an outline of the plate tectonics of china china is principally a part of the eurasian plate but the margins of the indian and philippine sea plates are involved in the himalayas and in the coastal range of taiwan respectively within the eurasian plate the cathaysian paleoplate is separated from the angaraian paleoplate by the junggar hegen suture which contains paleozoic ophiolites and rare blueschists the three microplates of the cathaysian paleoplate consist of precambrian cratons and or phanerozoic accretionary fold belts these coalesced precambrian cratons record at least six stages of intense orogeny before cratonization the paleozoic to cenozoic accretionary fold belts of china can be correlated with similar events now found in west pacific andean and atlantic type active continental margins ophiolites occupying many of these tectonic zones provide evidence for the age and igneous history of oceanic crust formed during the paleozoic to cenozoic the presence of blueschist in some of these chinese sutures reveals evidence of large scale subduction and tectonic exhumation during consolidation of the eurasian plate cenozoic collision of the eurasian and indian plates produced deformation and uplift of the himalayas strongly influencing the tectonics of western china in contrast mesozoic tertiary evolution of eastern china is typical basin range geology similar to that of the western united states which included development of deep sedimentary basins along with calc alkaline plutonic and volcanic activity associated with crustal thinning and high heat flow the complicated tectonic evolution of china is greatly illuminated by the presence of ophiolites and blueschists in proterozoic to tertiary convergent boundaries these petrotectonic assemblages provide evidence of an extremely mobile history of plate movement in china

formation and evolution of the tancheng lujiang wrench fault system a major shear system to the northwest of the pacific ocean abstract in the northwestern peri pacific tectonic belt on the continental margin of east asia there is a series of major faults trending ne nne i e the tancheng lujiang wrench fault system this fault system extends more than 5000 km with a width of 800 1000 km in the continent and a general strike of n30 e on the basis of the results of special research on the major faults and a lot of new information about the fault system the authors discuss early mesozoic triassic jurassic period sinistral transcurrent faulting in the different regions it is suggested that in the eastern continent of east asia the e w trending tectonic pattern of the paleozoic and beginning of the mesozoic appear in the nuclei of the sino korean continent massif and the yangtze continent massif these ancient continent massifs accreted both southwards and northwards which finally led to their collision and suturing to the angura continent massif later this tectonic framework was changed greatly by the tancheng lujiang wrench fault system along which left lateral horizontal displacement of 1000 1500 km took place since the mesozoic the dislocation and deformation of horizontal displacement of the tancheng lujiang fault system produced a series of structures trending ne nne in the continental margin which have greatly transformed the ancient structures of the preceding mesozoic this is an important diktyogenese in the continent of east asia during the horizontal displacement motion of these faults the folds nappes and decollement structures pull apart basins and subductions within the continent occurred in the continent at the same time some large sinistral ductile shear zones of horizontal displacement appeared the depth of the deformed horizon of ductile shear which belongs to simple shear was controlled by the tectonic element and distance away from the continental margin whilst the ductile shear deformation occurred the fault dynamo thermal metamorphism and the fault remelting took place and magma activity appeared within the continent in the mesozoic the fault zones used to be high energy zones and recently became the seismic belts within the continent formation of the tan lu fault system was due to the collision between the southern and northern blocks its large sinistral horizontal displacement in the mesozoic was closely related to the kula plate moving northwards therefore the continent disintegrated by shearing which produced some new terranes the shear edge belt was formed between the continent and ocean the change of relative motion between the continent and pacific ocean plate transformed the tan lu fault system into first extension and then compression clarifying the characteristics of the tan lu fault system is an important key in understanding the evolution of the east asia continent since the mesozoic

