early radar echoes from small warm cumulus bragg and hydrometeor scattering abstract studies of small cumulus clouds in florida using x and s band radar 3 and 10 cm wavelengths reveal both hydrometeor and bragg scattering signals turbulent mixing between cloudy and drier environmental air can produce centimeter scale variations in refractive index that can lead to strong mantle echoes around the sides and tops of the clouds when the environmental air is exceptionally dry the s band bragg scattering signals are as strong as 10 dbz at cloud boundaries with weaker echoes in the cloud cores where hydrometeor scattering is also present the bragg signal at s band is typically about 19 db stronger than that at x band as expected from theory however there is in many cases an unexplained bragg like return from the clouds at s band that correlates with the x band echo but is only about 10 db stronger the x band echo is often dominated by backscattering from the cloud droplets and shows adiabatic ascent within the cloud cores fairly often up to at least 1 km above cloud base

simulation of braided river elevation model time series with multiple point statistics abstract a new method is proposed to generate successive topographies in a braided river system indeed braided river morphology models are a key factor influencing river aquifer interactions and have repercussions in ecosystems flood risk or water management it is essentially based on multivariate multiple point statistics simulations and digital elevation models as training data sets on the one hand airborne photography and lidar acquired at successive time steps have contributed to a better understanding of the geomorphological processes although the available data are sparse over time and river scales on the other hand geostatistics provide simulation tools for multiple and continuous variables which allow the exploration of the uncertainty of many assumption scenarios illustration of the approach demonstrates the ability of multiple point statistics to produce realistic topographies from the information provided by digital elevation models at two time steps

palaeoseismology review of the state of the art abstract historical seismicity provides only a partial indication of the seismotectonic character i e earthquake potential of a given region even in italy where a relatively long historical record exists available catalogues are generally unsatisfactory for this purpose fortunately strong earthquakes often leave geological evidence herein referred to as seismites that are mainly related to surface faulting folding or other deformation and occasionally to secondary ground failures e g landslides liquefaction features etc these features may be preserved and therefore palaeoseismological studies may detect and date them thereby permitting extension of knowledge beyond the local historical threshold up to 2000 years in the most fortunate cases this paper provides a summary of criteria which may aid in the identification of areas suitable for palaeo earthquake investigation historical seismicity and the presence of well developed tectonic geomorphic features are recognized as the most reliable criteria for identifying active faulting however lack of these characteristics cannot be considered conclusive evidence for lack of activity palaeoseismological techniques aim at identifying not only the obvious effects of surface faulting such as offset of young geologic units but also the more subtle tectonic or non tectonic features including liquefaction structures gravity features and coseismic uplift and or subsidence finally we discuss some questions that pertain to palaeoseismicity evaluation techniques among these are the reliability of the quaternary dating techniques the evaluation of the seismic energy released minimum magnitude and principally the unequivocal identification of a seismic origin for the considered geological structures

paleoseismology along the 1980 surface rupture of the irpinia fault implications for earthquake recurrence in the southern apennines italy the irpinia fault was the source of the ms 6 9 1980 irpinia earthquake and produced the first unequivocal historical surface faulting in italy trenching of the 1980 fault scarp at piano di pecore a flat intermontane basin about 5 km south of the 1980 instrumental epicenter provides the first data on earthquake recurrence intervals slip per event and slip rate on a major normal fault in the southern apennines fault zone the trenches exposed evidence of four pre 1980 paleoearthquakes that occurred during the past 8600 years a best estimate average recurrence interval is 2150 years although the time interval between individual events varies by as much as a factor of 2 each paleo earthquake is similar to the 1980 surface rupture in amount of slip and style of deformation which suggests that the 1980 event is characteristic for the irpinia fault slip per event values average 61 cm the net vertical displacement of 2 12 2 36 m since 8600 cal year b p observed in the trenches gives a vertical slip rate of 0 25 0 35 mm yr a dip slip rate of 0 29 0 40 mm yr and an extension rate of 0 14 0 20 mm yr although fault behavior data are only available for the irpinia fault they provide a starting point for evaluating earthquake recurrence and rates of deformation in southern apennines they suggest that 1 fault specific earthquake recurrence intervals based on the historical seismic record overestimates the occurrence of large magnitude m7 earthquakes and 2 the holocene rate of extension across the apennines is 1 mm yr the 1980 earthquake and the paleoseismologic observations show that repeated and localized surface faulting occurs in southern apennines and leaves subtle but distinct geomorphic evidence that can be detected with detailed and careful investigation

palaeoseismological investigation of the tyrnavos fault thessaly central greece abstract a palaeoseismological investigation has been carried out along the tyrnavos fault an ese wnw trending north dipping normal fault representing one of the major tectonic structures bordering the late pleistocene holocene tyrnavos basin northern thessaly central greece according to geological structural morphotectonic and geophysical researches the tyrnavos fault has been geometrically and kinematically characterised as a typical aegean type active fault six trenches have been excavated and logged in detail in order to quantify the most important seismotectonic parameters like the characteristics of past earthquakes their ages the elapsed time from the last event the short term slip rate and the mean return period several samples have been also collected for absolute dating that has been performed with different techniques like tl osl and ams sedimentological structural and chronological data document a late pleistocene to holocene morphogenic activity of the tyrnavos fault which is characterised by vertical co seismic displacements of 20 40 cm and possible recurrence interval of 2 2 5 ka the comparison between the estimated short term ca 0 05 0 1 mm a and long term 0 1 0 2 mm a slip rates and the elapsed time from the last earthquake suggest the occurrence of a possible seismic gap along the tyrnavos fault due to the peculiar position of the selected site at the termination of the fault scarp in the bedrock the lateral variability in morphogenic behaviour of an active fault is also observed the location of the fault within a highly populated region and the proximity to the third largest town of greece larissa increases the seismic hazard of the area

the 1 october 1995 dinar earthquake sw turkey the dinar earthquake ms 6 1 usgs pde of 1 october 1995 occurred on the nwse trending dinar fault the earthquake is associated with a 10 km long surface rupture with predominantly normal faulting the mainshock was preceded by a series of foreshocks that started 6 days before the mainshock and included two md 4 5 events the mainshock source mechanism derived from the inversion of broad band p waves revealed that two sub events occurred on a nw se trending normal fault with a small strike slip component according to the source model estimated in this study the first rupture started at a depth of about 8 km and reached to a depth of about 12 km propagating north west the total seismic moment found from the inversion of p waveforms is 2 0 times 10 18 nm the seismic moment of the second sub event was about four times larger than the first one field observations gps measurements and slip vector obtained from the inversion of broad band p waveforms suggest that the nw se trending dinar fault is due to the internal deformation of sw anatolia moving south westwards

