additional evidence on some relationship between seismic electric signals ses and earthquake focal mechanism abstract investigating the period 1983 1994 for western greece a possible correlation between the selectivity characteristics of the ses seismic electric signals of the van method and earthquake parameters has been reported by uyeda et al uyeda s al damegh k s dologlou e nagao t 1999 some relationship between van seismic electric signals ses and earthquake parameters tectonophysics 304 41 55 they found that the earthquake source mechanism changed from largely strike slip type to thrust type at the end of 1987 and this coincided with a shift in the ses sensitive site from pirgos pir to ioannina ioa van station here we report the results for the period january 1 2002 july 25 2004 during which the ses sensitive site of pir became again active after a 10 year period of quiescence this activation was followed by strike slip earthquakes on august 14 2003 and march 17 2004 with magnitude 6 4 and 6 5 respectively in the hellenic arc which provides additional evidence on the correlation reported by uyeda et al the ses activities recorded at pir have been discriminated from artificial noise by employing the natural time domain analysis introduced recently

microseimicity and strain pattern in northwestern greece during a 7 week microearthquake experiment conducted in epirus akarnania and the ionian islands of western greece we located approximately 600 earthquakes with magnitudes between 2 and 4 2 no event was deeper than 40 km the seismicity cannot be clearly associated with any single fault except the lixourion right lateral fault located west of the ionian islands focal mechanisms of about 100 earthquakes show for a narrow band of earthquakes located along the coast ene wsw shortening consistent with the surface tectonics farther east focal mechanisms show nnw sse extension beneath the foothills of the pindus mountains which is unrelated to surface faulting but is consistent with the presently subsiding basins this strain pattern is seen far north and south of the lixourion fault and is similar to the one observed in the peloponnese it suggests that a large scale mechanism is responsible for the recent geodynamics of both the northwestern and southwestern aegean

surface water temperature salinity and density changes in the northeast atlantic during the last 45 000 years heinrich events deep water formation and climatic rebounds we developed a new method to calculate sea surface salinities sss and densities ssd from planktonic foraminiferal 18o and sea surface temperatures sst as determined from planktonic foraminiferal species abundances sst sss and ssd records were calculated for the last 45 000 years for biogeochemical oceanic flux study bofs cores 5k and 8k recovered from the northeast atlantic the strongest feature is the dramatic drop in all three parameters during the heinrich ice rafting events we modelled the possibility of deepwater formation in die northeast atlantic from the ssd records by assuming that the surface waters at our sites cooled as they flowed further north comparison with modelled north atlantic deepwater densities indicates that there could have been periods of deepwater formation between 45 000 and 30 000 14c years b p interrupted by iceberg meltwater input of heinrich event 3 and 4 at 27 000 and 38 000 14c years b p and during the holocene no amount of cooling in the northeast atlantic between 30 000 and 13 000 years could cause deep water to form because of the low salinities resulting from the high meltwater inputs from icebergs our records indicate that after each heinrich event there were periods of climatic rebound with milder conditions persisting for up to 2000 years as indicated by the presence of warmer and more saline water masses after these warm periods conditions returned to average glacial levels these short term cold and warm episodes in the northeast atlantic are superimposed on the general trend towards colder conditions of the last glacial maximum lgm heinrich event 1 appears to be unique as it occurs as insolation rose and was coeval with the initial melting of the fennoscandian ice sheet we propose that meltwater input of heinrich event 1 significantly reduced north atlantic deep water formation reducing the heat exchange between the low and high latitudes thus delaying deglaciation by about 1500 radiocarbon years 2000 calendar years

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

centroid moment tensor solutions for january march 1992 abstract centroid moment tensor solutions are presented for 160 earthquakes that occurred during the first quarter of 1992 the solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model sh8 u4l8 of dziewonski and woodward

millennial scale deep water oscillations reflections of the north atlantic in the deep pacific from 10 to 60 ka northeast pacific benthic foraminiferal 18o and 13 reveal repeated millennial scale events of strong deep sea ventilation associated with nutrient depletion and or high gas exchange during stadial cool high ice volume episodes from 10 to 60 ka opposite the pattern in the deep north atlantic two climate mechanisms may explain this pattern north pacific surface waters chilled by atmospheric transmission from a cold north atlantic and made saltier by reduced freshwater vapor transports could have ventilated the deep pacific from above alternatively faster turnover of pacific bottom and mid depth waters driven by southern ocean winds may have compensated for suppressed north atlantic deep water production during stadial intervals during the younger dryas event 11 6 13 0 cal ka ventilation of the deep ne pacific 2700 m lagged that in the santa barbara basin 450 m by 500 years suggesting that the ne pacific was first ventilated at intermediate depth from above and then at greater depth from below this apparent lag may reflect the adjustment time of global thermohaline circulation

