present day kinematics of the mediterranean a comprehensive overview of gps results i combine recently published gps results to derive a geodetic horizontal velocity field consistent at the scale of the mediterranean and the surrounding alpine belts the velocity field is then used to discuss the boundary conditions around each major deforming area in the mediterranean to describe the main patterns of motion and deformation to critically review the existing kinematics models and to finally point out the main unresolved kinematics questions strain rate in europe north of the alpines belt is dominated by the signature of the glacial isostatic adjustment and tectonic strain remains below the current accuracy of gps results in the western mediterranean deformation is restricted to the betics the alboran and the morrocan rif with west to southwestward motion with respect to iberia which is part of stable europe shortening consistent with the relative nubia eurasia plate motion is found throughout the maghrebides but the distribution of deformation in northern africa remains largely unknown the central mediterranean is dominated by the counter clockwise rotation of the adriatic the junction between the southern adriatic domain and nubia has yet to be firmly established the deformation over a wide area east of the maghrebides in tunisia and the gulf of sirte in libya still remains to be quantified in the eastern mediterranean the velocity field is dominated by a general anti clockwise rotation and a general trend towards the hellenic trench with velocity magnitude increasing with decreasing distances from the trench this trend is observed not only in the aegean and anatolia but also in the southern balkans geodetic results emphasize that the convergence of the nubia and arabia plates towards eurasia directly controls the deformation across only very few segments along the plate boundary zone additional processes are therefore required to explain the observed velocity field and deformation pattern

paleoseismic study on active normal faults in the southeastern weihe graben central china abstract field investigations and trench excavations can provide direct and indirect geological evidence for the occurrence of paleo earthquakes in this study we present geological and topographical evidence for the occurrence of great paleo earthquakes produced by active normal faults in the southeastern weihe graben central china field and trench observations in combination with radiocarbon ages reveal that i four surface faulting events occurred in the past 4000 years with an average recurrence interval of 1000 years which is in contrast with the previously estimated interval of 2000 2900 years ii the most recent fault event is correlated to the 1556 m 8 5 huaxian earthquake iii an alluvial terrace riser that formed at 5300 yr b p has been vertically offset by 9 11 m indicating an average vertical slip rate of 1 7 2 1 mm yr in the late holocene our results confirm that normal faults in the southeastern weihe graben have been active in the late holocene as source seismogenic faults and that these faults have the potential to trigger large earthquakes of m 7 in the future therefore it is important to urgently reevaluate the seismic potential and seismic hazard in the densely populated weihe graben region

petrogenesis of permian a type granitoids in the cihai iron ore district eastern tianshan nw china constraints on the timing of iron mineralization and implications for a non plume tectonic setting abstract the geochronology and geochemistry of granitoids in the eastern tianshan nw china provide important constraints on the timing of iron mineralization as well as in understanding evolution history of the southern central asian orogenic belt caob here we present results from a detailed study on granitoid rocks from the cihai iron ore district in the beishan region southern part of the eastern tianshan the granitoid rocks are composed of granodiorite quartz monzonite granite and monzonite zircon u pb analyses yielded the ages of 294 1 2 2 ma 286 5 0 7 ma 284 3 3 3 ma and 265 6 3 0 ma respectively suggesting they were formed in early middle permian among these granitoid rocks the ages of quartz monzonite and granite are close to the timing of iron mineralization 282 ma indicating they may provide a source of iron in the cihai ore district geochemically the granodiorite granite and quartz monzonite samples are characterized by high feo t feo t mgo and ga al ratios 0 84 0 94 and 2 28 3 27 respectively as well as high zircon saturation temperatures 781 908 c similar to those of typical a type granitoids isotopically they display consistently depleted hf isotopic compositions e hf t 1 18 to 15 37 geological geochemical and isotopic data suggest that the cihai a type granitoids were derived from melting of juvenile lower crust some early permian a type granitoids were recently identified in the tarim and eastern tianshan with the ages between 294 and 269 ma the a type granitoids in the eastern tianshan formed earlier between 294 284 ma and exhibit characteristics of a 2 type granitoids whereas the a type granitoids in the tarim formed later between 277 269 ma and show a 1 granitoids affinity we suggest that the permian tarim mantle plume does not account for the formation of the a type granitoids in the eastern tianshan area and the eastern tianshan was in a non plume tectonic setting during early permian time a slab break off event has been suggested as the possible tectonic mechanism that triggered the formation of early permian a type granitoids in the eastern tianshan

late early triassic microbial reefs of the western united states a description and model for their deposition in the aftermath of the end permian mass extinction abstract research in the western united states to reinvestigate and characterize the previously reported stromatolites of the latest early triassic spathian virgin limestone member of the moenkopi formation has shown that these microbial build ups formed patch reef mounds detailed field analysis of these reef mounds and the surrounding beds has established that they attained 1 2 m of topographic relief above the seafloor a petrographic study of these microbial mounds illustrates that they consisted of microbial fabrics as well as voids with early marine cements and formed in the absence of in situ metazoans these reef mounds formed during the aftermath of the end permian mass extinction that spanned the early triassic due to the devastation of marine metazoans at this extinction the early triassic has often been deemed a reef gap because no metazoan reefs are found at this time whereas colonial metazoan reefs are globally absent from lower triassic strata microbial build ups similar to these described from the western united states have been found in south china armenia southern turkey and greenland a regional early permian to late early triassic unconformity exists in the study region however analysis of these microbial reefs within a global context suggests that conditions favouring microbial reef development must have existed as long as 4 8 m y after the end permian mass extinction a depositional model of these microbial mounds indicates that flooding of the shelf with anoxic and or co2 rich deep waters may have fostered their occurrence

active faulting and paleoseismology along the bree fault lower rhine graben belgium paleoseismic analysis of the 10 km long bree fault scarp in the lower rhine graben yields numerous lines of evidence of earthquake activity in the holocene and late pleistocene this active normal fault a part of the feldbiss fault system dips 70 ne and is expressed at the surface by a prominent nw se trending 7 to 20 m high scarp formed since the deposition of the maas river main terrace 700 kyr b p trenches and geophysical prospecting show that the fault which is known to have 100 m of vertical offset since the late pliocene breaks late pleistocene and holocene deposits ground penetrating radar seismic refraction and electric tomography suggest that at shallow depth the amount of displacement is larger than the youngest vertical offset visible in the trenches and corresponds to cumulative fault displacements the analysis of 36 leveling profiles across the scarp indicates that its height can be classified into three groups likely corresponding to different events a morphologic dating gives approximate ages of 2 1 5 kyr b p 14 5 kyr b p and 41 6 kyr b p for the past three surface faulting earthquakes analysis of faulted stratigraphy and earthquake induced deformation structures exposed in trenches suggests the occurrence of three large earthquakes during the past 45 l03 years and yields 0 07 mm yr of relative vertical deformation rate the most recent seismic event occurred between a d 610 and 890 the first identification of an active fault with surface ruptures in the lower rhine graben area emphasizes that large earthquake sources exist within intraplate europe and that at least some of these events are preserved in the geologic record

continuous gps and broad scale deformation across the rhine graben and the alps in order to study the ongoing tectonic deformation in the rhine graben area we reconstruct the local crustal velocity and the strain rate field from gps array solutions following the aim of this work we compile the velocities of permanent gps stations belonging to various networks euref agnes regal and rgp in central western europe moreover the strain rate field is displayed in terms of principal axes and values while the normal and the shear components of the strain tensor are calculated perpendicular and parallel to the strike of major faults the results are compared with the fault plane solutions of earthquakes which have occurred in this area a broad scale kinematic deformation model across the rhine graben is provided on the basis of tectonics and velocity results of the gps permanent stations the area of study is divided into four rigid blocks between which there might be relative motions the velocity and the strain rate fields are reconstructed along their borders by estimating a uniform rotation for each block the tectonic behaviour is well represented by the four block model in the rhine graben area while a more detailed model will be needed for a better reconstruction of the strain field in the alpine region

quantitative compositional analysis of a triassic carbonate platform southern alps italy abstract we have estimated abundance and distribution of automicrite marine cements and skeletal grains in the triassic sella massif an isolated platform flanked by steep 25 35 clinoforms 108 samples were taken at constant intervals from measured sections of the major zones of the platform edifice the platform top margin upper slope and lower slope in a first step carried out in the field and on hand specimen purely detrital deposits were separated from automicrite facies i e beds with automicrite cement filled primary vugs and admixtures of skeletal carbonate and lithoclasts in the second step samples with automicrite facies were thin sectioned and point counted the categories used for point counting were a automicrite b vugs and cement c microspar or neomorphic spar d skeletal grains and e internal sediments at the platform top 46 of samples are pure detrital deposits 27 consist of automicrite facies and 27 are too strongly altered by dolomitization to allow classification at the margin upper slope 68 of samples consist of automicrite facies 22 are pure detrital sediments and 10 are strongly altered at the lower slope 63 are detrital deposits 10 automicrite facies and 27 are extensively dolomitized the most important contributors to the automicrite facies are automicrite 41 on the platform top 29 on the margin upper slope 28 on the lower slope and early marine cement 35 on the platform top 48 on the margin upper slope 27 on the lower slope the amount of skeletal grains is less than 10 the automicrite facies stabilized the platform margin and upper slope automicrite abundant early marine cements and micro organisms such as tubiphytes formed a rigid framework thus substituting for the lack of a metazoan reef on the upper slopes the framework of automicrite facies stabilized the slope but intermittently the automicrite layers are frequently dissected by sediment filled fractures or are broken into clasts we assume that they slid on the layers of loose detritus bigger slides turned into rubbly debris flows that formed metre thick breccias at the lower slope and the proximal basin floor the planar shape and steep angle of the clinoforms indicate that the large scale geometry of the slope was not controlled by the automicrite but rather by non cohesive layers of sand and rubble piled up to the angle of repose the production mode of the sella is comparable of that of a mud mound factory this factory was highly productive in 1 ma the platform aggraded over 300 m and prograded over 2000 m in all directions

multiarchive paleoseismic record of late pleistocene and holocene strong earthquakes in switzerland a multiarchive approach has been applied to the investigation of the late pleistocene and holocene record of strong earthquakes in switzerland the geological archives used for this study include active faults lake deposits slope instabilities and caves in the basle area eight trenches were opened across the basle reinach fault nearby rockfall deposits were systematically investigated sediment cores were taken from two lakes and nine caves were studied in central switzerland five lakes were investigated by means of high resolution seismic lines and sediment cores furthermore three caves were studied in central switzerland altogether the investigations are based on more than 350 km of high resolution reflection seismic lines 450 m of core samples 260 m of trenches and 245 radiocarbon age determinations the measured co seismic displacements along the basle reinach fault supply independent information for the magnitude of the ad 1356 basle earthquake exclusively based on geological evidence deformation features related to three well documented strong historic earthquake shocks were identified deformation features of the ad 1774 altdorf and ad 1601 unterwalden earthquakes can be used to calibrate paleoseismic evidence in central switzerland altogether traces of 13 earthquakes could be found in the two study areas all of them with magnitudes mw 6 or greater for the first time the earthquake catalogue for switzerland can be extended back beyond historic records into the late pleistocene spanning 15 000 years d 2005 elsevier b v all rights reserved

