regional moment tensor inversion for strong aftershocks of the august 17 1999 izmit earthquake mw 7 4 we analyzed the source mechanisms of the thirty largest aftershocks 4 0 ml 6 2 of the august 17 1999 izmit earthquake mw 7 4 by applying the regional moment tensor inversion method using data from near regional broadband stations the inversion solutions were compared to 17 well constrained first motion solutions and were seen to be in good agreement we found that the dominance of strike slip motion is the main characteristic of the izmit earthquake sequence significant aftershock activity was recorded to the west and east of the un ruptured extremities in the east the aftershocks located near the town of duzce represent an early replica of the november 12 1999 duzce earthquake mw 7 2 in terms of locations and source mechanisms in the marmara sea where the fault geometry is still very poorly resolved most aftershocks have right lateral strike slip solutions with strike direction parallel to the submerged branches of the north anatolian fault

geobarometry geothermometry and late archean geotherms from the granulite facies terrain of south india geobarometry and geothermometry of garnet bearing chamockitic and metapelitic assemblages from the high grade terrain from south india indicate three fields of equilibration high pressure granulites p 8 3 pm 1 0 kb t 760 pm 40 circ c are restricted to the charnockites and mafic granulites of the north slopes of the nilgiris these place a minimum constraint of 30 km on the maximum thickness of late archean crust medium pressure granulites p 6 4 pm 1 0 kb t 735 pm 40 circ c characterize the charnockites of the central nilgiris and the madras granulites to the east low pressure granulites p 5 0 pm 1 0 kb t 700 pm 20 circ c characterize the charnockites and metapelites south of the bhavani shear zone although migmatites from the kodaikanal massif may reflect somewhat higher temperatures all three granulite fields lie on a metamorphic geotherm piezothermic array which is strongly convex to the temperature axis and characteristic of convective heat transfer

deformation due to the 17 august 1999 izmit turkey earthquake measured from spot images the geometry of the ruptured areas and the coseismic slip distribution data are key to highlighting the behavior of seismic faults this information is generally retrieved from field investigations and geodetic measurements or synthetic aperture radar sar interferometry here we show that spot images can also be used to accurately map the fault zone and to determine the slip distribution by subpixel correlation of images acquired before and after an earthquake the measured slip includes the contribution of possible distributed shear that might not be clearly expressed in surface ruptures and smoothes out possible along strike variability due to near surface fault complexities we apply the technique to the m s 7 4 1999 izmit earthquake our results reveal a 100 m wide and very linear fault zone that can be traced for 70 km from golcuk to akyazi along which supershear rupture has been inferred the obtained slip distribution compares well with the field measurements and is consistent with ground deformation measured at some distance from the fault zone using sar images very little deformation was accommodated off the main fault plane maximum slip is observed near sapanca lake at a small fault jog that has probably influenced rupture propagation

geobarometers involving clinopyroxene garnet plagioclase ilmenite rutile sphene and quartz estimation of pressure in quartz absent assemblages enthalpy of formation and third law entropy for andradite ca3fe2si3o12 and hedenbergite cafesi2o6 at standard state have been retrieved from experimental p t f o2 data on the stability relations of these phases the data for hedenbergite were combined with the thermodynamic data for related phases berman 1988 to formulate the geobarometers based on the reactions cafesi2o6 2caal2si2o8 2fetio3 ca3al2si3o12 fe3al2si3o12 2tio2 cpg ir 3cafesi2o6 3caal2si2o8 3fetio3 ca3al2si3o12 2fe3al2si3o12 3catisio5 cpg is and 3cafesi2o6 3caal2si2o8 2ca3al2si3o12 fe3al2si3o12 3sio2 cpg o the geobarometers involving rutile and sphene are proposed for the first time in several granulite terranes pressures have been estimated from the three geobarometers for basic granulites and charnockitic suite of rocks containing the above assemblages in clinopyroxene garnet plagioclase quartz ilmenite rutile assemblages pressures obtained from cpg ir are within 500 bars of pressures calculated from the cpg q barometer however if rutile is absent the pressures computed from the cpg ir barometer are 300 to 1 200 bars higher than those calculated from the cpg q barometer for maximum differences in pressures obtained from the two equilibria tio2 activity a tio2 in the rocks is calculated to be 0 8 the sphene bearing geobarometer cpg is also registers pressures comparable 500 bars to those obtained from the cpg q barometer the close agreement in pressure values obtained from the cpg ir and the cpg is equilibria with those registered by the cpg q geobarometer in assemblages containing quartz implies that the rutile and sphene bearing geobarometers which do not involve quartz can also be applied to estimate pressures from quartz absent assemblages assemblages which are not amenable to quantitative geobarometry using existing formulations