faulting associated with historical and recent earthquakes in the eastern mediterranean region summary this paper summarizes evidence for surface faulting in historical and recent earthquakes in the eastern mediterranean region and in the middle east such information is particularly important for studies of active tectonics and for palaeoseismology we have found 78 cases of faulting pre 1900 and 72 post 1900 some of which show that faults that have apparently been inactive this century had already ruptured before 1900 for some cases faulting could not have been predicted from 20th century activity and in others it could have been expected but has not been observed during the instrumental period the data are suycient to allow the derivation of relationships between magnitude and rupture length

morphological controls on the downstream passage of a sediment wave in a gravel bed stream sediment waves in river systems have been widely reported although few studies have examined the interaction between these waves and the morphology of the reaches through which they pass this interaction determines how waves are modified as they propagate downstream this study documents the origin and downstream passage of an avulsion generated sediment wave through a 374 m study reach of the allt dubhaig scotland a nested survey framework was adopted with volumes calculated from cross sections spaced between 10 and 40 m apart documenting the origin and downstream passage of the wave the wave moved through an intensively c 1 m cross section spacing monitored 120 m stretch reach a within the study reach allowing assessment of sediment exchanges between the incoming wave and the local morphology successive surveys show the movement of the wave through and out of the reach and also that areas where wave sediment was deposited did not always correspond with areas of subsequent erosion reach a was divided into three morphologically distinct sub reaches 1a 2a and 3a within which sediment fluxes and the three dimensional distribution of erosion deposition were estimated sediment wave input into 1a and 2a relatively stable sub reaches caused forced bar aggradation and erosion of sediment from elsewhere within the reach which then became part of the wave the downstream transfer of this sediment into unstable 3a caused aggradation and in response widespread erosion which increased the magnitude of the sediment wave as it exited reach a sediment exchange between the recipient reach and the wave depends upon local morphological stability and is a crucial process affecting wave magnitude and attenuation the macroscale sediment wave interacted with rather than overwhelmed the recipient morphology 1998 john wiley sons ltd

radar and in situ observations of small cumulus physical interpretations of radar bragg scatter radar observations of small cumulus clouds are compared to predictions of radar measurements based on in situ measurements and the theory of radar back scatter at the wavelengths used both rayleigh and bragg scatter can be important in small cumulus a theoretical derivation of radar back scatter from small cumulus clouds in which both terms are succinctly derived using a common mathematical model is presented for the earliest stages of cumulus clouds the predictions of bragg scatter based on in situ measurements of water vapour fluctuations are in close agreement with radar measured bragg scatter this suggests that the theory is adequate and our interpretations of the radar observations are correct these interpretations include identifying regions where entrainment and mixing are ongoing identifying adiabatic cores and estimating the kolmogorov microscale of turbulence as the small cumulus develop and enter the early collision and coalescence stages another source of bragg scatter can become significant it is argued via observations that the additional bragg scatter comes from anomalous liquid water fluctuations these liquid water fluctuations are called anomalous because they exceed what would result if liquid water mixed as a passive scalar the bragg scatter caused by liquid water may reach effective values of 5 10 dbz for a 3 cm wavelength x band radar and thus confounds attempts to derive rayleigh scatter values below this level using a dual wavelength x and s band radar system copyright 2007 royal meteorological society

hydraulic modeling of bed load transport in gravel bed laba river on the basis of a field study of a piedmont braided reach of the gravel bed laba river in the northern caucasus russia an undistorted 1 50 scale mobile bed hydraulic model was constructed in an outdoor experimental plot of the state hydrological institute st petersburg russia channel and hydraulic regimes of the laba river were studied in this model attention was paid to the regime of bed load transport and its relation to the hydraulic characteristics of the flow the same problems were investigated in an 100 m long 1 m wide flume with glass walls also located at the state hydrological institute and in an 18 m long 2 46 m wide steel tilting flume at hr wallingford ltd u k quantitative characteristics of bed load transport were obtained from the laboratory experiments and compared with the field data proximity of the field and scaled up laboratory data demonstrates that the processes of bed load transport of gravel bed rivers can be faithfully reproduced in small scale models and flumes

variability of bedload transport and channel morphology in a braided river hydraulic model this paper investigates variability in bedload transport and channel morphology for 11 replicate experimental runs in an approximately 1 50 braided river model the experiments each of 90 h duration were carried out in a 20 3m tilting flume all the experiments started with the same initial conditions bedload transport was measured at 5 min intervals in a collection drum at the exit from the flume the model showed reasonable hydraulic similarity when compared to prototype rivers results show that mean bedload transport rates for the 11 runs vary in the range 0 98 to 1 49gs 1 mean 1 21 coefficient of variation 11 per cent within run transport rates commonly vary from close to zero to two and occasionally three or four times the mean rate within the bedload series several irregular phases of transport intensity can be observed but time series analysis of the data show little underlying serial structure an ar 2 autoregressive model is appropriate channel patterns are narrow braided are established quickly and remain relatively stable throughout the runs although channel widths increase between 20 and 103 per cent over the 11 runs channel behaviour varies from aggradational to transitional between aggradation and degradation time averaged bedload transport rate is weakly correlated with braiding intensity in general these results demonstrate that for a given set of controlling variables bedload transport and channel morphology can be approximately replicated

very early formation of big liquid drops revealed by zdr in continental cumulus abstract examination of the early radar echo histories of several vigorous cumulus clouds in northeast colorado and northwest kansas with sensitive dual polarization radar reveals the formation of millimeter sized water drops at about the same time that the conventional first precipitation echo from ice forms aloft the early positive zdr values appear in the vicinity of the 0 c level the radar data do not specify height accurately and soon extend both above and below it positive zdr is found within and to the upwind side of the updraft separate from the conventional first precipitation echoes which appear first at higher altitude generally downwind of the updraft core and have no significantly positive zdr big liquid drops were not expected this early in the formation of continental cumulus the early presence of supercooled water drops larger than cloud droplets may be a significant factor in the glaciation of these clouds the kind of early radar coverage illustrated here would be a pr

measurements of turbulent mixing and subsiding shells in trade wind cumuli abstracthigh resolution measurements of the turbulent thermodynamic and microphysical structure of the edges of trade wind cumuli have been performed with the airborne cloud turbulence observation system lateral entrainment of subsaturated air into the cloud region leads to an evaporative cooling effect the negatively buoyant air partly enhances the compensating downdraft forming a subsiding shell at cloud edge based on the presented observations the subsiding shell is divided into a turbulent and humid inner shell adjacent to the cloud interior and a nonbuoyant nonturbulent outer shell in the trade wind region continuous development of shallow cumuli over the day allows for an analysis of the properties of both shells as a function of different cloud evolution stages the shallow cumuli are divided into actively growing decelerated and dissolving based on cloud properties as the cumuli evolve from actively growing to dissolving the subsaturated environmental air is mixed deeper and deeper i