the effect of geological anisotropies on the detectability of seismic electric signals abstract the detectability of seismic electric signals was examined in relation to the geological anisotropies both at the large scale of geotectonics and neotectonics and at the smaller scale of electric stations the distribution of the detected seismic events in the cases of the ioannina and assiros stations showed a strong dependence upon the geotectonic zonation and especially upon the ophiolite suture zones of north pindos and almopia axios vardar the major neotectonic transcurrent faults did not show an important effect keratea station and especially point a on a granitic dyke showed an extraordinary detectability independant of the geotectonic zonation attributed to the local anisotropy and to its connecton with batholiths at depth within the aegean paleo volcanic arc of upper miocene age

physical properties of the variations of the electric field of the earth preceding earthquakes ii determination of epicenter and magnitude abstract as reported in the preceding paper a transient change of the electric field of the earth seismic electric signal hereafter called ses appears many hours before an earthquake eq by measuring this change in a given direction and dividing it with a suitable relative effective resistivity one obtains a quantity that reflects the current density in this direction measurements in two directions e w and n s give the relative signal intensity jrel at the station under consideration by measuring jrel at a number of stations and considering that it attenuates according to a 1 r law the epicenter can be determined with an accuracy usually around 100 km once the epicenter has been determined the product jrel r can be evaluated so that the magnitude m can be estimated by resorting to an empirical log jrel r versus m plot the uncertainty of m is around 0 5 units following sobolev 1975 and for the statistics to be beyond any doubt predictions were officially documented before the eq occurrence for 23 earthquakes with a magnitude equal or greater than ms 5 0 two events were missed the present method is compared to other electrical methods used in china japan and soviet union a number of problems concerning the origin of the effect its directivity and the attenuation with distance remain open for further studies

equatorial western atlantic ocean circulation changes linked to the heinrich events deep sea sediment evidence from the amazon fan this paper is included in the special publication entitled geological evolution of ocean basins results from the ocean drilling program edited by a cramp c j macleod s v lee and e j w jones the amazon fan is an excellent area to obtain climatic records of the last glacial interglacial cycle glacial sedimentation rates ranging from 1 to over 50 m ka 1 provide an opportunity to obtain marine records approaching the resolution of the greenland ice cores ocean drilling program leg 155 sites 932 and 933 from the eastern middle amazon fan complex have been studied at a resolution of 50 cm 100 400 years the identification of palaeomagnetic excursions distinctive patterns in the palaeomagnetic remanence intensity records and ams 14c dates have provided an age framework for both sites 932 and 933 however due to extensive reworking in the site 933 records it was only possible to construct a detailed age model for site 932 planktonic foraminiferal stable oxygen and carbon isotope records of six species were obtained for both sites the planktonic foraminiferal carbon isotope records of both sites 932 and 933 show a distinct negative deviation during termination i 13 15 calendar ka we suggest this could have been caused by an increase in the sediment discharge of the amazon river because of the deglaciation of the andes and or the release of significant quantities of gas hydrates as large parts of the amazon fan sediment column failed because of increased sea level positive 18o deviations are also observed in the site 932 records which seem to be coeval with the heinrich events it is suggested that the enhanced ice rafting in the north atlantic during the heinrich events increased the latitudinal thermal gradient and thus the zonal component of the wind system this reduced the northward penetration of the inter tropical convergence zone curtailing the cross equatorial export of the north brazilian coastal current nbcc and resulting in a permanent nbcc retroflection this increased the surface water salinity of the amazon fan and thus led to the observed positive 18o deviations

latest aspects of earthquake prediction in greece based on seismic electric signals ii abstract since 1983 continuous monitoring of the electrotelluric field has been carried out using an array of measuring stations located at various sites in greece the basic physical properties of the transient changes seismic electric signals ses in the electrotelluric field that are forerunners of earthquakes were first described six years ago since then a large body of data has been collected resulting in new insight into various aspects of the method the present paper reviews the latest developments in ses based earthquake prediction and describes the current procedures used to predict the epicenter and magnitude of an impending earthquake a detailed list of the predictions officially issued in greece during the past 3 years january 1 1987 november 30 1989 is also given public warnings were issued well before the most destructive seismic activity

