lidar and 2d electrical resistivity tomography as a supplement of geomorphological investigations in urban areas a case study from the city of wroclaw sw poland in urbanized areas particularly in lowland terrains and floors of large river valleys the natural land configuration is often hard to recognize due to a long history of human activity accordingly archaeological works in cities which supply knowledge on settlement conditions are usually accompanied by geological and geomophological research lately data from light detection and ranging lidar have become a valuable source of information on urban land configuration geophysical methods are also becoming increasingly popular in background studies the paper presents a method of using and linking these sources of spatial information about landforms in such areas the main aim is to identify to what extent these complementary sources of data and the proposed method can be used in such a specific environment to reconstruct natural buried terrain morphology the city of wroclaw in central europe serves as an example to this end geomorphometric studies were conducted with the use of digital elevation models dems based on lidar scanning and derivated land surface parameters saga wetness index channel network base level and altitude above channel network the study also involved determining morphological edges and measurements of the meanders of the odra as well as expanding information on the spatial distribution of alluvia and the structure of slope breaks to this end geophysical measurements were conducted using the two dimensional electrical resistivity tomography method additionally five typical sequences of man made ground present within the perimeter of the city were distinguished as a result a map of the main landforms of wroclaw is presented finally we argue that although high resolution dem and derivate land surface parameters are very useful in terrain analysis places with thick man made ground or strongly levelled areas must be recognized by geoarchaeological excavations or geological bore holes the geophysical survey is useful to identify buried morphological edges and older relief elements in open areas

shallow geophysical survey at the archaeological site of san miguel tocuila basin of mexico abstract a combined near surface geophysical survey conducted in san miguel tocuila show that geophysical methods offer the possibility to characterize and reconstruct the geometry of subsurface structures without destroying the deposits providing a way to find solutions to the questions of archaeological or engineering significance the survey consisted of the application magnetometry seismic refraction tomography srt and ground penetrating radar gpr within a depth range of 10 m before spanier conquest san miguel tocuila was a very prominent suburb of the main aztec ceremonial complex located on the eastern margin of lake texcoco central mexico where several mounds known as tlateles in nahuatl language have been identified nowadays the rapid expansion of mexico city s metropolitan area within the last four decades has strongly influenced tocuila s environment and has compromised several of its archaeological and ancient human settlements this study shows how the high resolution imagining of non invasive geophysical methodologies in addition with surface archaeological studies parsons j r 1971 prehistoric settlement patterns in the texcoco region mexico memoirs of the museum of anthropology university of michigan number 3 provide different kinds of information that characterize the subsoil and a buried structure based on the history of the ancient settlements in the zone and considering the characteristics of shape and height of the structure we interpreted that the subsurface images obtained depict a buried tlatel which corresponds to a ceremonial civic center of late aztec times

spatial variability of hurst statistics in the castagnola formation tertiary piedmont basin nw italy discrimination of sub environments in a confined turbidite system

sedimentary processes and origin of sediment gravity flow deposits on the western algerian margin during late pleistocene and holocene seven piston cores retrieved from the algerian margin from oran to 80 km east of algiers were studied to identify sediment gravity flow deposits and their sources at the foot of the slope five sediment cores indicate a decreasing frequency of turbidite sequences from the transgressive systems tract to the highstand systems tract resulting in lower off shelf sediment fluxes during the last highstand episode there is an approximately log normal frequency distribution of bed thickness that increases for larger grain size class but this relationship is frequently altered by truncation of the top of the turbidite sequence in the deep basin off algeria two sediment cores indicate that turbidite sequences are both thicker and more preserved than at the foot of the slope and are observed through the entire sediment core implying various origin of the gravity flow eustatic change seismicity

altered carbon cycling and coupled changes in early cretaceous weathering patterns evidence from integrated carbon isotope and sandstone records of the western tethys abstract in this study we investigate if a major perturbation of the early cretaceous carbon cycle was accompanied by altered weathering and erosion rates the large aptian carbon isotope anomaly records the response of the biosphere to widespread volcanic activity and probably resulting changes in atmospheric pco 2 levels elevated pco 2 levels should also result in an accelerated hydrological cycle and increased silicate weathering creating a negative feedback loop removing co 2 from the atmosphere we propose to interpret the widespread occurrence of quartz sandstones in the tethys atlantic seaway as a result of altered weathering and erosion rates in the wake of the aptian carbon cycle excursion we challenge the traditional notion that these are flysch deposits associated with early cretaceous orogenic movements in the western tethys we propose that these sandstones were most likely part of a large conveyor belt system acting along the iberian and european margin of the tethys seaway using chemostratigraphic correlations we show that the activity of this system was only short lived and coeval with changes in coastal ecology and the aptian carbon cycle perturbations we tentatively relate the existence of this system to a transient climate regime characterized by fluctuating pco 2 levels

the thick bedded tail of turbidite thickness distribution as a proxy for flow confinement examples from tertiary basins of central and northern apennines italy this study reviews the thickness statistics of non channelized turbidites from four tertiary basins of central northern apennines italy where bed geometry and sedimentary character have been previously assessed though very different in terms of size and arguably character of feeder system these basins share a common stratigraphic evolution consisting in transition from an early ponded to a late unconfined setting of deposition based on comparison of thickness subsets from diverse locations and stratigraphic heights within the studied turbidite fills this paper seeks to answer the following questions i how data collection procedures and field operational constraints e g measure location outcrop quality use of thicknesses data from single vs multiple correlative sections stratigraphic thickness of the study interval can affect statistics of sample data ii how depositional controls of confined vs unconfined turbidite basins can result in different thickness frequency distributions and iii is there in thickness statistics a flow confinement signature which can be used to distinguish between confined and unconfined turbidites results suggest that i best practices of data collection are crucial to a meaningful interpretation of sample data statistics especially in presence of stratigraphic and spatial trends of turbidite bed thickness ii a systematic bias against cm thick tcd bouma sequence turbidites exists in sample data which can result in the low end tail of empirical thickness frequency distributions to depart significantly from the actual distribution of turbidite thickness and iii thickness statistics of beds starting with a basal ta tb bouma division bear a coherent relationship to the transition from ponded to unconfined depositional settings consisting in reduction of variance and mean and consequently parameters or even type of best fit model distribution this research highlights the role of flow stripping sediment by pass and bed geometry in altering the initial thickness distribution of ponded turbidites and suggests how fully ponded mini basins represent the ideal setting for further research linking turbidite thickness statistics and frequency distribution of parent flow volumes