early history of scleractinian corals and its geological consequences conventional views have implied that scleractinian corals were hermatypic and thus were potentially reef building from the onset of their appearance in early mesozoic time in shallow shelf carbonate environments however for almost 25 m y they held rather subordinate positions and generally did not participate in extensive ecologic reef framework evidence from both north america and europe demonstrates that triassic corals had ecologic preferences quite different from those in the cenozoic a key step in the evolutionary success of these corals may have been the advent of a symbiotic association with algae this association believed to have developed at the end of the triassic could have been responsible for thrusting scleractinians into prominent positions as reef builders and may account for their dramatic radiation in mesozoic time

oldest scleractinian coral reefs on the north american craton upper triassic carnian northeastern british columbia canada abstract bioclastic accumulations composed of crinoids brachiopods molluscs spongiomorphs and scleractinian corals occur within upper triassic strata of the lower baldonnel formation at pardonet hill in northeastern british columbia canada these small buildups 100 to 500 m3 have planar bases and broadly convex tops these mounds are interpreted as small patch reefs composed of packstone bioclastic floatstone rudstone and carbonate breccia intercalated with mixed siliciclastic carbonate sediments deposited in a shallow subtidal setting i e above fairweather wave base amalgamated hummocky cross stratified to current ripple laminated quartz dominated sandstone beds and numerous sharp based normally graded bioclastic commonly encrinitic packstone grainstone quartz sandstone couplets characterize inter reef lithologies conodont biostratigraphy indicates that the pardonet hill patch reefs occur within strata dated as earliest upper carnian lower nodosus zone the pardonet hill patch reefs originated and developed during an interval of regional sea level lowstand strata within which these patch reefs occur represent the westernmost migration of the triassic shoreline in western canada disappearance of coral reefs in the study area may have been affected by rapid marine transgression and failure of reef faunas to recolonize the new shore zone further to the east the pardonet hill locality occurred on the western margin of the north american craton during the triassic prior to their discovery reef like structures dominated by corals in the western panthalassa were limited to allochthonous terranes now part of the cordillera the pardonet hill patch reefs occur at approximately 30 triassic paleolatitude in modern settings this is at the extreme latitudinal margin of subtropical zooxanthellate reef development the presence of benthic faunas characteristic of low paleolatitude settings on the northwestern coast of pangea has significant implications in paleotectonic and paleoenvironmental reconstructions

near fault broadband ground motion simulations using empirical green s functions application to the upper rhine graben france germany case study seismic hazard estimation relies classically on databased ground motion prediction equations gmpes giving the expected motion level as a function of several parameters characterizing the source and the sites of interest however records of moderate to large earthquakes at short distances from the faults are still rare for this reason it is difficult to obtain a reliable ground motion prediction for such a class of events and distances where also the largest amount of damage is usually observed a possible strategy to fill this lack of information is to generate synthetic accelerograms based on an accurate modeling of both extended fault rupture and wave propagation process the development of such modeling strategies is essential for estimating seismic hazard close to faults in moderate seismic activity zones where data are even scarcer for that reason we selected a target site in upper rhine graben urg at the french german border urg is a region where faults producing micro seismic activity are very close to the sites of interest e g critical infrastructures like supply lines nuclear power plants etc needing a careful investigation of seismic hazard in this work we demonstrate the feasibility of performing near fault broadband ground motion numerical simulations in a moderate seismic activity region such as urg and discuss some of the challenges related to such an application the modeling strategy is to couple the multi empirical green s function technique multi egft with a k 2 kinematic source model one of the advantages of the multi egft is that it does not require a detailed knowledge of the propagation medium since the records of small events are used as the medium transfer function if at the target site records of small earthquakes located on the target fault are available the selection of suitable events to be used as multi egf is detailed and discussed in our specific situation where less number of events are available we then showed the impact that each source parameter characterizing the k 2 model has on ground motion amplitude finally we performed ground motion simulations showing results for different probable earthquake scenarios in the urg dependency of ground motions and of their variability are analyzed at different frequencies in respect of rupture velocity roughness degree of slip distribution stress drop and hypocenter location in near source conditions ground motion variability is shown to be mostly governed by the uncertainty on source parameters in our specific configuration magnitude distance the directivity effect is only observed in a limited frequency range rather broadband ground motions are shown to be sensitive to both average rupture velocity and its possible variability and to slip roughness ending up with a comparison of simulation results and gmpes we conclude that source parameters and their variability should be set up carefully to obtain reliable broadband ground motion estimations in particular our study shows that slip roughness should be set up in respect of the target stress drop this entails the need for a better understanding of the physics of earthquake source and its incorporation in the ground motion modeling

seismic slip rates potential subsurface rupture areas and seismic potential of the vienna basin transfer fault the vienna basin transfer fault vbtf is a slow active fault with moderate seismicity i max 8 9 m max 5 7 passing through the most vulnerable regions of austria and slovakia we use different data to constrain the seismic potential of the vbtf including slip values computed from the seismic energy release during the 20th century geological data on fault segmentation and a depth extrapolated 3 d model of a generalized fault surface which is used to define potential rupture zones the seismic slip of the vbtf as a whole is in the range of 0 22 0 31 mm year for a seismogenic fault thickness of 8 km seismic slip rates for individual segments vary from 0 00 to 0 77 mm year comparing these data to geologically and gps derived slip velocities 1 mm year proofs that the fault yields a significant seismic slip deficit segments of the fault with high seismic slip contrast from segments with no slip representing locked segments fault surfaces of segments within the seismogenic zone 4 14 km depth vary from 55 to 400 km2 empirical scaling relations show that these segments are sufficiently large to explain both earthquakes observed in the last centuries and the 4th century carnuntum earthquake for which archeo seismological data suggest a magnitude of m 6 based on the combination of all data incomplete earthquake catalog seismic slip deficits locked segments potential rupture areas indications of strong pre catalog earthquakes we argue that the maximum credible earthquake for the vbtf is in the range m max 6 0 6 8 significantly larger than the magnitude of the strongest recorded events m 5 7

magnitudes and source areas of large prehistoric northern alpine earthquakes revealed by slope failures in lakes we identify evidence for three large paleo earthquakes in central switzerland with moment magnitudes m 6 5 7 0 significantly exceeding historically known values these earthquakes occurred during the past 15 k y and were strong enough to simultaneously affect a large region that includes the present day major cities of lucerne and zurich we reconstruct the chronology magnitudes and epicenters of these prehistoric earthquakes using temporal and spatial correlation of multiple subaqueous landslide deposits in lake zurich and lake lucerne through high resolution seismic surveys radiocarbon dated sediment cores and spatial calculations using an empirical seismic attenuation model our data indicate ongoing alpine deformation that generated and could potentially generate destructive events in heavily populated regions that have been unaccustomed to seismic activity during historic time

reef fabrics biotic crusts and syndepositional cements of the latemar reef margin middle triassic northern italy the latemar reef buildup of the central dolomites northern italy provides a rare opportunity to examine an in place middle triassic upper anisian to lower ladinian platform margin that is not strongly deformed or dolomitized the margin lies between the flat lying platform interior and steeply dipping foreslope clinoforms across this transition the depositional profile relates directly to a consistent lateral facies pattern 1 restricted biota grainstone of the platform interior 2 tubiphytes rich boundstone and 3 diverse biota grainstone that grades into 4 foreslope breccia beds the boundstone and diverse biota grainstone facies comprise the platform margin the boundstone facies consists of a framework of small 10 cm skeletal remains 10 by volume with associated biotic crusts internal sediments and syndepositional cements crusts and cements constitute most of the rock volume and created the boundstone fabric biotic crusts exhibit gravity defying geometries and range from a light grey structure grumeleuse rind to dark grey micritic laminae both cements and biotic crusts occur as redeposited talus in the foreslope talus deposits indicating a syndepositional origin the diverse biota grainstone facies primarily consists of skeletal peloidal grainstone with a diverse open marine biotic assemblage in contrast to the restricted biota grainstones of the platform interior that have a low diversity restricted marine biota metre scale hexacoral boundstone and centimetre scale sponge boundstone and microbial boundstone occur as isolated patches tens to hundreds of metres apart within the diverse biota grainstone facies the depositional profile facies zonation and biotic constituents all indicate that the latemar buildup had a shallow water reef margin in contrast to previous interpretations that these were upper slope reefs the syndepositional biotic crusts and inorganic cementation played key roles in stabilizing the boundstone fabric to form a wave resistant reef fabric

active normal faulting in the upper rhine graben and paleoseismic identification of the 1356 basel earthquake we have identified an active normal fault in the epicentral area of the basel switzerland earthquake of 18 october 1356 the largest historical seismic event in central europe the event of 1356 and two prehistoric events have been characterized on the fault with geomorphological analysis geophysical prospecting and trenching carbon 14 dating indicates that the youngest event occurred in the interval 610 to 1475 a d and may correspond to the 1356 basel earthquake the occurrence of the three earthquakes induced a total of 1 8 meters of vertical displacement in the past 8500 years for a mean uplift rate of 0 21 millimeters per year these successive ruptures on the normal fault indicate the potential for strong ground movements in the basel region and should be taken into account to refine the seismic hazard estimates along the rhine graben

combining amphibious geomorphology with subsurface geophysical and geological data a neotectonic study at the front of the alps bernese alps switzerland abstract in the vicinity of lake thun at the front of the bernese alps switzerland we performed a multidisciplinary neotectonic study combining onshore and offshore geological data and geophysical measurements in order to identify potentially active fault structures paleoseismic reconstructions on the northern margin of the alps have documented several strong earthquakes with moment magnitudes 6 during the late quaternary which have long recurrence intervals of 1 000 to 2 000 years such earthquakes are expected to produce surface ruptures in this light we investigated the study area located near lake thun primarily for on fault evidence to date still a shortcoming in switzerland we detected several features indicating potential fault activity such as aligned subaquatic morphological depressions offset horizons observed in reflection seismic profiles of lake sediments and in ground penetrating radar images all delineating a fault trace observations of fluvial deposits in a nearby gravel pit in the prolongation of the inferred structure supports these findings a narrow zone with rotated long axes of pebbles inclining at 60 is clearly distinguishable and crosscuts the original bedding with predominantly horizontal orientation of pebble axes this zone further shows an apparent 1 1 m offset of oxidized horizons and is therefore considered as a potential fault plane in a normal faulting regime a dated radiocarbon age of 11 000 years bp of the gravel deposits hence suggests a younger fault activity during the holocene the einigen fault zone efz proposed on the basis of these observations is considered as a complex fault system with a combination of dextral strike slip and normal faulting as suggested by gpr images observations in the gravel pit and radar data independently show that it includes at least two fault strands however while five earthquakes with epicentral intensities i 0 vi and numerous smaller seismic events are known within less than 30 km epicentral distance to lake thun over the past 400 years none of these seem to coincide with the location of the efz

rockfalls triggered by the ad 1356 basle earthquake in the basle region of switzerland we demonstrate that rockfall blocks can be dated accurately using the radiocarbon method soil beneath rockfall blocks containing organic macro remains was sampled at four cliff sites in the tabular jura south east of basle a lightweight drilling rig drills a 101 mm diameter hole through rockfall blocks up to 6 m in height a downhole sampler is used to recover soil samples from below the blocks eighteen radiocarbon dates on charcoal wood needles of conifers and organic macro remains from 11 blocks gave dates between 970 and 440 bp calibrated ages range between ad 1210 and ad 1450 these results along with field observations and historical research suggest that a large number of blocks toppled as rockfalls within a short time interval in the epicentral area of the ad 1356 basle earthquake