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

the active main marmara fault abstract this paper presents selections from and a synthesis of a high resolution bathymetric sparker and deep towed seismic reflection data set recently acquired by the french ifremer r v le suroit in an e w deep trough that forms the northern half of the sea of marmara in nw turkey it includes the first high resolution complete bathymetric map of this area a single throughgoing dextral strike slip fault system which is the western continuation of the northern branch of the north anatolian fault cuts this trough lengthwise and joins the 1999 8 17 kocaeli earthquake fault with the 1912 8 09 arkoy murefte earthquake fault both of which display strike slip offset in its eastern one fourth the structure follows closely the northern margin of the deep trough whereas in the west it hugs its southern margin the eastern one fourth of the structure has a minor component of its displacement distributed across the deep trough owing to a possible original bend in the course of the dextral structure the present course of the north anatolian fault in the sea of marmara originated some 2 105 a ago by cutting across the older basin fabric generated by a dominant nne ssw extension before it began taking up major motion in the pliocene

metamorphism of the koraput alkaline complex eastern ghats province india evidence for reworking of a granulite terrane abstract an assemblage of predominantly metasedimentary rocks in the eastern ghats province india underwent granulite facies metamorphism and deformation in early neoproterozoic times and was subsequently intruded by the koraput alkaline complex the intrusion was earlier believed to be syn to late tectonic the gabbroic core of the complex hosts nepheline bearing syenitic dykes and veins following emplacement magmatic amphibole within the syenites and early orthopyroxene in feldspathic gneisses within the country rocks were retrogressed to biotite during pervasive solid state deformation subsequent prograde metamorphism resulted in the formation of anhydrous assemblages at the expense of relict magmatic amphibole within the syenites and metamorphic biotite in both the complex and the country rocks reactions reconstructed from textural observations indicate breakdown of biotite and amphibole to garnet clinopyroxene orthopyroxene bearing assemblages schreinemakers analysis on the relevant mineral associations suggests that heating was followed by loading of the region this indicates thermal rejuvenation of the complex and the host granulites during an intracrustal orogeny that post dates emplacement and cooling of the pluton available ages suggest that this event occurred in the mid neoproterozoic and is probably unrelated to the amalgamation of the granulite belt with the archaean bastar dharwar craton

aluminous titanite sphene from the eclogite zone south central tauern window austria abstract highly aluminous titanite with al 2 o 3 contents up to 14 wt 50 of the caalsio 4 f oh end member occurs in siliceous dolomites from the eclogite zone south central tauern window austria 140 chemical analyses of titanites from 13 samples from the eclogite zone and adjacent tectonic units reveal that al is incorporated into titanite primarily by the mechanism ti o al f oh there is also a strong positive correlation between al and f content of these titanites indicating that the combined substitution is enhanced by the presence of f al contents of titanite vary between tectonic units with the most aluminous varieties occurring in the high pressure eclogite zone variations also occur from sample to sample within a single tectonic unit and both between and within individual grains in a single sample complex zoning with sharp chemical and optical discontinuities is observed with al 2 o 3 variations of up to 6 wt within a single sample individual grains generally have low al cores mantled by high al zones and rimmed by low al edges it is suggested that the incorporation of al into titanite is favoured by high p low t and high f activity

garnet orthopyroxene plagioclase quartz barometry refinement and application to the english river subprovince and the minnesota river valley recent experimental theoretical and thermodynamic studies permit better calibration of two reactions for geobarometry grossular pyrope quartz anorthite enstatite grossular almandine quartz anorthite ferrosilite if both reactions are applied using the same thermodynamic data and activity models they should yield the same pressure for a given garnet pyroxene plagioclase quartz assemblage application to a variety of high grade terrains generally yielded excellent results however poor results have been obtained for high fe rocks which can be traced to errors in activity models for garnet and or pyroxene either a two site ideal mixing model for orthopyroxene cf wood and banno 1973 underestimates enstatite activity for high fe orthopyroxenes or the ganguly and saxena 1984 model overestimates pyrope activity in low mg garnets

