statistical analysis of the results of earthquake prediction based on bursts of aftershocks abstract the premonitory seismicity pattern described as a burst of aftershocks is analysed in 13 regions of the world its high statistical significance is ascertained the mathematical approach developed here may be useful in the analysis of other earthquake precursors

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

particle dynamics of the changjiang estuary and adjacent coastal region determined by natural particle reactive radionuclides 7be 210pb and 234th 1 the timescale of transport processes in estuarine and coastal regions can be evaluated using natural radionuclides with different half lives the distribution patterns of 7be 210pb and 234th in the water column from april to july 2008 were used to calculate the removal and residence times in the changjiang estuary the results showed that the maximum particulate activities of 7be 210pb and 234th were observed approximately 150 km downstream the turbidity maximum zone of the freshwater end number the mean distribution coefficients kd cm3 g 1 of the high suspended particulate matter spm group are higher than those of the lower spm group for 7be and 210pb for 234th the reverse is true based on a material balance in two dimensional models of 7be 210pb and 234th in the changjiang river mouth the removal times of these nuclides were approximately 0 66 12 1 6 21 and 1 2 5 4 days respectively the residence times increased toward the seaward side in the coastal region the removal times of 7be 210pb and 234th calculated by material balance in one dimensional models were approximately 1 1 26 1 2 27 and 0 70 23 days respectively moreover an enhanced resuspension process not only controlled the partitioning of 7be 210pb and 234th between the particulate and dissolved phases but also this process may play a dominant role in controlling the dynamic behavior of spm in the water column compared with the advection input output fluxes of the spm in the river mouth areas the removal and the resuspension fluxes were comparable in the estuary meanwhile old composition whose deposition into the seabed for a long time is enough for 7be to decay completely occupied only a small part in the resuspended sediment during resuspension process

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

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

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

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

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

tidal hydrodynamics and fine grained sediment transport on the radial sand ridge system in the southern yellow sea abstract the large radial sand ridge rsr system located in the southern yellow sea off the jiangsu coast is characterized by a radial current field and high suspended sediment concentrations sscs significant rectilinear currents are present over the northern sand ridge area whereas rotary currents prevail over the southern area the transition between the two being dominated by a locally generated trapped wave observations undertaken in 2006 and 2007 indicate a seasonal pattern in the ssc and associated dynamic characteristics the results of a calibrated hydrodynamic model show that the m2 tide dominates the rsr area the maximum tidal amplitude in the core region close to land being approximately 2 m an amphidromic point is located some distance north of the rsr off the abandoned yellow river mouth 121 686 e 34 6 n specifically the eulerian and lagrangian residual currents flow southward in both summer and winter whereas the stokes drift is directed southward in the north and northward in the south moreover in deep water the lagrangian residual current is mainly determined by the eulerian residual current whereas it is strongly influenced by the stokes drift in shallow water the seasonal variation in the residual current in the southern yellow sea is a good indicator for the location of the yellow sea warm current yswc in both summer and winter measurements show that a ssc peak appears off the abandoned yellow river delta in response to the strong currents and plentiful supply of fine grained sediment from coastal erosion another ssc peak lying close to the north branch of the changjiang river mouth is related to the abundant suspended sediment supplied by the river seasonal variations in ssc are observed in the study area maximum average values and widest diffusion from land occurring in winter this being contrasted by minimum mean values in summer sensitivity experiments demonstrate that the main factor influencing the distribution of ssc is the tide while river discharge wind and wave effects are small and very localized to explain the seasonal variation in ssc the role of hydrodynamics initial conditions and temperature are tested in the model the results show that the hydrodynamics play a significant role whereas the initial conditions only have a minor regional influence temperature on the other hand is also shown to greatly influence the seasonal variation in ssc because of substantial changes in the viscosity of the water and the erosion shear stress the modeled results are used to calculate sediment fluxes which are shown to be consistent with the lagrangian residual current pattern while wind waves can significantly change the fluxes in winter bed elevations change substantially on a monthly time scale in general the deep channels are undergoing erosion while the shallow ridges and coastal tidal flats are accreting the net sediment transport being directed towards the coastal tidal flat and the changjiang yangtze river subaqueous delta