eustatic sea level controls on the flushing of a shelf incising submarine canyon turbidity currents are the principal processes responsible for carving submarine canyons and maintaining them over geological time scales the turbidity currents that maintain or flush submarine canyons are some of the most voluminous sediment transport events on earth long term controls on the frequency and triggers of canyon flushing events are poorly understood in most canyon systems due to a paucity of long sedimentary records here we analyzed a 160 m long ocean drilling program odp core to determine the recurrence intervals of canyon flushing events in the nazare canyon over the last 1 8 m y we then investigated the role of global eustatic sea level in controlling the frequency and magnitude of these canyon flushing events canyon flushing turbidity currents that reach the iberian abyssal plain had an average recurrence interval of 2770 yr over the last 1 8 m y previous research has documented no effect of global eustatic sea level on the recurrence rate of canyon flushing however we find that sharp changes in global eustatic sea level during the mid pleistocene transition 1 2 0 9 ma were associated with more frequent canyon flushing events the change into high amplitude long periodicity sea level variability during the mid pleistocene transition may have remobilized large volumes of shelf sediment via subaerial weathering and temporarily increased the frequency and magnitude of canyon flushing turbidity currents turbidite recurrence intervals in the iberian abyssal plain have a lognormal distribution which is fundamentally different from the exponential distribution of recurrence intervals observed in other basin turbidite records the lognormal distribution of turbidite recurrence intervals seen in the iberian abyssal plain is demonstrated to result from the variable runout distance of turbidity currents such that distal records are less complete with possible influence from diverse sources or triggering mechanisms the changing form of turbidite recurrence intervals at different locations down the depositional system is important because it ultimately determines the probability of turbidity current related geohazards

resistivity and induced polarization monitoring of salt transport under natural hydraulic gradients we demonstrate the use of resistivity induced polarization ip monitoring of salt transport under natural hydraulic loads electrical monitoring of saline tracer transport during forced injection has been demonstrated previously detection of tracer transport under natural hydraulic loading is difficult because neither the hydraulic load nor the tracer resistivity can be controlled in one study we identify the electrical response to salt transport in a dynamic beach environment resistivity ip imaging resolved the structure of the saltwater freshwater interface and evidence for tide induced groundwater transport resistivity increases in the near surface and at depth upbeach of the high tide mark accompanied by tidal transgression we attribute this to desaturation and decreasing salinity in the near surface and to decreasing salinity at depth despite tidal transgression monitoring of groundwater levels indicates a phase lag between the tide level and groundwater level supporting the electrical da

jurassic deep water fans in the neo tethys ocean the kashafrud formation of the kopet dagh basin iran abstract the middle jurassic kashafrud formation of northeast iran was deposited in the kopet dagh basin linked to the neo tethys ocean the 2 km thick succession commences with fluvio marine boulder conglomerates that occupy bedrock valleys but the bulk of the formation comprises a deep water succession of interbedded sandstone and mudstone packages with trace fossils and sparse ammonites neogene collisional events deformed the strata to create the kopet dagh mountains the deep water succession represents channel lobe systems and associated levees and overbank areas on slope to basin floor fans northward paleoflow suggests that rivers drained uplands along the paleo tethys suture zone forming fan deltas on a narrow shelf with associated sediment transport to deeper water coarse sands extrabasinal pebbles and plant fragments are present throughout the formation and a thick boulder conglomerate unit lies within the turbidite succession these observations suggest proximity to terrestrial sources throughout deposition sandstone packages are mainly less than 10 m thick maximum 84 m and numerous lensoid packages of thick bedded sandstone tens of meters thick and up to 200 m wide represent submarine channel fills thick bedded lenses and sheets show a relatively narrow range of paleoflow direction and represent major submarine conduits whereas the more varied paleoflow direction of thin bedded packages suggests that many were deposited on levees the presence in the kashafrud formation of potential source rocks in the form of organic rich mudstones and abundant plant fragments suggests that the formation may have contributed to hydrocarbon fields within overlying formations sandstone sheets and channel fills could form local reservoirs

the detection of monumental tombs buried in tumuli by seismic refraction a tumulus is a construction erected to cover a tomb some tumuli are impressively massive and may conceal architectural masterpieces seismic refraction is employed to locate the tomb and to allow selective excavation without destroying the tumulus the detectors are spread along a circular profile on the periphery of the tumulus and acoustic waves are generated on its top time delays observed in the arrivals of the headwaves reveal the position of the monument the delays are not caused by the monument itself but are an effect caused by the presence of a ramp that was dug in the undisturbed soil to help in the construction of the tomb three case histories in northern greece establish the efficiency of the technique in the first example an experiment was conducted at a previously excavated tumulus and time delays attributed to the revealed ramp are observed the second case study led to the discovery of an impressive monument 3 d modeling by finite difference verifies the interpretation a third s

long term 17 ma turbidite record of the timing and frequency of large flank collapses of the canary islands volcaniclastic turbidites on the madeira abyssal plain provide a record of large volume volcanic island flank collapses from the canary islands this long term record spans 17 ma and comprises 125 volcaniclastic beds determining the timing provenance and volumes of these turbidites provides key information about the occurrence of mass wasting from the canary islands especially the western islands of tenerife la palma and el hierro these turbidite records demonstrate that landslides often coincide with protracted periods of volcanic edifice growth suggesting that loading of the volcanic edifices may be a key preconditioning factor for landslide triggers furthermore the last large volume failures from tenerife coincide with explosive volcanism at the end of eruptive cycles many large volume canary island landslides also occurred during periods of warmer and wetter climates associated with sea level rise and subsequent highstand however these turbidites are not serially dependent and any association with climate or sea level change is not statistically significant