triggered slip observations of the 17 august 1999 izmit turkey earthquake using radar interferometry we use synthetic aperture radar interferometry insar to map the displacement field of the 17 august 1999 izmit earthquake which largely conforms to that predicted for an elastic upper crust we determine the earthquake source parameters and show that slip continues farther west than the mapped fault ruptures we also show that additional sub surface displacements occurred on parallel strands of the north anatolian fault zone we argue that this was caused by changes in static stress accompanying the mainshock or by the dynamic release of regional stresses

granulite facies metamorphism and retrogressive evolution of the monts du lyonnais metabasites massif central france abstract garnet bearing pyriclasites have been found within the monts du lyonnais formation near st andrela cote in the eastern part of the massif central the rocks appear to have differentiated from a tholeiitic magma of continental affinity and they may be genetically related to quartzofeldspathic granulites considered to be the products of crustal melts by means of electron microprobe analyses the consistent pressure and temperature estimates based essentially on pyroxene garnet equilibria show that the peak of metamorphism was at about 860 c and 10 kbar furthermore this study tends to confirm the affiliation of monts du lyonnais granulites to the early variscan granulite eclogite facies metamorphism which extends from bohemia to spain through central europe this event may be expected in the vicinity of an ancient suture zone where a continental collision followed a subduction

asymmetric slip partitioning in the sea of marmara pull apart a clue to propagation processes of the north anatolian fault between 1939 and 1999 the north anatolian fault naf experienced a westward progression of eight large earthquakes over 800 km of its morphological trace the 2000 km long north anatolian transform fault has also grown by westward propagation through continental lithosphere over a much longer timescale 10 myr the sea of marmara is a large pull apart that appears to have been a geometrical mechanical obstacle encountered by the naf during its propagation the present paper focuses on new high resolution data on the submarine fault system that forms a smaller pull apart beneath the northern sea of marmara between two well known strike slip faults on land izmit and ganos faults the outstandingly clear submarine morphology reveals a segmented fault system including pull apart features at a range of scales which indicate a dominant transtensional tectonic regime there is no evidence for a single continuous purely strike slip fault this result is critical to understanding of the seismic behaviour of this region of the naf close to istanbul additionally morphological and geological evidence is found for a stable kinematics consistent both with the long term displacement field determined for the past 5 myr and with present day anatolia eurasia motion determined with gps however within the sea of marmara region the fault kinematics involves asymmetric slip partitioning that appears to have extended throughout the evolution of the pull apart the loading associated with the westward propagation process of the naf may have provided a favourable initial geometry for such a slip separation

effect of sediment column on weak motion site response for a deep basin fill unique challenges arise when projecting dynamic site response in a deep steep sided irregularly shaped sediment filled basin the influence of shallow sediments on site response was investigated for a 1 km deep alluvial column in the las vegas basin subjected to weak ground motions a one dimensional equivalent linear model was applied response analyses for deep deposits are complicated because dynamic material properties at depth are uncertain to compensate the model half space was placed well above the physical bottom of the sediment column the depth to half space was selected by matching characteristics of projected surface response to measured data or expectations weak ground motion datasets resulting from underground nuclear tests were considered the best match half space depth 375 m greatly exceeded the depth of the threshold shear wave velocity for engineering bedrock the analysis captured site response over the period range 0 3 1 3 s when the parameterization was tested for a weak

high grade metamorphism in the chapleau foleyet area ontario archean rocks superior province kapuskasing structural zone in migmatitic mafic gneiss paragneiss dioritic and tonalitic rocks a lower grade garnet clinopyroxene plagioclase gt cpx pl zone and patchy higher grade orthopyroxene zones are distinguished based on mineral melt equilibria minimum conditions for the gt cpx pl zone are 750 degrees c 6 kbar a h 2 o 0 5 0 7 and for the orthopyroxene zone 770 degrees c 6 kbar a h 2 o 800 degrees c pressure values are 5 4 8 4 kbar and define a nne trending area of relatively high p in the kapuskasing zone supporting the interpretation of a tilted crustal section modified journal abstract