structural characteristics of two strong earthquakes in the north aegean ierissos 1932 and agios efstratios 1968 abstract structural analysis has been carried out on the volcanics of the island of agios efstratios and along the highly faulted zone of se chalkidiki south and north of the north aegean trough respectively northern greece the areas have been affected by strong earthquakes and a comparison is made between the available structural and seismological data together with new seismotectonic information at agios efstratios the earthquake of 1968 m7 1 occurred on a principal displacement zone with dextral strike slip movement while the fault geometry of the whole area supports the view of transtensional deformation the strong m7 0 earthquake of 1932 at ierissos was directly connected with an e w trending normal fault striations on the seismic fault surfaces and the corresponding fault mechanism indicate a n s direction of active extension the hangingwall is also affected by smaller antithetic e w and nw se trending structures

a palaeoseismological and geoarchaeological investigation of the eliki fault gulf of corinth greece abstract palaeoseismological and morphotectonic analyses enable us to define a 400 m wide actively deformed zone associated with the active eliki normal fault central greece bounded on the south by a second order fault and on the north by a composite and prominent fault scarp this scarp is further analysed by trenching based on colluvium stratigraphy displacement of distinct horizons and deposition of sedimentary layers three faulting events have been identified along four fault strands affecting unconsolidated sediments in the trench the two younger events with throws of 0 93 and 1 37 m respectively the third event with a throw of 0 44 m and the penultimate 373 bc event suggest a variable seismic history the entire alluvial plain of the kerynitis and vouraikos rivers which cross the eliki fault has subsided at a rate of 1 4 mm year resulting in the burial of the late hellenistic roman occupation horizons under 3 m of fluvial and colluvial sediments in places extension in the broader area is accommodated by the seismically active eliki and egion faults structural and palaeoseismological analysis of those two faults indicates that they accommodate 1 5 mm year or about 10 of the geodetically estimated extension of up to 13 mm year

formation of stationary alternate bars in a steep channel with mixed size sediment a flume experiment alternate bars were formed by sediment transport in a flume with froude modelled flow and relative roughness characteristic of gravel boulder channels with steep slopes the flume 0 3 m wide 7 5 m long was filled with a sand gravel mixture which was also fed into the top of the flume at a constant rate under constant discharge channel slope was set at 0 03 initially coarse particles accumulated on incipient bar heads near one side of the flume and diverted flow and bedload transport across the flume toward a pool scoured against the opposite flume wall downstream sorting in the pool directed coarse particles onto the next bar head downstream alternate sequences of pools and coarse bar heads were thereby linked down the entire flume by interactions of sediment sorting flow and channel morphology during episodes of bar construction unsorted bedload invaded interior bar surfaces and was deposited persistent deposition of coarse particles on bar heads prevented downstream migration of bars by inhibiting bar head erosion and bedload transport over bars likely factors leading to bar head stabilization in modelled gravel bed channels are coarse mixed size sediment steep channel gradients and shallow depths

estimation of discharge from braided glacial rivers using ers 1 synthetic aperture radar first results using multitemporal ers 1 synthetic aperture radar sar satellite imagery and simultaneous ground measurements of streamflow a strong correlation r2 0 89 was found between water surface area and discharge for a braided glacial river in british columbia canada satellite derived effective width we was found to vary with discharge q as we 27 5q0 42 where we is defined as the total water surface area within a 10 km 3 km control section divided by the section length this area discharge rating curve yields instantaneous discharge estimates with a mean error of 275 m3 s for ground measured flows that ranged from 242 to 6350 m3 s

how do gravel bed rivers braid sedimentary processes and bed forms leading to the onset of braiding were observed in small scale hydraulic models of gravel bed streams the laboratory streams had a variety of combinations of constant discharge and slope but identical bed material particle size distributions from initially straight channels braiding occurred by four different processes deposition and accumulation of a central bar chute cutoff of point bars conversion of single transverse unit bars to mid channel braid bars and dissection of multiple bars in these experiments the chute cutoff mechanism was the most common but the predominant braiding mechanism depends upon sediment mobility excess bed shear stress and the bed form regime at very low excess bed shear stress the central bar process dominates but at higher excess bed shear stress slip face unit bars are more common bed scour at confluences is more pronounced and propogation of alternate convergence scour and divergence deposition is more likely thus chu

the meandering braided river threshold a reappraisal abstract the concept of a threshold discharge slope q s combination that separates braided from meandering streams is critically re examined partly by review of previous data and partly by analysis of new data from south island new zealand it is argue d that discriminant functions that use mean annual discharge provide a poor physical basis for interpretations based on natural processes while bankfull discharge is also deficient because it is not a fully independent variable the common use of channel rather than valley slope adds a further misleading component because channel slope is partly dependent on channel pattern sinuosity most previous studies have inadequately treated the role of bed particle size in pattern discrimination failing to recognize that active gravel streams must plot higher on a q s chart than sand bed channels irrespective of pattern because of the greater power requirements for bed material movement within any one size class of bed material there is no evidence to indicate a clear discrimination between braiding and meandering only a weak statistical association between pattern and slope discharge values while this association may be explicable in terms of the high shear stress and stream power that accompany high qs values promoting braiding the real prerequisite for braiding appears to be high loads of bed calibre material producing wide shallow channels a factor that is only partly controlled by stream power accordingly the search for a pattern threshold based on discharge and slope seems to be a futile exercise an interpretation of existing pattern discriminant functions from the perspective of the threshold shear stress for particle movement is made it is concluded that in effect these functions merely state that gravel bed streams are more likely to be braided than channels in finer sediment statistically this appears to be valid and reasons for that difference are offered based on the balance between imposed bed material load and channel capacity

modelling bedload yield in braided gravel bed rivers abstract this paper outlines an approach for estimating the annual bedload yield of a braided channel this procedure is based on the extension of theory of flow and sediment transport in braided rivers recently presented by paola 1996 the revised approach accounts explicitly for the relationship between increasing discharge and varying channel hydraulics and is suitable for use in obtaining bedload transport rate estimates over a range of discharges integration of such estimates using flow duration data allows annual bedload yield to be determined model parameterisation is achieved using topographic survey data for the waimakariri river new zealand comparison of modelled bedload yield with values estimated from repeated topographic surveys indicates that the model is able to accurately predict both the medium term c 30 years mean annual bedload yield of the waimakariri at crossbank the section 17 8 km upstream of the river mouth and also short term fluctuations in bedload yield associated with varying annual flow statistics streamwise patterns of volumetric erosion and deposition determined for a 45 km length of the waimakariri using the model are also in broad agreement with trends identified in topographic survey data for the period 1961 1997 however significant deviations between modelled and surveyed volumes of cut and fill are evident at some locations comparison of model performance with conventional applications of bedload transport equations which tend to underestimate transport rates for braided channels suggests that the approach presented here may represent a significant improvement this is the case because the model quantifies the relationship between braid intensity and spatial variability in flow hydraulics at a cross section output from the model suggests that braided rivers may transport a significant proportion of their annual bedload at lower discharges than those indicated by earlier theoretical approaches results also provide quantitative support for the argument that increased intensity of braiding may promote higher rates of bedload transport in gravel bed rivers