eocene turbidite population statistics from shelf edge to basin floor spitsbergen svalbard abstract there is a need for better tools in the interpretation of depositional sub environments of deep marine facies using seismic scale outcrops of eocene shelf margin clinoforms in spitsbergen we have statistically characterized the turbidite beds in terms of grain size bed thickness and dominant sedimentary structure at four different lowstand sites in individual mappable clinoforms these sub environments include 1 upper slope canyon and gully fill 2 upper to middle slope late prograding wedge 3 lower slope channel levee complex and 4 basin floor fan the falling stage basin floor fan and slope canyon gully deposits are generally coarser grained than the rising stage sub environments they also have far fewer siltstone and mudstone beds and have significantly more beds of upper medium to very coarse grain size compared to the rising stage channel levee and prograding wedge deposits thin beds are particularly voluminous in the late prograding wedge and channel levee systems whereas only the basin floor fans and canyon fill have large numbers of beds thicker than 10 cm turbidity currents deposit sediment at distinctly different sites between shelf edge and basin floor at different times during the development of the base level cycle differences between these sub environments are both qualitative and quantitative and are demonstrable using statistical analysis the results of this statistical analysis from well exposed easily identifiable architectural elements can be used to reconstruct the shelf margins of analogous basins where only sparse outcrop or well data are available

nonlinear processes in earthquake foci the results of laboratory experiments on biaxially compressed physical models of a seismic source are presented discussed and interpreted in terms of nonlinear dynamics the relation is shown between the degree of seismic pulse coherency expressed through the amplitude frequency spectra development and energy or magnitude in a series of model experiments it has been ascertained that the degree of radiated waves coherency plays a more important role concerning the seismic energy release than the size radius of the seismic source

integrated geophysical surveys at the archaeological site of tindari sicily italy abstract the results of geophysical survey carried out at the archaeological site of tindari located 70 km west north west of messina sicily italy are presented and discussed the site is one of the most important archaeological sites about 90 ha large on the north eastern side of sicily and it was one of the last greek settlements in sicily keeping in mind the vastness of the site according to the archaeologists an area of about 1200 m2 was selected for a geophysical survey electrical resistivity tomography ert including induced polarization ip measurements and seismic refraction tomography were applied in the course of geophysical exploration in the area the objective of this preliminary geophysical investigation was to verify the effectiveness of the technique for a spatial definition of the buried archaeological structures mostly walls columns etc to determine their characteristics and to study the presence of collapsed columns within the zone of archaeological interest in view of their application in the rest of the site that for obvious reasons could not be entirely excavated in brief times the geophysical data visualized in 3d space revealed a distribution of low contrast shallow anomalies that indicate the presence of different types of buried structures in the surveyed area also the probable accumulations of collapsed columns could be determined these results confirm the hypothesis of a large northern extension of the archaeological site and provide useful information to design a more efficient excavation plan

source complexity of small earthquakes near matsushiro japan abstract broad band seismograms from a suite of small strike slip earthquakes which occurred in the matsushiro region of honshu japan during the period august 1971 september 1974 and recorded on carnegie seismograph mat are used to study source properties for events ranging in size from 10 11 10 15 nm in an earlier study dysart et al modelled frequency spectra of these events with a single brune pulse and made estimates of moment corner frequency and stress drop they employed cepstral filtering to suppress the effects of structure and to increase the stability of parameter estimates the same 32 waveforms considered here display a notable variation in complexity which cannot be explained by size local structure or stopping phases in order to understand better the time history of the complex events within the suite the sh waveforms were divided into successive time segments and the same modelling procedure was applied to the segments as was applied to the initial sh arrivals cepstral filtering was particularly helpful in reducing the interference effects of the s coda the results indicate that corner frequency changes little from subevent to subevent this suggests that small earthquakes proceed by incremental slippage on the same fault in a sequence of partial stress releases

marine electrical resistivity tomography for shipwreck detection in very shallow water a case study from agropoli salerno southern italy abstract a marine electric resistivity survey was carried out over a submerged beach along the agropoli shore salerno italy to detect buried objects of archaeological interest below the sandy seabed we found a shipwreck a military vessel that probably sunk during the salerno landing operations of the allied forces in the second world war resistivity data provide information on the vertical and horizontal extension of the shipwreck which is characterized by very low calculated resistivity values about 2 5 ohm m such values differ significantly from the sand and the bedrock values 5 40 ohm m although the presence of the shipwreck is clearly visible from geoelectric data the joint application of electric magnetic and multibeam bathymetric techniques reduces the ambiguities inherent in each method as shown in the electrical resistivity tomography ert and confirmed by the digital elevation model obtained from the processing of bathymetric data the shipwreck extends more than 30 m in ne sw direction and it is about 13 m wide the global extension of the relic is consistent with the magnetic data that are characterized by a magnetic anomaly with an amplitude of about 1800 nt and similar dimension as inferred from the estimation of source boundaries obtained from the computation of the analytic signal the results of our survey encourage the use of marine geoelectrical methods for the detection of buried archaeological targets particularly in locations where the use of seismic prospecting is not effective e g very shallow water with sandy sea bottoms the integration of different geophysical methods allows to better define the extension depth and thickness of buried objects suggesting that such an approach is the most effective for underwater archaeological investigations

geophysical prospecting and remote sensing for the study of the san rossore area in pisa tuscany italy abstract with the dual purpose of extending knowledge about the archaeological site of san rossore and of assisting archaeologists in the recovery process of the ships geophysical surveys integrated with remote sensing analyses were performed the surveys were conducted at selected locations placed on the plan of excavation approximately 5 m above the ancient surface and near the archaeological excavation area passive self potentials and active induced polarization electrical methods were used the choice of geophysical methods was due to the peculiarity of the geological characteristics of the site in fact the sediments embodying the archaeological remains are mainly silts and silty sands which are moderately conductive furthermore a shallow groundwater hosted in the alluvial deposits at approximately 2 m below the surface plane is present in the site induced polarization results inside the excavation area allowed identifying some anomalies related to the ship boundaries as well as other anomalies probably attributable to archaeological features additionally the self potentials measurements carried out in the area near the archaeological excavation evidenced the presence of other archaeological features such as two ships a pier and other structures furthermore the multitemporal remote sensing data allow the identification of many traces related to filling of channels and ditches finally the integration of the data contributed to a better interpretation of the archaeological site

