probabilistic seismic hazard deaggregation for selected egyptian cities a probabilistic seismic hazard analysis in terms of peak ground acceleration pga and spectral acceleration sa values has been performed for the egyptian territory eighty eight potential seismic sources for shallow and intermediate depth seismicity in and around egypt were identified and characterized based on an updated and unified earthquake catalog spanning the time period from 2200 b c until 2013 a d a logic tree approach was followed after a sensitivity analysis to consider the epistemic uncertainty in the different input parameters including the selected ground motion attenuation models to predict the ground motion for the different tectonic environments then the seismic hazard deaggregation results in terms of distance and magnitude for the most important cities in egypt have been computed to help understanding the relative contributions of the different seismic sources seismic hazard deaggregation in particular was computed for pga and sa at periods of 0 2 1 0 and 2 0 s for rock site conditions and for 10 probability of exceedance in 50 years in general the results at most of the cities indicate that the distance to the seismic sources which mostly contribute to the seismic hazard is mainly controlled by the nearby seismic sources especially for pga however distant events contribute more to the hazard for larger spectral periods for 1 0 and 2 0 s a significant result of this type of work is that seismic hazard deaggregation provides useful data on the distance and magnitude of the contributing seismic sources to the hazard in a certain place which can be applied to generate scenario earthquakes and select acceleration records for seismic design

fluvial dispersal potential of guanaco bones lama guanicoe under controlled experimental conditions the influence of age classes to the hydrodynamic behavior hydrodynamic sorting is a taphonomic process able to transport and scatter bones deposited in archaeological and paleontological sites this study presents the results of experimentation performed in an artificial flume with guanaco lama guanicoe bones of different ontogenetic development dry and saturated in water in hydric flows velocities of 15 and 30 cm s the obtained results show that bone global density the age of the individual the dry or wet bone state and the hydric flow velocity influence significantly bone dispersion in this way bones from immature individuals with unfused secondary growth centers and relatively low bulk density have better possibility of being transported than fused bones from adult individuals taking into account the results obtained in this experimentation and the feasibility of discriminating age categories in fossil assemblages two bone groups with differential potential transport are presented in this paper these transport groups constitute a methodological tool to evaluate the role hydric current may had played in the formation of a fossil assemblage

human impact and slope dynamics evolutionary trends in the monoclinal relief of adriatic area of central italy abstract the present work deals with a large area of the marche abruzzi monoclinal relief which is made up of a clayey sediment succession with sandy conglomeratic levels alternating at varying stratigraphic heights the east verging monocline was generated by an intense quaternary tectonic uplifting it differs approximately in the west east and in the southern directions forming three wide morphostructures the deep fluvial down cutting disjointed the monoclinal relief into a succession of high hills which give the area a typical cuesta morphology with fronts facing the western quadrants the present study aims at contributing to the knowledge of recent slope morphodynamics by analyzing the spatial distribution and state of activity of fast hydro erosion processes and superficial mass movements correlations are made between these phenomena and the morphotectonic and lithological features of the various sectors in the area with particular reference to agricultural land use the present research underlines how the badlands represent the most spectacular form of fast erosion whereas the landslide phenomena which affect the prevalently loamy clayey eluvial colluvial covers are the most widespread processes despite the distribution density and recent or current evolutionary trends are generally associated with different morphostructural features of the various sectors of the area they prove to be strictly controlled by agricultural exploitation and by the connected techniques and types of cultivation

location performance and detection threshold of the spanish national seismic network spain is a low to moderate seismicity area with relatively low seismic hazard however several strong shallow earthquakes have shaken the country causing casualties and extensive damage regional seismicity is monitored and surveyed by means of the spanish national seismic network maintenance and control of which are entrusted to the instituto geografico nacional this array currently comprises 120 seismic stations distributed throughout spanish territory mainland and islands basically we are interested in checking the noise conditions reliability and seismic detection capability of the spanish network by analyzing the background noise level affecting the array stations errors in hypocentral location and detection threshold which provides knowledge about network performance it also enables testing of the suitability of the velocity model used in the routine process of earthquake location to perform this study we use a method that relies on p and s wave travel times which are computed by simulation of seismic rays from virtual seismic sources placed at the nodes of a regular grid covering the study area given the characteristics of the seismicity of spain we drew maps for m l magnitudes 2 0 2 5 and 3 0 at a focal depth of 10 km and a confidence level 95 the results relate to the number of stations involved in the hypocentral location process how these stations are distributed spatially and the uncertainties of focal data errors in origin time longitude latitude and depth to assess the extent to which principal seismogenic areas are well monitored by the network we estimated the average error in the location of a seismic source from the semiaxes of the ellipsoid of confidence by calculating the radius of the equivalent sphere finally the detection threshold was determined as the magnitude of the smallest seismic event detected at least by four stations the northwest of the peninsula the pyrenees especially the westernmost segment the betic cordillera and tenerife island are the best monitored zones origin time and focal depth are data that are far from being constrained by regional events the two iberian areas with moderate seismicity and the highest seismic hazard the pyrenees and betic cordillera and the northwestern quadrant of the peninsula are the areas wherein the focus of an earthquake is determined with an approximate error of 3 km for m l 2 5 and m l 3 0 this error is common for almost the whole peninsula and the canary islands in general errors in epicenter latitude and longitude are small for near surface earthquakes increasing gradually as the depth increases but remaining close to 5 km even at a depth of 60 km the hypocentral depth seems to be well constrained to a depth of 40 km beneath the zones with the highest density of stations with an error of less than 5 km the m l magnitude detection threshold of the network is approximately 2 0 for most of spain and still less almost 1 0 for the western sector of the pyrenean region and the canary islands