surface fault traces fault plane solution and spatial distribution of the aftershocks of the september 13 1986 earthquake of kalamata southern greece a shallow earthquake ofms 6 2 occurred in the southern part of the peloponnesus 12 km north of the port of the city of kalamata which caused considerable damage the fault plane solution of the main shock geological data and field observations as well as the distribution of foci of aftershocks indicate that the seismic fault is a listric normal one trending nne ssw and dipping to wnw the surface ruptures caused by the earthquake coincide with the trace of a neotectonic fault which is located 2 3 km east of the city of kalamata and which is related to the formation of messiniakos gulf during the pliocene quaternary tectonics field observations indicate that the earthquake is due to the reactivation of the same fault

a revised conceptual model of the tropical marine boundary layer part ii detecting relative humidity layers using bragg scattering from s band radar abstractpersistent layers of enhanced equivalent radar reflectivity factor and reduced spectral width were commonly observed within cloud free regions of the tropical marine boundary layer tmbl with the national center for atmospheric research s pol radar during the rain in cumulus over the ocean rico field campaign bragg scattering is shown to be the primary source of these layers two mechanisms are proposed to explain the bragg scattering layers bsls the first involving turbulent mixing and the second involving detrainment and evaporation of cloudy air these mechanisms imply that bsls should exist in layers with tops bases defined by local relative humidity rh minima maxima the relationship between bsls and rh is explored an equation for the vertical gradient of radio refractivity n is derived and a scale analysis is used to demonstrate the close relationship between vertical rh and n gradients this is tested using the derived radar bsl boundary altitudes 131 surface based soundings

a refined view of vertical mass transport by cumulus convection the purpose of this letter is to show that the traditional view of transport by shallow cumulus clouds needs important refinement on the basis of a straightforward geometrical analysis of large eddy simulation results of shallow cumulus clouds we conclude 1 that the upward mass transport by clouds is strongly dominated by regions close to the edge of clouds rather than by the core region of clouds and 2 that the downward mass transport is dominated by processes just outside the cloud the latter finding contradicts the accepted view of a uniformly descending dry environment we therefore advocate a refined view which distinguishes between the near cloud environment and the distant environment the near cloud environment is characterized by coherent descending motions whereas the distant environment is rather quiescent and plays no significant role in vertical transport

radar observations of updrafts downdrafts and turbulence in fair weather cumuli abstract observations from a 94 ghz radar are used to define the vertical structure of marine fair weather cumuli doppler spectra obtained from the radar provide mean vertical velocities as well as detailed spectral shapes that can be used to infer small scale vertical velocity shear illuminate cloud microphysical processes and provide estimates of turbulence dissipation rates these new observations facilitate the analysis and understanding of in cloud circulations and the physical processes involved since the cloud boundaries and dimensions are mapped along with the internal structure of the clouds coincident observations from a 915 mhz radar wind profiler were used to further define the turbulence structure in and around the clouds the observations document the detailed vertical and horizontal dimensions of updraft and downdraft circulations in the clouds observed the two cumuli studied in detail have similar circulation patterns an updraft core surrounded by downdrafts although the clouds ha

combining multi physical measurements to quantify bedload transport and morphodynamics interactions in an alpine braiding river reach abstract understanding the interactions between bedload transport and morpholdynamics in braided streams has important applications in river management and restoration direct field measurements addressing this question are however scarce as they are often challenging to perform here we report an extensive two month field campaign in an alpine braided reach la severaisse river french alps that experienced predictable daily peak discharge 48 events observed generating significant bedload transport and morphological changes during the melting season we monitored these processes using a wide range of direct and indirect techniques bedload sampling continuous seismic measurements pebbles tracking topographic surveys remote sensing using ground control cameras and drone flights doing so surrogate measurements allowed to extend temporally discrete manual bedload sampling and to extend spatially local riverbed cross section measurements these measurements provide unique complementary constraints on the targeted physics at various spatial and temporal scales which enabled us to draw robust conclusions data showed a progressive decrease in bedload transport for a given flow rate along the two months period simultaneously river morphology in the braided sections changed from an incised to a more distributed configuration which led to a decrease of local maxima in dimensionless shear stresses in the braided reach for similar flow conditions this control of bedload transport by maximum local shear stresses was in line with tracked pebble surveys indicating that coarse bedload particles were mostly transported in the main active channel at the reach scale this transport was found to be more efficient in laterally confined sections than in braided ones which has important implications in terms of bedload estimation in alternative confined and braided unconfined rivers finally this study highlight the interest to combine a large variety of traditional and innovative measurements techniques to better understand complex sediment transport processes in the field

geodetic constraints on the fault pattern of the 1978 thessaloniki northern greece earthquake ms 6 4 summary repeated measurement of a 110 km long high precision spirit levelling traverse indicates that between 1958 and 1978 about 25 cm of subsidence occurred along a distance of 30 km in the mygdonian quaternary graben near thessaloniki northern greece observed displacements are significant against random and systematic errors and most are unrelated to near surface effects and can be assigned to the 1978 thessaloniki destructive earthquakes the available data do not permit a formal inversion but an elastic dislocation analysis indicates that the main shock of the seismic sequence ms 6 4 was probably associated with a ne dipping wnw trending blind normal fault marking the southwestern margin of the mygdonian graben in agreement with seismological and structural data there also exists evidence for incipient faulting in the central southern part of the mygdonian graben

channel morphology and bedload pulses in braided rivers a laboratory study bedload pulses in gravel bed rivers have been widely reported in recent years and attempts have been made to relate them to channel morphology bedload transport and channel morphology were measured in a small scale generic model of braided gravel bed streams two experiments are described in which braided channels developed in a 14 m 3 m sand tray total bedload output from the tray was weighed every 15 minutes stream bed geometry was surveyed every four hours pulses were observed in the bedload output time series and were qualitatively related to the channel morphology immediately upstream of the measuring section the bagnold 1980 bedload equation generally overpredicts measured bedload transport rates when applied to channels that were in equilibrium or aggrading underprediction occurred when applied to degrading channels aggradation was associated with channel multiplication and bar deposition channel pattern simplification occurred when degradation took place and bars emerged from the water flow development of phases of aggradation and degradation is dependent upon the three dimensional geometry of the stream beds spatial and temporal feedback loops can be identified enabling links between channel morphology and bedload transport rate to be directly identified

