a high resolution pollen and geochemical analysis of late holocene human impact and vegetation history in southern cumbria england the historic era which in cumbria begins with the roman invasion of ad 71 is a frequently neglected period in palaeoecological research but its study can bring benefits in improving knowledge of landscape history and in understanding the significance and limitations of palaeoecological records pollen and geochemical data are presented for late holocene records from deer dyke and hulleter mosses in southern cumbria the records show initially low levels of anthropogenic impact followed by a phase of forest clearance and mixed agriculture from the 7th to 11th centuries ad the timing of these clearances suggests that they were initially anglo saxon in origin rather than norse further clearances in the 16th century ad are interpreted as a response to monastic dissolution and late tudor population pressures the landscapes reached their contemporary form following extensive clearances in the 17th century ad silicon and titanium concentrations at deer dyke moss were used to reconstruct past levels of atmospheric dust loading which is broadly related to soil erosion geochemical influx was found to peak during periods of landscape transition rather than from established land use this relationship with pollen data is thought to reflect the predominantly low levels of anthropogenic impact in the region which changes as substantial woodland clearances during the 16th century ad and continuous land use pressure since then have greatly increased the supply of airborne dust

theory of quantitative reconstruction of vegetation i pollen from large sites reveals regional vegetation composition quantitative reconstruction of past vegetation is one of the primary goals in quaternary palynology and palaeoecology but still remains difficult this paper proposes a model reveals that estimates regional vegetation composition using pollen from large lakes that have small site to site variations of pollen assemblages even if vegetation is highly heterogeneous once these data have been used to quantify regional vegetation composition within 104 105 km2 background pollen one of the parameters crucial for vegetation reconstruction can be estimated for smaller sized sites and incorporated into the landscape reconstruction algorithm lra a multistep framework for quantitative reconstruction of vegetation in smaller areas 104 ha simulations using the pollscape modelling show that reveals can provide accurate estimates of regional vegetation composition in various landscapes and under different atmospheric conditions if pollen assemblages from lakes that are much smaller than large lakes a

the butte valley and layton well thrusts of eastern california distribution and regional significance the butte valley and layton well thrusts are major structural features in two adjacent mountain ranges west of southern death valley the butte valley thrust in the southern panamint range underlies most of the range and emplaces proterozoic rocks over strata as young as jurassic in age the layton well thrust to the southwest in the slate range has been interpreted to have proterozoic rocks juxtaposed on rocks as young as jurassic suggesting that the butte valley thrust and the layton well thrust might be correlative new information indicates that the allochthonous rocks of the layton well thrust are mesozoic in age and are not likely part of the same allochthon as that above the butte valley thrust in addition the butte valley thrust cuts sharply downward to the north and west across lower plate paleozoic strata suggesting that the fault roots beneath the layton well thrust the layton well thrust probably belongs to the east sierran thrust system and thus would be in the upper plate of the butte valley thrust

early permian thrust faults in east central california one exposed and another inferred thrust fault in the southeastern inyo mountains of east central california are interpreted as early permian in age these faults both apparently of local extent are temporally and geographically related to a major episode of basin formation which occurred along a southeast trending segment of the permian north american plate margin the close relationship between basin formation and thrust faulting supports a previous interpretation by us that this segment of the margin was undergoing active wrench tectonism during the early permian resulting in the essentially simultaneous development of local extensional and compressional structures similar to those now forming in the california continental borderland

anisotropic radiation modelling of macroseismic intensities for estimation of the attenuation structure of the upper crust in greece a method is suggested for the analysis of macroseismic intensity data in order to accurately determine an average attenuation structure of the upper part of the crust in an area the method is based on a model which assumes that the observed intensities depend on source properties radiation pattern size focal depth geometrical spreading and anelastic attenuation the method is applied to 13 008 intensity values observed in corresponding sites of greece and grouped in 4228 groups according to their spatial clustering in order to diminish observational errors and site effects an average intensity attenuation coefficient c 0 0039 0 0016 corresponding to a quality factor q 350 140 is determined for the upper 20 km of the crust in this area this value is relatively low in good agreement with the relatively high heat flow and high seismic activity of this area a byproduct of the present study is the determination for each earthquake of a macroseismic focal depth and of a macroseismic size which is strongly correlatted with both the earthquake s magnitude and its seismic moment determined by independent methods

