involving the southern ocean 1 i review the characteristic patterns of low frequency interannual and subdecadal variation in atmospheric circulation over the southern hemisphere sh extratropics and their climatic associations e g temperature precipitation winds sea surface temperatures ssts and sea ice conditions for the southern ocean the considerable spatial and temporal limitations of the observational database have strongly conditioned the pace of our understanding of sh teleconnections particularly for the pacific sector where the tropical el nino southern oscillation enso exerts a dominant influence an enso signal appears in the intensity interannual variations of the amundsen sea mean low pressure asl jet streams and long waves these variations comprise the so called pacific south america psa teleconnection patterns of low frequency variability in sh circulation that are mostly extratropical in origin but which can interact with enso are dominated by the zonally symmetric high latitude mode or antarctic oscillation aao the aao involves an alternation of atmospheric mass between middle and high southern latitudes a zonally asymmetric mode of wave number 1 is represented by an oscillation in pressure height between australian and south american sectors depicted by a trans polar circulation index a significant wave number 2 oscillation in the coupled atmosphere ocean ice system or antarctic circumpolar wave acw has a similar periodicity to enso and is strongest in the pacific sw atlantic sectors atmospheric teleconnections involving the southern ocean including those to enso show evidence of recent changes and the climatic implications of these are discussed

synchronous variability in the southern hemisphere atmosphere sea ice and ocean resulting from the annular mode zonally symmetric fluctuations of the midlatitude westerly winds characterize the primary mode of atmospheric variability in the southern hemisphere during all seasons this is true not only in observations but also in an unforced 15 000 yr integration of a coarse resolution r15 coupled ocean atmosphere model here it is documented how this mode of atmospheric variability known as the southern annular mode sam generates ocean circulation and sea ice variations in the model integration on interannual to centennial timescales that are tightly in phase with the sam the positive phase of the sam is associated with an intensification of the surface westerlies over the circumpolar ocean around 608s and a weakening of the surface westerlies farther north this induces ekman drift to the north at all longitudes of the circumpolar ocean and ekman drift to the south at around 308s through mass continuity the ekman drift generates anomalous upwelling along the margins of the antarctic continent and downwelling around 458s the anomalous flow diverging from the antarctic continent also increases the vertical tilt of the isopycnals in the southern ocean so that a more intense circumpolar current is also closely associated with positive sam in addition the anomalous divergent flow advects sea ice farther north resulting in an increase in sea ice coverage finally positive sam drives increases in poleward heat transport at about 308s while decreases occur in the circumpolar region ocean and sea ice anomalies of the opposite sign occur when the sam is negative the ocean and sea ice fluctuations associated with the sam constitute a significant fraction of simulated ocean variability poleward of 308s year round the robustness of the mechanisms relating the sam to oceanic variability suggests that the sam is likely an important source of large scale variability in the real southern hemisphere ocean

the main characteristics of the lithosphere asthenosphere system in italy and surrounding regions we present a summary of the available information on rayleigh wave dispersion data for the italian area the dispersion curves can be grouped into two main families according to their shape one with an almost linear trend in the period range from 40 to 150 sec the other with a relatively flat portion in the period range from 40 to 80 sec the inversion of these data shows that there are strong lateral variation in the lithosphere system a very rapid transition in the lithospheric thickness from about 130 km to about 30 km as well as in the s wave velocity of the lithosphere and asthenosphere