seismic faults in the aegean area abstract reliable fault plane solutions of shallow earthquakes and information on surface fault traces in combination with other seismic geomorphological and geological information have been used to determine the orientation and other properties of the seismic faults in the aegean and surrounding area thrust faults having an about nw se strike occur in the outer seismic zone along western albania westernmost part of mainland of greece ionian sea south of crete south of rhodes the inner part of the area is dominated by strike slip and normal faulting strike slip with an about ne sw slip direction occurs in the inner part of the hellenic arc along the line peloponnesus cyclades dodecanese southwest turkey as well as along a zone which is associated with the northern aegean trough and the northwesternmost part of anatolia all other regions in the inner part of the area are characterized by normal faulting the slip direction of the normal faults has an about sw ne direction in crete n38 e and an about e w direction n81 e in a zone which trends n s in eastern albania and its extension to western mainland of greece in all other regions central greece southern yugoslavia and bulgaria western turkey the slip of the normal faults has an about n s direction

centroid moment tensor solutions for april june 1993 abstract centroid moment tensor solutions are presented for 196 earthquakes that occurred during the second quarter of 1993 the solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model sh8 u4l8 of dziewonski and woodward

centroid moment tensor solutions for july september 1993 abstract centroid moment tensor solutions are presented for 186 earthquakes that occurred during the third quarter of 1993 the solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model sh8 u4l8 of dziewonski and woodward

some relationship between van seismic electric signals ses and earthquake parameters abstract a possible correlation between ses seismic electric signals of the van method characteristics and earthquake parameters is investigated for the period january 1 1983 december 31 1994 for western greece during this period there were total of 55 earthquakes of mb 5 0 in the region of the so called selectivity maps of the ioannina ioa and pirgos pir van stations cmt solutions are available for 29 of these earthquakes eighteen were preceded by ses at ioa and eleven at pir none of them was preceded by simultaneous ses at both stations the main results are as follows 1 the direction of the ses vector at ioa is correlated with the focal position of predicted earthquakes although nearby earthquakes often have ses with dissimilar vector directions 2 the ses of all nine thrust events of the 29 earthquakes were observed at ioa but their vector direction was not unique 3 eleven earthquakes in the zone west of kefallinia to peloponese preceded by ses at pir were of the strike slip type with varying degrees of normal component the vector direction of ses at pir for these earthquakes was predominantly westward 4 the source mechanism changed from largely strike slip type to thrust type in the above zone at the end of 1987 and this coincided with a shift in the sensitive site from pir to ioa indicating a possible correlation between the source mechanism and selectivity characteristics of van stations

regional focal mechanisms for earthquakes in the aegean area the distribution of the focal mechanisms of the shallow and intermediate depth h 40 km earthquakes of the aegean and the surrounding area is discussed the data consist of all events of the period 1963 1986 for the shallow and 1961 1985 for the intermediate depth earthquakes with m s 5 5 for this purpose all published fault plane solutions for each event have been collected reproduced carefully checked and if possible improved accordingly the distribution of the focal mechanisms of the earthquakes in the aegean declares the existence of thrust faulting following the coastline of southern yugoslavia albania and western greece extending up to the island of cephalonia this zone of compression is due to the collision between two continental lithospheres apulian eurasian the subduction of the african lithosphere under the aegean results in the occurrence of thrust faulting along the convex side of the hellenic arc these two zones of compression are connected via strike slip faulting observed at the area of cephalonia island the p axis along the convex side of the arc keeps approximately the same strike throughout the arc 210 nne ssw and plunges with a mean angle of 24 to southwest the broad mainland of greece as well as western turkey are dominated by normal faulting with the t axis striking almost ns with a trend of 174 for greece and 180 for western turkey the intermediate depth seismicity is distributed into two segments of the benioff zone in the shallower part of the benioff zone which is found directly beneath the inner slope of the sedimentary arc of the hellenic arc earthquakes with depths in the range 40 100 km are distributed the dip angle of the benioff zone in this area is found equal to 23 this part of the benioff zone is coupled with the seismic zone of shallow earthquakes along the arc and it is here that the greatest earthquakes have been observed m s 8 0 the deeper part inner of the benioff zone where the earthquakes with depths in the range 100 180 km are distributed dips with a mean angle of 38 below the volcanic arc of southern aegean