coesite bearing eclogites from the dabie mountains central china petrogenesis p t paths and implications for regional tectonics coesite and kyanite bearing eclogites are abundant in the southern part of the dabie mountains southern dabie terrane sdt two types of eclogites from the sdt types iii and iv were selected for detailed paragenetic study type iii eclogites most abundant in the northern part of the sdt occur as blocks in gneisses and marble and contain eclogitic assemblages of omphacite garnet phengite epidote coesite kyanite carbonate rutile ilmenite these minerals exhibit weak compositional zoning and contain few mineral inclusions type iv eclogites mostly in the southern part of the sdt occur as coherent layers interbedded with gneisses and amphibolites and have assemblages of omphacite garnet glaucophane kyanite epidote phengite quartz rutile ilmenite garnets of type iv eclogites exhibit a prograde compositional zoning and have mineral inclusions of paragonite phengite epidote quartz and rutile in the core and omphacite barroisite and mg katophorite in the rim prograd

critical slip surface and landslide volume of a soil slope under random earthquake ground motions finding the critical slip surface and estimating the landslide volume are of primary importance for slope seismic design however this may be difficult due to the uncertainty of ground motions to address this problem a new method for calculating uncertainties is recommended in this paper especially for the critical slip surface and landslide volume under random earthquake ground motions firstly a series of intensity frequency nonstationary random earthquake ground motions were generated based on an improved orthogonal expansion method a given number of potential slip surfaces were set in a soil slope subsequently the factor of safety fos of each slip surface for all ground motions was calculated and the minimum fos curves were obtained it was found that the critical slip surfaces and failure times are uncertain under different earthquakes the monte carlo method was used to verify the accuracy of probability density evolution method pdem and the results of the pdem and the monte carlo method are consistent meaning that the pedm has higher computational efficiency moreover the distributions of earthquake triggered landslide volume and landslide depth were analyzed by considering equivalent extreme events both landslide volume and depth exhibit a normal distribution for a homogeneous soil slope the framework of this study is meaningful for slope seismic design in engineering for example the location of critical slip surface can be used for slope reinforcement and the distribution of sliding volume can be used for disaster assessment

effects of near fault seismic loadings on run out of large scale landslide a case study this study presents the run out analysis of the daguangbao landslides subjected to near fault multi direction earthquake forces using discontinuous deformation analysis dda the daguangbao landslide is the largest landslide induced by the 2008 wenchuan earthquake in order to investigate the effects of near fault seismic force on landslide run out kinematic behavior of sliding mass is simulated by a dynamic discrete numerical analysis method called dda in this simulation based on the shape of failure surface and the feature of slope geology the whole slope is divided into three parts base block upper sliding mass and lower sliding mass then two sliding masses are divided into the smaller discrete deformable blocks based on pre existing discontinuities size effect of the huge landslide is also considered baseline corrected real horizontal and vertical ground motions are taken as volume force acting to the base block the results show that seismic force has a significant influence on the landslide progression sliding distance and shape of post failure results of the horizontal and vertical situation are in good agreement with those obtained from post earthquake field investigation remote sensing image and description from the survivors

palaeomagnetic constraints on the collision and rotation of north and south china the eastern half of china is dominated by the north china block ncb and south china block scb separated by a complex fold system that trends roughly east west interpretation of the geology of this fold belt has led to a variety of estimates of the age of amalgamation of these two blocks1 7 palaeomagnetic results are few and have also been subject to conflicting interpretations8 11 here we present our own palaeomagnetic results for late permian rocks for both the scb and ncb and summarize other relevant palaeomagnetic data by reinterpreting the polarity given in some previous studies we are able to synthesize the results for the widespread emeishan basalts of the scb and to suggest a new model for the collision and relative rotation of the two blocks