an early onset of enso influence in the extra tropics of the southwest pacific inferred from a 14 600 year high resolution multi proxy record from paddy s lake northwest tasmania abstract tropical el nino southern oscillation enso is an important influence on natural systems and cultural change across the pacific ocean basin el nino events result in negative moisture anomalies in the southwest pacific and are implicated in droughts and catastrophic wildfires across eastern australia an amplification of tropical el nino activity is reported in the east pacific after ca 6 7 ka however proxy data for enso driven environmental change in australia suggest an initial influence only after ca 5 ka here we reconstruct changes in vegetation fire activity and catchment dynamics e g erosion over the last 14 6 ka from part of the southwest pacific in which enso is the main control of interannual hydroclimatic variability paddy s lake in northwest tasmania 1065 masl australia our multi proxy approach includes analyses of charcoal pollen geochemistry and radioactive isotopes our results reveal a high sensitivity of the local and regional vegetation to climatic change with an increase of non arboreal pollen between ca 14 6 13 3 ka synchronous with the antarctic cold reversal and a sensitivity of the local vegetation and fire activity to enso variability recorded in the tropical east pacific through the holocene we detect local scale shifts in vegetation fire and sediment geochemistry at ca 6 3 4 8 and 3 4 ka simultaneous with increases in el nino activity in the tropical pacific finally we observe a fire driven shift in vegetation from a pyrophobic association dominated by rainforest elements to a pyrogenic association dominated by sclerophyllous taxa following a prolonged 1 ka phase of tropical enso amplification and a major local fire event at ca 3 4 ka our results reveal the following key insights 1 that enso has been a persistent modulator of southwest pacific climate and fire activity through the holocene 2 that the climate of northwest tasmania is sensitive to long term shifts in tropical enso variability and 3 that there has been possible stationarity in the spatial influence of enso over this region through the holocene

definition of antarctic oscillation index following walker s work about his thmous three oscillations published during the 1920 30s many papers were written about atmospheric oscillations a iburth atmospheric oscillation in the middle and high southern latitudes was lbund and nanted the grotarctic oscillation ao a refiers to a large scale alternation of atmospheric mass between the mid latitudes and high latitudes surthce pressure in order to understand the spatial structure of sea level pressure variation in detail empirical orthogonal fitnction analysis is applied an objective index of the antarctic oscillation index aoi is defined as the diffierence of zonal mean sea level pressure between 40os and 65os the aoi has the potential tbr clarifying climate regimes in the southern hemisphere similar to how the na and the npo has been used in the northern hemisphere were there other oscillation s besides nao npo and s especially in the southern hemisphere it had been supposed that there might be other atmospheric oscillation s in the high southern latitudes although as early as in the first quarter of this century walker 1928 had stated that just as in the north atlantic there is a pressure opposition between the azores and iceland there is an opposition between the high pressure belt across chile and the argentine on the one hand and the low pressure area of weddell sea and the bellingshausen sea on the other the scarcity of data in the southern hemisphere hindered the search tbr new oscillation s during the last two decades more comprehensive data over the southern hemisphere became available and more analyses were carried out see kidson 1975 rogers and van loon 1982 mo and l 7 ite 1985 2 4o 1986 connolley 1997 gong and wang 1998 a tburth atmospheric oscillation in the middle and high southern latitudes was tbund and nanted as the antarctic oscillation a wang 1992 gong and wang 1998 the term ao relrs to a large scale alternation of atmospheric mass between the mid latitude sur hce pressure

beno gutenberg contribution to seismic hazard assessment and recent progress in the european mediterranean region abstract the fundamental work of beno gutenberg has inspired and guided an appreciable part of research in modern seismology both from the experimental and the theoretical point of view among the several topics of seismology that have benefited from the fundamental contribution of gutenberg we consider particularly relevant the description of the asthenospheric low velocity channel the definition of the surface waves magnitude and the gutenberg richter law since they are pivotal tools for seismic hazard assessment the quite revolutionary model for the lithosphere asthenosphere system in the european area predicts the existence of almost aseismic lithospheric roots these roots are located in correspondence of most of the orogenic belts and interrupt the asthenosphere low velocity channel that has been identified by beno gutenberg in 1948 the model of the european upper mantle proposed for the first time in 1979 and subsequently refined has stimulated a considerable amount of research which has nicely confirmed the major innovative features of the early model at present the subduction of the lithosphere at continent continent collisions supported not only by seismological data is a widely accepted concept within the community of earth scientists even if it contradicts one of the basic dogmas of the original formulation of plate tectonics the proposed model for the alpine apennines area supplies a new and unifying framework for the interpretation of the quaternary magmatism at present generally accepted by petrologists and geochemists the theoretical basis for the gutenberg s surface wave magnitude calibration function has been supplied by the use of complete synthetic seismograms and thus it has been possible to formulate the theoretical m s depth correction the introduction of the depth correction for m s enables the computation of surface wave magnitude for all earthquakes regardless of their focal depth this is especially important for the quantification of subcrustal historical earthquakes for which the seismic moment may be difficult to estimate from recordings of early mechanical seismographs the new m s calibrating function yield both distance and depth independent magnitude estimates the analysis of the global seismicity using the seismotectonic regionalization in subduction zones mid oceanic ridge zones island arcs shows that a single gutenberg richter gr relation is not universally applicable and that a multiscale seismicity model can reconcile two apparently conflicting paradigms the self organized criticality mechanism and the characteristic earthquake concept the multiscale representation has been applied to italy where the zones at the space scale of 400 500 km quite well reproduce the shapes of the regions used to apply the globally tested cn intermediate term earthquake prediction algorithm