large magnitude permian shortening and continental margin tectonics in the southern cordillera the last chance allochthon with displacement estimated to be 55 to 105 km and lateral extent possibly exceeding 300 km was inferred to be middle triassic and thus kinematically distinct from a belt of permian triassic deformation in the western mojave desert correlations of structures forming the death valley thrust belt which includes the last chance allochthon several subjacent structures and their inferred lateral equivalents suggest that prior to tertiary extension individual structures were laterally continuous for distances exceeding 150 km along strike from the nevada test site area southwest to the darwin plateau their inferred mesozoic age and the presence of an early triassic overlap sequence on the darwin plateau precluded projection of these structures farther south in spite of long recognized strain compatibility problems associated with large displacement on thrusts that apparently terminated there without suitable accommodation structures such as tear faults or lateral ramps these problems may be resolved if the last chance allochthon is permian consistent with structural correlations new isotopic data from post tectonic stocks and stratigraphic evidence a large permian turbidite basin near the darwin plateau can be interpreted as a marine foredeep resulting from emplacement of the 5 km thick allochthon rather than a local trough caused by transcurrent faulting during inferred permian triassic continental truncation i propose that anomalous eugeoclinal rocks in the western mojave desert have been emplaced against cratonic strata there by the last chance allochthon which foreshortened an originally narrow continental margin

attenuation of intensities and effect of local site conditions on observed intensities during the corinth greece earthquakes of 24 and 25 february and 4 march 1981 abstract field investigations conducted immediately after the gulf of corinth earthquake of 24 february 1981 provide an extensive set of data on intensity at different sites for the main shock and two of its principal aftershocks each site of intensity observation was characterized by the local site geologic condition the hypocenters of the three shocks were relocated by using the joint epicenter location technique with the aftershock of 12 march 1981 01 49 utc recorded by six portable stations as well as stations of the greek national seismographic network as the calibration event isoseismal maps prepared by using all intensity data for the three shocks were used to derive new attenuation relations analysis of the intensity residuals observed calculated intensity shows that local site geologic condition has a significant effect on the intensity observed at a site on an average under similar circumstances sites located on soil foundations experience about one intensity unit more shaking than sites located on rock foundations likewise sites located on neogene sediments intermediate foundation condition experience about 1 2 unit greater intensity effect than sites located on rock foundations attenuation relations derived by using intensity data for the three february march 1981 earthquakes show lower attenuation than the relation derived by using published isoseismal maps for 19 earthquakes which occurred in the corinth saronikos region during 1861 to 1975

crustal structure of the central sector of the betic cordillera se spain deep seismic reflection gravimetric and magnetometric data allow the main features of the deep structure of the central sector of the betic cordillera to be established the moho is horizontal or dips slightly toward the s below the mountain chain and its morphology has no direct relationship with the region s topography the deep reflectors are not deformed by the neogene kilometric scale folds that produced the main topographic features probably due to the existence of detachment levels in the crust the crust is slightly thickened in the betic cordillera almost 35 km and has an abrupt transition to the thin crust of the alboran sea 15 km in the central alboran sea along an e w oriented narrow band subparallel to the coast line where the moho dips more than 60 n the neogene evolution of the mountain chain caused compressive deformation in the external zones in the internal zones pre tortonian low angle normal faults developed after the alpine metamorphism and later high and low angle normal faults and strike slip faults occurred up to the quaternary geophysical and field geology data can be used to establish a geological model for the recent evolution of the crustal deformation in this model the recent evolution of the region is probably determined by thrusting of the thin continental crust of the alboran sea toward the nw over the southern margin of the iberian massif this deformation could be a consequence of the oblique convergent movement between the african and eurasian plates which may have uplifted the entire region causing regressions in the sedimentary basins and the formation of folds and extensional structures in the upper part of the thickened crust