granulites in the tongbai area qinling belt china geochemistry petrology single zircon geochronology and implications for the tectonic evolution of eastern asia the tongbai area of the eastern qinling belt in china includes granulite grade metamorphic assemblages qinling complex which were previously regarded as archean to early proterozoic in age and belonging to the southern margin of the north china plate craton our petrological and geochemical data characterize these rocks as two pyroxene granulites and garnet granulites which formed at temperatures of 757 840 c and pressures of about 9 5 kbar and are now found as xenoliths in granodioritic gneisses the protoliths of these rocks were granodiorites and tholeiitic basalt or gabbro the 207pb 206pb ratios derived from evaporation of single zircons yield ages of 470 20 and 470 14 ma respectively for the basic granulites which we interpret to reflect the time of protolith emplacement these are intruded by a 435 14 ma granodioritic gneiss post dating granulite formation a metaquartzite sample contains detrital zircons as old as 2555 8 ma two samples of granitoid gneiss from the tongbai complex s of the qinling granulites have single zircon 207pb 206pb evaporation ages of 776 8 and 746 10 ma respectively and document late proterozoic igneous activity we suggest that the qinling granulites document an important and hitherto unknown phase of early silurian crustal thickening following subduction and continental collision and that both the qinling and tongbai complexes were part of the southern margin of the north china craton prior to this event and record late proterozoic igneous activity

coesite and pure pyrope in high grade blueschists of the western alps a first record and some consequences a pyrope quartzite originally described by vialon 1966 from the dora maira massif was resampled and reinvestigated garnet up to 25 cm in size phengite kyanite talc and rutile are in textural equilibrium in an undeformed matrix of polygonal quartz the garnet is a pyrope almandine solid solution with 90 to 98 mol mg end member it contains inclusions of coesite which has partially inverted to quartz resulting in a typical radial cracking of the host garnet around the inclusions several lines of evidence show that coesite crystallised under nearly static pressure conditions and that the whole matrix has once been coesite

cenomanian early turonian carbonate platform of northern oman stratigraphy and palaeo environments abstract the jebel akhdar and adam foothills outcrops in northern oman arabian peninsula offer the opportunity to study in detail the lateral and vertical changes of a cenomanian early turonian carbonate platform formed by the natih formation wasia group eleven sections with less than 5 km offset were logged to express metre scale lithological and biostratigraphical vertical changes the first rudist zonation is established complementing classical benthonic foraminifer and ammonite biozones typical cenomanian rudist association caprinids and radiolitids occur in the natih e c d a lower part whereas lower turonian hippuritid rudists are represented in the upper part of the natih a a sedimentological and palaeoecological approach leads to identification and interpretation the facies and discontinuities of the natih carbonate platform and to a reconstruction of its spatial organization application of the concepts of sequence stratigraphy allows interpretation of the units of the natih in terms of systems tracts an attempt is made to correlate the sequence stratigraphical model to eustatic sea level changes and regional tectonic events three palaeoenvironmental models taking into account bio and lithofacies are proposed

distribution pattern of earthquake induced landslides triggered by the 12 may 2008 wenchuan earthquake abstract this paper presents the preliminary results of an extensive study of the mapping the distribution of landslides triggered by the wenchuan earthquake in sichuan province china on 12 may 2008 an extensive landslide interpretation was carried out using a large set of optical high resolution satellite images e g aster alos cartosat 1 spot 5 and ikonos as well as air photos for both the pre and post earthquake situation landslide scarps were mapped as points using multi temporal visual image interpretation taking into account shape tone texture pattern elevation and ridge and valley orientation nearly 60 000 individual landslide scarps were mapped the landslide distribution map was compared with the inventory map that was prepared directly after the earthquake which contains about 11 000 individual landslide points through the calculation of normalized landslide isopleths maps remarkable differences were observed as the earlier inventory mapping did not consider the pre earthquake situation and did not consider all individual landslides as part of the landslide inventory landslides were identified that had blocked the drainage and had formed landslide dams the landslide distribution was compared with a number of aspects such as the seismic parameters distance to epicenter distance to fault rupture co seismic fault geometry and co seismic slip distribution and geology the most remarkable correlation found was with the co seismic slip distribution and the fault geometry landslide distribution in the section of the fault that had mainly a thrust component with low angle fault plane was found to be much higher than the sections that had steeper fault angles and a major strike slip component