microseismicity and stresses in the lesser antilles dipping seismic zone abstract microearthquake data from a telemetered array have been used to study the central antilles arc system the zone lying between lat 14 17 n and long 59 5 62 w has been investigated during the period 1979 1980 no shock with a magnitude larger than 4 5 was recorded results are well correlated with previous conclusions derived from teleseismic records the dip of the subducting plate is 60 everywhere in this area no composite focal mechanism can be produced for the region north of dominique for the southern region composite focal mechanisms reveal two zones for depths between 45 and 80 km the stress field seems mainly related to the interplate action beneath 80 km the slab dominantly neither in compression nor in tension earthquakes are more likely related to local stress fields a double layered structure has not been found in the earthquake distribution in the subducted plate nor in the stress field deduced from focal mechanisms

testing the sensitivity of past climates to the indirect effects of dust mineral dust particles are important ice nuclei in and as such indirectly impact earth s radiative balance via the properties of cold clouds using cesm1 0 6 cam5 1 and a new empirical parameterization for ice nucleation on dust particles we investigate the radiative forcing induced by dust in for different dust loadings dust emissions are representative of global conditions for the last glacial maximum and the mid pliocene warm period increased dust leads to smaller and more numerous ice crystals in mixed phase clouds impacting cloud opacity lifetime and precipitation this increases the shortwave cloud radiative forcing resulting in significant surface temperature cooling and polar amplification which is underestimated in existing studies relative to paleoclimate archives large hydrological changes occur and are linked to an enhanced dynamical response we conclude that dust indirect effects could potentially have a significant impact on the model data mismatch that exists for paleoclimates

seismicity and seismic gap in the lesser antilles arc and earthquake hazard in guadeloupe summary a seismic study of the lesser antilles arc has been carried out first for the period 1950 1978 for which we can use local seismic networks to draw maps of instrumental seismicity then for the period 1530 1950 for which we have catalogues of felt earthquakes the striking feature of the spatial distribution of foci is the cluster of epicentres in the northern half of the arc all large earthquakes m 7 5 are located north of 14 latitude seismicity cross sections through the arc show a variable dipping subduction zone along the arc the deep seismic zone is steeper in the centre of the arc than on the extremity the time space diagram for historical seismicity and the evidence of a seismic gap at the east of guadeloupe lead us to consider the northern half arc as a likely site for a large earthquake in the near future the seismic slip rate calculated from all major earthquakes since 1530 is of much greater value than that obtained from recent plate tectonic models suggesting that the recurrence rate of earthquakes is more than many hundreds of years with a possible aseismic creep

recent sediment accumulation and carbon burial in the east china sea 1 sediment and carbon budgets were constructed for the east china sea ecs shelf based on up to date data the total annual sediment flux in the ecs shelf is approximately 96 of the terrestrial input there is high retention of sediment on the ecs shelf owing to the broad nature of the shelf edge i e 500 600 km and because of an along shore sediment dispersal path driven by the east china sea coastal current ecscc and the taiwan warm current twc organic carbon oc burial was also observed based on the results for sediment accumulation and the oc proportion in surface sediment a total of 7 4 106 t of oc is preserved in shelf sediments source discrimination of sedimentary oc revealed that the percentage of oc burial for both terrigenous and marine oc sources was higher than the global mean value at 10 and 5 5 respectively presumably owing to high sediment accumulation high oc flux to sediment in the estuary and shelf break suggests that riverine discharge and upwelling of the kuroshio intrusion are key factors regulating oc burial over the shelf estimated using a mass balance model 15 20 of the carbon inventory is buried in the shelf sediment while 80 of the carbon inventory must be transported out of shelf area in the form of dissolved carbon organic and inorganic the accumulation of carbon in sediments and the outflow of dissolved carbon sustain a high carbon sink in the ecs