clustering of earthquake events in the himalaya its relevance to regional tectonic set up abstract the earthquake events of himalaya of magnitude 5 0 from the time window 1905 2000 are statistically analysed the inter event time between earthquakes shows hurst phenomena of temporal clustering which are spatially located in five distinct domains along the himalayan fold thrust belt out of these two domains one around uttaranchal nepal border and the other around nepal sikkim border reveal maximum number of temporal clusters and thus considered as seismically most potential zones of the himalaya both these zones are located at the interface of the orthogonally disposed major tectonic discontinuities of the peninsular shield and himalayan fold thrust belt such zones are geologically most favourable locales for strain accumulation during later tectonic movement statistical analysis points towards a probability of recurrence of seismic events in near future in these two zones however validity of such statistical results can be ascertained by detailed geological and geophysical modelling of the terrain

the lithosphere of the earth as a nonlinear system with implications for earthquake prediction the lithosphere of the earth can be viewed as a hierarchy of volumes from tectonic plates to grains of rock their relative movement against the forces of friction and cohesion is realized to a large extent through earthquakes the movement is controlled by a wide variety of independent processes concentrated in the thin boundary zones between the volumes a boundary zone has a similar hierarchical structure consisting of volumes separated by boundary zones etc altogether these processes transform the lithosphere into a large nonlinear system featuring instability and deterministic chaos from this background some integral grossly averaged empirical regularities emerge indicating a wide range of similarity collective behavior and the possibility of intermediate term earthquake prediction

long term record of barents sea ice sheet advance to the shelf edge from a 140 000 year record the full glacial extent and deglacial behaviour of marine based ice sheets such as the barents sea ice sheet is well documented since the last glacial maximum about 20 000 years ago however reworking of older sea floor sediments and landforms during repeated quaternary advances across the shelf typically obscures their longer term behaviour which hampers our understanding here we provide the first detailed long term record of barents sea ice sheet advances using the timing of debris flows on the bear island trough mouth fan ice advanced to the shelf edge during four distinct periods over the last 140 000 years by far the largest sediment volumes were delivered during the oldest advance more than 128 000 years ago later advances occurred from 68 000 to 60 000 39 400 to 36 000 and 26 000 to 20 900 years before present the debris flows indicate that the dynamics of the saalian and the weichselian barents sea ice sheet were very different the repeated ice advance and retreat cycles during the weichselian were shorter lived than those seen in the saalian sediment composition shows the configuration of the ice sheet was also different between the two glacial periods implying that the ice feeding the bear island ice stream came predominantly from scandinavia during the saalian whilst it drained more ice from east of svalbard during the weichselian

statistical analysis of facies clustering in submarine fan turbidite successions abstract the hurst statistic converted easily into a fractal dimension quantifies the degree of clustering of high and low values in spatial or temporal series of data in an effort to better understand the stratigraphic organization of submarine fan deposits the hurst statistic was calculated for nineteen turbidite sections that span a wide range of geological time tectonic settings facies characteristics and depositional environments three bed by bed variables were considered coarse division thickness i e net thickness in a single bed of conglomerate sandstone siltstone grain size and coarse division thickness percentage relative to thickness of overlying mudstone caps sixteen of the 19 turbidite sections analyzed 84 2 show the hurst phenomenon i e irregular long term clustering of high and low values of the three bed by bed variables this clustering is related to stratigraphic changes of sedimentary facies caused by lateral shifting of sub environments on a submarine fan surface there is no evidence that the clustering is controlled by sea level fluctuations the strength of the clustering inferred from hurst k values holds promise as an index to distinguish submarine fan sub environments preliminary results suggest that channel levee deposits tend to have strong clustering lobe interlobe deposits tend to display moderate clustering and basin floor sheet sand systems tend to have weak clustering combining facies characteristics with these statistical results provides more reliable criteria for the identification of submarine fan sub environments than are available from recently discredited models based on asymmetric cycles of bed thickness or grain size

on the frequency distribution of turbidite thickness the frequency distribution of turbidite thickness records information on flow hydrodynamics initial sediment volumes and source migration and is an important component of petroleum reservoir models however the nature of this thickness distribution is currently uncertain with log normal or negative exponential frequency distributions and power law cumulative frequency distributions having been proposed by different authors a detailed analysis of the miocene marnoso arenacea formation of the italian apennines shows that turbidite bed thickness and sand interval thickness within each bed have a frequency distribution comprising the sum of a series of log normal frequency distributions these strata were deposited predominantly in a basin plain setting and bed amalgamation is relatively rare beds or sand intervals truncated by erosion were excluded from this analysis each log normal frequency distribution characterizes bed or sand interval thickness for a given basal grain size or basal bouma division measurements from the silurian aberystwyth grits in wales the cretaceous great valley sequence in california and the permian karoo basin in south africa show that this conclusion holds for sequences of disparate age and variable location the median thickness of these log normal distributions is positively correlated with basal grain size the power law exponent relating the basal grain size and median thickness is different for turbidites with a basal a or b division and those with only c d and e divisions these two types of turbidite have been termed thin bedded and thick bedded by previous workers a change in the power law exponent is proposed to be related to i a transition from viscous to inertial settling of sediment grains and ii hindered settling at high sediment concentrations the bimodal thickness distribution of thin bedded and thick bedded turbidites noted by previous workers is explained as the result of a change in the power law exponent this analysis supports the view that a and b divisions were deposited from high concentration flow components and that distinct grain size modes undergo different depositional processes summation of log normal frequency distributions for thin and thick bedded turbidites produces a cumulative frequency distribution of thickness with a segmented power law trend thus the occurrence of both log normal and segmented power law frequency distributions can be explained in a holistic fashion power law frequency distributions of turbidite thickness have previously been linked to power law distributions of earthquake magnitude or volumes of submarine slope failure the log normal distribution for a given grain size class observed in this study suggests an alternative view that turbidite thickness is determined by the multiplicative addition of several randomly distributed parameters in addition to the settling velocity of the grain sizes present