diamond from the dabie shan metamorphic rocks and its implication for tectonic setting diamond occurs in ultrahigh pressure metamorphic rocks from dabie shan anhui province eastern china diamond bearing rocks include eclogite gamet pyroxenite and jadeitite diamond occurs in a mineral assemblage with coesite and jadeite the diamonds and diamondiferous rocks of dabie shan are interpreted to be the products of ultrahigh pressure metamorphism in the underthrust basement of the yangtze continental plate during the early mesozoic at greater than 4 0 gigapascals and 900 c this interpretation is based on the distribution of rock units the stability field of diamond and isotopic data indicating a crustal origin for the rocks most diamonds occur as euhedral inclusions in garnets and are 10 to 60 micrometers across although some are up to 700 micrometers across

microtremor recordings in northern mississippi abstract this paper presents the results of 305 single point microtremor recordings covering northern mississippi that is situated within the upper mississippi embayment area both long and short term recordings were obtained by a le 3d 20s seismometer over a large network of points where the unconsolidated sediment thickness ust varies from zero to 1400 m applying the nakamura method the recordings were processed to determine predominant frequency f0 and its relation to ust initial results of wind influence on the frequency spectra particularly in low frequency band 0 05 0 2 hz and dominant vibration direction are also presented it is shown that analysis of systematic microtremor recordings can provide a stable and reliable estimation of the predominant frequency from which estimates of average shear wave velocity of overall sediment profile can be derived predominant frequency and average shear wave velocity is reasonably well correlated with ust wind and human activities are found to produce peaks over the low frequency band

paleomagnetic constraints on the geodynamic history of the major blocks of china from the permian to the present paleomagnetic study of china and its environs has been the center of a major international effort for the last 10 years in this paper we critically review all available paleomagnetic poles of upper permian to tertiary age from the main blocks of china with the goal of placing constraints on models of the formation and the subsequent deformation of the region after selecting reliable poles by applying objective criteria we divide our analysis into first order motions of blocks and second order deformation within blocks for first order analysis apparent polar wander paths are constructed for the major blocks we discuss the compatibilities and contradictions between the geological and paleomagnetic records a sequence of paleogeographic configurations taking into account geological constraints but remaining within paleomagnetic uncertainties is presented in general the major blocks were probably in contact throughout the permian and triassic but the jurassic was the key age during which most of the movement toward china s present configuration took place our reconstructions include certain details which are suggested by the paleomagnetic record but whose geological signatures seem to have been hidden by subsequent events during the cretaceous chinese poles agree with poles from other continents transferred onto eurasia at the second order we observe that for almost each period with sufficient data the paleomagnetic poles are streaked along a small circle centered on the sampling region indicating that much of china has been affected by small 20 differential rotations this we interpret as deformation caused in part by the extrusion of the chinese blocks away from the indian collision the complete annotated list of poles is given as an appendix

north south extension within the convergent himalayan region recent work by burg et al 1984 indicates the presence of east west striking gently north dipping normal faults in the higher himalayas and southern tibet that formed during postcollisional convergence of india and tibet these faults extend for at least 800 km along strike we interpret these normal faults as probable late miocene extensional features with perhaps several tens of kilometres of down to the north displacement a simple elastic model suggests that these normal faults may have formed during gravitational collapse of the miocene topographic front between india and tibet in this interpretation gravitational collapse occurred by southward motion relative to india and tibet of a wedge of crustal rocks bounded above by gently north dipping normal faults and below by thrust faults that probably dip north north south extension produced in this way is probably confined to upper crustal levels only and does not reflect regional extension of the entire lithosphere

regional ultrahigh pressure coesite bearing eclogitic terrane in central china evidence from country rocks gneiss marble and metapelite the dabie mountains represent a fault bounded coesite bearing eclogite gneissic terrane within the collisional belt between the sino korean and yangtze cratons the following geologic evidence indicates that this terrane has been subjected to regional ultrahigh pressure metamorphism 1 the country rocks have a metamorphic pressure temperature evolution compatible with that of the eclogites on the basis of the occurrence of quartz pseudomorphs after coesite calcite pseudomorphs after aragonite relict high pressure assemblages in different rock types of the country rocks and consistent comparable compositional zonations of garnets in both country rocks and eclogites 2 peak metamorphic pressure temperature conditions consistently decrease both from east to west in the collisional belt and from north to south in the dabie mountains and clockwise pressure temperature paths are common for eclogites over the region 3 layered eclogites interbedded with gneisses and amphibolites contain omphacite kyanite and garnet indicating a minimum pressure of 20 kbar at 600 c for formation of these rocks