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

mid continental earthquakes spatiotemporal occurrences causes and hazards abstract large earthquakes in north china australia northwestern europe central and eastern united states and other mid continents show complex spatiotemporal patterns that do not fit existing earthquake models individual faults or fault zones tend to fall into long term thousands of years or longer dormancy after a cluster of ruptures whereas large earthquakes seem to roam between widespread faults these behaviors are characteristic of complex dynamic systems of interacting faults in such systems widespread faults collectively accommodate slow tectonic loading and a major fault rupture both transfers stress to the neighboring faults and perturbs loading conditions on distant faults because of the slow tectonic loading local stress variations from fault interaction or nontectonic processes or changes of fault strength could trigger mid continental earthquakes the precise spatiotemporal occurrence of large mid continental earthquakes may be unknowable an intrinsic limitation of complex dynamic systems but their qualitative system behavior may be understood by a system approach this approach would render some commonly used concepts such as seismic cycles recurrence intervals characteristic earthquakes and seismic gaps inadequate or irrelevant in mid continents and calls for rethinking of the probability estimates based on these concepts it requires a better understanding of fault interactions on multiple spatial and temporal scales rather than focusing solely on the balance of tectonic loading and yield strength of individual faults or fault segments it also indicates the need for paleoseismic and geodetic studies extending beyond areas where recent large earthquakes occurred and for hazard assessments to reduce the biasing influence of the most recent large earthquakes that tend to dominate the short and incomplete earthquake records

depth transect of an upper triassic rhaetian reef from gosau austria microfacies and community ecology abstract in the late triassic 235 201 3 ma scleractinian corals and hypercalcified sponges built large diverse reef ecosystems the most famous of which are the dachstein reefs this study presents a depth transect along an upper triassic lower rhaetian dachstein reef from the gosausee margin of the dachsteingebirge gosau austria the gosausee microbial sponge coral reef is a complete barrier reef with an almost continuous fore reef to lagoon transect preserved a very rare occurrence for the triassic and thus provides a window into depth zonation of dachstein type reef facies and biotic succession the gosausee reef facies exhibit strong depth control and five classic reef facies or zones are identified the fore reef reef front reef crest back reef and lagoon facies thin rare microbial fabrics and a high abundance of fine grained mud rich skeletal wackestones transported reef debris characterize the deepest fore reef as the reef shallows muddy sediments decrease in abundance and are replaced by microbial fabrics corals and cements abundant sponges microbial crusts and thick marine cements typify the reef crest whereas microbialite coated phaceloid corals are dominant in the back reef facies heavily cemented oncoids or microbial sponge bindstones are characteristic of the lagoon based on their compositional and biotic similarities the gosausee reef was likely part of the same barrier reef systems as the source reef for the gosaukamm reef breccia one of the classic norian rhaetian dachstein reefs the reef zones of the gosausee margin can be used to interpret the depth or reef zone of less well preserved reef fragments can inform models of community ecology and niche utilization in the late triassic and highlight the need for additional research into the environmental factors that controlled biotic distribution in upper triassic reefs

pioneer reef communities within a middle triassic anisian to upper triassic carnian mixed carbonate siliciclastic ramp system from the star peak group south canyon central nevada abstract reef patterns change drastically between the late paleozoic and early mesozoic due to the effects of the end permian mass extinction reef communities follow an ecological transition from the stabilization stage in the anisian to the colonization stage in the carnian through norian to the final diversification and domination stages in the norian through the rhaetian most eastern panthalassa reef studies focused on documenting framework supported reef structures elevated from the seafloor during the late triassic diversification stage however to fully understand reef development we also need to record the precursor stages here we examine field based and microfacies data using a sequence stratigraphic lens to develop a quantitative assessment of non skeletal and skeletal carbonate grains our results indicate that a reef mound and biostromes developed during an overall transgressive sequence due to substrate cementation caused by flooding events although taxonomic differences between biostromes and the reef mound change through time we conclude that these taxonomic changes do not record true first occurrence data instead these fossil accumulations probably occurred due to random chance of larval recruitment even though the reef types found here preserve similar taxa that have been shown to promote high reef growth e g calcified demosponges calcareous algae and bivalves low reef growth structures are found at our site thus reefs containing large amounts of micrite built by low growing binding and encrusting organisms typify this middle and upper triassic section confirming that this section records the colonization stage of reef recovery

intraplate deformation in western europe deduced from an analysis of the international terrestrial reference frame 1997 itrf97 velocity field although tectonic deformation in western europe is essentially concentrated in the appenines and alpine alps pyrenees mountain ranges several large historical and instrumentally recorded earthquakes m 6 are known in the supposedly stable part of europe because of its accuracy and internal consistency at a global scale the international terrestrial reference frame 1997 itrf97 velocity field allows testing of intraplate rigidity in western europe at a millimeter per year level using the full statistical information available on the itrf97 velocities we identify a subset of sites located in central europe that satisfies a rigid cap rotation with residual velocities 1 mm yr and therefore provide a stable europe reference frame serf in this reference frame we find residual velocities at european itrf sites that are consistent with known active tectonic features we identify a northward motion at sites located in italy with internal deformation of the adriatic block rather than rigid plate motion and a westward motion of the westernmost part of europe of the order of 1 2 mm yr relative to central europe the relative motion of the adriatic block and western europe agrees with the current extension known in the tyrrhenian sea and the apennines in central europe we find active deformation 1 mm yr in the eastern alps and western carpathians in the alpine range our results indicate e w extension across the western alps and n s compression across the central and eastern alps in agreement with the strain regime deduced from seismotectonic observations in belgium and the netherlands we find residual velocities of 1 1 5 mm yr to the northwest at all the sites most likely accommodated along the upper and lower rhine graben structures an important outcome of this study is the identification of internal deformation of the order of 1 2 mm yr in an area usually interpreted as stable europe this result should be further checked as new denser and more accurate space geodetic data sets with longer observation time spans become available for europe

simulation of mw 6 0 earthquakes in the upper rhinegraben using empirical green functions summary in low seismicity areas such as southwestern germany quantitative statements on strong ground motion suffer from the lack of instrumental strong motion data although the historic catalogue indicates that events of moment magnitudes up to mw 6 are conceivable this is the situation in the upper rhinegraben area were moderate earthquakes with low probability but high impact caused by the significant aggregation of population infrastructure and industrial facilities are expected to happen we have developed scenarios of crustal earthquakes with moment magnitudes mw 6 0 for a source region southeast of basel switzerland itself being struck by a strong earthquake in 1356 with an intensity of up to ix ems98 intensity in order to synthesize strong ground motion seismograms we are using an empirical green s function egf approach we utilize records in the frequency range of 0 5 25 hz of permanent stations in the rhinegraben and the adjacent black forest in southwestern germany as egfs to be consistent with the local seismicity we model earthquakes with a left lateral strike slip focal mechanism the applied egf approach allows one to define independently a variety of rupture scenarios on the fault plane by varying the hypocentre location rupture velocity fault plane geometry slip distribution and rise time therefore we can create worst case scenarios for the chosen sites we compare peak horizontal acceleration pha and response spectra in terms of spectral accelerations and phas with attenuation laws proposed for europe our results encourage the application of the egf approach as a supplementary tool for site specific strong ground motion prediction in low seismicity regions such as the upper rhinegraben area

evidence for active tilting of the nw german basin from correlations between fluvial landscape and geological subground the catchment basin of the river hunte lower saxony nw german basin was studied on a mesoscale length of 90 km to investigate the influence of the geological subground on modern morphology a geo information system gis was used to calculate linear correlation coefficients between the depth of geological strata base zechstein to base quaternary and the height of the modern landscape holocene alluvial plain lower weichselian terrace catchment basin and watershed high linear correlation coefficients between the base of tertiary and the height of the modern topography catchment basin r2 0 87 lower weichselian terrace r2 0 95 and holocene alluvial plain r2 0 95 indicate control of the modern topography by the depth of the geological subsurface via tilting of the entire basin most likely northward tilting of the nw german basin forces the river hunte to flow in a northerly direction by relative uplift of the hinterland wiehengebirge rhenish massif and subsidence of the north sea area

stress tensor determination in france and neighbouring regions abstract the tectonic behaviour of different seismic regions of france is inferred from the properties of the local stress tensor obtained from focal mechanisms of regional earthquakes polarities of p wave arrivals for several earthquakes are used in the inversion of the stress tensor and individual focal mechanisms the principal axes and the shape of the tensor are closely related to the forces which generate seismic ruptures on pre existing faults we analyse 142 earthquakes of magnitude above 3 7 which occurred between 1965 and 1989 good results are obtained for some regions the northern alps and the southern end of the upper rhinegraben show a quasi compressive strike slip tectonic regime with a maximum stress axis oriented nw se the tectonic regime changes to an extensional strike slip type in the rhenish massif and the lower rhinegraben the direction of the minimum stress axis being nne ssw the central and western regions of france central and armorican massifs exhibit an extensional tectonic regime combined with strike slip faulting the minimum stress axis strikes in a ne sw direction a strongly non homogeneous stress field seems to be present in the southwestern alps and no unique stress tensor could be obtained for that region this problem is likely to be related to a rapid variation of the stress field in space which could be expected given the arc like geometry of the mountain range the pyrenean domain is unresolved due to lack of data and moreover existing focal mechanisms are globaly inconsistent nevertheless those mechanisms which are well constrained suggest a nnw sse to nw se direction of maximum stress in the western part of the pyrenees thus the stress field in france is fairly homogeneous at a regional scale for most of the territory except for the highly deformed belts

nonskeletal peloidal precipitates in upper triassic reefs yukon territory canada abstract peloidal sediments and crusts form up to 75 percent of framework limestones in upper triassic reefs in the yukon territory the peloids are spherical to irregular in shape 20 250 m in size and are commonly surrounded by one or more rims of sparry calcite the peloidal sediments occur in confined cavities and in open spaces between reef framebuilders the peloidal crusts generally coat calcareous sponges and tabulozoans internal evidence suggests that the peloids are not detrital grains or fecal pellets and comparisons with mg calcite peloids and peloidal crusts in modern environments suggest that they are precipitates possibly resulting from bacterial activity

new hypotheses on the maximum damage area of the 1356 basel earthquake switzerland abstract this paper revisits the historical chronicles traditionally used to define the maximum damage area generated by the 1356 basel switzerland earthquake one of the largest and most damaging intra plate earthquake ever known in europe this work was prompted by a little known historical study detailing the castles in existence at the time of the earthquake and mentioning whether they suffered damage or not during the quake this new data set suggests that a few damaged castles assumed to be situated in french sundgau were probably ill located starting from the original historical chronicles we propose new locations for these castles applying the hypothesis that chroniclers listed the damaged castles as if following an itinerary we found localities where castle ruins are still in place today and were bearing similar names to the inappropriately located castles the new damage distribution of the 1356 basel earthquake is now more compact and concentrated around basel to extend the value of this new interpretation we modelled the fault and the earthquake parameters that generated the damage with boxer a macroseismic intensity inversion software the modelled earthquake has a magnitude of 6 2 and was located on a modelled fault striking ene wse the distribution of the 650 years old seismic damages however only recounts the cumulated effects of two main shocks and about a dozen aftershocks therefore substantial ambiguities remain on the field identification of the seismogenic fault