application of catastrophe theory in earthquake hazard assessment and earthquake prediction research abstract catastrophe theory is a mathematical theory for the description of natural and social catastrophic phenomena however its application in the fields of earthquake hazard assessment and earthquake prediction research has not been reported based on real seismicity time series data in a specific region a method for earthquake hazard assessment and earthquake prediction by incorporating cusp catastrophe a 3 is presented through experimental computation of real earthquake sequences the effectiveness of the method is demonstrated it is therefore shown that the catastrophe theory has potential for application in the fields of earthquake hazard assessment and earthquake prediction research

mechanical fault interaction within the los angeles basin a two dimensional analysis using mechanical efficiency 1 mechanical models examine deformation within eight different structural cross sections proposed by davis et al 1989 and shaw and suppe 1996 along a northeast southwest transect across the los angeles basin california horizontal contraction of the models constrained by geodetic measurements yields varying dip slip rates along frictionally sliding faults within the different cross sections mechanical efficiency analysis using effective stiffness and strain energy density assesses the overall fault system deformation as well as the partitioning of work between fault slip and host rock strain the cross section interpreted by shaw and suppe 1996 has the best fit to paleoseismically determined slip rates and the greatest mechanical efficiency greatest proportion of work toward fault slip however this model produces excessive reverse slip along the newport inglewood fault a modified fault configuration with a wedge or blind puente hills thrust fault rather than a ramp detachment configuration better matches the paleoseismic data with slightly lower mechanical efficiency slip rates in the mechanical models based on interpretations of shaw and suppe 1996 have much closer match to the geologically determined rates than those estimated from kinematic models this difference is due to 1 differing time spans of slip rate estimates and 2 deformable rather than rigid host rock in the mechanical models the mechanical efficiency analysis provides quantitative indicators of overall fault system deformation including the cumulative effect of interaction between individual faults assessment of effective stiffness and strain energy density furthers our understanding of two dimensional fault interactions in the los angeles basin and offers great potential for future applications

rapid least squares inversion of apparent resistivity pseudosections by a quasi newton method1 a fast inversion technique for the interpretation of data from resistivity tomography surveys has been developed for operation on a microcomputer this technique is based on the smoothness constrained least squares method and it produces a two dimensional subsurface model from the apparent resistivity pseudosection in the first iteration a homogeneous earth model is used as the starting model for which the apparent resistivity partial derivative values can be calculated analytically for subsequent iterations a quasi newton method is used to estimate the partial derivatives which reduces the computer time and memory space required by about eight and twelve times respectively compared to the conventional least squares method tests with a variety of computer models and data from field surveys show that this technique is insensitive to random noise and converges rapidly this technique takes about one minute to invert a single data set on an 80486dx microcomputer

magnetic imaging and electrical resistivity tomography studies in a roman military installation found in satala archaeological site northeastern anatolia turkey abstract satala is one of the last great military centers in the roman east available for archaeological and historical investigations this archaeological site is situated on the crossing of two singularly important routes in north east asia minor only little archaeological fieldwork in and around satala has so far been carried out thus delimiting our knowledge of the site and its role within the roman military structure of the east in order to provide further data on the site we carried out geophysical surveys including the application of magnetic and electrical resistivity techniques in an area north of the sadak village the geophysical surveys within this area supposedly part of the roman military camp proceeded in two stages the first stage saw magnetic gradiometer imaging studies being carried out on 2 1 ha measured by a geoscan fm 36 fluxgate gradiometer by using 0 5 1 m grid intervals for the second stage a different geophysical technique was used resistivity tomography resistivity data were collected using a number of combined 2d resistivity pseudosections in the eastern part of the area which contained very regular magnetic anomalies the 3d data were obtained by the combination of all survey lines collected from 2d data sets and thereafter the arranged data were processed by using the 3d robust inversion modified from the smoothness constrained algorithm electrical resistivity tomography investigations revealed that the buried archaeological structures might be located near the surface except for some structures found in the middle of the studied area the archaeological structures were furthermore determined by realistic model sections and volumetric representations magnetic imaging and electrical resistivity tomography surveys show that the combined usage of these techniques advances the understanding of archaeological structures beneath the surface

regional spectral scaling relations of source parameters for earthquakes in the baltic shield abstract spectral analysis of regionally recorded lg waves is performed to determine source parameters such as seismic moment source radius and stress drop of earthquakes in the baltic shield and to derive regional spectral scaling relations the data consist of about 350 lg phases on short period vertical component analog seismograms from earthquakes with magnitude m l ranging from 2 to 5 2 source radii estimated from the corner frequency show only a slight increase with increasing seismic moment in the range 3 10 18 to 5 10 20 dyn cm while the increase is more rapid for larger events baltic shield earthquakes show increasing stress drops ranging from about 0 1 to 10 bars for increasing seismic moment the relatively low stress drops could in part be explained by bias due to band limited analog data the slope of the curve relating seismic moment to corner frequency is steeper than 3 which suggests a departure from a constant stress drop scaling relation proposed for large earthquakes the derived relationship between the seismic moment m o and magnitude m l is log m o 16 93 1 01 m l for 2 m l 5 2