structure and tectonic evolution of the tongbai dabie range in the east qinling collisional belt china recent work demonstrates that the tongbai dabie range which is considered to be the eastern segment of the important qinling belt in central china shows ample evidence of the collisional nature of this orogenic zone it is characterised by large thrust decollement structures with at least 140 km of horizontal displacement and it includes a melange nappe overthrust continental crust underthrust continental crust a marine nonmarine molasse formation and a foreland fold thrust belt its interpreted tectonic evolution can be subdivided into four main periods 1 ocean continent north dipping subduction during the silurian early devonian 2 continental collision in the late devonian 3 intracontinental subduction and large scale shallow crustal deformation beginning in the middle carboniferous and 4 upwarping and slicing by huge e w left lateral strike slip faults after the late jurassic and before the cenozoic right lateral movements on the faults which bound this belt

coesite bearing eclogite from the dabie mountains in central china coesite and coesite pseudomorphs are recognized in eclogite from the dabie mountains a collision zone between the sino korean and yangtze cratons in central china this third known occurrence of coesite in deep crustal rocks is within an archean gneiss terrane and is the first locality where coesite has been identified as an inclusion in both omphacite and garnet crystals at the same location coesite bearing eclogite is estimated to form at pressures of 28 kbar and temperatures from 600 to 710 c the dabie mountains eclogite underwent retrograde metamorphism to amphibolite facies after its formation the preservation of coesite in eclogite is found to be strongly controlled by the pressure temperature time path that coesite bearing eclogite followed during its uplift and retrograde metamorphism

coesite in clinopyroxene in the caledonides and its implications for geodynamics coesite is reported for the first time from the caledonide orogen it occurs as inclusions in clinopyroxene in the dolomite eclogite at grytting norway and provides valuable new evidence to support the hypothesis of extremely high pressure 30 kbar in certain norwegian eclogites this finding has implications for the geodynamics and kinetics of the concepts of microscale intracrystalline tectonic overpressure and of macroscale local or regional tectonic overpressure and for the hypotheses of subduction and obduction involving a more than 100km vertical component of transport

landslide seismic signal recognition and mobility for an earthquake induced rockslide in tsaoling taiwan abstract landslide seismic signal processing and the newmark s sliding block analysis are used in this research to analyze the initiation time and mobility of the tsaoling rockslide triggered by the 1999 chi chi earthquake in central taiwan a new technique the time frequency spectrum analysis is employed to identify the rockslide initiation and landing times from four real time seismic records of strong ground motion stations the results suggest that higher frequencies ranging from 30 to 70 hz correspond to the rockslide initiation and sliding process which are opposed to the low signal frequency of earthquake the landslide began at 32 5 s the sliding block sped up at 37 5 s and impacted on the opposite riverbank at 76 s on the seismic time record the mobile scenario of tsaoling rockslide induced by chi chi earthquake is simulated using newmark s sliding block analysis the maximum sliding velocity reaches approximately 75 1 m s despite being a simple conceptual model the newmark s sliding block analysis provides consistent results with the real time seismic signal analysis and details of the rockslide kinematics