modeling of solute transport in a single fracture using streamline simulation and experimental validation abstract streamline simulations have been extensively used in petroleum engineering due to its computational speed and the freedom from numerical dispersion this study applies streamline simulation to the modeling of solute transport in a single fracture and verifies the streamline method with experimental data in order to model dispersive transport a new term the advection dispersion ratio is employed which is defined as the relative extent of advection to dispersion along streamlines it is observed that the tracer breakthrough curves from the simulation match well with those from the experiments in addition the tracer displacement profiles from the simulation also show resemblance to those from the experiments simulations with various link transmissivity types result in no serious disparities the distributions of time of flight and tracer breakthrough curves from the simulations using different link transmissivity types are much alike transport simulation is performed by allocating different advection dispersion ratios along streamlines afterwards the results are compared with the simulation result using single representative advection dispersion ratio over the flow domain although streamlines actually have different advection dispersion ratios its effect is found to be not severe therefore a representative advection dispersion ratio can be used for modeling transport through the whole streamlines in a single fracture

the european african collision and its effects on the lithosphere asthenosphere system abstract in the european area lateral changes in the shear wave velocities of the lithosphere asthenosphere system are quite pronounced gravity data imply a positive density contrast 0 03 0 07 g cm 3 in the upper mantle related to almost aseismic lithospheric roots which seem to characterize many orogenic belts the analysis of a transect along the longitudinal axis of the alps seems to indicate that relevant lateral variations in density are also present in the lithospheric part of the mantle

stress in the descending relic slab beneath the vrancea region romania we examine the effects of viscous flow phase transition and dehydration on the stress field of a relic slab to explain the intermediate depth seismic activity in the vrancea region a 2 d finite element model of a slab gravitationally sinking in the mantle predicts 1 downward extension in the slab as inferred from the stress axes of earthquakes 2 the maximum stress occurring in the depth range of 70 km to 160 km and 3 a very narrow area of the maximum stress the depth distribution of the annual average seismic energy released in earthquakes has a shape similar to that of the depth distribution of the stress in the slab estimations of the cumulative annual seismic moment observed and associated with the volume change due to the basalt eclogite phase changes in the oceanic slab indicate that a pure phase transition model cannot solely explain the intermediate depth earthquakes in the region we consider that one of the realistic mechanisms for triggering these events in the vrancea slab can be the dehydration of rocks which makes fluid assisted faulting possible

the central china north south seismic belt seismicity ergodicity and five year pi forecast in testing instrumentally recorded seismicity from 1970 01 01 to 2014 01 01 of the central china north south seismic belt 21 0 41 5 n 97 5 107 5 e was analyzed emphasizing the applicability of the predictive algorithms based on the assumptions of meta stable equilibrium the seismicity in this region was shown to exhibit ergodicity from 1980 to the present with sub region dependence and interrupted by the 2008 wenchuan earthquake pattern informatics algorithm a statistical physics based predictive model for five year time scale is put to forward forecast test for the period 2014 01 01 to 2019 01 01