evidence for a 4700 2100 bc palaeoearthquake recorded in a fluvial archaeological sequence of the segura river se spain abstract the archaeological excavation of a rock shelter abrigo del pozo in one of the slopes of the segura river se spain has revealed a exceptionally preserved sedimentary record spanning from the paleolithic to the present day which includes an anomalous layer of stones rfb fallen from the roof the sedimentary analysis of the stratigraphic sequence exhumed by the excavation indicates that human occupation of the rock shelter was controlled by fluvial environmental evolution however the rfb level resulted in a disturbance of human occupation and normal fluvial sedimentation from the sedimentary and archaeological pieces of evidence the rfb level has been interpreted as related to a palaeoearthquake responsible for the collapse of the roof and walls of the rock shelter the palaeoearthquake has been dated between 5820 50 bp the 14 c age of the neolithic occupation level directly below the rfb and 3710 40 bp the 14 c age of the chalcolithic level above the rfb a nearby earthquake of m 5 5 6 5 appears as the most plausible cause for the shelter collapse these data suggest that the seismic activity of this sector in the eastern betics has been continuous during the holocene but with larger magnitudes than the ones instrumentally recorded nowadays more palaeoseismic data are required to determine whether or not regional faults such as the nearby socovos fault are silent faults with a discontinuous seismic behaviour that could modify the current hazard assessment

modeling source zone boundary uncertainty in seismic hazard analysis most probabilistic seismic hazard studies assume that future earthquakes will occur in clearly defined seismically homogeneous areal source zones this assumption means that modeled seismic rates change abruptly at source zone boundaries with the result that predicted acceleration levels may differ considerably at sites a few kilometers apart near a boundary e g changes of 50 to 80 per cent or more at sites 20 km apart however homogeneous source zones are at best an approximation and the areal extent of such zones is usually not well determined i propose modifying the model so that the seismicity originally associated with each point in a source zone instead be regarded as normally distributed with standard deviation about that point this permits seismicity to vary smoothly across source zone boundaries when this variability is modeled if is 25 per cent or less of the width of the source zone acceleration levels calculated at sites at the center of the zone and at sites on the boundary are about the same as those calculated when no location variability 0 is assumed however calculated levels decrease at sites between the center and the boundary and increase at sites outside the boundary the changes tend to become larger at the higher accelerations corresponding to longer exposure times when earthquakes are modeled as ruptures along well defined linear faults predicted accelerations also increase significantly as the site location approaches the fault however in many cases neither the location of a fault nor the definitions of its end points can be precisely stated acceleration as a function of site location will vary more smoothly if possible fault locations are regarded as either normally or uniformly distributed

deaggregation in magnitude distance and azimuth in the south and west of the iberian peninsula we present the results of the seismic deaggregation in 15 of the most important cities with the greatest seismic hazard in the south and west of the iberian peninsula spain and portugal the deaggregation was carried out based on the calculation of the seismic hazard in the zone taking into account the peak horizontal acceleration with 10 probability of exceedance in 50 years return period of 475 years we first performed a deaggregation study in terms of magnitude and distance in order to subsequently carry it out in azimuth the aim of both studies is to determine the relative contribution of the different seismic foci and sources to the seismic hazard in a given location due to the lack of enough seismotectonic data in the study region we could not obtain information about the contribution of specific active faults and we have not been able to include a characteristic earthquake model however by starting from a calculated hazard using smoothed background seismicity it is possible to determine the contribution of the different seismic foci of the region to the seismic hazard at each location the results reveal that there are cities where the hazard is entirely or almost entirely due to the local seismicity e g in portugal lisbon 87 coimbra 82 in spain almero a 99 cordoba 99 granada 99 we have also determined that there are cities where seismic foci at 200 km away or more can be the most important or at least contribute significantly to the hazard e g beja and faro in portugal and cadiz and huelva in spain

autochthonous anisotropy of archaeological materials by the action of water experimental and archaeological reassessment of the orientation patterns at the olduvai sites abstract anisotropic patterns documented indirectly through m leakey s drawings of olduvai archaeological sites have led to questions about the integrity of these sites most experiments on bone transport by water have been carried out using complete elements that do not replicate specimen bone breakage and size as documented in archaeological sites in the present work an experimental framework is provided using experimental proxies of archaeological assemblages results show that autochthonous assemblages affected by hydraulic processes can adopt anisotropy in their fabric archaeological comparisons between drawings and excavated sites at olduvai stress the bias in leakey s drawings of flk zinj and flk north in bed i a large scale open excavation recently carried out at tk bed ii exposes an area comparable in size to leakey s excavations comparing the orientation patterns of this site to those reported by leakey shows how biased the drawing of the site is and how easily this can lead to misinterpretations of isotropy anisotropy with fatal consequences for the understanding of site formation processes