magnitude versus faults surface parameters quantitative relationships from the aegean region historical and seismotectonic data from the broader aegean region have been collected and all possible information relative to ground deformation associated to earthquakes that hit the area have been re evaluated all events associated to co seismic surface faulting have been selected and further investigated while geomorphologic and geological criteria have been used to recognise and characterise the seismogenic faults associated to these morphogenic earthquakes sensu bull inqua 16 1993 24 in particular in order to perform seismic hazard analyses we compiled a list of all earthquakes where the surface rupture length srl the maximum vertical displacement mvd or the average displacement ad is available we thus obtained reliable values of these source parameters for 36 earthquakes of which 26 occurred during the 20th century 6 in the 19th century and the 3 remaining earlier magnitude versus srl and mvd has been compiled for estimating empirical relationships the calculated regression equations are ms 0 90 log srl 5 48 and ms 0 5 9log mvd 6 75 showing good correlation coefficients equal to 0 84 and 0 82 respectively co seismic fault rupture lengths and especially maximum displacements in the aegean region have systematically lower values than the same parameters worldwide but are similar to those of the eastern mediterranean middle east region the envelopes of our diagrams are also calculated and discussed for estimating the worst case scenario furthermore for all investigated seismogenic structures based on several geological criteria we measured the geological fault length gfl which is the total length of the neotectonic faults showing cumulative recent activity we then compared srl with gfl and their ratio shows a clear bimodal distribution with a major peak at 0 8 1 0 indicating that about 50 of the investigated earthquakes ruptured almost the entire fault length while a second peak around the value of 0 5 is clearly related to a segmentation process of longer neotectonic structures further implications of this distribution are also discussed eventually from the distribution of gfl versus magnitude we also infer an important geological threshold for the occurrence of morphogenic earthquakes at about 5 5 degrees

late holocene earthquakes in southern apennine paleoseismology of the caggiano fault although southern apennines are characterized by the strongest crustal earthquakes of central western mediterranean region local active tectonics is still poorly known at least for seismogenic fault recognition is concerned research carried out in the maddalena mts southeast of irpinia the region struck by the mw 6 9 1980 earthquake indicates historical ruptures along a 17 km long n120 normal fault system caggiano fault the system is characterized by a bedrock fault scarp carved in carbonate rocks which continues laterally into a retreating and eroded smoothed scarp affecting the clayey siliciclastic units and by smart scarps and discontinuous free faces in holocene cemented slope debris and in modern alluvial fan deposits the geometry of the structure in depth has been depicted by means of electrical resistivity tomography while paleoseismic analysis carried out in three trenches revealed surface faulting events during the past 7 ky bp 14c age the latest occurred in the past 2 ky bp 14c age and probably during after slope debris deposition related to the little ice age 1400 1800 a d preliminary evaluation accounts for minimum slip rates of 0 3 0 4 mm year which is the same order of rates estimated for many active faults along the apennine chain associated earthquakes might be in the order of mw 6 6 to be compared to the historical events occurred in the area e g 1561 and 1857 p p earthquakes

paleoseismicity of the 1981 corinth earthquake fault seismic contribution to extensional strain in central greece and implications for seismic hazard we present paleoseismological trenching results for the active skinos fault which ruptured the surface on the alkyonides gulf basin margin in the 1981 gulf of corinth earthquake sequence three trenches expose evidence of up to six previous events which are comparable to the 1981 deformation in terms of size and geometry vertical displacement produced by the 1981 earthquake ranged from 0 45 to 1 3 m at the bambakies fan trench sites decreasing towards the eastern fault tip east of the trenches trench 1 reveals two previous events with vertical displacements between 0 5 and 1 2 m since 390 a d trench 2 reveals five or six previous events but these are not dated trench 3 reveals four previous events since 670 a d vertical displacements associated with interpreted paleoearthquakes at the trench sites are 1 2 m the recurrence interval on the skinos fault is estimated to average 330 years however significant variation in recurrence interval is allowed by the available radiometric dates average vertical displacement rates derived from the trenches are in the range 0 7 2 5 mm yr a similar long term average vertical displacement rate of 1 2 2 3 mm yr is estimated for the lifespan of the basin bounding fault this equates to a horizontal seismic strain contribution of 2 5 mm yr from the skinos fault this local seismic strain rate overlaps within error with geodetically determined velocities across the alkyonides gulf assumed to represent uniform deep crustal strain thus seismic deformation on the basin bounding fault system may take up the major part of extension across the basin and aseismic strain is not necessitated by the data if correct this would imply that geodetically determined strain rates may be used as a proxy for potential seismic moment release in seismic hazard analyses for this region

late holocene evolution of the east eliki fault gulf of corinth central greece abstract trench stratigraphy and morphotectonic analysis was used to examine the recent evolution of the helike eliki plain and eliki fault the entire alluvial plain of the kerynites and vouraikos rivers which cross the eliki fault has subsided at rate of 1 4 mm yr resulting in the burial of the late hellenistic roman occupation horizons under 3 m of fluvial and colluvial sediments along the eastern segment of the eliki fault five trenches have been excavated and their 5000 yr old fluvial and colluvial deposits have been studied in association with the fault strand imprinted on them the kerynites river crosses at high angle the eliki fault and appears to be sensitive in tectonic movements related with the eliki fault sedimentation in the alluvial plain and the fluvial geomorphology of the kerynites river is important for understanding the fault evolution and the burial of the ancient 4th century bc helike city the kerynites river course highlights breaching deformation is the more likely to connect east and west eliki fault segments and that postseismic deformation is a significant mechanism for stress accommodation for part of the west end of the gulf of corinth

active faults in eurasia general remarks abstract the database and map of active faults of eurasia 1 5 000 000 have been compiled according to the ilp project ii 2 world map of major active faults the map shows the complicated distribution of active faulting the major faults group in broad mobile belts between relatively weakly faulted parts of the main plates the faults form the plates microplates and crustal blocks boundaries there and are accompanied by deformation of the boundary areas using active fault data for the seismic hazard assessment estimation of maximum possible magnitudes of earthquakes in fault zones it is necessary to take into account the total neotectonic activity of the territory and average rate and sense of motion on the fault because trenching gives a possibility to determine only vertical earthquake offset on a fault it is necessary to make corrections for strike slip faults to estimate the earthquake magnitude by using this parameter