origin and assembly of the tethyside orogenic collage at the expense of gondwana land abstract the tethysides are a superorogenic complex flanking the eurasian continent to the south and consisting of the cimmerides and alpides products of palaeo and neo tethys respectively we here review their evolution mainly on the basis of new maps showing the distribution of sutures magmatic rocks certain palaeobiogeographically and palaeoclimatologically significant taxa and facies and fragments of pan african 900 450 ma orogenic system forming the basement of many tethyside blocks these are supplemented by palaeomagnetic data reported in the literature a fundamental tenet of this paper is that major sutures which contain ophiolite fragments represent tectonic sections between continental blocks where oceanic crust has been subducted palaeo tethys came into existence largely in late carboniferous time coevally it began to be consumed by both internal and peripheral subduction zones which continued into the permian some of these had been inherited from pre tethyan times in the later permian rifting subparallel with the northern margin of gondwana land began between the zagros and malaysia separating a cimmerian continent from n gondwana land and thus heralding the opening of neo tethys and other smaller oceans that were back arc basins of palaeo tethys this rifting possibly also extended farther west into crete and mainland greece however the north china block yangtze block huanan block the eastern moity of the qangtang block north tibet and annamia all originally pieces of the end proterozoic early palaeozoic gondwana land had already separated from it in pre late carboniferous times possibly during the devonian all of these blocks and the cimmerian continent were characterized by cathaysian floral elements in late palaeozoic time palaeomagnetic and palaeontological data showing the original gondwana land affinity of these continental blocks are supplemented by correlating late proterozoic early palaeozoic pan african sutures orogenic belts and sedimentary basin fragments across tethyside sutures late permian foraminiferal provinces are related to this palaeogeographical interpretation by triassic times most cimmeride subduction zones were already in existence the cimmerian continent accelerated its separation from gondwana land and locally in the late permian began disintegrating internally along the waser rushan pshart banggong co nu jiang mandalay ocean by late triassic time all of the chinese blocks except lhasa and annamia had collided with each other and with laurasia the resulting enormous orogenic collage had a soft cushion between itself and laurasia in the form of the enormous accretionary complex of the songpan ganzi this connection enabled laurasian land vertebrates to reach south east asia by late triassic time in late triassic to middle jurassic times most major cimmeride collisions were completed widespread aridity in central asia occurred in late jurassic time probably in the rain shadow of the newly formed cimmeride mountain wall neo tethyan subduction systems formed along the s margin of the cimmerides or within neo tethyan oceanic lithosphere during the jurassic most if not all were north or east dipping they continued the northerly migration of the tethyside blocks evolution of the tethysides influenced the distribution of marine and terrestrial organisms and affected sea level changes and patterns of atmospheric circulation during much of the mesozoic and cainozoic it is likely to have reflected the surface expression of a persistent trend in the large scale convective circulation in the mantle that continuously transported material northward into the tethyan domain

landslide dam deformation analysis under aftershocks using large scale shaking table tests measured by videogrammetric technique abstract the ms 8 0 wenchuan earthquake triggered at least 257 landslide dams more than 849 aftershocks with magnitudes higher than ms 4 0 occurred after the wenchuan earthquake by 12 march 2012 shen et al 2013 which might largely influence the structure and soil properties of these dams this paper aims to study the dynamic deformation of landslide dams under aftershocks through larger scale shaking table tests videogrammetric technique was applied to measure the dynamic deformation of the model dams two groups of shaking table tests were conducted with two types of landslide dam materials one with quartz sands containing 10 kaolin dam i and the other with only quartz sands dam ii the dam deformation and its influencing factors were analyzed with the results measured by videogrammetric technique the deformations were generally higher on the surface of the dams either on the crest or on the both upstream and downstream slopes higher peak ground acceleration pga resulted in larger dam deformations due to higher seismic force the deformations under the combination of x and z directional shakings were larger than those under x directional shaking for sufficient vibratory compaction water rising led to the increase of dam deformations because that the water seepage reduced the effective soil stress especially reduced the matric suction the settlements of the dam composed of more fine particles were larger than that composed of large particle size because that the soil pores in the former were filled more sufficiently with fine particles the aftershocks may not directly trigger the failures of landslide dams but accelerate the overtopping failures by lowering the dam crest with settlement and cracking