taphonomy of some articulated skeletal remains transport potential in an artificial environment flume experiments demonstrated that disarticulated bones did not display the same behaviour when combined as articulated elements the character of movement and rates of movement were recorded skeletal elements were identified as displaying either a transportable or a non transportable potential some of which were common to all three species that were tested the experiments demonstrated that articulated bones displayed a greater transport potential and that in one species the rate of movement was significantly faster than when disarticulated it is suggested that the taphonomic history of a fluvial transported assemblage could be misinterpreted if the bones were treated as a mixture of individually transported elements

effects of land use changes on badland erosion in clayey drainage basins radicofani central italy abstract hillslopes of the radicofani area in the upper valley of the orcia river southern tuscany region italy consist mainly of early pliocene clayey sediments and are widely affected by frequent badland erosion reforestation with frugal conifers has been carried out in the area over the last 50 years the goal of the present study is to evaluate the impact of reforestation and land use change on erosion rates in nine small drainage basins through a multidisciplinary approach geological geomorphological hydrological and land use characteristics were analyzed by a diachronic confrontation between pre reforestation 1954 and post reforestation 2007 situations aerial photo interpretation and processing in gis allowed us to quantify changes in areas affected by badland erosion land use and variations in erosion rates moreover dendrometric data were gathered from 18 circular sample plots in forest stands of 40 years old this allowed us to evaluate both the adaptability of different forest species to the clayey substrate and reforestation fragmentation the differences between the pre and post reforestation situations led to increases in arable land and forest areas and considerable decreases in erosion rates and badland areas however no significant correlation between the erosion rates and the forest area emerged due to the excessive fragmentation of reforestation cores and relatively small reforested surfaces land reclamation seems to have played a more important role in reducing erosion in the clayey substrate the integrated method presented here is an important tool useful to understand the morphological dynamics of badlands in relation to forest vegetation and for land planning and management

identifying instrumental and historical earthquake records in the sw iberian margin using 210pb turbidite chronology 1 textural mineralogical and geochemical analyses of near surface sediments from six different stations offshore sw iberian peninsula revealed the presence of thin detrital intervals corresponding to very fine grained turbidites precise dating of the two most recent sedimentary layers based on 210pb and 137cs geochronology provides ages of 1971 3 ad and 1908 8 ad these ages correspond to high magnitude historical and instrumental earthquakes that occurred in the region the 1969 horseshoe earthquake mw 8 0 and the 1909 benavente earthquake mw 6 0 such a good correlation between turbidites and high magnitude mw 6 historical and instrumental seismic events suggests that the record of mass transport deposits can also be used as a paleoseismic indicator in low convergence margins

seismic hazard estimate at the iberian peninsula seismic hazard at the iberian peninsula has been evaluated by using a methodology which combines both zonified and non zonified probabilistic methods seismic sources are used when considering zones where certain calculation parameters may be considered homogeneous as in zonified methods while on the other hand earthquakes are considered wherever it has taken place as in non zonified methods the methodology which is applied in this paper has been originally used to calculate the seismic hazard maps in the united states in our case it has been necessary to adapt the method to the specific features of the seismicity in the iberian peninsula and its geographical surroundings not only with respect to its distribution and characteristics but also with respect to the properties of the seismic catalog used geographically the main feature of the result is the fact that it reflects both historical seismicity and current seismic clusters of the region despite the smoothing maps show marked differences between several seismic zones these differences becoming more noticeable as exposure time increases maximum seismic hazard is found to be in the southwestern region of the peninsula especially in the area of the cape st vicent and around lisbon the uncertainty of the results without considering that due to the attenuation laws as deduced from the other evaluation parameters is quite stable being more sensitive to the parameters b and m max of the gutenberg richter relation

relationships between suspended sediment concentrations and discharge in two small research basins in a mountainous mediterranean area vallcebre eastern pyrenees abstract the relationships between suspended sediment concentrations and discharge were studied at the can vila 0 56 km2 and ca l isard 1 32 km2 sub basins of the vallcebre research area eastern pyrenees during a period of 5 years that included 67 events of diverse magnitude abandoned agricultural fields and forests are the main land use in the can vila basin whereas the ca l isard basin is mainly forested though there are also some heavily eroded landscapes badlands the most frequent events were of a single discharge peak although double and multiple peaked events were also recorded clockwise positive hysteretic loops occurred in both catchments mainly during the wet seasons when precipitation was of moderate intensity average of 18 mm h 1 and baseflow before the event was rather high average for ca l isard 8 1 l s 1 km 2 and for can vila 11 76 l s 1 km 2 the bulk of stream discharge came from saturated areas whereas sediments came mainly from the stream channels counter clockwise negative hysteretic loops were much more frequent in the ca l isard basin mainly in summer when rainfall intensity was high average of 32 5 mm h 1 and baseflow was low average for ca l isard 0 94 l s 1 km 2 and for can vila 0 73 l s 1 km 2 most of the water and sediment came from the badlands eight shaped loops occurred in transition periods mainly in the ca l isard basin