lake sediments as natural seismographs a compiled record of late quaternary earthquakes in central switzerland and its implication for alpine deformation central switzerland lies tectonically in an intraplate area and recurrence rates of strong earthquakes exceed the time span covered by historic chronicles however many lakes are present in the area that act as natural seismographs their continuous datable and high resolution sediment succession allows extension of the earthquake catalogue to pre historic times this study reviews and compiles available data sets and results from more than 10 years of lacustrine palaeoseismological research in lakes of northern and central switzerland the concept of using lacustrine mass movement event stratigraphy to identify palaeo earthquakes is showcased by presenting new data and results from lake zurich the late glacial to holocene mass movement units in this lake document a complex history of varying tectonic and environmental impacts results include sedimentary evidence of three major and three minor simultaneously triggered basin wide lateral slope failure events interpreted as the fingerprints of palaeoseismic activity a refined earthquake catalogue which includes results from previous lake studies reveals a non uniform temporal distribution of earthquakes in northern and central switzerland a higher frequency of earthquakes in the late glacial and late holocene period documents two different phases of neotectonic activity they are interpreted to be related to isostatic post glacial rebound and relatively recent re activation of seismogenic zones respectively magnitudes and epicentre reconstructions for the largest identified earthquakes provide evidence for two possible earthquake sources i a source area in the region of the alpine or sub alpine front due to release of accumulated north west south east compressional stress related to an active basal thrust beneath the aar massif and ii a source area beneath the alpine foreland due to reactivation of deep seated strike slip faults such activity has been repeatedly observed instrumentally for example during the most recent magnitude 4 2 and 3 5 earthquakes of february 2012 near zug the combined lacustrine record from northern and central switzerland indicates that at least one of these potential sources has been capable of producing magnitude 6 2 to 6 7 events in the past

the descriptive nomenclature and classification of growth fabrics in fossil scleractinian reefs abstract framework sensu stricto is a concept originally relating to modern reefs and is defined by structural ecological and sedimentological criteria however in the geological literature the term framework has come to be applied to almost any organically influenced in situ accumulation including non calcareous non rigid facies associated with sea grasses this drastic departure from the original meaning is misleading and scientifically unhelpful the concept of wave resistance is integral to that of framework but in the geological record it is not easy to evaluate and the term may be of little comparative use between reef environments it is suggested that the term growth fabric be generally applied as a descriptive term for the presence of aggregated in situ corals or other organisms in growth position within a facies the term growth fabric should be used as an alternative to framework as a purely descriptive term the term framework should be restricted to its original definition and used only where the criteria for framework can be clearly demonstrated two end member types of scleractinian growth fabric genesis are recognised termed superstratal and constratal terms adapted from gili e masse j p skelton p w 1995 rudists as gregarious sediment dwellers not reef builders on cretaceous carbonate platforms palaeogeogr palaeoclimatol palaeoecol 118 245 267 in a superstratal growth fabric the constituent organisms collectively projected decimetres to metres above the substratum creating positive topographic relief in contrast constratal growth is where vertical organic accretion occurred at a similar rate to sediment accumulation hence the majority of the skeletal material remained continuously embedded in the sediments and only a small proportion of the skeleton projected centimetres above the sediment surface the architectural palaeoecological sedimentological and diagenetic implications of different types of growth fabric genesis is discussed a review of the classification of reef fabrics suggests that there is currently no adequate system to describe fossil scleractinian growth fabrics the most commonly used classification of reefal fabrics is that of embry and klovan 1971 embry a f klovan j e 1971 a late devonian reef tract on northeastern banks island northwest territories bull can pet geol 33 730 781 there are a number of shortcomings in this scheme which may be grouped into three categories 1 the interpretative nature of the classification 2 problems in interpreting biological effect from form and 3 insufficient categories to adequately describe mesozoic and cenozoic growth fabrics moreover there appears to be a lack of a standardised nomenclature for growth fabrics which has hindered meaningful comparisons of scleractinian growth fabrics through time and space a descriptive system based on a modification and expansion of the embry and klovan system 1971 is proposed and a revised nomenclature for growth fabrics presented the system is designed to be flexible in its application it can be used simply to describe a growth fabric or through the use of genetic and non genetic modifiers to imply types of reef building processes and growth fabric heterogeneity although the concepts and terminology discussed in this paper relate to scleractinian growth fabric they are equally applicable to fabrics comprising other organisms

recent surface displacements in the upper rhine graben preliminary results from geodetic networks abstract datasets of the gnss upper rhine graben network gurn and the national levelling networks in germany france and switzerland are investigated with respect to current surface displacements in the upper rhine graben urg area gurn consists of about 80 permanent gnss global navigation satellite systems stations the terrestrial levelling network comprises 1st and 2nd order levelling lines that have been remeasured at intervals of roughly 25 years starting in 1922 compared to earlier studies national institutions and private companies made available raw data allowing for consistent solutions for the urg region we focussed on the southern and eastern parts of the investigation area our preliminary results show that the levelling and gnss datasets are sensitive to resolve small surface displacement rates down to an order of magnitude of 0 2 mm a and 0 4 mm a respectively the observed horizontal velocity components for a test region south of strasbourg obtained from gnss coordinate time series vary around 0 5 mm a the results are in general agreement with interseismic strain built up in a sinistral strike slip regime since the accuracy of the gnss derived vertical component is insufficient data of precise levelling networks is used to determine vertical displacement rates more than 75 of the vertical rates obtained from a kinematic adjustment of 1st order levelling lines in the eastern part of urg vary between 0 2 mm a and 0 2 mm a indicating that this region behaves stable higher rates up to 0 5 mm a in a limited region south of freiburg are in general agreement with active faulting we conclude that both networks deliver stable results that reflect real surface movements in the urg area we note however that geodetically observed surface displacements generally result from a superposition of different effects and that a separation in tectonic and non tectonic processes needs additional information and expertise

timing of holocene paleo earthquakes along the langshan piedmont fault in the western hetao graben north china implications for seismic risk abstract geological evidence and precise age constraints for faulting events during the holocene are vital for assessing the seismic potential of active faults especially in regions lacking instrumental and historical records of earthquakes for this study we constrained the timing and recurrence intervals of holocene paleo earthquakes along the 160 km long ne sw trending langshan piedmont fault lpf which forms the nw boundary of the hetao graben north china the results of outcrop observations and radiocarbon dating reveal that 1 at least four surface rupturing earthquakes occurred during the past 9810 yr with an average recurrence interval of 2450 yr 2 the most recent earthquake mre probably took place within the past 1880 yr 3 rupturing of the entire lpf could produce an earthquake of mw 7 8 posing a significant seismic risk in the region of the western hetao graben we suggest that more detailed paleoseismological studies on the active lpf are needed in order to have a better understanding of its seismogenic behavior

structure and tertiary tectonic history of the mulhouse high upper rhine graben block faulting modified by changes in the alpine stress regime 1 the mulhouse high horst is situated in the southernmost upper rhine graben and changes in its tectonic history record the interaction with the adjacent alpine front recently released seismic data show that the mulhouse high consists of the sierentz and the altkirch tilted blocks separated by the ferrette fault zone with a throw of several hundred meters during the eocene early rupelian main rifting phase the mulhouse high was the elevated flank of the dannemarie basin with sedimentation affected by the nearby southern boundary of the rhine graben the miocene jura compression extended into the mulhouse high creating a series of semiparallel buried folds with no evidence for thin skin tectonics the change to a nw se regional compressive stress reactivated the main graben faults as wrench faults it also resulted in transpression on the ne sw trending faults particularly the northern segment of the illfurth fault zone consequently the northern part of the mulhouse high was uplifted strike slip motion along the ferrette fault zone is shown to be small

sedimentary evidence of historical and prehistorical earthquakes along the venta de bravo fault system acambay graben central mexico abstract the venta de bravo normal fault is one of the longest structures in the intra arc fault system of the trans mexican volcanic belt it defines together with the pastores fault the 80 km long southern margin of the acambay graben we focus on the westernmost segment of the venta de bravo fault and provide new paleoseismological information evaluate its earthquake history and assess the related seismic hazard we analyzed five trenches distributed at three different sites in which holocene surface faulting offsets interbedded volcanoclastic fluvio lacustrine and colluvial deposits despite the lack of known historical destructive earthquakes along this fault we found evidence of at least eight earthquakes during the late quaternary our results indicate that this is one of the major seismic sources of the acambay graben capable of producing by itself earthquakes with magnitudes mw up to 6 9 with a slip rate of 0 22 0 24 mm yr 1 and a recurrence interval between 1940 and 2390 years in addition a possible multi fault rupture of the venta de bravo fault together with other faults of the acambay graben could result in a mw 7 earthquake these new slip rates earthquake recurrence rates and estimation of slips per event help advance our understanding of the seismic hazard posed by the venta de bravo fault and provide new parameters for further hazard assessment

environmental significance of microbialites in reef environments during the last deglaciation in situ microbialites occurring in reef rocks dredged between 80 and 130 m water depth on the modern fore reef slopes of tahiti and the marquesas islands yield ages ranging from 17 100 2900 to 4410 2250 years bp suggesting that they played a prominent role during the last deglacial sea level rise microbialites developed in both shallow and deep water depositional environments where they characterize various zones of the reef tracts reef crests upper reef slopes deep fore reef slopes reflecting contrasting scenarios of microbialite development involving reefal microbialites in shallow water settings and slope microbialites that formed in environments deeper than 10 20 m and extending down to more than 100 m reefal microbialites correspond to a late stage of encrustation of the dead parts of coral colonies or more commonly of related encrusting organisms red algae and foraminifers thus forming surface crusts slope microbialites generally form the ultimate stage of a biological succession indicating a deepening sequence whereby shallow water corals and associated encrusting organisms are replaced by deeper water assemblages of red algae and foraminifers before microbialite growth the precipitation of phosphatic iron manganese crusts and the deposition of planktonic micritic limestones on the microbialites characterize a deepening upward sequence the widespread development of microbialites in reef sequences from the last deglaciation characterizes a period of environmental degradation consequential on the rapid sea level rise and abrupt climatic changes of that time the reported biological succession reflects changes in water quality and especially an increase in nutrients in shallow water settings increased alkalinity and nutrient availability in interstitial waters were related to surface fluxes and terrestrial groundwater seepage while slope environments were exposed to continuous upwelling of nutrient rich deeper waters during the last deglacial sea level rise the age differences between corals and overlying slope microbialites range from 1600 to 8400 years based on high precision u series age measurements of both corals and microbialites and indicates that a significant time several thousand years elapsed between the development of the coralgal frameworks and the growth of slope microbialite crusts microbialites cannot be considered as part of the drowning event some 14 000 years ago that resulted in the demise of reef frameworks in the 90 110 m present depth range but are substantially younger