tectonics of an ultrahigh pressure metamorphic terrane the dabie shan tongbai shan orogen china ultrahigh pressure metamorphic rocks with coesite and diamond form a tectonic slice over 20 km thick called the eclogite zone within the dabie shan complex in the qinling orogen in central china the orogen separates the sino korean block in the north from the yangtze block in the south the dabie shan complex is a composite terrane made up of eclogite facies and amphibolite facies gneiss slices and represents fragments of the lower continental crust of the yangtze block the dabie shan complex is bounded in the south by a triassic foreland fold thrust belt and in the north by a greenschist facies metaclastic unit the foziling group which probably represents the passive continental apron deposits of the yangtze block farther north is a granulite facies gneiss complex the qinling group which has ultramafic slivers and includes the remnants of an island arc with two bounding suture zones north of the qinling group are early paleozoic active margin deposits of the sino korean block the eclogite zone in the dabie shan complex is sandwiched between amphibolite facies gneiss slices dating by sm nd rb sr and ar ar of two eclogite samples from the eclogite zone gives early to middle triassic ages 236 246 ma the initial end values indicate reworking of a 2 11 and 1 55 ga continental crust a himalayan type tectonic evolution is envisaged for the qinling orogen with the creation of a 100 km thick crustal thrust wedge through continuous underplating during the subduction of the yangtze continental lithosphere exhumation of the ultrahigh pressure metamorphic rocks was chiefly achieved by the southward propagation of the thrust planes thereby isostatically uplifting and eroding the earlier deeply subducted parts of the orogen a total of 680 km of southward thrusting in front of dabie shan is inferred based on the abrupt termination of the tanlu fault normal faulting possibly caused by gravitational collapse probably also had a role in the exhumation process

response of high strength rock slope to seismic waves in a shaking table test studies on landslides by the 2008 wenchuan earthquake showed that the topography is of great importance in amplifying the seismic shaking the present study carried out experiments on rock slopes by means of a shaking table the recorded wenchuan earthquake waves are scaled to excite the model slopes measurements from accelerometers installed on free surface of the model slope simulating high strength rocks are analyzed with much effort on acceleration responses to both horizontal and vertical components of seismic shaking it is found that the amplification factor of peak horizontal acceleration pha is increasing with elevation of the model slope though the upper and lower halves of the slope exhibit different increasing patterns the amplification factor of peak vertical acceleration pva exhibits a lying s shaped changing trend with the elevation indicating attenuations of pvas at the toe and top of a slope in addition the xz direction shaking produces a horizontal and vertical response stronger than x direction and z direction shaking alone both pha and pva increase with the excitation intensity however the corresponding amplification factors generally decrease indicating the acceleration response of a slope weakens with the excitation intensity of shaking finally the statistic of ratio of pva to pha indicates that 85 of the slope height especially the upper middle part is likely subject to pvas greater than or equal to 2 3 of pha and 32 of the slope height to pvas greater than or equal to pha this indicates the nonignorable role of pva in responses of a slope to an earthquake and necessity of considering during design work

simplified procedure for estimating earthquake induced deviatoric slope displacements a simplified semiempirical predictive relationship for estimating permanent displacements due to earthquake induced deviatoric deformations is presented it utilizes a nonlinear fully coupled stick slip sliding block model to capture the dynamic performance of an earth dam natural slope compacted earth fill or municipal solid waste landfill the primary source of uncertainty in assessing the likely performance of an earth waste system during an earthquake is the input ground motion hence a comprehensive database containing 688 recorded ground motions is used to compute seismic displacements a seismic displacement model is developed that captures the primary influence of the system s yield coefficient ky its initial fundamental period ts and the ground motion s spectral acceleration at a degraded period equal to 1 5 ts the model separates the probability of zero displacement i e 1 cm occurring from the distribution of nonzero displacement so that very low values of calculated