holocene earthquake record offshore portugal sw iberia testing turbidite paleoseismology in a slow convergence margin the sw margin of the iberian peninsula hosts the present day boundary between the eurasian and african plates convergence 4 5 mm yr is accommodated through a wide deformation zone characterized by moderate magnitude seismic activity this zone has also been the source of the most important seismic events in western europe such as the 1755 lisbon earthquake and tsunami and 1969 horseshoe earthquake despite efforts to identify active seismogenic structures in the gulf of cadiz in the last ten years little is known about its paleoseismic history the turbidite paleoseismology approach was applied for the first time in a low rate convergent margin to determine the recurrence interval of large earthquake events that occurred in sw iberia during the holocene four sediment cores collected at strategically located sites offshore portugal i e tagus abyssal plain infante don henrique basin and horseshoe abyssal plain reveal that these deep sea basins preserve a record of episodic deposition of turbidites in the sw iberian margin excluding special climatic events earthquakes are the most likely triggering mechanism for synchronous widely spaced distributed turbidites during the holocene when the sea level was relatively stable age correlation together with textural mineralogical physical properties and geochemical signatures of the new cores complemented by pre existing multicores and gravity cores reveals a total of 7 widespread turbidite events for the holocene precise dating of the most recent turbidite event e1 based on

fluvial transport of bovid long bones fragmented by the feeding activities of hominins and carnivores this study explores the hydraulic transportability of bovid long bone fragments created through hominin and carnivore carcass consumption in order to determine the effect of fluvial transport on the incidences of hominin and carnivore induced bone surface modifications transportability was determined using an oval race track flume and 311 long bone fragments from modern control collections of hominin and carnivore modified bone results show that the fluvial transport of long bone fragments is predicted by animal size class and bone specimen size as measured by maximum cortical thickness maximum length and maximum width all of these variables can be measured on fossil specimens long bone portion midshaft near epiphysis and epiphysis does not affect transport and hydraulic transport does not substantially modify the incidences of tooth percussion and cut marking in transported or lag assemblages in low energy fluvial environments implications of this study are 1 animal size classes and cortical thickness length and width of long bone fragments can be used to identify fluvial winnowing in fossil assemblages 2 analyses concerning the relative timing of hominin and carnivore carcass consumption based on the proportions of long bone fragments bearing tooth percussion or cut marks can be meaningfully applied to fossil assemblages deposited in low energy fluvial environments

accounting for site effects in probabilistic seismic hazard analyses of southern california overview of the scec phase iii report this article presents an overview of the southern california earthquake center scec phase iii effort to determine the extent to which probabilistic seismic hazard analysis psha can be improved by accounting for site effects the contri butions made in this endeavor are represented in the various articles that compose this special issue of bssa given the somewhat arbitrary nature of the site effect distinction it must be care fully defined in any given context with respect to psha we define the site effect as the response relative to an attenuation relationship averaged over all damaging earthquakes in the region a diligent effort has been made to identify any attributes that predispose a site to greater or lower levels of shaking the most detailed maps of quaternary geology are not found to be helpful either they are overly detailed in terms of distinguishing different amplification factors or present southern california strong motion observations are inadequate to reveal their superiority a map based on the average shear wave velocity in the upper 30 m however is found to delineate significantly different amplification factors a correlation of amplification with basin depth is also found to be significant implying up to a factor of two difference between the shallowest and deepest parts of the los angeles basin in fact for peak accel eration the basin depth correction is more influential than the 30 m shear wave ve locity questions remain however as to whether basin depth is a proxy for some other site attribute in spite of these significant and important site effects the standard deviation of an attenuation relationship the prediction error is not significantly reduced by making such corrections that is given the influence of basin edge induced waves subsur face focusing and scattering in general any model that attempts to predict ground motion with only a few parameters will have a substantial intrinsic variability our best hope for reducing such uncertainties is via waveform modeling based on first principals of physics finally questions remain with respect to the overall reliability of attenuation re lationships at large magnitudes and short distances current discrepancies between viable models produce up to a factor of 3 difference among predicted 10 in 50 yr exceedance levels part of which results from the uncertain influence of sediment nonlinearity

the significance of giant seismites in the plio pleistocene baza palaeo lake s spain terra nova 22 172 179 2010 abstract giant load type seismites uncommon in the geological record are described in plio pleistocene lacustrine deposits of the baza basin betic cordillera s iberia deformed beds of the marginal lacustrine and distal alluvial facies of the baza palaeo lake can be traced continuously for several kilometres soft sediment deformation is represented by load type structures of large dimensions pillows around 4 m in width and 2 m in height three dimensional exposures show ellipsoidal pillows separated by fluidized channels without any preferred orientation the final size of these load type seismites is strongly influenced by sedimentary factors such as the presence of a reverse density gradient in sediments and the bed thickness the giant seismites of the baza basin are located in a region which is unlikely to have been subjected to high magnitude earthquakes maximum around 7 0 therefore magnitude is not the main factor that controls the size of these load type structures