uniqueness of geological correlations an example from the death valley extended terrain the northern death valley furnace creek fault zone is a major northwest trending fault system in the death valley region but the magnitude of offset and its significance to extensional tectonism in the region are controversial stratigraphic data have provided first order constraints on offset across the fault zone but offer limited resolution previous correlations of mesozoic thrust faults across the fault zone have relied on regional stratigraphic trends to fingerprint structurally similar thrust plates we show that a northeast trending mesozoic backfold within the predominantly east directed fold and thrust belt was probably continuous from the southern panamint range california to the belted range nevada the relative position of this antithetic structure allows uniquely compatible correlations of three mesozoic structures between two range blocks across the northern death valley furnace creek fault zone independent of stratigraphic arguments the offset structures have geometric properties of size vergence order and spacing that indicate a probability less than 10 4 of the mesozoic orogen identically repeating this structural suite in two unrelated places reconstruction of these correlative structures indicates 68 4 km n48 w 6 w of apparent dextral offset between the cottonwood and funeral mountains in general agreement with previous estimates based on stratigraphic observations but of substantially higher precision this reconstruction and the restoration of a 30 km separation between the funeral and grapevine mountains indicated by offset segments of the backfold suggest a simple pre extensional geometry for the mesozoic orogen in the death valley region consistent with observations from unextended blocks and analogous to that of the cordilleran orogen at the latitude of calgary alberta

three dimensional model of the late cenozoic history of the death valley region southeastern california the accumulation of a large database on the timing and kinematics of late cenozoic deformation in the death valley region of southeastern california indicates a complex three dimensional history on the basis of paleogeographic reconstructions we suggest the system was initiated as a localized pull apart between two conjugate strike slip faults the garlock and furnace creek faults and evolved into a system characterized by distributed transtension related to the eastern california shear zone our reconstructions differ from previous models in the incorporation of significant vertical axis rotations of a number of crustal blocks to explain paleomagnetic data from the region the model may resolve 1 a long standing problem of the eastern termination of the garlock fault which is explained here as a complex system of splays that initially terminated in the pull apart between the furnace creek and garlock systems and 2 the complex architecture of the black mountains which is explained here in terms of initial extreme attenuation between the garlock and furnace creek systems with overprinting by a fold and normal fault system that operated simultaneously as a result of distributed transtension this model suggests much of the displacement field is taken up in rotations and translations and the actual crustal thinning in our model is relatively small 50 66 of original thickness

advances and limitations of the environmental seismic intensity scale esi 2007 regarding near field and far field effects from recent earthquakes in greece implications for the seismic hazard assessment the new environmental seismic intensity scale esi 2007 introduced by inqua incorporates the advances and achievements of palaeoseismology and earthquake geology and evaluates earthquake size and epicentre solely from the earthquake environmental effects eee this scale is tested and compared with traditional existing scales for the 1981 alkyonides earthquake sequence in the corinth gulf ms 6 7 ms 6 4 ms 6 3 the 1993 pyrgos event ms 5 5 and the 2006 kythira event mw 6 7 these earthquakes were of different magni tudes focal mechanisms and focal depths and produced well documented environmental effects the esi 2007 intensity values and the isoseismal pattern for the 1993 pyrgos and the 2006 kythira events are similar to those resulting from the traditional scales demonstrating that for moderate intensity levels vii and viii the esi 2007 and the traditional scales comply well in contrast the 1981 alkyonides earthquake sequence shows that there is an inconsistency between the esi 2007 and the traditional scales both in the epicentral area where higher esi 2007 intensity values have been assigned and for the far field effects the esi 2007 scale offers higher objectivity in the process of assessing macroseismic intensities particularly in the epicentral area than traditional intensity scales that are influenced by human parameters the esi 2007 scale follows the same criteria environmental effects for all events and can compare not only events from different settings but also contemporary and future earthquakes with histori cal events a reappraisal of historical earthquakes so as to constrain the esi 2007 scale may prove beneficial for seismic hazard assessment by reducing the uncertainty implied in the attenuation laws which constitute one of the most important seismic hazard parameters

comment on the butte valley and layton well thrusts of eastern california distribution and regional significance by chester t wrucke calvin h stevens and joseph l wooden