statistical analysis of turbidite bed thickness patterns from the alpine fold and thrust belt of western and southeastern greece abstract a statistical evaluation of turbidite bed thickness was performed for 11 turbidite successions which constitute part of foreland basins formed along the alpine fold and thrust belt of western and southeastern greece the purpose was to compare the results from this study with previously published investigations and discuss if and how statistical approaches could contribute to the environmental analysis of turbidite deposits in tectonically complex areas bed thickness datasets exhibit a clear non normal signal in their distribution behavior statistical analysis was focused on i fitting of widely used non normal theoretical distribution models using robust non parametric goodness of fit statistical tests and ii detecting the possible presence of asymmetric bed thickness cycles and or non random bed thickness clustering results indicate that the studied bed thickness datasets are well characterized by a bimodal lognormal distribution model probably reflecting deposition from both high and low density turbidity currents several datasets exhibit distributions characterized by power law tails exponential distribution types were not observed all datasets exhibit non random thinning upward bed thickness trends probably due to tectonically induced gravity flows proposed methods for identifying depositional sub environments using turbidite bed thickness statistics were found to have limited applicability observations of the present study may prove useful for the environmental analysis of turbidite deposits in fold and thrust belt areas characterized by limited outcrop exposures

recent developments in shallow depth electrical and electrostatic prospecting using mobile arrays application of mobile electrical and electrostatic quadripoles during the past ten years has allowed a considerable increase in the size of the surveyed areas together with keeping a high spatial resolution and a reduction of the total cost of a survey two new developments of towed arrays are illustrated here 1 a pole pole array pulled by the operator provides a lightweight solution for mapping large surfaces at a unique given depth of investigation as shown by the prospection of the roman british city of wroxeter and 2 a multipole multidepth system allows a 3 d investigation of the ground resistivity as illustrated by the experiments undertaken on the test site of garchy and on the archaeological site of montbaron indre france

three dimensional image of seismic refraction tomography and electrical resistivity tomography survey in the castle of occhiola sicily italy a geophysical survey was carried out at the ruins of occhiolacastle sicily italy a medieval village located at the north western part of a hill named terravecchia at 491 m asl in order to map the archaeological structures such as walls and burrows electrical resistivity to mography ert and seismic refraction tomography methods were used the resistivity variations are known to correlate quite well with the lithology thus providing important information for identifying the buried archaeological remains on the other hand seismic velocity variations provide information about the geometrical features of the remains the two geophysical methods are used in an enjoined way to better aid the interpretation and evaluate the significance and reliability of the results obtained with each single method the electrical and seismic data are displayed in three dimensions by using the iso resistivity and iso velocity surfaces respectively this allows us to effectively define the location of the anomalies present in the single electrical and seismic sections the results obtained in the survey highlight the presence of structures of regular shape probably due to features of archaeological interest 2006 elsevier ltd all rights reserved

seismic hazard in greece i magnitude recurrence two different methods are applied to the earthquake catalogue for greece makropoulos and burton 1981 mb catalogue to evaluate greek seismic hazard in terms of magnitude earthquake strain energy release and gumbel s third asymptotic distribution of extreme values it is found that there is a close relationship between results from the two methods in places where the cumulative strain energy release graphs include at least one well defined cycle of periodicity of strain release then the parameters of the third type asymptote are well defined with small uncertainties in almost all cases the magnitude distribution shows a remarkably good third type asymptotic behaviour the results are presented in the form of graphs and contour maps of annual and 80 year modes and magnitudes with 70 probability of not being exceeded in the next 50 and 100 years for six of the most heavily industrial and highly populated centres of greece magnitude hazard parameters are also derived and examined in more detail thereby illustrating the direct applicability of the methods in terms of zoning the close agreement between observed and predicted extreme magnitudes shows that the sample period considered 1900 1978 is long enough to obtain statistically stable estimates for athens the upper bound magnitude is found to be 6 7 0 3 within 100 km and 6 8 0 4 100 km from the two methods respectively whereas for corinth an earthquake of magnitude 6 5 has a mean return period of 43 years greece as a whole has an upper bound magnitude 8 7 0 6 and earthquakes of a size similar to the 1903 kithira event m 8 0 have a mean return period of about 200 years the significantly different maps contouring magnitudes of the annual and 80 year modes result from the fact that each place has its own distribution curvature for magnitude occurrence and thus they are not a linear extrapolation of each other however as longer return periods are considered these differences become small because the expected magnitudes approach the regional upper bound a feature common to all these maps is the existence of three well defined aseismic blocks 1 a the attikocycladic block 2 b the ptolemais basin and 3 c the block formed by the northeastern part of greece well defined areas of high seismic hazard which correlate with the most tectonically active areas are 1 a along the hellenic arc the greek albania border leukas cephalonia islands and the southeastern end of the arc 2 b the western end of the north anatolian fault and 3 c the chalkidiki peninsula and the northern sporadhes islands

aseismic controls on in situ soft sediment deformation processes and products in submarine slope deposits of the karoo basin south africa intervals of soft sediment deformation features including vertical fluid escape and load structures are common and well exposed in permian lower slope deposits of the tanqua depocentre karoo basin the structures mainly comprise elongated flames and load structures associated with ruptured sandstones and structureless siltstones observed over a range of scales the presence of an upper structureless siltstone layer linked to the flames interpreted as a product of the debouching of fine grained material transported through the flame onto the palaeo seabed together with the drag and upward folding of lower sandstone layers is evidence that the flames were formed in situ by upward movement of sediment rich fluids flames are oriented parallel to the deep water palaeoslope in lateral splay deposits between two major slope channel complexes statistical correlation and regression analyses of 180 flame structures from seven stratigraphic intervals suggest a common mechanism for the deformation and indicate the importance of fluidization as a deformation mechanism importantly deformation occurred in an instantaneous and synchronous manner liquefaction and fluidization were triggered by incremental movement of sediment over steeper local gradients that were generated by deposition of a lateral splay on an inherited local north west facing slope seismic activity is not invoked as a trigger mechanism because of the restricted spatial occurrence of these features and the lack of indications of earthquakes during the time of deposition of the deep water succession the driving mechanisms that resulted in the final configuration of the soft sediment deformation structures involved a combination of vertical shear stress caused by fluidization development of an inverse density gradient and a downslope component of force associated with the local slope ground penetrating radar profiles confirm the overall north east orientation of the flame structures and provide a basis for recognition of potential larger scale examples of flames in seismic reflection data sets