active faulting offshore se spain alboran sea implications for earthquake hazard assessment in the southern iberian margin the southern margin of the iberian peninsula hosts the convergent boundary between the european and african plates the area is characterised by low to moderate magnitude shallow earthquakes although large historical events have also occurred in order to determine the possible sources of these events we recently acquired swath bathymetry tobi sidescan sonar and high resolution seismic data on the almeria margin eastern alboran sea the new dataset reveals the offshore continuation of the ne sw trending carboneras fault a master fault in the eastern betic shear zone and its associated structures n150 and ns faults these structures are active since they cut the late quaternary sedimentary units the submarine carboneras fault zone is 100 km long 5 10 km wide and is divided into two n045 and n060 segments separated by an underlapping restraining stepover geomorphic features typically found in subaerial strike slip faults such as deflected drainage water gaps shutter ridges pressure ridges and ben echelonq folds suggest a strike slip motion combined with a vertical component along the submarine carboneras fault considering the nnw sse regional shortening axis a left lateral movement is deduced for the carboneras fault whereas right lateral and normal components are suggested for the associated n150 and ns faults respectively the offshore portion of this fault is at least twice as long as its onshore portion and together they constitute one of the longest structures in the southeastern iberian margin despite the fact that present day seismicity in the almeria margin seems to be associated with the n150 to ns faults the carboneras fault is a potential source of large magnitude mw 7 2 events hence the carboneras fault zone could pose a

attenuation of intensity with epicentral distance in the iberian peninsula we have classified the attenuation of the medveded sponheuer and karnik msk intensity into five types each as a function of the epicentral intensity i o based on the mean radii of 254 isoseismal maps mainly historical earthquakes in the iberian peninsula geographically representing each earthquake with its corresponding attenuation tendency it can be seen that those with low attenuation lie west of the peninsula and those with high attenuation in the south and east this regionalization seems to be due as much to the seismotectonic characteristics different crustal types and size of the earthquakes as to the different construction types in each region these attenuation values are similar to those of southern europe but much higher than those found in the united states from the point of view of seismic hazard evaluation these laws represent an improvement with regard to those used so far we have extended previous attenuation studies to the whole of the iberian peninsula and in some points differences of attenuation assignment of almost two degrees of intensity have been corrected

seismic hazard in northern algeria using spatially smoothed seismicity results for peak ground acceleration seismic hazard in terms of peak ground acceleration pga has been evaluated in northern algeria using spatially smoothed seismicity data we present here a preliminary seismic zoning in northern algeria as derived from the obtained results initially we have compiled an earthquake catalog of the region taking data from several agencies afterwards we have delimited seismic areas where the b and mmax parameters are different finally by applying the methodology proposed by frankel seismol res lett 66 1995 8 and using four complete and poissonian seismicity models we are able to compute the seismic hazard maps in terms of pga with 39 3 and 10 probability of exceedance in 50 years a significant result of this work is the observation of mean pgavalues of the order of 0 20 and 0 45 g for return periods of 100 and 475 years respectively in the central area of the tell atlas d 2003 elsevier b v all rights reserved

geomorphic agents versus vegetation spreading as causes of badland occurrence in a mediterranean subhumid mountainous area abstract previous evidence on the chief role of physical weathering on badland development in the vallcebre area south eastern pyrenees led to the study of the amounts of energy available for the main geomorphic agents and to analyze the results in the light of the patterns of vegetation cover and species distribution in order to explain both the occurrence of these badland forms and their preference for north facing shady hillslopes results showed that the weathering potential provided by freezing is about two orders of magnitude greater than rainfall kinetic energy and that the former strongly depends on hillslope aspect the study of vegetation demonstrated that vegetation is poorer in cover and species composition on shady hillslopes than on sunny ones spontaneous revegetation of these surfaces being restrained by cold thermal conditions rather than by water availability these results show that the occurrence of these badland areas depends on montane climatic attributes that control geomorphic and biological processes and that are different from those that promote the occurrence of badlands in dry mediterranean areas the preference for northern aspects provides evidence for these differences

use of active fault data versus seismicity data in the evaluation of seismic hazard in the granada basin southern spain in this article we evaluate the seismic hazard in the granada basin southern spain using for the first time the slip rate of known active faults our study as an attempt to compute seismic hazard using active fault data in low to moderate seismicity regions relies on a complete database of these faults containing information relevant to their seismic potential we obtain peak ground acceleration values above 0 4g for a return period of 475 years this result is compared with previous evaluations carried out on the basis of the historical seismicity of the area and the application of the well known theorem of total probability in these cases maximum values of 0 2g are obtained we explain the discrepancies found between the slip rate derived and seismicity derived estimates of seismic hazard as owing to the different strikes of the faults in relation to the directions of the main stresses affecting the granada basin in the context of the betic cordilleras some of them with evidence of aseismic slip

a preliminary probabilistic seismic hazard assessment in terms of arias intensity in southeastern spain financiado por el grupo de investigacion peligrosidad sismica y microzonificacion de la junta de andalucia rnm 0217 y por el proyecto de la cicyt ries ctidib 2002 177