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

extensional tectonics in the death valley area california transport of the panamint range structural block 80 km northwestward in the hypothesis presented here the panamint range is a structural block that was detached during late cenozoic time from underlying rocks that now form the black mountains and was transported tectonically an estimated 80 km to the northwest transport occurred along a single low angle westward dipping detachment fault or perhaps along a system of such faults the estimate of 80 km of transport distance is based on the apparent right lateral offset of late precambrian and paleozoic facies and thickness trends along the furnace creek fault zone that bounds the detached block on the northeast the death valley turtleback surfaces are considered to be gigantic mullions related to the detachment surface

ashtead common the evolution of a cultural landscape a spatially precise vegetation record for the last 2000 years from southeast england the results of palaeoecological pollen and fungal spores investigations of an abandoned clay pit on ashtead common surrey are presented and compared with archaeological and documentary evidence the pit lies adjacent to a roman industrial complex with early saxon activity recorded nearby prior to the early twentieth century ad the common was managed as wood pasture and it has a high nature conservation designation as a result of c 2000 veteran pollarded oak trees which remain from this phase the pit provides a record of landscape history from the roman c cal ad 150 to the modern c ad 1850 era which in terms of spatial and temporal resolution is unrivalled in southeast england from the late roman into the middle saxon period the palaeoecological data are consistent with archaeological evidence for the continuity of settlement and land use subtle changes in woodland cover probably reflecting changes in the importance of grazing against the exploitation of wood are evident up to c cal a

sedimentology of the debris flow dominated warm spring canyon alluvial fan death valley california facies analysis of widely distributed exposures of the 32 6 km2 and 8 1 km long warm spring canyon fan central death valley shows that it has been built principally by debris flow deposits these deposits were derived from a mature panamint range catchment mostly underlain by precambrian mudrock quartzite and dolomite stacked clast rich and matrix supported debris flow lobes of slightly bouldery muddy pebble cobble gravel in beds 20 150 cm thick dominate the fan from apex to toe accounting for 75 98 of most exposures interstratified with the debris flows are less abundant 2 25 of cuts thinner 5 30 cm and more discontinuous beds of clast supported and imbricated pebble cobble gravel deposited by overland flows and gully flows this facies formed by the surficial fine fraction water winnowing of the debris flows primarily during recessional flood stage of the debris flow events two other facies associations make up a small part of the fan the incised channel tract consists of a 250 m wide clast supported ribbon of irregularly to thickly bedded boulder pebble cobble gravel nested within debris flow deposits this channel fill is oriented generally perpendicular to the panamint range front it formed by extensive erosion and winnowing of debris flows deposited within the incised channel into which all water discharge from the catchment is funnelled the limited presence of this facies only straddling the present incised channel indicates that this channel overall has maintained a consistent position on the fan except for slight lateral shifts some caused by strike slip offset fault offset temporarily closed the upper incised channel causing recessional debris flow mud to be ponded behind the dam the other local facies assemblage consists of subrounded to rounded moderately sorted pebble gravel in low angle cross beds that slope both basinwards and fanwards this gravel was deposited in beachface backshore and shoreface barrier spit environments that developed where lake manly impinged on the warm spring fan during late pleistocene time these deposits straddle headcuts into and were derived from erosion of the debris flow deposits wave energy sorted finer sediment from the shore zone concentrated coarser sediment and rounded the coarse to very coarse pebble fraction by selective reworking

the attenuation of seismic intensity in italy part i theoretical and empirical backgrounds abstract we critically analyze the results on seismic intensity attenuation in italy derived by albarello and d amico 2004 and gasperini 2001 we demonstrate that due to the inadequacy of certain underlying assumptions the empirical relationships determined in those studies did not best reproduce the decay of intensity as the distance from the source increases we reconsidered some of the relevant concepts and assumptions used in these intensity attenuation studies macroseismic epicenter epicentral intensity data completeness to suggest some useful recipes for obtaining unbiased estimates in particular we suggest that 1 data for distances from the source at which an intensity below the limit of diffuse perceptibility iv is expected should be excluded from attenuation computations because such data are clearly incomplete 2 attenuation equations that include a term proportional to the epicentral intensity i 0 with a coefficient different from 1 0 must not be used because they imply a variable offset between i 0 and the intensity expected at the epicenter and 3 epicentral intensities must be recomputed consistently with the attenuation equation because those reported by the italian catalog do not generally correspond with the intensity predicted at the epicenter by the attenuation relationships so far proposed following these suggestions produces a significant reduction in the standard deviation of the model that might lead to a corresponding reduction of the estimates of seismic hazard