the pacific south american modes and tropical convection during the southern hemisphere winter abstract atmospheric circulation features and convection patterns associated with two leading low frequency modes in the southern hemisphere sh are examined in multiyear global reanalyses produced by ncep ncar and nasa dao the two leading modes referred to as the pacific south american psa modes are represented by the first two eof patterns the two patterns are in quadrature with each other and are dominated by wavenumber 3 in midlatitudes with large amplitudes in the pacific south american sector in the pacific anomalies in the subtropics and in the midlatitudes are opposite in phase taken together the two psa modes represent the intraseasonal oscillation in the sh with periods of roughly 40 days the evolution of the psa modes shows a coherent eastward propagation a composite analysis was conducted to study the evolution of tropical convection and the corresponding circulation changes associated with the psa modes outgoing longwave radiation olr anomaly composites during the mature phase

a late quaternary record of vegetation and climate change from hazards lagoon eastern tasmania a late quaternary pollen and charcoal record from hazards lagoon on the east coast of tasmania provides a continuous record of vegetation and climate change the pollen record shows an epacridaceae and poaceae dominated grassland community replaced dry sclerophyll forest during the last glacial maximum lgm 22 18 cal ka bp eucalyptus and casuarinaceae increased from the beginning of the deglacial period 18 12 cal ka bp indicating early warming on the east coast of tasmania abundant myriophyllum and sedimentary characteristics indicate hazards lagoon was a permanent source of water throughout the lgm and until 16 cal ka bp suggesting either increased precipitation and or decreased evaporation rates a positive moisture balance throughout the lgm contrasts with records from the west coast of tasmania and parts of mainland australia fire was suppressed at the site until 14 cal ka bp corresponding with reduced woody vegetation and a positive moisture balance dry sclerophyll forest established during the deglacial period remaining stable throughout the holocene a coastal vegetation community developed in response to sea level rise characterised by abundant eucalyptus pollen and increasing values of casuarinaceae by the mid holocene the hazards lagoon pollen record is typical of a tasmanian coastal site dominated by casuarinaceae this research highlights the need for spatially diverse studies throughout the southern hemisphere to identify drivers of environmental change during the late quaternary

effect of fracture aperture variations on the dispersion of contaminants dispersion of dissolved contaminants in fractured rocks is strongly dependent on the variability of fracture aperture large fracture aperture regions result in significant channeling of the fluid flow accelerating the movement of solutes in a particular direction which may differ locally with respect to the main flow direction from high to low hydraulic potential this may result in very early breakthrough of the contaminants significantly earlier than in the conventional parallel plate simplification of fluid flow in fractured systems in addition flow and transport in the low aperture regions can be orders of magnitude smaller which has major implications for remediating contaminated fractured media in this study we observed the transport of a nonsorbing solute in a naturally fractured rock which was characterized at very high resolution using computed tomography scanning to determine the fracture aperture distribution we compared the observed breakthrough curve of the solute at various flow rates with the predicted breakthrough curve using the fracture s geostatistics and small perturbation analysis as well as direct numerical simulation of flow through the fracture using the measured fracture aperture distribution the experimentally determined fracture transmissivity and dispersivity are within a factor of 2 of those predicted using either the small perturbation approach using the fracture geostatistics or explicit numerical modeling of breakthrough which differ by around 20 indicating that the geostatistics of the fracture aperture can be used to predict the approximate shape of the breakthrough curve for a fracture

upper mantle properties of the tuscan tyrrhenian area a framework for its recent tectonic evolution abstract within the alpine mediterranean deformational system several interesting features in the physical properties of the upper mantle have been recognized through the regional analysis of surface wave dispersion a large upper mantle anomaly uma here called the tuscan uma has been identified in the area northeast of corsica which includes part of the northern tyrrhenian sea and part of the north central apennines this anomalous upper mantle area together with the upper mantle characteristics of the tyrrhenian sea located further to the south provides a natural framework for comprehensive interpretation of the large data set of geological and geophysical observations such as land and marine geology volcanism gravity magnetic data seismic data and seismology deep temperatures and surface heat flow