seismic hazard estimate for a low seismicity region example of bohemia the contribution reviews basic concepts of earthquake hazard assessment for sites of nuclear power plants taking into account the delineation of earthquake source regions intensity frequency relations upper intensity thresholdsi max and intensity attenuation curves we determine the seismic hazard for a site in south bohemia and calculated the quantities defining the seismic hazard i e return period in years probability of exceedance for different intensities and different periods of interest the adopted procedure has some limitations due to the poor definition of seismogenic zones boundaries n i i max and lack of strong motion observations in central europe

statistical facies classification from multiple seismic attributes comparison between bayesian classification and expectation maximization method and application in petrophysical inversion we present here a comparison between two statistical methods for facies classifications bayesian classification and expectation maximization method the classification can be performed using multiple seismic attributes and can be extended from well logs to three dimensional volumes in this work we propose for both methods a sensitivity study to investigate the impact of the choice of seismic attributes used to condition the classification in the second part we integrate the facies classification in a bayesian inversion setting for the estimation of continuous rock properties such as porosity and lithological fractions from the same set of seismic attributes the advantage of the expectation maximization method is that this algorithm does not require a training dataset which is instead required in a traditional bayesian classifier and still provides similar results we show the application comparison and analysis of these methods in a real case study in the north sea where eight sedimentological facies have been defined the facies classification is computed at the well location and compared with the sedimentological profile and then extended to the 3d reservoir model using up to 14 seismic attributes

facies clustering in turbidite successions case study from andaman flysch group andaman islands india abstract bed thickness data of two turbidite sections viz corbyn s cove section south andaman and kalipur section north andaman those belong to oligocene andaman flysch group a forearc submarine fan system were assessed for facies clustering employing hurst statistics both the sections show hurst phenomenon and reveal clustering in terms of thick and thin beds forcing behind event bed depositions in either of the studied sections was assessed statistically and inferred to be non random and with cyclicities of irregular physical length the inferred paleogeography through hurst criteria though worked well for distal fan setting i e basin floor sheet sandstones of corbyn s cove section its unequivocal application in proximal fan deposits remains to be tested the mismatch in paleogeographic interpretation between hurst test result lobe interlobe and field observation channel levee for the inner fan deposit is explained through differential facies stacking between fans grow in sea level lowstand and highstand lower bed amalgamation poor sand to mud ratio and subordinately present thick event deposits may be the result of active growth of andaman flysch fan in sea level highstand and expressed in lower hurst k value for inner fan channel levee association kalipur section compared to many of the channel levee deposits of lowstand fan systems observed world over

evaluation of landfill disposal boundary by means of electrical resistivity imaging this paper deals with an employment of electrical resistivity imaging eri for survey of leachate content on the waste disposal site in northern israel the research consisted of conducting ten eri lines and drilling investigation wells data simulation used a 2d earthimager inversion program analysis of 2d eri interpretation results shows that determination of the boundary between the landfill body bottom intensively saturated with leachates and underlying layers of highly water saturated fat nonconsolidated clays presents a challenge however statistical analysis of eri data indicates that standard deviation and confidence interval of a set of resistivity data measured in the landfill body are significantly larger than those in underlying clays moreover maximum changes of these parameters are found on the boundary between landfill body and underlying soil thus reflecting natural differences in scattering of resistivity data measured in these two objects

turbidite bed thickness statistics of architectural elements in a deep marine confined mini basin setting examples from the gres d annot formation se france abstract statistical analysis of bed thickness was performed for sampled turbidite successions from well documented architectural elements of the gres d annot formation to characterize confined deep water mini basins of the tertiary foreland basin of se france the purpose was to use advanced statistical processing techniques in order to evaluate whether a discrimination of different architectural elements is feasible through observed statistical signatures of bed thickness statistical methods were focused on i fitting of widely used non normal theoretical distribution models using robust non parametric goodness of fit statistical tests and ii detecting the possible presence of non random bed thickness clustering using existing and new clustering estimation methods results indicate that the bed thickness data are best characterized by a multi modal lognormal distribution model which probably reflects a background sedimentological process several datasets exhibit power law as well as exponential thick bedded tails the data also exhibit non random clustering of bed thickness discrimination of architectural elements in this confined turbidite succession seems to be feasible based on the characteristics of the observed composite lognormal distributions such as number and variability of the detected components the estimation of the degree of facies clustering has potential for the discrimination of architectural elements in confined basin settings if used in conjunction with alternative estimation methods such as periodogram estimation this methodology may now be applied to other confined turbidite successions be they outcrops with less certain architecture or subsurface datasets with borehole imaging

the terramare and the surrounding hydraulic structures a geophysical survey of the santa rosa site at poviglio bronze age northern italy abstract the terramara santa rosa is a middle and late bronze age archaeological site located in the po alluvial plain northern italy it is constituted of two moated villages delimited by earthen ramparts the peripheral structures of the site are sealed by fine textured flood plain deposits and they have not been fully explored through excavation due to their large extent because the shape of the villages and their relation to moats and the fluvial network are of paramount importance to understanding the landscape management and the use of water resources in the terramare civilisation a geophysical survey was planned to extend the results of the existing archaeological excavations to the site scale a frequency domain electro magnetic sounding fdem and electrical resistivity imaging eri covered an area of approximately 26 ha eri was conducted for a total length 9000 m despite the predominance of electrically conductive fine textured sediments electrical resistivity anomalies were observed and they were attributed to subtle lithological differences in the sedimentary context of the alluvial plain the geophysical interpretation after the calibration with the excavation data revealed the structures of the terramara and of the surrounding hydraulic network which are not visible at the surface due to flood plain deposits the santa rosa site was founded in a favourable geomorphological position on the top of a crevasse splay lobe of the adjoining po palaeo channel rising above the surrounding alluvial plain the terramara and their surroundings were delineated through an artificial modification of this pre existing crevasse splay lobe and a well targeted urban design with the objective of diverting water most likely from a palaeo channel of the po river through the digging of peripheral moats used to collect water around the site and to distribute it to the surrounding fields for irrigation the water management documented by this study in the terramara santa rosa can be considered as paradigmatic for the whole terramare civilisation which is therefore responsible of the introduction of the irrigated agriculture into western europe for the first time