isoseismal map of the 2015 nepal earthquake and its relationships with ground motion parameters distance and magnitude abstract a devastating earthquake of mw 7 8 struck central nepal on 25th april 2015 6 11 25 ut which resulted in more than 9000 deaths and destroyed millions of houses standing buildings roads and electrical installations worth 25 30 billions of dollars are reduced to rubbles the earthquake was widely felt in the northern parts of india and moderate damage have been observed in the northern part of up and bihar region of india maximum intensity ix according to the usgs report was observed in the meizoseismal zone surrounding the kathmandu region in the present study we have compiled available information from the print electronic media and various reports of damages and other effects caused by the event and interpreted them to obtain modified mercalli intensities mmi at over 175 locations spread over nepal and surrounding indian and tibet region we have also obtained a number of strong motion recordings from india and nepal seismic network and developed an empirical relationship between the mmi and peak ground acceleration pga peak ground velocity pgv we have used least square regression technique to derive the empirical relation between the mmi and ground motion parameters and compared them with the empirical relationships available for other regions of the world further seismic intensity information available for historical earthquakes which have occurred in the nepal himalaya along with the present intensity data has been utilized for developing an attenuation relationship for the studied region using two step regression analyses the derived attenuation relationship is useful for assessing damage of a potential future large earthquake earthquake scenario based planning purposes in the region

age of jurassic volcanism and tectonism southern owens valley region east central california remnants of the eastern fringe of the volcanic and volcanogenic sedimentary cover of the mesozoic sierra nevada batholith are exposed in the southern inyo mountains and adjacent alabama hills of east central california six new u pb dates on volcanic units and crosscutting intrusions reveal that the upper parts of both the inyo mountains and alabama hills sections accumulated during middle and late jurassic time during this same interval both sections were steeply tilted and locally folded during one or more episodes of contractile deformation occurring in the east sierran thrust belt differences between the largely undated lower parts of the inyo mountains and alabama hills sections suggest that they were once located farther apart then later brought into proximity by thrust faulting or strike slip faulting the inyo mountains and alabama hills sections are similar to partly coeval strata in the white mountains in that both contain abundant sedimentary strata that were in part deposited in or near terrain of moderate topographic relief together these areas seem to compose a distinctive arc marginal depositional province different than that represented by partly coeval strata preserved in pendants to the west

strong motion seismology strong motion seismology is concerned with earthquake ground motion in the amplitude range that poses the threat of human injury or property damage because the occurrence of strong motion cannot be predicted in advance and because the time between significant events at any one place may range from tens to thousands of years strong motion data is recorded on triggered instruments that typically must be maintained in readiness for years between periods of significant recording as a consequence the strong motion data set is sparse because of the engineering need for estimates of future ground motion the scope of the field of strong motion seismology encompasses seismic source theory and any other aspect of seismology that can provide insights helpful in making the best possible estimates given the limited data this relationship with the rest of seismology is a reciprocal one in that strong motion data gives perhaps the best information available on earthquake source processes