mapping small elevation changes over large areas differential radar interferometry a technique that uses synthetic aperture radar sar images to measure very small 1 cm or less surface motions with good resolution 10 m over large swaths 50 km is presented along with experimental results the method could be used for accurate measurements of many geophysical phenomena including swelling and buckling in fault zones residual displacements from seismic events and prevolcanic swelling the method is based on sar interferometry where two images are made of a scene by simultaneously flying two physically separated antennas then the phases of corresponding pixels are differenced and altitude formation is deduced from some simple computation and image rectification it is also possible to use one antenna flown twice over the same scene then if the second flight exactly duplicates the track of the first an interesting possibility occurs there would be no phase changes between the images at all unless there was a physical change in the scene such as ground swelling that would alter the distance from some resolution element to the antenna since the phase changes all occur at the short carrier wavelength the basic limitation on sensitivity is only the phase noise in the system when the two imaging passes are made from flight tracks that are separated which is the case with the seasat images used here it is no longer possible to distinguish surface changes from the parallax caused by topography however with some additional computation a third image made at some other baseline may be used to remove the topography and leave only the surface changes this method was applied using seasat data to an imaging site in imperial valley california where motion effects were observed that were ascribed to the expansion of water absorbing clays phase change images of this area are shown along with associated ground truth about the presence of water problems with the technique are explored along with a discussion of future experimental possibilities on upcoming sar missions like earth observing system eos earth resources satellite ers 1 sir c and the venus imaging radar magellan

time dependent distributed afterslip on and deep below the izmit earthquake rupture surface deformation transients measured with the global positioning system during the 87 days between the 17 august 1999 izmit earthquake and the 12 november 1999 duzce earthquake indicate rapidly decaying aseismic fault slip on and well below the coseismic rupture elastic model inversions for time dependent distributed fault slip using a network inversion filter approach show that afterslip was highest between and below the regions of maximum coseismic slip and propa gated downward to or even below the base of the crust maximum afterslip rates decayed from greater than 2 m yr immediately after the i zmit earthquake to about 1 2 m yr just prior to the duzce earthquake maximum afterslip occurred below the eastern karadere rupture segment and near the i zmit hypocenter afterslip in the upper 16 km decayed more rapidly than that below the seismogenic zone these observations are consistent with a phase of rapid aseismic fault slip concentrated near the base of the seismogenic zone continued loading from the rapid deep afterslip along the eastern rupture zone is a plausible mechanism that helped trigger the nearby mw 7 2 12 november duzce earthquake

empirical model for basin effects accounts for basin depth and source location empirical relationships are developed to predict amplification factors for 5 damped response spectral acceleration that incorporate basin response effects the parameters considered are depth to the 1 5 km sec shear wave isosurface z 1 5 as well as the location of the source beneath or outside the perimeter of the basin in which the site is located sites located in a basin overlying the source are denoted as having coincident source and site basin locations cbl and are differentiated from distinct source and site basin locations dbl amplification factors for cbl and dbl sites are evaluated from simulated data developed by others and strong motion data amplification factors derived from strong motion recordings are taken as residuals of rock attenuation relations coupled with amplification factors for shallow site conditions models relating amplification to z 1 5 were developed separately for the cbl and dbl data groups the results indicate that the use of basin models is generally worthwhile for periods t 0 75 sec at those long periods residuals are significantly sensitive to z 1 5 for cbl but not for dbl the standard deviation is also reduced for long periods to an extent that the standard deviations for long and short periods are similar

attenuation and excision of a crustal section during extensional exhumation the carratraca massif betic cordillera southern spain extensional dismemberment of the betic cordillera during late oligocene to early miocene time caused attenuation and excision of a crustal section overlying mantle peridotite an integrated study of metapelites overlying the peridotite sheet in the carratraca area shows truncation of a typical orogenic cycle of burial and heating by rapid exhumation and late to post tectonic low pressure metamorphism attenuation by a factor of five or more condensed a greenschist to granulite section to 4 km structural thickness initially coaxial attenuation of the sequence involving formation of a flat lying foliation and conjugate shear bands was superseded by non coaxial deformation concentrated along low angle top to the ne extensional fault zones these excised parts of the metamorphic section a 2 km loss was calculated across one fault zone thermobarometry throughout this section demonstrates that the structural attenuation was related to isothermal decompression to low pressures 2 4 kbar even at the base of the crustal section a late thermal event largely postdates the ductile stage of attenuation particularly in the upper part of the section thermal modelling implies that this thermal event could not have been produced by the hot peridotite sheet alone rapid tectonic exhumation and asthenospheric upwelling are the probable causes following detachment of material from the base of the lithosphere