subduction of aseismic ridges beneath the caribbean plate implications for the tectonics and seismic potential of the northeastern caribbean normal seafloor entering the puerto rico and northern lesser antillean trenches in the northeastern caribbean is interrupted by a series of aseismic ridges on the north and south american plates these topographic features lie close to the expected trend of fracture zones created about 80 110 m y ago when this seafloor was formed at the mid atlantic ridge the northernmost of the ridges that interact with the lesser antillean subduction zone the barracuda ridge intersects the arc in a region of high seismic activity some of this seismicity including a large shock in 1974 occurs within the overthrust plate and may be related to the deformation of the caribbean plate as it overrides the ridge a large bathymetric high the main ridge is oriented obliquely to the puerto rico trench and intersects the subduction zone north of the virgin islands in another cluster of seismic activity along the inner wall of the trench data from a seismic network in the northeastern caribbean indicate that this intersection is also characterized by both interpolate and intraplate seismic activity magnetic anomalies bathymetric trends and the pattern of deformed sediments on the inner wall of the trench strongly suggest that the main and barracuda ridges are parts of a formerly continuous aseismic ridge a segment of which has recently been overridden by the caribbean plate reconstruction of mid miocene to recent plate motions also suggest that at least two aseismic ridges and possibly fragments of the bahama platform have interacted with the subduction zone in the northeastern caribbean the introduction of these narrow segments of anomalous seafloor into the subduction zone has segmented the arc into elements about 200 km long these ridges may act as tectonic barriers or asperities during the rupture processes involved in large earthquakes they also leave a geologic imprint on segments of the arc with which they have interacted a 50 km landward jump of the locus of island arc volcanism occurred in late miocene time along the northern half of the lesser antilles we postulate that the subduction of a segment of seafloor of anomolously thick crust being more buoyant than adjacent seafloor resulted in a marked shoaling in the dip of the descending slab and therefore a shift of the locus of volcanism in the region near western puerto rico and eastern hispanolia plio pleistocene interaction with a similar feature in this case a part of the bahama platform about 3 4 m y ago led to a jump in the locus of subduction as evidenced by a gap in the downgoing seismic zone that segment of the bahama platform interferred with the subduction process and was subsequently sutured onto the caribbean plate when the boundary jumped about 60 km to the northeast the maximum size of historic shallow earthquakes along the lesser antillean arc varies from about 7 0 7 5 in the center of the arc where the dip of the shallow part of the plate boundary is steep to 8 0 8 5 along the northern part of the arc where the dip is shallow the interaction of anomalous seafloor as along the northern lesser antilles can lead to the development of a wider than normal zone of interplate contact and hence to earthquakes that are larger than those associated with more typical seafloor entering subduction zones major seismic gaps and regions of high seismic potential currently exist along the northern lesser antilles and to the north of puerto rico both gaps are bounded by anomalous features on the downgoing plate the intersection of these features with the plate boundary created large asperities that may be good places to search for precursors to future large earthquakes a great shock in 1787 may have ruptured an existing seismic gap north of puerto rico between 65 and 67 w thus that gap can be expected to eventually rupture again in a great shock and not to accommodate plate motion by totally aseismic processes

influence of organic matter on the adsorption of 210 pb 210 po and 7 be and their fractionation on nanoparticles in seawater abstract improved applications of 210po 210pb and 7be as geochemical proxies require more detailed understanding of their interactions with particles here laboratory sorption experiments were carried out to examine the adsorption of 210po 210pb and 7be and their fractionation on inorganic nanoparticles including sio2 caco3 al2o3 tio2 and fe2o3 in the presence or absence of macromolecular organic compounds mocs that include humic acids ha acid polysaccharides aps and proteins bsa in natural seawater results showed that nanoparticle sorption was not greatly enhanced over that of microparticles as would be expected from their much higher specific surface areas likely indicating their aggregation in seawater it was found that synergistic interactions between inorganic nanoparticles mocs and radionuclides determined the sorption although their adsorption was particle composition dependent mocs enhanced the sorption of selected nuclides on most nanoparticles on average in the presence of mocs partition coefficients k c of 210po 210pb and 7be on nanoparticles increased 2 9 5 0 and 5 9 fold respectively the effect of mocs could be explained for 210po and 210pb from their different log k c values on inorganic nanoparticles in addition fractionation effects between 210po and 210pb or between 210pb and 7be could be quantified from their relative log k c values on end member sorbent components applications of both 210po 210pb and 7be 210pb pairs as particle dynamics tracers could be more quantitative when the nature of the organic coatings is taken into account