evidence of seismic deformation of the paved floor of the decumanus at tindari ne sicily summary most of the ancient town of tindari ne sicily was settled on a plateau the most surficial layer of which was made of unconsolidated material ongoing excavations at the archaeological site at tindari uncovered a large portion of the decumanus which suffered deformations preliminarily assigned to coseismic effects an analysis of the local dynamic response through the simulation of strong seismic shaking to the bedrock and modelling of spectral ratios of the bedrock soft soil was carried out to verify the susceptibility of superficial terrains of the promontory to coseismic deformations to perform this simulation the finite element method fem was used four accelerometric recordings of three earthquakes of medium high magnitude recorded on rocky sites were chosen to simulate the seismic shaking using a constitutive law for the materials composing the promontory layers both of linear elastic type and of elastoplastic type the analysis of the linear elastic field allowed the definition of the frequencies for which the spectral ratios of the accelerations recorded the highest amplifications in particular the frequency range 31 5 37 2 hz can be combined with deformation of the paved floor of the decumanus the analysis in the elastoplastic field highlighted the zones of promontory more susceptible to suffer plasticization process the results show that the topmost layer of the decumanus is the most susceptible to suffer plasticization therefore the performed analysis lends greater support to the hypothesis that the deformations were produced by seismic shaking

integrated application of geophysical methods for investigation of the al berktain archaeological site in the city of jerash jordan the application of electrical resistivity tomography ert techniques involving the wenner and schlumberger electrode configurations was conducted at the ancient site of al berktain of jerash n jordan during june 2011 it may be considered as the first archaeogeophysical survey at this site the city lived by succession of ancient cultures and still has archaeological remains e g water pools which gave it historical value and boosted the archaeological interest to make this study the objective of the work was to determine the layout dimension and the depth of expected buried structures i e water channels related to the pool structure within the site and to provide recommendations for future excavation projects the results showed high resistivity anomalies red color located within the site these anomalies were interpreted as a part of a general infrastructure of ancient man made buried channels or supporting basins draining out or feeding water to the two the water pools especially at the western and eastern sides inside the pool the main structure in the site results of the survey showed anomalous thin shallow zone interpreted as a layer limestone pavement of a thickness of 1 m the ert successfully determined the dimensions of the buried features and proved that this site was water reservoirs to serve the ancient city of jerash or irrigations purposes beside its use for leisure i e presence of the theatre roman path and the pools

seismic hazard in greece ii ground acceleration abstract in a previous paper makropoulos and burton 1985 the seismic hazard in greece was examined in terms of magnitude recurrence using gumbel s third asymptotic distribution of extreme values and concepts of the physical process of strain energy release the present study extends the seismic hazard methods beyond magnitude to the estimation of expectations of levels of peak ground acceleration exceedance thus allowing for a direct comparison between these two methodologies as well as establishing information relevant to design and planning criteria the limited number of strong motion records do not permit regional study of attenuation of ground vibration in greece an average formula is derived from eight well known formulae which resulted from worldwide studies this is a 2164 e0 70m r 20 1 80 cm s 2 where a is peak ground acceleration m is earthquake magnitude and r is hypocentral distance in kilometres this formula agrees with the observed values of peak ground acceleration values recorded in greece acceleration seismic hazard is calculated at each of six chosen cities values of maximum acceleration with probability 70 of not been exceeded in the next 25 50 100 and 200 years are obtained along with corresponding values of velocity and displacement the same detailed acceleration evaluation is then applied to the whole area of greece by dividing it into cells of 0 5 lat 0 5 long and the results are illustrated through isoacceleration maps differences in magnitude and acceleration hazard maps reflect the fact that in acceleration hazard assessment the focal distance from a particular place in an important factor the cities of heraklion and rodhos have the lowest acceleration hazard although the expected earthquakes may have large magnitude intermediate depth earthquakes characterise these two cities acceleration estimates unlike magnitude hazard parameters refer to a particular place and not to an area around it hence even if two places have similar earthquake depth distributions the hazards may differ significantly because of the different spatial distribution of the foci this is observed in the case of athens and corinth these cities have almost the same magnitude hazard but the acceleration hazard is much lower for athens where the hazard is mainly due to more distant earthquakes the isoacceleration maps for greece as a whole also define areas of high seismic hazard these are the areas around cephalonia and leukas islands in the ionian sea and the eastern sporadhes lesbos islands and chalkidiki in the northern aegean sea at the 70 probability level the maximum acceleration is expected to be around 0 2g within the next 50 years the areas where the maximum acceleration at the 70 probability level is expected to reach a value of 0 3g in the next 200 years are around cephalonia and leukas islands and near the dardanelles

submarine fan environment inferred from turbidite thickness distributions recent studies of turbidite bed thickness distributions have demonstrated power law as well as log normal statistical distributions the different distributions may reflect different fan processes and environments and therefore could be used as a quantitative method to help identify those environments including those devoid of sequential patterns the cumulative distributions of well known turbidite deposits spanning a range of interpreted fan subenvironments are used to illustrate the potential correlation between cumulative distribution and environments assuming that power law distributions may for some systems be the primary input signal one dimensional modelling allows semi quantitative characterization of the effects of different fan processes such as erosion and bed amalgamation environments indicative of different fan processes may be characterized based on the degree to which processes have acted as a filter to modify the assumed power law distribution systematically this model of the effect of fan processes on the power law distribution is used to help to account for bed thickness distributions observed in several field sites

achievements and probable trends in seismic hazard assessment abstract the seismic hazard can be expressed in different ways from simple observed macroseismic fields to seismostatistical calculations for analyzing earthquake occurrences in time and space and assessing their dynamic effects in a certain site or region to sophisticated seismogeological approaches for evaluating the maximum expected earthquake effects on the earth s surface the advantages and shortcomings of each method means of delineating source regions testing the quality of input data processing such data to suit the chosen method of hazard assessment and estimates of the maximum expected earthquake magnitude and of the attenuation relationships as well as the extent of the errors in all these factors will be presented