seismotectonic properties and zonation of the far eastern eurasian plate around the korean peninsula regional seismotectonics provides crucial information for seismic hazard analysis which is difficult to address with short term earthquake records the far eastern eurasian plate around the korean peninsula presents a stable intraplate environment with diffuse seismicity of which responsible tectonics and active faults are difficult to identify combined analysis of instrumental and historical earthquake records is required for assessment of long term seismicity properties seismotectonic provinces are identified from the spatial distribution of seismicity properties controlled by the medium properties and stress field the boundaries of the seismotectonic provinces are defined considering the medium properties that can be inferred from geological geophysical and tectonic features the gutenberg richter frequency magnitude relationships and maximum magnitudes for the seismotectonic provinces are determined using instrumental and historical earthquake records the validity of maximum magnitude estimation is tested with synthetic data a parametric method the tate pisarenko method produces more accurate estimates than non parametric methods a modified tate pisarenko method is proposed for estimation of maximum magnitudes for incomplete short term earthquake catalogs the maximum magnitude of events for the whole region is approximately the same as the average of the maximum magnitudes of events for subdivided provinces causing apparent variation in maximum magnitudes depending on the number of seismotectonic provinces consideration of a reasonable number of seismotectonic provinces may be needed for proper assessment of seismic hazard potentials is recommended the combined analysis of historical and instrumental earthquake records suggests maximum magnitudes greater than 7 around the peninsula

diagnosis of the time of increased probability of earthquakes of magnitude 5 5 or greater in the lesser antillean arc abstract the intermediate term premonitory seismicity pattern before a strong earthquake magnitude 5 5 or greater in lesser antillean arc can be diagnosed using the earthquake catalogue issued by the departement des observatoires of the institut de physique du globe de paris the cn algorithm applied to this catalogue identifies two times of increased probability of such earthquakes the first precedes the only strong earthquake 16 march 1985 m 1 local magnitude 6 2 which occurred during the period considered the second is a current alarm during both times of increased probability the seismic activity increased above a depth of 40 km and decreased below it the results suggest at least a partial similarity in subduction zones of this type and in other seismotectonic environments where the algorithm was previously applied shallow earthquakes make a major contribution to formation of the patterns considered

have the southern westerlies changed in a zonally symmetric manner over the last 14 000 years a hemisphere wide take on a controversial problem the prevailing view in the palaeoclimate literature of the last 20 years is that the southern westerly winds sww were intensified over southern australia and tasmania during the warmer than present early holocene 11e8 ka at similar latitudes on the opposite side of the southern mid latitudes palaeoclimate studies have suggested a poleward shift of the northern edge of the westerlies and focusing at 49 s in southern south america this zonal asymmetry contrasts with the modern day zonal symmetry displayed by the sww and poses a formidable challenge to an understanding of the modes of climatic variability of the southern extra tropics this paper presents an updated synthesis of continuous radiocarbon dated palaeoenvironmental data from the westerlies zone of influence in all southern hemisphere continents synchronous multi millennial trends in moisture vegetation fire and hydrologic balance are remarkably consistent with the way the sww changes impact upon the climate in southern hemisphere landmasses in the modern climate considering the modern relationships between local precipitation and zonal wind speeds it is suggested that the sww changed in a zonally symmetric manner at multi millennial scale between 14 and 5 ka regional asymmetry develops after 5 ka across the southern hemisphere with a pattern of precipitation anomalies akin to the modern functioning of el nino e southern oscillation which started w6200 years ago