centroid moment tensor solutions for january march 1993 abstract centroid moment tensor solutions are presented for 177 earthquakes that occurred during the first quarter for 1993 the solutions are obtained using corrections for aspherical earth structure represented by dziewonski and woodward s whole mantle shear velocity model sh8 u4l8

earthquake predictions issued in greece by seismic electric signals since february 6 1990 abstract the present paper describes the results of all official predictions that were issued on the basis of seismic electric signals recorded in greece during the period feb 6 1990 may 31 1991 they amount to four cases of activities multiple events in two cases the predictions were also submitted for publication to tectonophysics before the beginning of the corresponding seismic activities while in a third case the prediction was announced during an international conference held in japan also before the occurrence of the earthquake after the submission of the manuscript a number of earthquakes occurred during the period up to may 31 1992 they are summarized along with their predictions in appendix 1

patterns of seismic release in the southern california region southern california experiences earthquakes on the san andreas system of vertical right lateral predominantly strike slip faults and on a second system of faults that includes thrusts oblique slip left lateral and other faults pattern recognition and cluster analysis are used to analyze the catalog of earthquakes with magnitudes 5 5 from 1915 to 1994 we use pattern recognition to find a suite of traits that would characterize each of these two systems and distinguish them from each other both pattern recognition and cluster analysis show that epochs of seismic release occur in which one or the other system is the predominant form of earthquake activity for the past 2 decades the second system has been the active one small changes in the direction of plate movements could account for this phenomenon seismic release on the san andreas system is preceded by episodes of activity in the great basin or in the gulf of california presumably these episodes would represent extension in the former region and spreading and slip on transform faults in the latter

seismo induced effects in the near earth space combined ground and space investigations as a contribution to earthquake prediction abstract the paper aims at giving a few methodological suggestions in deterministic earthquake prediction studies based on combined ground based and space observations of earthquake precursors up to now what is lacking is the demonstration of a causal relationship with explained physical processes and looking for a correlation between data gathered simultaneously and continuously by space observations and ground based measurements coordinated space and ground based observations imply available test sites on the earth surface to correlate ground data collected by appropriate networks of instruments with space ones detected on board of leo satellites at this purpose a new result reported in the paper is an original and specific space mission project esperia and two instruments of its payload the esperia space project has been performed for the italian space agency and three esperia instruments arina and lazio particle detectors and egle search coil magnetometer have been built and tested in space the egle experiment started last april 15 2005 on board the iss within the eneide mission the launch of arina occurred on june 15 2006 on board the resurs dk 1 russian leo satellite as an introduction and justification to these experiments the paper clarifies some basic concepts and critical methodological aspects concerning deterministic and statistic approaches and their use in earthquake prediction we also take the liberty of giving the scientific community a few critical hints based on our personal experience in the field and propose a joint study devoted to earthquake prediction and warning

short term earthquake prediction current status of seismo electromagnetics abstract loss of human lives as a result of earthquakes is caused overwhelmingly by the collapse of buildings within less than a few minutes of main shocks the most urgent countermeasure consists of two key elements one is strengthening of weak structures and the other is short term earthquake prediction short term prediction needs precursors although some promising precursors are reported the prevailing views in japan and elsewhere are overly pessimistic the pessimism largely roots in the fact that short term precursors are generally non seismic and tools developed for seismology are not designed to detect them nonetheless nationally funded large scale earthquake prediction programs always emphasize the need to reinforce seismometer networks they do not take into account the views of those in the science community who point to the importance of non seismic precursors while there are well founded causes to be skeptical the situation needs to be improved one reason for skepticism is that the observations of precursors have not yet been perfect enough and another is that some important fundamental aspects of non seismic precursors are still unresolved we review some of these problems