late jurassic coral microbial reefs from the northern paris basin facies palaeoecology and palaeobiogeography abstract during the late middle oxfordian patch reefs grew on the northern margin of the paris basin according to the facies analysis of the reef and inter reef sediments the environment was a warm clear and agitated sea with highly episodic sedimentation the bioherms were a short lived phenomenon during the third phase of regional reefal development sequence stratigraphically they are associated with a highstand system tract volumetrically and trophically dominant organisms were microbes now represented by massive clotted leiolite stalactitic hemispheroids with purely thrombolitic texture are restricted to open caves corals were of structural reef building importance due to their rapid upward growth the patch reefs are characterised by thickets of ramose corals which developed a very open framework in the vicinity of these patch reefs though in hydrodynamically higher energy environments grew thickets of more stoutly branched corals however they are rarely preserved in situ and are generally represented as abundant coral rubble the reef taxa are characterised by the notable absence of several groups e g oysters serpulids bryozoans pectinids occurring at other localities where reefs of similar age developed in similar environmental conditions the reefs also have strikingly modern aspects to them in particular the presence of cryptic elements within caves and a sponge dominated borer association dwellers belong to various life form types although encrusting taxa are exceedingly rare this may be explained by the presence of soft microbial films on most surfaces the palaeoecological analysis suggests that the major controls on faunal composition and high diversity were elevated nutrient levels highly episodic sedimentation and probably seasonal environmental disturbances structural and functional aspects of the reef community grazers trigger framebuilders borers trigger binders binders hamper borers allow ecological comparisons to be made with contemporaneous as well as recent reefs the unique combination of ecological factors resulted in a specialised previously undescribed community which differs from both tethyan and northern localities in various aspects these include cavities with cryptofauna prominence of grazing gastropods and high faunal diversity in a microbially dominated build up

aseismic deformation in the alps gps vs seismic strain quantification neotectonics of the western and central alps is characterized by ongoing widespread extension in the highest zones of the chain and transcurrent compressive tectonics at the external limits of the belt the overall geodetically measured deformations also indicate extension across the western alps there is a good qualitative coherency between seismotectonic and geodetic approaches here we attempt to quantify the seismic part of the deformation the seismic strain is compared to the deformation derived from geodesy in sub areas of homogeneous seismic stress strain we computed the total seismic moment tensor and related strain tensor this study provides new quantitative elements about the ongoing geodynamic processes in the alpine belt the important discrepancies obtained between seismic strains and geodetically measured deformations raise the issue of aseismic deformation in the alps which could be related to elastic loading creeping and or a slower ductile style deformation

neotectonics and intraplate continental topography of the northern alpine foreland research on neotectonics and related seismicity has hitherto been mostly focused on active plate boundaries that are characterized by generally high levels of earthquake activity current seismic hazard estimates for intraplate domains are mainly based on probabilistic analyses of historical and instrumental earthquake catalogues the accuracy of such hazard estimates is limited by the fact that available catalogues are restricted to a few hundred years which on geological time scales is insignificant and not suitable for the assessment of tectonic processes controlling the observed earthquake activity more reliable hazard prediction requires access to high quality data sets covering a geologically significant time span in order to obtain a better understanding of processes controlling on going intraplate deformation the alpine orogen and the intraplate sedimentary basins and rifts in its northern foreland are associated with a much higher level of neotectonic activity than hitherto assumed seismicity and stress indicator data combined with geodetic and geomorphologic observations demonstrate that deformation of the northern alpine foreland is still on going and will continue in the future this has major implications for the assessment of natural hazards and the environmental degradation potential of this densely populated area we examine relationships between deeper lithospheric processes neotectonics and surface processes in the northern alpine foreland and their implications for tectonically induced topography for the environmental tectonics project entec the upper and lower rhine graben urg and lrg and the vienna basin vb were selected as natural laboratories the vienna basin developed during the middle miocene as a sinistral pull apart structure on top of the east alpine nappe stack whereas the upper and lower rhine grabens are typical intracontinental rifts the upper rhine graben opened during its late eocene and oligocene initial rifting phase by nearly orthogonal crustal extension whereas its neogene evolution was controlled by oblique extension seismic tomography suggests that during extension the mantle lithosphere was partially decoupled from the upper crust at the level of the lower crust however whole lithospheric folding controlled the mid miocene to pliocene uplift of the vosges black forest arch whereas thermal thinning of the mantle lithosphere above a mantle plume contributed substantially to the past and present uplift of the rhenish massif by contrast oblique crustal extension controlling the late oligocene initial subsidence stage of the lower rhine graben gave way to orthogonal extension at the transition to the neogene the entec project integrated geological geophysical geomorphologic geodetic and seismological data and developed dynamic models to quantify the societal impact of neotectonics in areas hosting major urban and industrial activity concentrations the response of europe s intraplate lithosphere to late neogene compressional stresses depends largely on its thermo mechanical structure which in turn controls vertical motions topography evolution and related surface processes

deterministic earthquake scenario for the basel area simulating strong motions and site effects for basel switzerland 1 the basel earthquake of 18 october 1356 is considered one of the most serious earthquakes in europe in recent centuries i0 ix m 6 5 6 9 in this paper we present ground motion simulations for earthquake scenarios for the city of basel and its vicinity the numerical modeling combines the finite extent pseudodynamic and kinematic source models with complex local structure in a two step hybrid three dimensional 3 d finite difference fd method the synthetic seismograms are accurate in the frequency band 0 2 2 hz the 3 d fd is a linear explicit displacement formulation using an irregular rectangular grid including topography the finite extent rupture model is adjacent to the free surface because the fault has been recognized through trenching on the reinach fault we test two source models reminiscent of past earthquakes the 1999 athens and the 1989 loma prieta earthquake to represent mw 5 9 and mw 6 5 events that occur approximately to the south of basel to compare the effect of the same wave field arriving at the site from other directions we considered the same sources placed east and west of the city the local structural model is determined from the area s recently established p and s wave velocity structure and includes topography the selected earthquake scenarios show strong ground motion amplification with respect to a bedrock site which is in contrast to previous 2 d simulations for the same area in particular we found that the edge effects from the 3 d structural model depend strongly on the position of the earthquake source within the modeling domain

three dimensional model of hellenic arc deformation and origin of the cretan uplift 1 the hellenic arc of greece is the most seismically active part of europe but little is know about its mechanics we modeled deformation along the arc using a finite element model the model was intended to capture large scale 3 d structure of nubian plate subduction beneath the aegean block and its deformational consequences the shape of the interface was developed using mapped traces at the surface and earthquake hypocenters at depth model block motions were constrained by recent compilations of gps velocity vectors we simulated a 10 ka period of convergence between nubia and the aegean and calculated the strain field in the overriding plate as well as the spatial distribution and orientation of differential stress 1 3 from these calculations we derived testable quantities such as the expected seismic moment rate on the interplate contact uplift pattern and distribution of strain modes our relatively simple model broadly reproduced observed uplift patterns earthquake activity and loci of extension and contraction the model showed a localization of uplift near the island of crete where the fastest aegean uplift rates are well documented comparison of calculated expected seismic moment and observed earthquake catalogs implies a nearly fully coupled interplate contact on the basis of our modeling results we suggest that south aegean deformation is driven primarily by the fast moving 33 mm a 1 aegean upper plate overriding a nearly stalled 5 mm a 1 nubian lower plate this tectonic setting thus more closely resembles a continental thrust than it does a typical oceanic subduction zone

paleogeographic trends in late triassic reef ecology from northeastern panthalassa the late triassic was a pivotal period in reef evolution but the majority of information about reef ecology during this time comes from buildups in the alps e g the tethys ocean recent studies of reefs in western north america have recognized unique ecologies along the eastern margin of the panthalassa ocean although there are numerous twenty five localities with putative reef builders only four buildups had syndepositional relief and a rigid framework i e true reefs the most paleo northern true reefs were microbial patch reefs with only a few large skeletal bioconstructors hypercalcified sponges and spongiomorphs built the mid latitude reefs with secondary microbial encrustation and branching phaceloid retiophyllia corals corals are the primary bioconstructors in panthalassa s most paleo equatorial reefs and calcareous microbes are sparse when all reefal deposits are analyzed the n s gradient is also present with microbial and bivalve deposits in the north sponge coral deposits in the mid latitudes and coral deposits near the equator this ecological gradient is not apparent in the tethys ocean tethyan reefs thrived in oligotrophic tropical waters without strong latitudinal gradients by contrast paleoceanographic considerations suggest that cool nutrient rich waters swept south along the western north american borderlands in the late triassic the eastern boundary current is interpreted to have created a strong north south differentiation of environments in northeastern ne panthalassa that was manifested in both the biotic and abiotic characteristics of eastern panthalassic reefs reefs from equatorial panthalassa are similar to tethyan reefs warm water photozoan coral reef structures whereas higher paleo latitude reefs from panthalassa are interpreted as cool water heterozoan buildups with abundant calcareous microbes diminutive biocalcifiers and few large framework building corals

seismic reflection evidence for thick skinned tectonics in the northern jura newly released seismic reflection data from the northern jura mountains and southern rhine graben provide the first high quality subsurface images from this area these throw light on the details of the fault patterns in the area and show that the ferrette and le glaserberg jura structures are largely the result of thrust faulting however the faults differ in their nature from those usually assumed in jura tectonics they are not low angle thrusts converging on a decollement zone in triassic evaporites they appear instead to be high angle faults that cross the entire sedimentary section indicating that thick skinned tectonics prevailed in this part of the jura embryonic jura folds can be seen on the images from the nearby mulhouse horst folds that are not supported by thickened triassic evaporites the existence of recent earthquake activity taken together with the prevalence of thick skinned tectonics suggests that occasional large earthquakes cannot be ruled out in this area

new insight in the tectonics of the southern rhine graben jura region using local earthquake seismology 1 a new seismic data set was acquired using a dense temporary network of mobile seismic stations it is combined with existing seismological data for the southern rhine graben the data yielded some new focal mechanisms and allowed for a detailed local earthquake tomography these methods give new insight in the structure of the crust and stress conditions in the area by combining the tomography with the earthquake hypocenter locations and focal mechanisms some of the structures in the p wave velocity model are interpreted as active faults the eastern boundary fault zone of the graben is found to be activated in a left lateral strike slip sense the southern continuation of these faults is formed by variscan structures in the basement a change in orientation of the graben axis between the main graben and its southern end have played a role during the development of the system this difference in orientation caused the development of the dannemarie and allschwil subbasins during a late stage of the opening of the rhine graben this study shows evidence for active faulting in the basement underneath the detachment of the jura mountains these faults which are interpreted as reactivated permo carboniferous troughs coincide with the frontal thrusts of the jura mountains it might be that these structures in the basement have influence on the detachment tectonics in the region