evaluating the seismic response of deep sandy soil deposits we investigated the influence of depth to the half space on evaluations of seismic response of a dry sandy soil deposit with thickness exceeding 100 m our investigation is based on the premise that the best estimate of surface response of such deposits is obtained using a statistically derived attenuation relationship and the best estimate of other parameters required for geotechnical earthquake engineering evaluations is obtained by calibrating the evaluated spectral characteristics of the site response using the best estimate surface response results of our site specific evaluations indicate that the preferred depth to the half space does not coincide with the depth to bedrock nor is the preferred depth uniquely defined in the seismic site response analysis we find that for a given accelerogram the preferred depth to the half space corresponds closely to the depth for which the peak horizontal ground acceleration phga predicted in the site response analysis matches the median phga developed from the appropriate statistical attenuation relationship our results further indicate that the effect of the magnitude of the shear wave velocity assigned to the half space is minor in comparison with depth to the half space

the formation of garnet in olivine bearing metagabbros from the adirondacks a regional study of olivine bearing metagabbros in the adirondacks has permitted testing of the p pressure t temperature x composition dependence of garnet forming reactions as well as providing additional regional metamorphic pressure data six phases olivine orthopyroxene clinopyroxene garnet plagioclase and spinel which can be related by the reactions orthopyroxene clinopyroxene spinel anorthite garnet and forsterite anorthite garnet occur together both in coronal and in equant textures indicative of equilibrium compositions of the respective minerals are typically fo25 72 en44 75 en30 44fs9 23wo47 49 pp13 42alm39 63gr16 20 an29 49 and sp16 58 when they occur in the same rock equant and coronal garnets are homogeneous and compositionally identical suggesting that chemical equilibrium may have been attained despite coronal textures extrapolating reactions in the simple cmas system to granulite temperatures and making thermodynamic corrections for solid solutions gives equilibration pressures using the thermometry of bohlen et al 1980b ranging from about 6 5 kb in the lowlands and southern adirondacks to 7 0 8 0 kb in the highlands for the assemblage olivine plagioclase garnet these results are consistent with inferred peak metamorphic conditions in the adirondacks valley and bohlen 1979 bohlen and boettcher 1981 thus the isobaric retrograde path suggested by whitney and mclelland 1973 and whitney 1978 for the formation of coronal garnet in olivine metagabbros may not be required application of the same equilibria gives 8 7 kb for south harris scotland and 0 9 kb for the nain complex disagreement of the latter value with orthopyroxeneolivine quartz barometry bohlen and boettcher 1981 suggests that the use of iron rich rocks olivines fa50 results in errors in calculated pressures

calculation and application of clinopyroxene garnet plagioclase quartz geobarometers recently published thermodynamic and experimental data in a variety of chemical systems have been evaluated to derive gibbs free energies for hedenbergite and pyrope these were used to calculate the geobarometric equilibria

the 17 august 1999 izmit earthquake on 17 august 1999 an earthquake of magnitude 7 4 shook northwestern turkey details on the earthquake9s characteristics and effects across northwestern turkey are provided and are put in the historical context of previous earthquakes in the region the earthquake was the seventh in a series of earthquakes migrating westwards along the north anatolian fault since 1939 information on historical earthquakes modeling and estimates of the slip rate along the fault indicate that the location and severity of the earthquake should not have come as a surprise