crust and upper mantle models along the active tyrrhenian rim the volcanic complexes from the eolian islands to the campania roman regions and tuscany further north rest on lithospheric sectors which overlie the adriatic continental lithosphere sinking along the apennine maghrebian orogenic belt evidence for this stems from the melting at mantle depth of upper crustal materials as indicated by the widespread interaction of s type and k alkaline melts the genesis of atypical magmas of the roman province central southern italy appears to be the result of an important block faulting and deep lithospheric rifting of the apennine continental margin lying parallel to and above relic sinking slabs intermediate and deep focus earthquakes indicate that the lithospheric slab is still seismically active under the eolian calabrian area and sporadically at the southern end of campania on the other hand in the roman tuscan region it seems to be almost inactive few earthquakes having been located with hypocentral depths not exceeding 150 km the analysis of the spectral content of seismic sources supports the existence of two distinct zones of lithospheric shortening in correspondence of tuscany and south tyrrhenian sea which are separated by a tensional region which extends from latium to calabria the existence of distinct lithospheric slabs along the tyrrhenian rim is supported by surface wave dispersion and scattering measurements as well as p wave residuals and is confirmed by the trend of long wavelength gravity anomalies bidimensional gravity models along transects in the tyrrhenian sea and italian peninsula interpreted within the geometrical constraints imposed by the results of the interpretation of aeromagnetic seismic and seismological data have been used to delimit the spatial distribution of the density contrasts in the upper mantle which might be due to the existence of the above mentioned lithospheric slabs

intermediate term medium range precursory accelerating seismicity prior to the 12 may 2008 wenchuan earthquake in the study of the predictability of great earthquakes in the perspective of seismicity analysis two issues are presently controversial and need more detailed studies based on real earthquake cases the first issue is whether there exists pre shock accelerating behavior of seismicity which is robust against the changing of spatio temporal ranges for the sampling of seismic events and the second is whether such an accelerating behavior is physically associated with an approach to the critical point to answer these two questions a retrospective case study was conducted on the 12 may 2008 wenchuan earthquake using the local earthquake catalogue in sichuan and yunnan provinces china with cutoff magnitude m l3 0 from 1977 to 2008 the results show that the answer to the first question appears to be yes that is in a finite spatial domain within the last couple of years before the event clear accelerating seismicity could be observed the answer to the second question cannot be obtained merely by examining seismicity data however detailed analysis of the accelerating behavior reveals a potential spatial correlation between the accelerating region and a known asperity which might be an evidence for that the observed acceleration may have a geometrical or mechanical rather than statistical origin

geodynamics and intermediate depth seismicity in vrancea the south eastern carpathians current state of the art abstract the vrancea region of the south eastern carpathians is a remarkable site of intra continental intermediate depth seismicity a large set of geological geophysical and geodetic observations has been accumulated for the last few decades and utilised to improve our knowledge of the shallow and deep structures beneath vrancea the crustal and mantle dynamics and the linkage between deep and surface processes in the region in this article we review geology and tectonics of the vrancea region including post collisional to recent deformations syn to post collisional magmatism and orogenic exhumation along the east and south carpathians the regional seismicity is analysed and the recent seismic studies including reflection refraction body and surface wave tomography are reviewed we discuss new geodetic measurements of horizontal and vertical movements in the region geoelectric studies density gravity and thermal modelling qualitative and quantitative including retrospective geodynamic models developed for vrancea are analysed the knowledge of regional tectonics geodynamics seismicity lithospheric deformation and stress regime in the vrancea earthquake prone region assists in an assessment of strong ground motion seismic hazard and risk the earthquake simulation seismic hazard and earthquake forecasting models have also been reviewed providing a link between deep geodynamic processes and their manifestation on the surface finally we discuss unresolved problems in vrancea in order to improve our understanding of the regional evolution present tectonics mantle dynamics intermediate depth seismicity and surface manifestations of the lithosphere dynamics and to enhance our ability to forecast strong earthquakes in the vrancea region the problems to be solved include i the origin of the high velocity body revealed by seismic tomography studies oceanic versus continental ii the lithospheric scale mechanism driving the miocene subsidence of the transylvania basin iii sub crustal structure between 40 and 70 km iv contemporary regional horizontal and vertical movements and v a comprehensive seismic hazard assessment in the region