evidence for holocene palaeoseismicity along the basel reinach active normal fault switzerland a seismic source for the 1356 earthquake in the upper rhine graben summary we conducted a palaeoseismic study with geomorphologic mapping geophysical prospecting and trenching along an 8 km long nne ssw trending fault scarp south of basel the city as well as 40 castles within a 20 km radius were destroyed or heavily damaged by the earthquake of 1356 october 18 io ix x the largest historical seismic event in central europe active river incisions as well as late quaternary alluvial terraces are uplifted along the linear basel reinach br fault scarp the active normal fault is comprised of at least two main branches reaching the surface as evident by resistivity profiles reflection seismic data and direct observations in six trenches in trenches the normal fault rupture affects three colluvial wedge deposits up to the base of the modern soil radiocarbon as well as thermoluminescence tl age determinations from other trenches helped to reconstruct the holocene event chronology we identified three seismic events with an average coseismic movement of 0 5 0 8 m and a total vertical displacement of 1 8 m in the last 7800 yr and five events in the last 13 200 yr the most recent event occurred in the interval ad 500 1450 2 and may correspond to the 1356 earthquake furthermore the morphology suggests both a southern and northern fault extensions that may reach 20 km across the jura mountains and across the rhine valley taking this fault length and a 10 km thick seismogenic layer suggests a mw 6 5 or greater event as a possible scenario for the seismic hazard assessment of the basel region

why earthquake hazard maps often fail and what to do about it abstract the 2011 tohoku earthquake is another striking example after the 2008 wenchuan and 2010 haiti earthquakes of highly destructive earthquakes that occurred in areas predicted by earthquake hazard maps to be relatively safe here we examine what went wrong for tohoku and how this failure illustrates limitations of earthquake hazard mapping we use examples from several seismic regions to show that earthquake occurrence is typically more complicated than the models on which hazard maps are based and that the available history of seismicity is almost always too short to reliably establish the spatiotemporal pattern of large earthquake occurrence as a result key aspects of hazard maps often depend on poorly constrained parameters whose values are chosen based on the mapmakers preconceptions when these are incorrect maps do poorly this situation will improve at best slowly owing to our limited understanding of earthquake processes however because hazard mapping has become widely accepted and used to make major decisions we suggest two changes to improve current practices first the uncertainties in hazard map predictions should be assessed and clearly communicated to potential users recognizing the uncertainties would enable users to decide how much credence to place in the maps and make them more useful in formulating cost effective hazard mitigation policies second hazard maps should undergo rigorous and objective testing to compare their predictions to those of null hypotheses including ones based on uniform regional seismicity or hazard such testing which is common and useful in similar fields will show how well maps actually work and hopefully help produce measurable improvements there are likely however limits on how well hazard maps can ever be made because of the intrinsic variability of earthquake processes

the nisi fault as a key structure for understanding the active deformation of the nw peloponnese greece abstract the previously unknown nisi fault in nw peloponnese was ruptured during the 2008 movri mountain earthquake attaining a maximum offset of 25 cm the fault is interpreted as a branch of a flower structure above a blind strike slip fault we investigate the nisi fault seismotectonic evolution using morphotectonic analysis in order to determine whether the landscape is affected by tectonic forcing and paleoseismology to determine earthquake recurrence interval and fault slip rates we applied several geomorphic indices such as the asymmetry factor af the stream length gradient index sl the valley floor width to valley height ratio vf the mountain front sinuosity smf the drainage basin shape bs and the hypsometric curve hc in four large drainage basins of the study area the results show that fault related vertical motions and the associated tilting influenced the drainage geometry and the landscape development values of stream gradient indices sl are relatively high close to the fault trace mountain front sinuosity smf mean values along the fault zones range from 1 12 to 1 23 valley floor width to valley height ratios vf mean values along the studied fault range between 0 21 and 2 50 drainage basin shape bs mean values along the fault range from 1 04 to 3 72 lateral fault growth was likely achieved by propagation primarily towards north northwestward the paleoseismic history of the fault investigated by a trench and 14c dating of seven samples indicates two morphogenic earthquakes in the last 1 kyr therefore we suggest that the nisi fault displays a slip rate on the order of 1 mm yr and a recurrence interval ranging between 300 and 600 years from a seismotectonic point of view the fault is classified as high activity rate with abundant but discontinuous geomorphic evidence of its activity other similar faults affecting the western peloponnese can be envisaged with a similar procedure additionally the seismic history and surface expression of the nisi fault resembles other faults of similar length in greece and italy particularly a crucial issue in terms of seismic risk management is that neotectonic analysis has to be envisaged carefully on short in length faults since these faults can be possibly related to strong earthquakes

historical coseismic surface deformation of fluvial gravel deposits schafberg fault lower rhine graben germany intraplate earthquakes pose a significant seismic hazard in densely populated rift systems like the lower rhine graben in central europe while the locations of most faults in this region are well known constraints on their seismogenic potential and earthquake recurrence are limited in particular the holocene deformation history of active faults remains enigmatic in an exposure excavated across the schafberg fault in the southwestern lower rhine graben south of untermaubach in the epicentral region of the 1756 duren earthquake m l 6 2 we mapped a complex deformation zone in holocene fluvial sediments we document evidence for at least one paleoearthquake that resulted in vertical surface displacement of 1 2 0 2 m the most recent earthquake is constrained to have occurred after 815 ad and we have modeled three possible earthquake scenarios constraining the timing of the latest event coseismic deformation is characterized by vertical offset of sedimentary contacts distributed over a 10 m wide central damage zone faults were identified where they fracture and offset pebbles in the vertically displaced gravel layers and fracture orientation is consistent with the orientation of the schafberg fault this study provides the first constraint on the most recent surface rupturing earthquake on the schafberg fault we cannot rule out that this fault acted as the source of the 1756 duren earthquake our study emphasizes the importance of and the need for paleoseismic studies in this and other intracontinental regions in particular on faults with subtle geomorphic expression that would not typically be recognized as being potentially seismically active our study documents textural features in unconsolidated sediment that formed in response to coseismic rupturing of the underlying bedrock fault we suggest that these features e g abundant oriented transgranular fractures in their context should be added to the list of criteria used to identify a fault as potentially active such information would result in an increase of the number of potentially active faults that contribute to seismic hazards of intracontinental regions

early triassic stromatolites as post mass extinction disaster forms aftermaths of mass extinctions have been thought to be characterized by relaxation of ecological constraints accompanied by increased prominence of opportunistic generalists such taxa termed disaster forms have been shown to increase dramatically in range and abundance after several mass extinction events the cambrian ordovician stromatolite decline in normal marine level bottom environments has been explained as a direct or indirect consequence of increases in ecological constraints such as greater levels of predation and or bioturbation of microbial communities caused by early paleozoic benthic invertebrate evolution and diversification thus one would predict that in post ordovician strata stromatolites might appear in normal marine level bottom environments as disaster forms in the aftermaths of mass extinction particularly devastating to the benthic biota such as during early triassic time mounded stromatolites are present in two beds up to 1 5 m thick of the lower triassic spathian virgin limestone member moenkopi formation in the southwestern spring mountains of nevada stromatolites from level bottom normal marine subtidal environments have also been described from other lower triassic strata in north america europe and asia these stromatolites unusual in level bottom normal marine settings may have developed locally during the long aftermath 4 5 m y of the permian triassic mass extinction because of partial relaxation of the ecological constraintsmore that typically restricted them from unstressed subtidal normal marine level bottom environments less

the ce 1303 hongdong earthquake and the huoshan piedmont fault shanxi graben implications for magnitude limits of normal fault earthquakes the ce 1303 hongdong earthquake with 270 000 deaths has been suggested as the first magnitude 8 earthquake recorded in north china we use 31 ams 14c ages to date earthquakes recorded in the huoshan piedmont fault which is interpreted to be the causative fault for the event we interpret fault traces and map the hongdong earthquake surface rupture in detail four events are identified with timings constrained at 1 060 590 year bp corresponding to the common era 1303 event 3 310 3 210 year bp 5 460 5 380 year bp and 26 380 year bp respectively the later three events have a recurrence interval of 2 000 3 000 years we find that the hongdong earthquake had a rupture length of 98 km a maximum throw of 5 0 m and a best estimate for magnitude in the range mw 7 2 7 6 we suggest that previous magnitude estimates are overestimates normal fault earthquakes have smaller upper limits to their magnitudes than thrusts because their relatively steep dips produce intersections at the base of the seismogenic layer at smaller downdip widths than gently dipping thrust faults the hongdong event was not an exception to this pattern the historic released seismic moment may be closer to the accumulated moment than previously calculated

palaeoseismicity studies on end pleistocene and holocene lake deposits around basle switzerland summary palaeoseismological investigations in the lakes of seewen and bergsee in the basle region switzerland and southern germany revealed characteristic event horizons in an otherwise uniform background sedimentary record dated and correlated based on radiocarbon ages palynostratigraphy and sedimentation rates some of these event horizons show soft sediment deformation features and fractures that can be interpretated as being the result of earthquake shaking two of the event horizons with clear indications for earthquake deformation were detected in both lakes showing approximately the same age as indicated by radiocarbon dating a third event horizon with fractures of apparent seismogenic origin was detected at several drill sites in only one lake bergsee three further event horizons two in the bergsee and one in lake seewen are of uncertain origin though they show some characteristics that could well be caused by earthquakes based on the observations in both lakes five events were detected of which three are most probably related to earthquakes which occurred between 180 bc 1160 bc 8260 bc 9040 bc and 10 720 bc 11 200 bc respectively the basle region is well known for the strongest historical earthquake north of the alps the ad 1356 basle earthquake based on combined historical and palaeoseismological data it has been inferred that earthquakes with size comparable to the ad 1356 basle earthquake have occurred several times within the last 12 000 yr and that the recurrence time for such strong earthquakes are in the range of 1500 3000 yr

active deformation in the eastern swiss alps post glacial faults seismicity and surface uplift abstract post glacial tectonic faults in the eastern swiss alps occur as single lineaments clusters of faults or extensive fault zones consisting of several individual faults aligned along the same trend the orientation of the faults reflects the underlying lithology and the pre existing structures joints pervasive foliations within these lithologies most post glacially formed faults in the area around chur which undergoes active surface uplift of 1 6 mm year trend e w and cut across alpine and glacial features such as active screes and moraines additionally there are nnw and ene striking faults reactivating pervasive alpine foliations and shear zones based on a comparison with the nodal planes of recent earthquakes e w striking faults are interpreted as active faults because of very short rupture lengths and mismatches of fault location with earthquake distribution magnitude and abundance the faults are considered to be secondary faults due to earthquake shaking cumulative deformation in post or interseismic periods or creep and not primary earthquake related faults the maximum of recent surface uplift rates coincides with the youngest cooling of the rocks according to apatite fission track data and is therefore a long lived feature that extends well into pre glacial times isostatic rebound owing to overthickened crust or to melting of glacial overburden cannot explain the observed surface uplift pattern rather the faults earthquakes and surface uplift patterns suggest that the alps are deforming under active compression and that the aar massif basement uplift is still active in response to ongoing collision

studies on precarious rocks in the epicentral area of the ad 1356 basle earthquake switzerland summary for the first time precarious rocks have been analysed in the epicentral area of the ad 1356 basle earthquake in northern switzerland several cliff sites in flat lying thickly bedded upper jurassic coral limestones in the jura mountains were investigated seven blocks are regarded as precarious with respect to earthquake strong ground motions the age of these precarious rocks could not be determined directly as for instance by radiometric dating methods however based on slope degradation processes it can be concluded that the formation of these blocks predates the ad 1356 basle earthquake the acceleration required to topple a precarious rock from its pedestal is estimated using geometrical data for individual block sections and earthquake strong motion records from stations on rock sites in the european strong motion database as input data for the computer program rocking v1 0 from the seismological laboratory university of nevada reno the calculations indicate that toppling of a precarious rock largely depends on earthquake strength but also on the frequency spectrum of the signal although most investigated precarious rocks are surprisingly stable for ground motions similar to those expected to have occurred during the ad 1356 basle earthquake at least two blocks are clearly precariously balanced with peak toppling accelerations lower than 0 3 g possible reasons why these blocks did not topple during the ad 1356 basle earthquake include incomplete separation from their base sliding of precarious rocks their size lower than assumed ground accelerations and or duration of shaking