coseismic and early post seismic slip associated with the 1999 izmit earthquake turkey from sar interferometry and tectonic field observations summary we use combined tectonic field observations and sar data to determine an improved model of the slip associated with the 1999 izmit earthquake which ruptured the north anatolian fault at the eastern end of the sea of marmara the leading goal is to understand the main features of the coseismic and post seismic deformation which are captured together in the sar data to achieve this we make a critical analysis of the ers1 2 sar data which allows atmospheric effects to be identified and removed we also use detailed field mapping and measurements of the earthquake surface rupture dislocations in elastic half space and a forward modelling strategy allow us to obtain a slip model by steps a trial and error approach is combined with conventional inversion techniques to determine the slip in the different regions of the fault the sar data are well explained with three main zones of high slip along the fault releasing a total moment of 2 3 10 20 nm mw 7 6 which is higher than the seismological estimates 1 7 2 0 10 20 n m the inhomogeneous slip distribution correlates with fault segments identified at the surface the izmit rupture appears to have extended 30 km west of the hersek peninsula into the sea of marmara with slip tapering fro m2mt ozero the western end of the rupture is located 40 km sse from istanbul we show that some features seen near to mudurnu and gevye and previously interpreted as slip on secondary faults are explained mostly as atmospheric effects correlated with the topography using our approach and the available gps data we obtain a slip model that represents the coseismic slip alone which suggests that the moment release during the main shock was 1 9 10 20 nm mw 7 5 consistent with the seismological estimates we conclude that the sar data include the effects of 2 m of fast after slip during the month following the main shock within a zone of the fault located 12 24 km below the epicentral region near the hypocentre at a depth of 18 km the fault appears to have experienced dynamic slip of 1 m associated with the main shock followed by 2 m of rapidly decelerating post seismic shear during the following month we suggest that the distribution of heterogeneous slip and loading along the different fault segments may be important factors controlling the propagation of large earthquake ruptures along the north anatolian fault

characteristics of nonlinear response of deep saturated soil deposits abstract recent epri seismic design guidelines call for dynamic soil properties shear modulus ratio and damping and liquefaction strength curves to be characterized as a function of the effective vertical stress or depth a modified version of the desra2 constitutive model for saturated soil has been applied to study the nonlinear seismic response including liquefaction of medium dense soil deposits of various thicknesses the results of the stress dependent soil properties model show lower deamplification and higher first mode resonant frequency than that of the stress independent soil properties model by using the stress dependent model with impulse base excitation the nonlinear behavior of various soil deposits has been investigated under a variety of conditions the results show that 1 the saturated soil deposit has a smaller surface amplitude and significantly lower resonant frequency than the unsaturated soil deposit of the same thickness 2 for the saturated soil conditions the larger the base excitation the lower the surface amplification and the resonant frequency 3 the deep soil deposits show lower surface amplification and resonant frequency compared to the response of shallow deposits 4 when shallow and deep deposits are compared the shallow deposits develop much higher residual pore water pressure and 5 the amplification and residual pore water pressure response of deposits deeper than 100 m or so are very similar the application of the method has also been illustrated using a strong synthetic base excitation applied to the base at a site near reno the results in general are consistent with those computed using the impulse loading the study reveals that the response predicted from the conventionally used stress independent soil properties model is unconservative for deep deposit

granulites in and around the bengal anorthosite eastern india genesis of coronal garnet and evolution of the granulite anorthosite complex granulites occur in and around an anorthosite massif commonly referred to as the bengal anorthosite in eastern india the central part of the anorthosite is massive in nature with locally developed fluxion structure in isolated blocks banding in the peripheral part is typical of that of the massif anorthosites of anderson morin the granulites bear imprints of polyphase deformation and the xenoliths of granulites within the anorthositic massif maintain their regional structural alignment the anorthosite syntectonic with the second fold movement in the terrane has developed second generation structures hornblende orthopyroxene clinopyroxene plagioclase and quartz with or without garnet and other minor phases consitute the granulites in the anorthosites orthopyroxene clinopyroxene hornblende and magnetite with or without garnet may constitute more than 15 of the mode garnet when present in the rocks is a late overprint symplectitic growth of garnet with one or more of the phases such as ilmenite quartz clinopyroxene and sodic plagioclase indicates genesis of garnet through decomposition of orthopyroxene and or prograde hornblende in the presence of calcic plagioclase the garnet formed during prograde dehydration reactions rather than cooling of the complex chemical characteristics of the mafic phases in the rocks indicate attainment of exchange equilibrium with respect to the major cations in closely associated hornblende clinopyroxene orthopyroxene and garnet estimated physical conditions of metamorphism from contrasted assemblages suggest a final equilibration of different granulitic assemblages as well as of the anorthositic assemblages under similar conditions there was however belated building up of water pressure in the anorthositic domains stabilizing a late hornblende during cooling of the complex absence of chilled margins in the anorthosite as well as absence of contact aureoles in the enveloping and enclosed granulites indicate emplacement of the anorthosite in a hot environment prior to cooling of the complex