geoelectric potential changes possible precursors to earthquakes in japan whether electromagnetic precursors to earthquakes eqs exist is an important question not only for eq prediction but also for understanding the physical processes of eq generation slow transient geoelectric potential changes have been observed before several recent eqs in japan in most cases they appeared 1 19 days before the eqs and their duration and intensity were several minutes to 1 h and 1 2 mv 100 m the changes appeared before five of all six eqs with magnitude 5 that occurred within 20 km of our stations during the observation period changes were also detected at greater epicentral distances up to 75 km before two other eqs including one eq of magnitude 4 7 which was preceded by a signal simultaneously recorded at three widely separated stations these geoelectric potential changes have been distinguished through the following criteria from a multitude of other changes which were noise of various origins i the selected changes were proportional in amplitude to the length of the recording station s short 100 m dipoles and were simultaneously detected also on long 1 10 km dipoles when the latter were in operation ii no such changes occurred during the observation period that were not followed by eqs although the eq precursory nature of these geoelectric potential changes is admittedly unproven it seems that the present results warrant continued serious research into the occurrence generation and transmission of these signals and their possible causal relationship to eqs

evidence for massive discharges of icebergs into the north atlantic ocean during the last glacial period sediments in the north atlantic ocean contain a series of layers that are rich in ice rafted debris and unusually poor in foraminifera1 here we present evidence that the most recent six of these heinrich layers deposited between 14 000 and 70 000 years ago record marked decreases in sea surface temperature and salinity decreases in the flux of planktonic foraminifera to the sediments and short lived massive discharges of icebergs originating in eastern canada the path of the icebergs clearly marked by the presence of ice rafted detrital carbonate can be traced for more than 3 000 km a remarkable distance attesting to extreme cooling of surface waters and enormous amounts of drifting ice the cause of these extreme events is puzzling they may reflect repeated rapid advances of the laurentide ice sheet perhaps associated with reductions in air temperatures yet temperature records from greenland ice cores appear to exhibit only a weak corresponding signal moreover the 5 10 000 yr intervals between the events are inconsistent with milankovitch orbital periodicities raising the question of what the ultimate cause of the postulated cooling may have been

physical properties of the variations of the electric field of the earth preceding earthquakes i abstract in an earlier paper we described the physical properties of the preseismic transient variations in the electrotelluric field the present letter clarifies a few points that were not properly emphasized in our previous publications furthermore recent results like that of the destructive kalamata earthquake on september 13 1986 indicate that the duration of a preseismic electric signal may reach considerably high values lasting up to several hours

statistical evaluation of the ses predictions issued in greece alarm and success rates earthquake prediction based on continuous measurements of the electric field of the earth has been systematically carried out by varotsos and co workers in greece predictions were issued by telegrams to greek authorities statistical evaluation of these predictions was made by comparing telegram prediction information with earthquake parameters determined by the us geological survey the space time domain selected for this evaluation was 20 24 e 36 41 n from january 1987 to june 1989 successfully predicted earthquakes are defined here as those that occurred within 22 days of the prediction within 100 km of the predicted epicenter and with a magnitude difference predicted minus true rot greater than 0 7 twelve predictions were issued for earthquakes with expected ms 5 3 following our criteria ten were successful two were not the magnitudes of the predicted earthquakes varied from 4 1 to 5 5 for earthquakes with mb usgs 5 0 the ratio of the predicted to the total number of earthquakes is 6 12 50 and the success rate of the prediction is also 612 50 with a probability gain of a factor of 4 with a confidence level of 99 8 the possibility of this success rate being explained by a random model of earthquake occurrence taking into account a regional factor which includes high seismicity in the prediction area can be rejected for earthquakes with mb usgs 4 5 a statistical significance could not be obtained because of the large number of small earthquakes

identification and analysis of electromagnetic signals in greece the case of the kozani earthquake van prediction an electric station was installed in july 1993 4 5 km away from the van station of ioannina and recorded in the following two years a number of anomalous signals including those of april 18 and 19 1995 interpreted by the van group as seismic electric signals precursors to the may 13 kozani earthquake west macedonia a magnetic station was also installed and clearly recorded the magnetic components of the same events the amplitude shape characteristic pattern and duration magnetic characteristics and polarisation of the anomalous signals suggest that they are generated by artificial industrial sources

a three year continuous sample of officially documented predictions issued in greece using the van method 1987 1989 abstract copies of all officially documented predictions issued in greece using the van method for the period 1987 1989 are presented a correlation between these predictions and earthquakes is attempted selectivity maps based on experimental data are drawn and the selectivity effect with relation to some earthquake source parameters is commented upon finally the quality of the predictions for large earthquakes is discussed