seismic hazard in terms of spectral accelerations and uniform hazard spectra in northern algeria seismic hazard in terms of spectral acceleration sa has been estimated for the first time in northern algeria for this purpose we have used the spatially smoothed seismicity approach the present paper is intended to be a continuation of previous work in which we have evaluated the seismic hazard in terms of peak ground acceleration pga using the same methodology to perform these evaluations four complete and poissonian seismic models have been used one of them considers earthquakes with magnitudes above ms 6 5 in the last 300 years that is the most energetic seismicity in the region firstly seismic hazard maps in terms of sa at periods of 0 1 0 2 0 3 0 4 0 5 1 0 1 5 and 2 0 sec with 39 3 and 10 probability of exceedance in 50 years have been obtained therefore uniform hazard spectra uhs are computed and examined in detail for twelve of the most industrial and populated cities in northern algeria all the reported results in this study are for rock soil and 5 of damping it is noteworthy that in the seismic hazard maps as well as in the uhs plots we observe maximum sa values in the central area of the tell the higher values are reached in the chleff region previously el asnam specifically around the location of the destructive earthquakes of september 9 1954 ms 6 8 and october 10 1980 ms 7 3 these maximum values 0 4 g and 1 0 g are associated with periods of about 0 2 and 0 3 sec for return periods of 100 and 475 years respectively

seismostratigraphy and tectonic architecture of the carboneras fault offshore based on multiscale seismic imaging implications for the neogene evolution of the ne alboran sea in the se iberian margin which hosts the convergent boundary between the european and african plates quaternary faulting activity is dominated by a large left lateral strike slip system referred to as the eastern betic shear zone this active fault system runs along more than 450 km and it is characterised by low to moderate magnitude shallow earthquakes although large historical events have also occurred the carboneras fault is the longest structure of the eastern betic shear zone and its southern termination extends further into the alboran sea previously acquired high resolution data i e swath bathymetry tobi sidescan sonar and sub bottom profiler show that the offshore carboneras fault is a ne sw trending upwarped zone of deformation with a length of 90 km long and a width of 0 5 to 2 km which shows geomorphic features typically found in subaerial strike slip faults such as deflected drainage pressure ridges and en echelon folds however the neotectonic depth architecture and neogene evolution of carboneras fault offshore are still poorly known in this work we present a multiscale seismic imaging of the carboneras fault i e topas high resolution multichannel seismic reflection and deep penetration multichannel seismic reflection carried out during three successive marine cruises from 2006 to 2010 the new dataset allowed us to define a total of seven seismostratigraphic units from tortonian to late quaternary above the basement to characterise the tectonic architecture and structural segmentation of the carboneras fault and to estimate its maximum seismic potential we finally discuss the role of the basement in the present day tectonic evolution of the carboneras fault and explore the northern and southern terminations of the fault and how the strain is transferred to nearby structures

glacis geometry as a geomorphic marker of recent tectonics the guadix baza basin south spain abstract the guadix baza basin occupies 4000 km 2 and constitutes the largest intramontane basin of the betic cordillera southern spain it has a well preserved geomorphic surface a glacis which started to be eroded when the basin conditions changed from endorheic to exorheic taking into account its large preserved surface area more than 1200 km 2 and its pre deformational geometry this geomorphic surface is a useful marker of recent deformation combining geological and geomorphological data and high resolution dem topographic profiles of the glacis have been produced to estimate vertical displacements caused by active compression and extension structures these structures have produced relative vertical displacements of up to 100 m from the late middle pleistocene to the present assuming an age for the glacis of between 205 and 600 ka it has been possible to estimate long term minimum and maximum vertical rates of the activity of normal faults and folds using this geomorphic surface as a marker vertical slip rates range from 0 07 to 0 49 mm year for the main active normal faults and vertical folding rates range from 0 05 to 0 17 mm year for several active folds these long term vertical slip and folding rates are in accordance with other values previously estimated in other sectors of the betic cordillera when present detailed geomorphic study of recent glacis is an excellent tool for evaluating active tectonics over large regions

one bone two bones wet bones dry bones transport potentials under experimental conditions flume experiments demonstrated that bones had varying hydraulic transport potentials depending on whether the bones were wet or dry articulated or disarticulated when placed into a water flow dry and articulated bones demonstrated the greatest transport potential while wet and disarticulated bones demonstrated the least the velocity at which bones were transported was plotted against a range of attributes such as the shape weight volume and density of the bones with varying degrees of success although several attributes did prove to be significant as indicators of bone transport potential no single attribute emerged as more useful than another