the record of historic earthquakes in lake sediments of central switzerland deformation structures in lake sediments in central switzerland can be attributed to strong historic earthquakes the type and spatial distribution of the deformation structures reflect the historically documented macroseismic intensities thus providing a useful calibration tool for paleoseismic investigations in prehistoric lake sediments the swiss historical earthquake catalogue shows four moderate to strong earthquakes with moment magnitudes of mw 5 7 to mw 6 9 and epicentral intensities of i0 vii to i0 ix that affected the area of central switzerland during the last 1000 years these are the 1964 alpnach 1774 altdorf 1601 unterwalden and 1356 basel earthquakes in order to understand the effect of these earthquakes on lacustrine sediments four lakes in central switzerland sarner see lungerer see baldegger see and seelisberg seeli were investigated using high resolution seismic data and sediment cores the sediments consist of organicand carbonate rich clayey to sandy silts that display fine bedding on the centimeter to millimeter scale the sediments are dated by historic climate and environmental records 137 cs activity and radiocarbon ages deformation structures occur within distinct zones and include large scale slumps and rockfalls as well as small scale features like disturbed and contorted lamination and liquefaction structures these deformations are attributed to three of the abovementioned earthquakes the spatial distribution of deformation structures in the different lakes clearly reflects the historical macroseismic dataset lake sediments are only affected if they are situated within an area that underwent groundshaking not smaller than intensity vi to vii we estimate earthquake size by relating the epicentral distance of the farthest liquefaction structure to earthquake magnitude this relationship is in agreement with earthquake size estimations based on the historical dataset d 2004 elsevier b v all rights reserved

triassic carbonate development and reefbuilding in western north america the cordilleran region of western north american contains numerous examples of middle to upper triassic carbonate sequences many of these developed as broad shallow water platforms associated with island arcs these platforms however were not characterized by extensive reef structure shallow water facies in many sequences contain abundant corals spongiomorphs sponges and a variety of rich invertebrate faunas most of these are endemic with the exception of the corals which show much similarity with the tethyan faunas small local reefoid buildups occur within many sequences especially those of norian age and contain local organic framework

a smoothed stochastic earthquake rate model considering seismicity and fault moment release for europe ec research fp7 projects share under grant agreement no 226967 and nera under grant agreement no 262330

active tectonics of the southeastern upper rhine graben freiburg area germany the upper rhine graben has two plio quaternary depocentres usually interpreted as resulting from tectonic reactivation the southern basin near freiburg im breisgau germany contains up to 250 m of sediments beneath the younger alluvial deposits related to the current drainage system a former river network deeply entrenched in the substratum reveals a very low regional base level of early pleistocene age the offset of channels at faults allows us to infer a pleistocene reactivation of the syn rift fault pattern and the estimation of slip rates maximum vertical movements along the faults have not exceeded 0 1 mm yr since the middle pleistocene current activity is concentrated along the westernmost faults morphologic markers indicate late pleistocene reactivation of the rhine river fault and geophysical prospecting suggests a near surface offset of young sedimentary deposits the size of the fault segments potentially reactivated suggests that earthquakes with magnitude larger than mw 6 3mw 6 3 could be expected in the area with a return interval of about 8000 years extrapolated to the duration of the plio pleistocene the strain rate estimates reveal that the tectonic forcing may account for only one third to one half of the whole thickness of the plio pleistocene sediments of the basin fill thus other processes must be invoked to understand the growth of the plio pleistocene basin especially the piracy of the rhine river to the north during the early pleistocene could explain these effects

regional intensity attenuation models for france and the estimation of magnitude and location of historical earthquakes summary intensity assignments for 33 calibration earthquakes were used to develop intensity attenuation models for the alps armorican provence pyrenees and rhine regions of france intensity decreases withmost rapidly in the french alps provence and pyrenees regions and least rapidly in the armorican and rhine regions the comparable armorican and rhine region attenuation models are aggregated into a french stable continental region model and the com parable provence and pyrenees region models are aggregated into a southern france model we analyse msk intensity assignments using the technique of bakun wentworth which provides an objective method for estimating epicentral location and intensity magnitude m i m i for the 1356 october 18 earthquake in the french stable continental region is 6 6 for a location near basle switzerland and moment magnitude m is 5 9 7 2 at the 95 per cent 2 confidence level m i for the 1909 june 11 trevaresse lambesc earthquake near marseilles in the southern france region is 5 5 and m is 4 9 6 0 at the 95 per cent confidence level bootstrap resampling techniques are used to calculate objective reproducible 67 per cent and 95 per cent confidence regions for the locations of historical earthquakes these confidence re gions for location provide an attractive alternative to the macroseismic epicentre and qualitative location uncertainties used heretofore

gps monitoring of vertical ground motion in northern ardenne eifel five campaigns 1999 2003 of the hard project we present the hard project of gps monitoring of vertical ground motion in ne ardenne and eifel western europe its main purposes are to get a better insight into the present day rates of vertical ground motion in intraplate settings and to identify the various causes of these motions since 1999 we have carried out yearly campaigns of simultaneous gps measurements at 12 sites situated so as to sample the different tectonic subunits of the study area and especially to record potential displacements across the seismogenic hockai fault zone five campaigns 1999 2003 have been processed currently key issues of the data processing with the gamit software are discussed and first results are presented though temporally consistent in many cases the obtained vertical motion rates are spatially highly variable they are also much too high several mm year to support a tectonic interpretation and a long term influence of groundwater level variations is proposed to account for the observed motions this influence should be distinguished from seasonal variations and from inter survey variations linked to the varying degree of soil and subsoil drying off during the successive spring surveys

quantified sensitivity of small lake sediments to record historic earthquakes implications for paleoseismology seismic hazard assessment is a critical but challenging issue for modern societies a key parameter to be estimated is the recurrence interval of damaging earthquakes this requires the establishment of earthquake records long enough to be relevant i e far longer than historical observations we study how lake sediments can be used for this purpose and explore conditions that enable lake sediments to record earthquakes this was achieved i through the compilation of eight lake sediment sequences from the european alps to reconstruct chronicles of mass movement deposits and ii through the comparison of these chronicles with the well documented earthquake history this allowed 24 occurrences of mass movements to be identified of which 21 were most probably triggered by an earthquake however the number of earthquake induced deposits varies between lakes of a same region suggesting variable thresholds of the lake sequences to record earthquake shaking these thresholds have been quantified by linking the mass movement occurrences in a single lake to both intensity and distance of the triggering earthquakes this method offers a quantitative approach to estimate locations and intensities of past earthquake epicenters finally we explored which lake characteristics could explain the various sensitivities our results suggest that sedimentation rate should be larger than 0 5 mm yr 1 so that a given lake records earthquakes in moderately active seismotectonic regions we also postulate that an increasing sedimentation rate may imply an increasing sensitivity to earthquake shaking hence further paleoseismological studies should control carefully that no significant change in sedimentation rates occurs within a record which could falsify the assessment of earthquake recurrence intervals

the angular velocities of the plates and the velocity of earth s centre from space geodesy summary using space geodetic observations from four techniques gps vlbi slr and doris we simultaneously estimate the angular velocities of 11 major plates and the velocity of earth s centre we call this set of relative plate angular velocities geodvel for geodesy velocity plate angular velocities depend on the estimate of the velocity of earth s centre and on the assignment of sites to plates most geodetic estimates of the angular velocities of the plates are determined assuming that earth s centre is fixed in an international terrestrial reference frame itrf and are therefore subject to errors in the estimate of the velocity of earth s centre in itrf2005 and itrf2000 earth s centre is the centre of mass of earth oceans and atmosphere cm the velocity of cm is estimated by slr observation of lageos s orbit herein we define earth s centre to be the centre of mass of solid earth ce we determine the velocity of ce by assuming that the portions of plate interiors not near the late pleistocene ice sheets move laterally as if they were part of a rigid spherical cap the geodvel estimate of the velocity of ce is likely nearer the true velocity of cm than are the itrf2005 and itrf2000 estimates because 1 no phenomena can sustain a significant velocity between cm and ce 2 the plates are indeed nearly rigid aside from vertical motion and 3 the velocity of cm differs between itrf2005 and itrf2000 by an unacceptably large speed of 1 8 mm yr 1 the velocity of earth s centre in geodvel lies between that of itrf2000 and that of itrf2005 with the distance from itrf2005 being about twice that from itrf2000 because the geodvel estimates of uncertainties in plate angular velocities account for uncertainty in the velocity of earth s centre they are more realistic than prior estimates of uncertainties geodvel differs significantly from all prior global sets of relative plate angular velocities determined from space geodesy for example the 95 per cent confidence limits for the angular velocities of geodvel exclude those of revel sella et al for 34 of the 36 plate pairs that can be formed between any two of the nine plates with the best constrained motion the median angular velocity vector difference between geodvel and revel is 0 028 myr 1 which is up to 3 1 mm yr 1 on earth s surface geodvel differs the least from the geodetic angular velocities that altamimi et al determine from itrf2005 geodvel s 95 per cent confidence limits exclude 11 of 36 angular velocities of altamimi et al and the median difference is 0 015 myr 1 geodvel differs significantly from nearly all relative plate angular velocities averaged over the past few million years including those of nuvel 1a the difference of geodvel from updated 3 2 myr angular velocities is statistically significant for all but two of 36 angular velocities with a median difference of 0 063 myr 1 across spreading centres eight have slowed down while only two have sped up we conclude that plate angular velocities over the past few decades differ significantly from the corresponding angular velocity averaged over the past 3 2 myr

estimation of small surface displacements in the upper rhine graben area from a combined analysis of ps insar levelling and gnss data the intra plate deformation of the upper rhine graben urg located in central europe is investigated using geodetic measurement techniques we present a new approach to calculate a combined velocity field from insar levelling and gnss measurements as the expected tectonic movements in the urg area are small less than 1mma 1 the best possible solutions for linear velocity rates from single technique analyses are estimated in a first step second we combine the velocity rates obtained from insar line of sight velocity rates in ascending and descending image geometries levelling vertical velocity rates and gnss horizontal velocity rates using least squares adjustment lsa focusing on the northern urg area we analyse sar data on four different image stacks ers ascending ers descending envisat ascending envisat descending using the persistent scatterer ps approach the linear velocity rates in ascending and descending image geometries respectively are estimated in an lsa from joint time series analysis of ers and envisat data vertical velocity rates from levelling are obtained from a consistent adjustment of more than 40 000 measured height differences using a kinematic displacement model horizontal velocity rates in east and north direction are calculated from a time series analysis of daily coordinate estimates at 76 permanently operating gnss sites in the urg region as the locations at which the measurement data of ps insar levelling and gnss reside do not coincide spatial interpolation is needed during several steps of the rigorous processing we use ordinary kriging to interpolate from a given set of data points to the locations of interest with a special focus on the modeling and propagation of errors the final 3 d velocity field is calculated at a 200 m grid which carries values only close to the location of ps points resulting in a mean horizontal and vertical precision of 0 30 and 0 13 mm a 1 respectively the vertical component of the combined velocity field shows a significant subsidence of about 0 5 mm a 1 in the northern part of the graben coinciding with a well known quaternary basin structure horizontal displacement rates of up to 0 8 mm a 1 in southeast direction are observed outside the graben in reasonable alignment with the average direction of maximum horizontal stress within the graben the velocity directions rotate toward east in the non subsiding part while an opposite trend is observed in the subsiding part of the graben the complexities of the observed velocity field are compatible to the geomechanical situation in our investigation area which is characterized by a transition from a restraining to a releasing bend setting glacial isostatic adjustment is another potential source influencing the observed velocity field as well as anthropogenic signals due to mining oil exploration and groundwater usage that have been identified in some places