regional seismic intensity anomalies in the korean peninsula and its implications for seismic hazard potentials the strength of seismic ground motion is a consequence of seismic source strength and medium response the dependence of seismic amplitudes and seismic intensity on regional geological structures and crustal properties in the stable intraplate region around the korean peninsula is investigated an instrumental seismic intensity scale based on spectral accelerations are proposed after calibrating with the reported macroseismic intensities a representative seismic intensity attenuation curve for the korean peninsula is given by i m text l l h 0 998 pm 0 222 1 72 pm 0 04 m text l 0 322 pm 0 027 text ln l 2 h 2 0 00608 pm 0 00049 sqrt l 2 h 2 where i m text l l h is the seismic intensity at an epicentral distance l in km for an earthquake with local magnitude m text l and focal depth h in km seismic intensities decay slowly with distance in the korean peninsula the observed decay rate for the korean peninsula is comparable with those for other stable intraplate regions while are lower than those for active regions the regional seismic intensity anomalies present a characteristic correlation with geological structures positive seismic intensity anomalies appear in the yeongnam massif okcheon belt and gyeongsang basin while negative seismic intensity anomalies in the gyeonggi massif the regional seismic intensity anomalies display positive correlations with crustal thicknesses crustal amplifications and seismicity density and negative correlations with heat flows positive seismic intensity anomalies are observed in the yeongnam massif and gyeongsang basin suggesting high seismic hazard potentials in the regions the regional crustal properties may provide useful information on potential seismic hazards

preliminary determination of the interdependence among strong motion amplitude earthquake magnitude and hypocentral distance for the himalayan region summary since the installation of three limited aperture strong motion networks in the himalayan region in 1986 six earthquakes with mw 5 2 7 2 have been recorded up to 1991 the data set of horizontal peak accelerations and velocities consists of 182 component data for the hypocentral distance range 10 400 km this data set is limited in volume and coverage and worst of all it is highly inhomogeneous thus we could not determine regional trends for amplitudes by means of the traditional approach of empirical multiple regression instead we perform the reduction of the observations to a fixed distance and magnitude using independently defined distance and magnitude trends to determine an appropriate magnitude dependent distance attenuation law we use the spectral energy propagation random function approach of gusev 1983 and adjust its parameters based on the residual variance in doing so we confirm the known rather gradual mode of decay of amplitudes with distance in the himalayas this seems to be caused by the combination of high qs and crustal waveguide effects for high frequencies the data are then reduced with respect to magnitude the trend of peak acceleration versus magnitude cannot be determined from observations and we assume that it coincides with that of abundant japanese data for the resulting set of reduced log10 peak acceleration data the residual variance is 0 372 much above commonly found values however dividing the data into two geographical groups western with two events and eastern with four events reduces the residual variance to a more usual level of 0 272 a station site component of 0 222 and an event component of 0 162 this kind of data description is considered acceptable a similar analysis is performed with velocity data and again we have to split the data into two subregional groups with our theoretically grounded attenuation laws we attempt a tentative extrapolation of our results to small distances and large magnitudes our minimum estimates of peak acceleration for the epicentral zone of mw 7 5 8 5 events is apeak 0 25 0 4 g for the western himalayas and as large as apeak 1 1 6 g for the eastern himalayas similarly the expected minimum epicentral values of vpeak for mw 8 are 35 cm s 1 for the western and 112 cm s 1 for the eastern himalayas to understand whether our results reflect the properties of the subregions and not of a small data set we check them against macroseismic intensity data for the same subregion the presence of unusually high levels of epicentral amplitudes for the eastern subregion agrees well with the macroseismic evidence such as the epicentral intensity levels of x xii for the great assam earthquake of 1897 therefore our results represent systematic regional effects and they may be considered as a basis for future regionalized seismic hazard assessment in the himalayan region we see the location of earthquake sources faults at a considerable depth within the relatively drier and higher strength shield crust as the main cause of the observed enhanced amplitudes for the eastern himalayas events western himalayas sources are shallower and occupy the tectonically highly fractured upper part of the crust of accretionary origin the low attenuation common to both subregions is due to the presence of cold low scattering and high q shield crust

timing and kinematics of deformation in the cronese hills california and implications for mesozoic structure of the southwestern cordillera a southeast vergent ductile shear zone is exposed in the cronese hills in the central mojave desert this shear zone formed under greenschist facies conditions and placed mylonitic metaplutonic and metavolcanic rocks upon folded triassic metasedimentary rocks u pb zircon ages of prekinematic and postkinematic plutons constrain the age of deformation to between 169 and 154 ma late middle or early late jurassic the authors believe that the cronese shear zone forms part of the southern continuation of the east sierran thrust system mesozoic thrust faults may have controlled preservation of jurassic arc related rocks and may be responsible for structural stacking of paleozoic eugeoclinal and miogeoclinal strata in the central mojave desert