local overturn of active and non active seismic zones as a precursor of large earthquakes in the lesser antillean arc abstract the effect of short term activation of locally less active seismic zones simultaneously with relative quiescence of locally more active zones before strong earthquakes has been studied in the region of the lesser antillean arc this precursory pattern has been found earlier in southern california it takes place in the epicentral area several months before strong earthquakes on the basis of this effect a new preliminary prediction algorithm has been developed the algorithm determines regions of 100 km 100 km approximately in which the probability of the occurrence of strong earthquakes is increased for the period of 1 year in the present work the algorithm is improved a new version of the algorithm is applied retrospectively in the lesser antillean arc the results for the period 1984 june 1995 are as follows of the seven earthquakes with m 5 five have occurred in time space areas of increased probability tsip for strong earthquakes the time space volume of tsips is 8 of the total considered volume two tsips are false alarms the precursory pattern can be explained by the break up of asperities which is reflected in activation of less active areas corresponding to the asperities on the background of the larger scale quiescence

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

subduction and seismic hazard in the northern lesser antilles revision of the historical seismicity an important set of french and british archives on the historical seismicity of the northern lesser antilles is analyzed we present the most significant data which help to constrain the 8 february 1843 the 16 may 1851 and the 29 april 1897 earthquakes the 1843 event is the largest reported historical earthquake of the lesser antilles subduction arc and produced intensity ix on a segment about 100 km long between antigua and grande terre guadeloupe which contradicts the 300 km long proposed by other authors who mainly rely on robson s catalog 1964 this suggests a magnitude 7 5 to 8 0 the absence of tsunami and noticeable vertical deformation of the coasts in the source area makes very unlikely a normal fault mechanism but does not rule out the possibility of a subduction event because of the low dip angle of the interplate plane the dominance of moderate instrumental thrust earthquakes in the source area suggests a subduction mechanism for the 1843 event the northern and southern limits of the 1843 source area roughly coincide with the barracuda ridge and the tiburon ridge respectively which may have acted as barriers during the rupture process the northwestern portion of the tiburon ridge is associated with a lack of instrumental seismicity near grande terre which could indicate a possible magnitude 7 5 to 8 0 event in the next future moreover its mechanism could be normal which would provide the additional risk of a damaging tsunami the evaluation of seismic hazard must also take into account possible shallow moderate earthquakes as the 1851 and the 1897 events which produced intensities vii to viii in guadeloupe and may be related to observed major plioquaternary faults in this island

magnetic properties of east china sea shelf sediments off the yangtze estuary influence of provenance and particle size abstract the east china sea continental shelf offshore from the yangtze river estuary is a sedimentary system characterized by complicated hydrodynamic conditions and large variability in sediment texture granulometric geochemical and environmental magnetic analyses were carried out on surface sediments from this area to investigate the spatial variations of sediment composition and their underlying mechanisms magnetic properties of three particle size fractions 63 m were further analyzed to assist data interpretation our results reveal four distinct units subaqueous yangtze delta and inner shelf mud deposits unit a relict sands on the middle shelf unit b the transitional environment between unit a and b unit c and the area northern to unit a unit d the distributions of organic carbon iron manganese and their ratios mn fe suggest minor effects of reductive diagenesis on the surface sediment magnetic properties because of differences in sediment source and hydrodynamic conditions sediments in unit a have the highest ferrimagnetic and antiferromagnetic mineral concentrations as well as the finest ferrimagnetic grain size the significant variations of magnetic properties within unit a indicate the effect of particle size sorting during sediment transportation and deposition sediments in unit b have the coarsest ferrimagnetic grain size and the highest proportion of ferrimagnetic versus antiferromagentic minerals unit c which has a bimodal size distribution can be subdivided into a southern and northern part magnetically reflecting the influence of provenance and particle size the distinct magnetic characteristics of unit d are probably due to the strong influence of materials from the yellow river our results provide a new method for characterizing east china sea shelf sediments offshore of the yangtze river mouth against which the extent of the influence of the yangtze river on the east china sea can be examined furthermore it may provide a baseline for future long term monitoring in this sensitive continental margin environment that is influenced by the yangtze river