bedload transport processes in a braided gravel bed river model a 1 50 scale hydraulic model was designed based on froude number similarity and using hydrological and sediment data from a small braided gravel bed river the north branch of the ashburton river canterbury new zealand eighteen experiments were conducted seven using steady flows and eleven using unsteady flows the experiments were carried out in a 20 m 3 m tilting flume equipped with a continuous sediment feed and an automated data acquisition and control system in all experiments water at 30 c was used to reduce viscosity related scale effects analyses of the experimental data revealed that bedload transport rates in braided channels are highly variable with relative variability being inversely related to mean bedload transport rate variability was also found to be cyclic with short term variations being caused by the migration of bedforms bedload transport was found to be more efficient under steady flow than under unsteady flow and it was postulated that this is caused by a tendency for channel form to evolve towards a condition which maximizes bedload transport for the occurring flow average bedload transport rate was found to vary with channel form although insufficient measurements were made to define a relationship

physical scale modelling of jokulhlaups glacial outburst floods with contrasting hydrograph shapes jokulhlaups glacial outburst floods are hazards in many glaciated environments jokulhlaups generated by different trigger mechanisms have different hydrograph shapes field evidence indicates that jokulhlaups with different hydrograph shapes produce different impacts however little attention has been paid to understanding the controls on jokulhlaups with differing hydrograph shapes and their subsequent impacts historically flume studies have been used to investigate fluvial processes under controlled laboratory conditions nevertheless few flume studies have replicated scaled hydrographs and none have attempted to model field jokulhlaups this study documents the technical procedure by which field prototype jokulhlaups were replicated using physical scale modelling techniques an exponentially rising jokulhlaup characterized by a prolonged rising stage and a rapid falling stage and a linearly rising jokulhlaup characterized by a rapid rising stage and a prolonged falling stage the parameters of water discharge time discharge acceleration and deceleration rate sediment size and sediment discharge were scaled to a 1 20 ratio better sorted sediment more uniform downstream sediment thickness and more gradual aggradation and deposition rates resulted from the prolonged rising stage of the exponentially rising hydrograph more time was available during the prolonged rising stage of the exponentially rising hydrograph for bedload sheets to migrate and for sand ripples to develop rapid rising stage deposition during the linearly rising hydrograph produced thick proximal deposits limited bedload sheet migration massive sand sheets and structureless and poorly sorted sediments during the prolonged falling of the linearly rising hydrograph sufficient time was available to support sand ripple development the study highlights that jokulhlaup hydrograph shape is important for controlling rates of sediment acquisition transport deposition erosion and bedform development the outcomes of these experimental investigations indicate that modelling of high magnitude floods is feasible in a laboratory flume this technical approach has proved very beneficial for developing a greater understanding of flood impacts and the processes that operate during jokulhlaups copyright 2006 john wiley sons ltd

magnitude distribution of linear morphogenic earthquakes in the mediterranean region insights from palaeoseismological and historical data we analyse the earthquake magnitude distribution of linear morphogenic earthquakes that reactivated dip slip normal faults within the mediterranean region information on past events is obtained following two distinct methodological approaches the geological one morphotectonic investigations and palaeoseismological excavations and the historical one contemporaneous descriptions and surveys of coseismic ruptures in order to homogenize the different data sets and therefore enabling a comparison we calculate moment magnitudes m w starting from seismic moments m 0 estimates the cumulative distributions thus obtained for the two data sets show differences that a series of non parametric tests suggests to be statistically significant coseismic displacements are systematically overestimated for strong m w 6 5 historically based earthquakes and for moderate 5 0 6 0 palaeoseismologically observed events also concerning the rupture length the geological information generally provides larger values for moderate earthquakes the possible causes of this discrepancy and the consequences in using the two data sets for seismic hazard assessment analyses are also discussed

subsiding shells around shallow cumulus clouds abstract in this study large eddy simulations les are used to gain more knowledge on the shell of subsiding air that is frequently observed around cumulus clouds first a detailed comparison between observational and numerical results is presented to better validate les as a tool for studies of microscale phenomena it is found that horizontal cloud profiles of vertical velocity humidity and temperature are in good agreement with observations they show features similar to the observations including the presence of the shell of descending air around the cloud second the availability of the complete 3d dataset in les has been exploited to examine the role of lateral mixing in the exchange of cloud and environmental air the origin of the subsiding shell is examined by analyzing the individual terms of the vertical momentum equation buoyancy is found to be the driving force for this shell and it is counteracted by the pressure gradient force this shows that evaporative cooling at the cloud edge

the causes of bedload pulses in a gravel channel the implications of bedload grain size distributions unsteady bedload transport was measured in two c 5 m wide anabranches of a gravel bed braided stream draining the haut glacier d arolla switzerland during the 1998 and 1999 melt seasons bedload was directly sampled using 152 mm square helley smith type samplers deployed from a portable measuring bridge and independent transport rate estimates for the coarser size fractions were obtained from the dispersion of magnetically tagged tracer pebbles bedload transport time series show pulsing behaviour under both marginal 1998 and partial 1999 transport regimes there are generally weak correlations between transport rates and shear stresses determined from velocity data recorded at the measuring bridge characteristic parameters of the bedload grain size distributions d50 d84 are weakly correlated with transport rates analysis of full bedload grain size distributions reveals greater structure with a tendency for transport to become less size selective at higher transport rates the bedload time series show autoregressive behaviour but are dif cult to distinguish by this method state space plots and associated measures of time series separation reveal the structure of the time series more clearly the measured pulses have distinctly different time series characteristics from those modelled using a one dimensional sediment routing model in which bed shear stress and grain size are varied randomly these results suggest a mechanism of pulse generation based on irregular low amplitude bedforms that may be generated in channel or may represent the advection of material supplied by bank erosion events copyright 2003 john wiley sons ltd

a method for estimating the mean bed load flux in braided rivers prediction of bed load flux remains a significant problem in understanding braided river morphodynamics for geomorphic and engineering applications two sets of data from laboratory experiments on braided networks performed at the university of trento italy and at the university of alberta canada provide the basis for development of a dimensionless bed load function and for testing a simple predictive model measured total sediment transport rates time averaged at equilibrium channel configuration collapse to a single dimensionless relationship based on dimensionless stream power bed load fluxes predicted by the parker and bagnold functions and cross section average hydraulic parameters under predict the bed load flux particularly at low shear stress this is consistent with previous observation and theory demonstrating the significant influence of transverse variability of the hydraulic parameters in controlling and predicting bed load flux a simple method for adjusting for this lateral variation is proposed for computing the sediment transport rate using topographic cross sections of braided rivers results show good agreement with the measured values suggesting that simple assumptions combined with the mean morphology of the channel may be sufficient to estimate mean bed load flux model predictions also highlight the significance of active bed width rather than bed shear stress as a fundamental ingredient in the prediction of the bed load rate and therefore as an important morphological property to be modelled the model also predicts similar behaviour in the at a station variability of bed load and in the importance of variation of active width relative to bed shear stress in the transport process