evidence for a global seismic moment release sequence temporal clustering of the larger earthquakes foreshock mainshock aftershock followed by relative quiescence stress shadow are characteristic of seismic cycles along plate boundaries a global seismic moment release history based on a little more than 100 years of instrumental earthquake data in an extended version of the catalog of pacheco and sykes 1992 illustrates similar behavior for earth as a whole although the largest earthquakes have occurred in the circum pacific region an analysis of moment release in the hemisphere antipodal to the pacific plate shows a very similar pattern monte carlo simulations confirm that the global temporal clustering of great shallow earthquakes during 1952 1964 at m 9 0 is highly significant 4 random probability as is the clustering of the events of m 8 6 0 2 random probability during 1950 1965 we have extended the pacheco and sykes 1992 catalog from 1989 through 2001 using harvard moment centroid data immediately after the 1950 1965 cluster significant quiescence at and above m 8 4 begins and continues until 2001 0 5 random probability in alternative catalogs derived by correcting for possible random errors in magnitude estimates in the extended pacheco sykes catalog the clustering of m 9 persists at a significant level these observations indicate that for great earthquakes earth behaves as a coherent seismotectonic system a very large scale mechanism for global earthquake triggering and or stress transfer is implied there are several candidates but so far only viscoelastic relaxation has been modeled on a global scale

times of increased probability of large earthquakes ms 7 5 along the mexican subduction zone abstract using the method of pattern recognition of infrequent events we explore the possibility of identifying the times of increased probability tip of occurrence of large earthquakes ms 7 5 along the mexican subduction zone a tip refers to a 5 year period within which a strong earthquake has a high probability of occurrence we analyzed the seismicity for the regions of chiapas eastern oaxaca 91 97 w region 1 western oaxaca guerrero 97 102 w region 2 and michoacan colima jalisco 102 106 w region 3 for the time interval 1970 1991 with the national oceanic and atmospheric administration seismic catalog as the source data the premonitory intermediate term seismic activation to identify a tip was measured using the algorithm m8 three out of the five earthquakes of ms 7 5 that occurred during the studied period are diagnosed by algorithm m8 and for the region 3 segment a tip is identified that will end between 1994 and 1996 we consider the area between the western colima gap and the jalisco region 103 7 106 0 w as the zone where the forecast earthquake has a higher than usual probability of occurrence our results by no means constitute a definitive earthquake prediction but suggest the need for detailed seismic analysis and the study of other geophysical precursors along the colima jalisco segment

el nino la nina and the nonlinearity of their teleconnections the paradigm of an atmospheric system varying linearly with respect to extreme phases of the el nino southern oscillation is questioned it is argued that the global response to tropical pacific sea surface temperature forcing will be inherently nonlinear a physical basis for this intrinsic nonlinearity is the thermodynamic control on deep convection climate statistics for warm and cold events of the tropical pacific are analyzed separately for the northern winter periods during 1950 96 composite analysis of 500 mb heights reveal planetary scale teleconnection patterns as noted in earlier studies a new result is the evidence for an appreciable 358 longitude phase shift between the warm and cold event circulation composites and the two wave trains appear to have different tropical origins a large nonlinear component in north american surface climate anomalies is also found which is consistent with such a phase shift in teleconnections in the tropics rainfall anomalies also show evidence of nonlinear behavior the maximum rain anomalies along the equator are located east of the date line during warm events but west of the date line during cold events the interpretation of this behavior is complicated however by the fact that composite warm event sst anomalies are not the exact inverse of their cold event counterparts idealized atmospheric general circulation model agcm experiments are performed in order to test the question of whether the observed nonlinearity is an intrinsic property of the atmospheric system the model is forced with a composite sst anomaly that undergoes a realistic seasonally varying enso life cycle as described by e rasmusson and t carpenter both positive and negative phases of the sst anomaly are used and a 40 member ensemble of warm and cold event model simulations is conducted a nonlinear climate response in the agcm is found that closely resembles the observed composites including a shift in the equatorial positions of the maxmium rain responses and a phase shift of teleconnection patterns in the upper troposphere barotropic model experiments indicate that the inherent nonlinearity in the tropical rain response may itself be responsible for the phase shift in the extratropical teleconnection patterns