detection of active crustal structures in the upper rhine graben using local earthquake tomography gravimetry and reflection seismics abstract this paper presents a case study in which three different geophysical methods are combined to link the large scale seismically active deformation of the basement to the deformation of the sedimentary cover in the seismically active southern end of the upper rhine graben local earthquake tomography shows velocity contrasts related to large scale faulting in the basement the observed faults coincide with the discontinuities in the bouguer anomaly map for the upper part of the basement and the sedimentary cover reflection seismic profiles show distinct faulting in the sedimentary cover at the position of the structures observed in the local earthquake tomography and the bouguer anomaly maps they provide the link of the seismogenic structures at depth and the near surface geology it is shown that the structure of the southern end of the rhine graben is dominated by faults that have a nne ssw trend slightly oblique to the graben axis the presence of earthquake hypocenters nearby the faults indicate their present day activity

the 1356 basel earthquake an interdisciplinary revision summary within historical times one of the most damaging events in intra plate europe was the 1356 basel earthquake given its significance for assessing regional seismic hazard in central europe an interdisciplinary project was launched in 2005 to re explore this event our effort aimed to incorporate techniques from history seismology archaeology paleoseismology and engineering new and reinterpreted historical data from basel and its surroundings plus archaeological findings on buildings that survived the event and still exist enabled this macroseismic assessment palaeoseismological studies combined with historical evidence provided additional data for the surrounding areas archaeology offers sparse information on some castles and churches sometimes supported by historical records a contemporary source allows some reconstruction of the stronger fore and aftershocks this expanded information base improves our sense of the event s damage and consequences for the city of basel the relatively abundant archaeological data allowed us to assess statistically the macroseismic intensity at ix although the pattern of damage was scattered data points for the expected area of damage around basel are not distributed regularly the absence of historical and archaeological findings for southern germany might be due to archival problems future investigation may improve this situation our results confirm that the basel earthquake was the most destructive known for central europe intensities up to viii are found within a radius of about 30 km analysing the macroseismic field confirms our former assessment of the event and shows an epicenter located about 10 km south of basel the most probable range for the moment magnitude mw is between 6 7 and 7 1

microbialite morphology structure and growth a model of the upper jurassic reefs of the chay peninsula western france abstract during the early kimmeridgian the northern margin of the aquitaine basin western france is characterised by a significant development of coral reefs the reef formation of the chay peninsula comprises two main reefal units in which the microbial structures can contribute up to 70 of framework the microbial crusts which played an important role in the stabilisation and growth of the reef body show the characteristic clotted aspect of thrombolitic microbialites corals are the main skeletal components of the build ups the bioconstructions of the chay area are thus classified as coral thrombolite reefs four main morpho structural types of microbial crusts are distinguished 1 pseudostalactitic microbialites on the roof of intra reef palaeocaves 2 mamillated microbialites found either on the undersides or on the flanks of the bioherms 3 reticular microbialites in marginal parts of the reefs and between adjacent bioconstructed units and 4 interstitial microbialites in voids of bioclastic deposits thrombolitic crusts developed on various substrates such as corals bivalves or bioclasts the thrombolites formed a dense clotted and or micropeloidal microbial framework in which macro and micro encrusters also occur variations in accumulation rate strongly influenced the reef morphology in particular its relief above the sediment surface the coalescence of the coral microbialite patches created numerous intra reef cavities of metre scale dimensions the direction of microbial growth which defined the macroscopic microbialite forms strongly depended on the position within the reef framework but was also controlled by water energy accumulation rate and light availability

nature and environmental significance of microbialites in quaternary reefs the tahiti paradox drill cores from the bamer reef edge of tahiti exhibit 85 93 m thick coralgal sequences recording at least 13 500 years of continuous reef growth in optimal environmental conditions the cored reef sequences form an overall shallowingupward succession with assemblages of branching or massive colonies of porires at the base overlain by a robust branching community acropom gr dmmi robirstn heavily encrusted by coralline algae sessile vermetid gastropods and arborescent foraminifers which grew at depths less than 6 m microbialites generally form the last stage of encrustation of coral colonies or more commonly of related encrusting organisms thus appearing as a major structural component of the reef sequence where they may locally form 809 of the rock by volume they developed in an open cavity system of the reef framework with freely circulating normal marine water microbialites include laminated crusts and clotted micritic masses commonly associated in compound crusts probably feflecting differences in the composition of the involved biological communities and in biomineralization processes that controlled the accretion of the crusts the isotopic composition of the microbialites 2 05 to 3 92 i they underwent also indivitlual processes of biominrlali2ation besicles the overall decrease in lizht and enqy conditions rttlecting progressive burial by conil growth the widespread development of microbialites within the reef framework may be related to increased alkalinity and niitrient availability in interstitial waters due to temstrial groundwwr seepage and puiodic runoffs the tlevelopment of micrubialites in the cryptic niches of the reef framework ceased about 6000 years

microbial framework in upper triassic carnian patch reefs from williston lake british columbia canada abstract the upper triassic carnian patch reefs from pardonet hill british columbia canada are the only known upper triassic reefal buildups from the craton margin of northwestern pangaea these buildups occur within the lower baldonnel formation and are characterized by a moderately diverse assemblage of corals spongiomorphs crinoids echinoderms bivalves gastropods brachiopods and microbialites despite the evidence that these buildups had a rigid structure e g brecciation and hardgrounds and relief above the seafloor visible in outcrop the exact nature and extent of the framework has previously been undetermined this study focuses on the microfacies within these patch reefs and highlights the importance of microbialites in the framework of these diminutive buildups 100 m3 to 500 m3 the pardonet hill patch reefs were mapped in outcrop to determine their structure geometry and the importance of large metazoan framework builders samples of the reefal horizons and surrounding strata were evaluated utilizing point count analyses of organisms cements lithic grains and microbial textures in thin section quantitative analysis of the microfacies in concert with traditional descriptions of reef construction and reef classification allow a more thorough understanding of organism abundance and reef structure despite the presence of corals and spongiomorphs throughout the outcrop they very rarely form a true intergrown framework except at the base of patch reef b instead cemented microbialites form a rigid framework in the core of some patch reefs detailed examination of the microfacies and reef construction demonstrates the importance of non skeletal framework builders in the structural fabric of these small buildups pardonet hill patch reef b is the first true reef with a microbial framework documented from the upper triassic of north america this microbial coral framework bears a striking similarity to some triassic and upper jurassic coral microbial reefs from the tethys although the depositional environment of the pardonet hill patch reefs is likely shallower and more energetic than the tethyan reefs

paleoecology biogeography and evolution of reef ecosystems in the panthalassa ocean during the late triassic insights from reef limestone of the sambosan accretionary complex shikoku japan upper triassic reefs from the panthalassa ocean have been understudied in comparison to their tethyan counterparts and are therefore pivotal to understanding the global reef evolution during the late triassic to fill this gap upper triassic reef limestone from ten localities of the sambosan accretionary complex at shikoku island japan has been investigated biotic assemblages quantitative microfacies analysis and integrated biostratigraphy allow us to characterize two types of reefs those attributed to the ladinian early carnian and those attributed to the late carnian rhaetian at the regional scale our data refine the biostratigraphic framework of the upper triassic sambosan limestone at the global scale multivariate analyses support a strong paleobiogeographic affinity of the western panthalassa reef biota with those of the south tethys ocean during the ladinian carnian and norian rhaetian additionally they indicate connections with east panthalassa reefs during the norian rhaetian

reconciling geodetic and geological rates of vertical crustal motion in intraplate regions abstract tectonic motion rates of individual faults and regional deformation in an intraplate setting are estimated based on the analysis of ten yearly surveys of a regional levelling network in ne ardenne w europe owing to the frequency and number of measurement epochs much greater than in classical comparisons of general surveys the tectonic and near surface components of ground motion are clearly separated the marked temporal variability in ground motion strongly depends on the amount of precipitation fallen during the six months preceding each survey and the subsequent drying off of the subsoil at the time of the surveys moreover the ground response to this influence varies from place to place leading to high differential movements at the local scale taking into account the percentage of surveyed faults which moved tectonically during the time of the study i calculate fault motion rates of 0 06 0 09 mm yr similar to geological rates moreover the data indicate that one way for intraplate normal faults to accommodate tectonic strain aseismically is intermittent fault creep with short episodes of a few mm displacement separated by many year long time intervals of fault quiescence a flexural deformation shows the superposition of a tilt event on a trend corresponding to a tilt rate of 0 16 rad yr for a 2 8 km long segment

geological and geophysical evidence for large palaeo earthquakes with surface faulting in the roer graben northwest europe from the analysis of geological geodetic and geophysical data we provide clear evidence of seismogenic faults capable of producing large earthquakes in intraplate europe previous studies paulissen vandenberghe gullentops 1985 van den berg et al 1994 geluk et al 1994 have yielded some constraints on the rate of crustal deformation along the roer valley a graben structure crossing the netherlands belgium and germany and have allowed us to address the fundamental questions can intraplate earthquakes rupture the surface in this part of stable continental europe and if so what is their return period detailed palaeoseismic investigations have been carried out in belgium along a 10 km long fault scarp which is the morphological expression of the feldbiss fault the southwestern border fault of the roer graben camelbeeck meghraoui 1996 the scarp is multiple and the frontal fault scarp offsets young deposits and alluvial terraces field investigations using geological and geomorphological methodologies combined with geophysical prospecting provide evidence of holocene seismic surface faulting from 14c dating it is suggested that the last earthquake along the fault scarp occurred between 610 ad and 890 ad levelling profiles across the scarp suggest that it produced a vertical coseismic displacement of 0 5 1 m along the scarp if we suppose that the last surface faulting earthquake ruptured the whole seismogenic layer 17 km thickness over a minimum length 10 km corresponding to the length of the bree scarp with an average slip of 0 6 m its seismic moment was at least 3 1 1018 n m mw 6 3 for an average rigidity 3 1010 pa by estimating the offset of the main terrace of the maas river by slippage along the feldbiss fault we calculate the average late pleistocene vertical deformation rate as 0 08 0 04 mm yr 1 palaeoseismic information combining the trench and geomorphic observations suggests the occurrence of two surface faulting earthquakes during the last 20 kyr a third dates before 28 35 kyr bp then if the time distribution of earthquakes is uniform a return period of 12 5 ka and a vertical deformation rate of 0 06 0 04 mm yr 1 are inferred