the role of giant and ultragiant nuclei in the formation of early radar echoes in warm cumulus clouds abstract observations of the formation of the first radar echoes in small cumulus clouds are compared with results of a stochastic coalescence model run in the framework of a closed parcel the observations were made with an instrumented aircraft and a high powered dual wavelength radar during the small cumulus microphysics study scms in florida the principal conclusion is that coalescence growth on giant and ultragiant nuclei may be sufficient to explain observations the concentration of cloud droplets varied from under 300 cm 3 when surface winds were from the ocean to over 1000 cm 3 when the wind direction was from the mainland although there is a slight tendency for the altitude of the first 0 dbz echo to be lower on average in maritime than in continental clouds there were several cases where it was higher the model results suggest that the lack of correlation is consistent with drops forming on giant and ultragiant nuclei the first 0 dbz echo was observed to form at higher altitudes in cloud

kinematic indicators on active normal faults in western turkey quaternary normal fault zones in western turkey comprise multiple slip planes and zone parallel layers of fault breccia they also contain several little known kinematic indicators that are probably typical of many formed at shallow levels in extending terrains the recent exhumation by contractors of about 2000 m2 of slip planes in a sse dipping fault zone separating quaternary colluvium from bedrock carbonates at yavansu 7 km se of kusadasi permits an unusually complete inventory of the indicators to be compiled the most spectacular indicators are metre scale 69 w pitching corrugations in slip planes and recemented breccia sheets underlying them corrugations characterized by sinusoidal profiles normal to their long axes and less commonly culminations and depression along their axes possibly developed as a result of upwards propagating slip planes seeking undemanding pathways through heterogeneous fault precursor breccias that formed in advance of tip lines parallel to corrugation long axes are those of gutters flat floored sleep sided channels a few centimetres wide probably related to the abrasion of subslip plane breccia sheets centimetre scale tool tracks scored in the uppermost subslip plane breccia sheet by resistant colluvial clasts are irregular at their proximal ends but distally they swing into alignment with corrugation axes frictional wear striae centimetres long but only a few millimetres wide and pitching 78 w are superimposed on the other slip parallel lineations comb fractures nearly perpendicular to slip planes define an intersection lineation which is normal to corrugation axes fault plane solutions of earthquakes on sse dipping active faults in the west anatolian extensional province indicate that mainly normal combined with minor dextral slip is the dominant mode a conclusion in accord with the sense of slip inferred from the indicators exposed on the yavansu slip planes

source inversion of the october 1 1995 dinar earthquake ms 6 1 a rupture model with implications for seismotectonics in sw turkey abstract an earthquake of ms 6 1 devastated the town of dinar sw turkey population 35 000 on october 1 1995 killing 90 people and destroying 30 of the town the earthquake generated complex body waveforms varying with azimuth at teleseismic distances the method of complex body waveform inversion developed by kikuchi and kanamori 1991 was used to infer a source process for the earthquake two subevents were necessary to explain the observed seismic records the inversion result suggests that the dinar earthquake initiated at the se end of the dinar fault with a subevent of seismic moment mo 0 5 1018 n m six seconds later the second subevent took place about 10 km to the northwest of the first subevent with a seismic moment a few times larger than the first the cmt depths of the first and second subevents were found to be 10 and 15 km respectively both subevents had a predominantly normal faulting mechanism with slip vectors oriented ne sw showing good agreement with the velocity vectors obtained from the recent slr and gps studies as well as with the regional stress orientation obtained from geological data the main shock was preceded by foreshock activity concentrated at the se end of the dinar fault where the first subevent took place while the aftershock activity was concentrated in the vicinity of the second subevent the spatial distribution of the foreshock and the aftershock activities and the locations of the subevents suggest that the first subevent broke an asperity and the second subevent broke a barrier on the fault following the definition by aki 1984 of an asperity and barrier earthquake model about 10 km of surface ruptures were associated with the earthquake while the estimates yield a rupture length of 25 km the calculated source parameters of the subevents and their locations suggest that the surface ruptures were probably associated with the first subevent the estimates also show that the rupture zones of the two subevents overlapped where the maximum vertical displacement was observed

analysis of a dryline during ihop implications for convection initiation abstract a detailed analysis of a dryline that formed on 22 may 2002 during the international h2o project ihop is presented the dryline was classified as a null case since air parcels lifted over the convergence boundary were unable to reach the level of free convection preventing thunderstorms from forming a secondary dryline associated with a distinct moisture discontinuity developed to the west of the primary dryline the primary dryline exhibited substantial along frontal variability owing to the presence of misocyclones this nonlinear pattern resembled the precipitation core gap structure associated with cold fronts during one of the analysis times although the misocyclones were positioned within the gap regions radar refractivity has been recently shown to accurately retrieve the low level moisture fields within the convective boundary layer however its use in forecasting the initiation of convection has been restricted to qualitative interpretations this study introduces the total derivati

mantle echoes associated with deep convection observations and numerical simulations abstract finescale radar observations of intense thermals starting plumes during the early stages of precipitation formation were collected by an airborne doppler radar on two separate days the radar data were recorded as the aircraft flew underneath the developing echoes mantle echoes echoes that often appear as an inverted u shape were observed on both days striking in one of the scans was the resemblance of the echo to a mushroom cloud resulting from a nuclear explosion numerical simulations using a two dimensional cloud resolving model were run to augment the interpretation of the observations one of the important conclusions was the proposed modification to the default bulk microphysical scheme used in the model the default scheme yields a rush to precipitation leading to the early establishment of large precipitation contents which is not supported by the observations suggested modifications to the scheme are presented

numerical simulation of bar and island morphodynamics in anabranching megarivers 1 bar and island morphodynamics in the world s largest anabranching rivers are investigated using a new numerical model of hydrodynamics sediment transport bank erosion and floodplain development operating over periods of several hundred years simulated channel morphology is compared to that of natural rivers and shown to be realistic both in terms of the statistical characteristics of channel width depth and bar shape distributions and mechanisms of unit bar compound bar and island evolution results demonstrate that bar and island stability may be sensitive to hydrologic regime because greater variability in flood magnitude encourages the formation of emergent bars that can be stabilized by vegetation colonization simulations illustrate a range of mechanisms of unit bar generation that are linked to local bed or bank instabilities this link may explain the reduced frequency of unit bars observed in some large anabranching rivers that are characterized by stable vegetated islands and slow rates of channel change model results suggest that the degree to which sand sized bed material is carried in suspension likely represents an important control on bar morphodynamics and channel network evolution because of its influence on sand transport direction consequently differences in the partitioning of the total sand load between bed load and suspension may provide a partial explanation for contrasting styles of anabranching in the world s largest sand bed rivers these results highlight a need for spatially distributed flow and sediment transport data sets from large rivers in order to support improved parameterizations of sand transport mechanics in morphodynamic models