interannual tasmanian rainfall variability associated with large scale climate modes interannual rainfall variability over tasmania is examined using observations and reanalysis data tas manian rainfall is dominated by an east west gradient of mean rainfall and variability the pacific south american mode psa el nino southern oscillation enso and the southern annular mode sam each show clear influences on the interannual variability of tasmanian rainfall composites of rainfall during each phase of enso and the psa suggest a notable islandwide influence of these climate modes on tasmanian rainfall in contrast the positive phase of the sam is associated with drier conditions over the west of the island the psa and the sam project most prominently over the southwest of the island whereas the enso signature is strongest in the north empirical orthogonal functions eofs of rainfall over tasmania show a leading mode explaining 72 of total variance of coherent islandwide in phase anomalies with dominant periods of 2 and 5 yr the second eof accounts for 14 of total variation characterized by out of phase east west anomalies which is likely a combination of all three modes the eof1 mode can be attributed to enso the psa and to a lesser extent the sam rainfall over tasmania an island off the southeast coast of australia is potentially influenced by several large scale climate modes operating over the surrounding oceans the island lies between 144 58 and 1488 ea nd stretches from 408 to 43 58s with the prevailing westerly winds responsible for the majority of rainfall tasmania also has a distinct gradient in orography with high mountains in the west extending into the central regions while the east remains relatively flat tasmania s prox imity to the southern ocean gives it a comparatively differentclimatefromtherest oftheaustralianmainland the combination of a westerly airstream and strong orographic influences results in a large gradient of rain fall from the west to the east of tasmania as seen in figs 1a b consequently tasmania is regularly clipped by extratropical cyclones and cold fronts embedded in these westerlies which also advect large amounts of moisture

southern westerly winds submit to the enso regime a multiproxy paleohydrology record from lake dobson tasmania abstract the el nino southern oscillation enso and southern westerly winds sww profoundly influence synoptic scale climate in the southern hemisphere although many studies have invoked either phenomenon to explain trends in proxy data few have demonstrated the transition from a climate dominated by sww flow to one controlled by el nino activity which is postulated to have occurred after 5 cal ka bp in the mid latitudes of the southern hemisphere tasmania southeast australia is ideally situated to detect changes in both of these climatic controls currently el nino and la nina events result in drier and wetter conditions island wide respectively with the greatest impact in the north further tasmania houses north south trending mountain ranges near its western coast as a result areas west of the mountains exhibit a positive correlation between sww flow and precipitation while eastern regions possess either no or a negative relationship here we present data from chironomid remains charcoal and geochemical proxies to investigate the paleohydrological history of lake dobson a site located in mount field national park tasmania the proxies revealed three broad periods 1 an early holocene 11 5 8 3 cal kyr bp characterised by generally high rainfall the occurrence of irregular fires and elevated charcoal influx at 11 4 and 10 2 cal ka bp conditions compatible with attenuated sww flow over the site 2 an ambiguous mid holocene 8 3 5 cal kyr bp that marks the transition from a sww to enso dominated climate and 3 a relatively dry and stable late holocene 5 cal kyr bp to present that is consistent with the onset of a climate controlled by enso activity i e characterised by a more mean el nino climate state the proxy record of lake dobson highlights the teleconnections between the equatorial pacific and southern australasia

holocene climate change in arid australia from speleothem and alluvial records new high resolution mc icpms u th ages and c and o isotopic analyses from a holocene speleothem in arid south central australia provide evidence for increased effective precipitation ep relative to present at c 11 5 ka and c 8 5 ka peak moisture at 7 6 ka and onset of an arid climate similar to present by c 5 ka 18o and 13c time series data exhibit marked 1 contemporaneous excursions over base line values of 5 3 and 11 0 respectively suggesting pronounced moisture variability during the early middle holocene climatic optimum optically stimulated luminescence and 14c ages from nearby terraced aggradational alluvial deposits indicate a paucity of large floods in the late pleistocene and at least five large flood events in the last c 6 kyr interpreted to mark an increased frequency of extreme rainfall events in the middle holocene despite overall reduced ep increased ep in south central australia during the early to middle holocene resulted from 1 decreased el nino southern oscil