lithology controls the regional distribution and morphological diversity of montane mediterranean badlands in the upper llobregat basin eastern pyrenees abstract badlands are pervasive in a wide range of environmental conditions across the mediterranean region including arid semiarid and humid environments on montane cold subhumid and humid mediterranean landscapes harsh thermal conditions on north facing hillslopes favour intense bedrock weathering by freezing and impose serious constraints on plant colonization the above are the customary arguments to explain the high abundance of montane badlands on north exposed shady aspects we studied the distribution and morphological diversity of badlands in the upper llobregat basin catalan pyrenees ne spain using remote sensing information high resolution orthophotos and complementary landsat 8 imagery digital elevation data and regional information on lithology badlands extend over about 200 ha in the upper llobregat basin and occur on two different parent materials swelling smectite rich continental garumnian lutites of late cretaceous age and nonswelling illitic marine eocene marls vegetation assessed by remote sensed vegetation greenness is less developed on north facing badland slopes however badland slope aspect distribution varies considerably with lithology while badlands on eocene marls show preferential distribution on north facing shady slopes badland occurrence on garumnian lutites does not reveal clear slope aspect anisotropy patterns lithology also affects slope gradient with badlands on eocene marls showing rougher topography 30 40 average slope angle than on garumnian lutites 20 30 badland morphological differences induced by lithology are discussed in terms of the greater weathering susceptibility and slope instability of the swelling smectite rich garumnian lutites than of the nonswelling eocene marls elevation which broadly controls annual precipitation and winter air temperature within the region shows no clear influence on badland distribution overall our results reveal lithology as the main factor controlling badland distribution and morphological diversity under the montane mediterranean conditions of the upper llobregat basin

biotic and abiotic processes affecting the formation of bk level 4c bed ii olduvai gorge and their bearing on hominin behavior at the site abstract excavations at bk have provided insights into the behavior of early hominins through the study of several archaeological levels the present study shows the results for a new archaeological sub level bk4c the main goal is to contribute to the knowledge of the different taphonomic processes that shaped bk4c and to better understand the role played by hominins in its formation due to the presence of a fluvial depositional context and a slight channel in bk4c a spatial analysis has been applied in order to determine the impact caused by water flows we conclude that water played a role in the rearrangement of the assemblage however the spatial properties of the assemblage indicate a limited impact of post depositional disturbance processes supporting the autochthonous nature of the site the taphonomic study of this sub level indicates that hominins had a primary role in the accumulation bulk defleshing and demarrowing of carcasses bk4 assemblages bk4b and bk4c indicate a repeated occupation of the site for short time periods this is interpreted by the overall fast sedimentation recorded in the fluvial system and the paucity of highly weathered bones showing extensive periods of sub aerial exposure in between sedimentary episodes the site functionality is potentially different from that inferred for earlier oldowan periods where sites were smaller and showed less marked spatial clustering of lithics and stone tools caused by hominin behavior

how mudrock and soil physical properties influence badland formation at vallcebre pre pyrenees ne spain abstract soils regoliths and their parent materials were investigated in relation to the development of badlands in the pre pyrenees in ne spain on late cretaceous mudrocks under a mountain mediterranean climate whilst all the soils in the area which are developed on mudrocks show a good structure and support a dense plant cover the bare parent materials slake very rapidly giving rise to badlands characterized by high erosion rates several physical chemical mineralogical and micromorphological properties of soils regoliths and related parent materials were analyzed in order to explain their different susceptibility to erosion and to determine which of all these properties are better related to such erosive behaviour only micromorphological and porosity properties were able to explain the erosion susceptibility whilst mineralogical chemical and physico chemical specific surface area properties were not among the aggregate stability tests performed to estimate the relationships of soil components with the susceptibility to erosion the emerson test for macroaggregate evaluation was particularly well suited although no good correlation was found between the emerson test classes and organic matter content we observed that the degree of slaking in organic rich horizons was always lower than in subsurface horizons and regoliths consequently as far as organic rich aggregates are present in the soil surface the influence of water in producing slaking swelling and then erosion will be minimum however when regoliths and rocks are uncovered the influence of water in these particular materials through freeze drying and swell shrinking will give rise to mudrock desintegration leading to accelerated erosion

regolith behaviour and physical weathering of clayey mudrock as dependent on seasonal weather conditions in a badland area at vallcebre eastern pyrenees abstract studies on badland areas in the vallcebre basin pyrenees suggest that erosion rates are controlled by the weathering rate of mudrocks to obtain the temporal pattern of physical weathering and its control on the erosive processes monitoring of regolith temperatures at different aspect depth and lithology and periodical determination of regolith moisture and bulk density were carried out changes in surface regolith have also been monitored by means of photographic techniques using an especially designed tripod finally the hydrological and erosive response of the regolith trough the seasons were studied using rainfall simulations the results obtained support and confirm previous knowledge on the role of frost action in mudrock weathering and the role of subsequent regolith development and wetness status on infiltration and runoff generation these seasonal changes of behaviour are so important that they raise serious questions about the validity of observations or experiments carried out in only one season this work confirms that erosion processes are controlled by regolith formation during winter and regolith depletion by storm rainfall erosion during summer spring and early autumn it also raises important points about annual trends of infiltration and erodibility that should be used as guidelines for modelling runoff and sediment production