disruptive earthquakes revealed by faulted archaeological relics in samnium molise southern italy 1 archaeoseismic and paleoseismic analyses carried out along the northern slope of the matese massif samnium southern apennines revealed cumulative offsets affecting the walls of the hercules s sanctuary of campochiaro 4th cent bc 5th cent ad and its foundation deposits on the basis of the archaeological data a first faulting event unknown in historical sources and seismic catalogues occurred during the 3rd cent bc followed by other displacements which are consistent with the catastrophic 1456 and 1805 earthquakes the sanctuary is located close to one of the e w strands of the northern matese fault system nw se trending to which we relate the observed deformation our data suggest that the activity of this fault system is characterized by high slip rates 0 9 mm yr if compared to other known active faults in the apennines and irregular return time for earthquakes with m 6 5

seismicity and associated strain of central greece between 1890 and 1988 summary we examined the seismicity of central greece between 1890 and 1988 using macroseismic and instrumental data to ask two questions 1 does the seismicity of this period reveal all the major tectonic structures that are known to be active and 2 what are the likely strains associated with the seismicity over this period many known active structures have been effectively aseismic for the last hundred years and even the inclusion of all known large events earlier than 1890 reveals no activity associated with the ne coast of evia gulf of argos or graben ne of mt parnassos it is clear that even 100 years data are inadequate for either a reasonable assessment of seismic risk or for a confident estimation of maximum magnitude however we are aware of no earthquakes in central greece during the last 200 yr that were larger than ms 7 0 it is probable that the maximum magnitude is restricted by the maximum length of fault segments which appears to be around 15 20 km the earthquakes of ms 5 8 during 1890 1988 can account for a n s displacement of around 45 70 cm with maximum and minimum estimates a factor of two greater and smaller than this across part of a 1890 1900 triangulation network in central greece that was resurveyed in 1988 the contribution of smaller events may increase this displacement by about 50 per cent this cumulative seismic displacement is similar to that estimated from the geodetic work about 100 cm but a detailed comparison of the two sets of observations will be reported elsewhere a re evaluation of all the important earthquakes of 1890 1988 in central greece is presented in the appendix which summarizes information of use to both earth scientists and engineers

a dual mass flux framework for boundary layer convection part i transport abstract this study considers the question of what is the least complex bulk mass flux framework that can still conceptually reproduce the smoothly varying coupling between the shallow convective cloud layer and the subcloud mixed layer to this end the model complexity of the classic single bulk mass flux scheme is enhanced inspired by recent large eddy simulation results the authors argue that two relatively minor but key conceptual modifications are already sufficient to achieve this goal i retaining a dry transporting updraft in the moist limit and ii applying continuous updraft area partitioning to this dual mass flux dualm framework the dry updraft represents all internal mixed layer updrafts that terminate near the mixed layer top whereas the moist updraft represents all updrafts that condense and rise out of the mixed layer as buoyant cumulus clouds the continuous area partitioning between the dry and moist updraft is a function of moist convective inhibition above the mixed layer top

the relationship between radar reflectivities and clouds associated with horizontal roll convection on 8 august 1982 abstract horizontal convective rolls hcrs and cloudstreets that occurred in northeastern colorado are studied using doppler radar data cloud photography and vertical soundings examination of the environment in which the hcrs form indicates a boundary layer wind speed that is much lower than those measured in previous studies evidence shows that the hcrs form in a well defined boundary layer yet the cloudstreets that develop seem to exist within a stable layer above a relationship between the radar reflectivity echoes and the cloudstreets is firmly established the echoes are aligned directly under the cloudstreets the echoes at lower levels are shown to be caused by convergence of particulate matter into updraft portions of the hcr circulation yet evidence indicates the cloud level echoes are due to backscatter from refractive index inhomogeneities at the surfaces of rising thermals examination of the echoes show that the strongest and tallest echoes are associated with cloud formation and tha

paleoseismologic investigation of the fault rupture of the 14 april 1928 chirpan earthquake m 6 8 southern bulgaria 1 seventy five years after the destructive chirpan earthquake of 14 april 1928 we conducted a paleoseismologic study of the causative fault combining a review of contemporary literature geomorphology geophysical prospecting and trenching we reidentified the fault scarp in the field and mapped it over a distance of 12 5 km geophysical profiles and boreholes demonstrate that chirpan scarp is the surface expression of a normal fault that was active throughout the pleistocene and holocene in 2002 we excavated a paleoseismologic trench to study the faulting history a narrow fault zone separates plio pleistocene alluvial sand in the footwall from holocene alluvial and colluvial silt in the hanging wall the 1928 earthquake is recorded by 0 45 m vertical offset of the topsoil in accordance with contemporary descriptions we identified three colluvial wedge like units in the hanging wall sediments next to the fault evidencing at least three surface rupturing paleoearthquakes since the atlantic their timing could only be loosely constrained using pollen the penultimate event had an offset of 0 40 0 45 m and occurred after circa 2600 calibrated years before present cal years b p event 3 displaced a subboreal semiarid calcic soil 0 55 0 70 m between circa 5750 and 2600 cal years b p the fourth event had a minimal offset of 0 50 0 70 m and occurred between circa 8900 cal years b p and 4900 b c when the region was first settled we obtain a holocene fault slip rate of 0 22 0 12 mm yr and an average recurrence interval of 2350 643 years for earthquakes comparable to or larger than the 1928 event

the evolution of the gulf of corinth greece an aftershock study of the 1981 earthquakes summary a preliminary study of the aftershocks of three earthquakes that occurred near to corinth greece in 1981 is combined with observations of the morphology and faulting to understand the evolution of the eastern gulf of corinth the well located aftershocks form a zone 60km long and 20km wide they do not lie on the main fault planes and are mostly located between the north dipping faulting on which the first two earthquakes occurred and the south dipping faulting associated with the third event a cluster of aftershocks also lies in the footwall of the eastern end of the south dipping fault of the third event morphologically it is observed that in the evolution of the eastern gulf of corinth antithetic faulting apparently predates the appearance of the main faulting at the surface this evolution can be explained by motion on a deep seated shallow angle aseismic normal fault a model based on such a fault also accounts for the aftershock distribution of the 1981 earthquakes