probabilistic seismic hazard assessment for portugal the probabilistic seismic hazard of portugal is analyzed with a logic tree approach a critical part of the work was the review of the seismic catalog and the moment magnitude m estimation for historical earthquakes to produce a cat alog with a uniform magnitude scale the instrumental magnitudes were converted to m through empirical relations two seismic zonations were considered each in cluding two broad tectonic zones and a set of smaller seismicity zones catalog completeness and the b value for the truncated exponential recurrence model were calculated for the broad sources defined by tectonic criteria the smaller seismicity sources were used to calculate the a value using the fixed b value of the correspond ing tectonic zone this approach allows for a larger amount of data to estimate the most critical parameters by statistical methods without compromising the spatial detail of hazard results three published attenuation relations were used in the logic tree with weights that were based on tectonic considerations and on the comparison with macroseismic data converted to horizontal peak ground acceleration pga the ambraseys et al 1996 attenuation model for pga used by most previous hazard studies of the region seems to underestimate considerably the ground motion for mainland portugal a total of 96 hazard curves were calculated with seisrisk iii for each point of the map the resulting mean hazard map for 10 exceedence probability in 50 years displays pga values that range from 0 05g to 0 20g these mean values are slightly higher than in previous pga studies the hazard patterns obtained display a maximum related to intraplate onshore seismicity whereas pre vious studies using intensities highlighted the southwest offshore contribution fur ther work on ground motion attenuation in western iberia is necessary to improve the seismic hazard assessment

comparing seismic parameters for different source zone models in the iberian peninsula abstract seismical parameters of five seismogenic zonings for the iberian peninsula have been determined in this work for that purpose this research has two key goals the first is to generate a seismic catalog the second to calculate the seismical parameters of all the zones of the seismogenic zonings selected the first key goal has been the creation of a catalog of earthquakes for the iberian peninsula and adjacent areas first the national geographic institute of spain s catalog has been completed and reviewed with the information from other catalog reviews and specific studies second all magnitude calculations have been homogenized third all dependent data have been eliminated through declustering finally the year of completeness for each magnitude has been considered the quaternary active faults database of iberia has also been used as input data all of this information has been integrated into a geographic information system the second key aim is the calculation of the seismical parameters the first parameter obtained has been the b value a method which considers different years of completeness in accordance with the magnitude has been used also the annual rate of earthquakes per square kilometer has been calculated moreover the maximum magnitude known that quaternary active faults might generate and maximum magnitude recorded in the catalog have been determined finally based solely on the statistical parameters obtained a critical discussion of the seismogenic zonings of the iberian peninsula has been conducted the results show that some zonings possess insufficient data for a proper calculation of the seismic parameters from a statistical point of view

structure and porosity of smectitic mudrocks as affected by experimental wetting drying cycles and freezing thawing cycles abstract the erosion rates in the vallcebre basin pyrenees are controlled predominantly by the physical weathering rate of bare regolith i e mudrocks to obtain information on the influence of thermic and moisture regimes on the weathering dynamics laboratory experiments were carried out to investigate how freezing thawing or wetting drying cycles under controlled conditions affect structure and porosity three different clayey mudrocks were selected to represent materials more susceptible to erosion in the studied area the three lithologies identified as ca1r ca2r carr differed mainly in mineral constituents type and quantity of the clay minerals and cation exchange capacity an automated non contact laser profile meter was used to analyse surface microtopography in order to monitor random roughness variations and to calculate bulk density porosity and pore size distribution were carried out with image analysis freezing thawing cycles were the most active in modifying soil surface and bulk structure roughness of ca1r and ca2r was more than doubled at the end of freezing thawing cycles this variation was mostly associated with the whole surface elevation related to the bulk volume increase roughness variations in carr were less pronounced and related to a modification of the microtopography micromorphological observations revealed a platy structure formation induced by repeated ice lensing also porosity was increased by freezing thawing cycles with the formation of a large number of irregular and rounded pores wetting drying cycles did not affect surface roughness and modified bulk density very little in all samples they increased porosity by the formation of large cracks and fissures overall data from wetting drying cycles showed that changes in water content alone did not produce deep structural modifications a mechanism of alteration of soil structure during freezing thawing cycles is proposed

updating the probabilistic seismic hazard values of northern algeria with the 21 may 2003 m 6 8 algiers earthquake included the occurrence of the algiers earthquake m 6 8 of may 21 2003 has motivated the necessity to reassess the probabilistic seismic hazard of northern algeria the fact that this destructive earthquake took place in an area where there was no evidence of previous significant earthquakes neither instrumental nor historical strongly encourages us to review the seismic hazard map of this region recently the probabilistic seismic hazard of northern algeria was computed using the spatially smoothed seismicity methodology the catalog used in the previous computation was updated for this review and not only includes information until june 2003 but also considers a recent re evaluation of several historical earthquakes in this paper the same methodology and seismicity models are utilized in an effort to compare this methodology against an improved and updated seismic catalog the largest mean peak ground acceleration pga values are obtained in northernmost algeria specifically in the central area of the tell atlas these values are of the order of 0 48 g for a return period of 475 years in the city of algiers the capital of algeria and approximately 50 km from the reported epicenter of this latest destructive earthquake a new mean pga value of 0 23 g is obtained for the same return period this value is 0 07 g greater than that obtained in the previous computation in general we receive greater seismic hazard results in the surrounding area of algiers especially to the southwest the main reason is not this recent earthquake by itself but the significant increase in the mmax magnitude in the seismic source where the city and the epicenter are included