stochastic seismic response of a slope based on large scale shaking table tests abstract slopes should be regarded as stochastic dynamic systems when investigating the uncertainty of ground motions in engineering this involves the propagation and spatial evolution of physical quantities e g acceleration that can be assessed with some probability more specifically stochastic stability and amplification effects are important issues under random seismic inputs in studying the above a large scale shaking table test is carried out to investigate the slope seismic response under random earthquake ground motions where 144 ground motion samples are generated using a time evolution power spectrum model in this test acceleration evolves in a way that its pdf changes with time and space in the time domain the pdf variability first increases and then decreases with the progression of the earthquake in the spatial domain the pdf variability increases upslope indicating that the mean and standard deviation of amplification factors increase with elevation moreover the stability of the upper part of the slope stochastic dynamic system is poor meanwhile the de amplification effect of the slope toe is identified under random seismic inputs finally we discuss different amplification factors and consider applications of the research results in slope engineering

landslides induced by the 2008 wenchuan earthquake sichuan china the 2008 wenchuan earthquake with a magnitude of mw 7 9 induced numerous slope movements on the hanging walls of fault surface ruptures and on steep inner valleys along the minjiang river landslide moving directions showed preferred orientations normal to the fault ruptures indicating the effect of the directivity of the seismic wave the most common landslides were of carbonate rocks which are easily dissolved and decrease the contact surfaces the largest non volcanic landslide in history was induced in bedded dolomite by the earthquake and was preceded by gravitational deformation with ridge top depressions valley fill materials were mobilized at 36 locations probably by pore water pressure build up

evidence for intracontinental thrust related exhumation of the ultra high pressure rocks in china coesite and diamond bearing ultra high pressure metamorphic rocks produced during the triassic continental collision between the sino korean and yangtze plates are offset by about 530 km along the sinistral tanlu fault in eastern china the tanlu fault terminates abruptly south of the ultra high pressure metamorphic terrain in dabie shan and does not extend into the foreland fold belt along the yangtze river this suggests that in this region the mesozoic major sinistral displacement along the tanlu fault was transferred to southward directed thrusting which led to the exhumation of the ultra high pressure metamorphic rocks formed earlier postcollisional himalayan type intracontinental thrusting and concomitant erosion appear to be the main agents in the exhumation of the very high pressure metamorphic rocks in china

mechanism and time of deformation and metamorphism of mylonitic orthogneisses from the shagou shear zone qinling belt china abstract the shagou shear zone south of xian shaanxi province is a branch of the shangdan fault zone in the qinling belt and documents ductile deformation that affected granitoid rocks mylonitization took place under conditions of the lower amphibolite facies at temperatures of ca 530 c followed by a phase of stagnation still under the same metamorphic conditions the last deformation was a weak event during retrogressive greenschist metamorphism the emplacement of the granitoid precursors of the mylonite is dated at 211 8 ma by the u pb zircon method much younger than nd model ages of 1 2 1 3 ga which indicates the involvement of older continental crust probably in an active continental margin environment the end of mylonitic deformation is given by a sm nd garnet whole rock age of 126 9 ma which is interpreted as a minimum age for the main deformation these geochronological data provide age brackets for the main deformation which must have occurred between the late triassic and the early cretaceous

shaking table tests and stability analysis of steep nailed slopes shaking table tests were performed on five model slopes to examine the effects of the angle and length of the nails and the frequency of excitation on the seismic resistance and failure mechanism of the slopes seismic excitation was also applied to slopes at various angles experimental results showed that nails markedly improved the seismic resistance of all model steep slopes additionally nailed slopes exhibit characteristics of ductility under strong excitation the angle of the nails influences the deformation of the slope but only slightly affects seismic resistance an increase in the length of the nails increased the seismic resistance of the slope and reduced the displacement of the facing only when subjected to strong excitation the slope at an angle of 90 to the horizontal has a markedly lower seismic resistance than that at 80 the rocking of the model slope was strong for the slope with inclined nails and the slope at 90 to the horizontal the failure surface of the soil mass is approxi

tectonics of the qinling belt build up and evolution of eastern asia the structure and history of the qinling range which separates the north and south china cratons are a key to the tectonic evolution of eastern asia the mountain range is composed of a northern palaeozoic belt and a southern mesozoic belt the palaeozoic orogeny probably involved the closure of an oceanic basin along a north dipping subduction zone followed by south vergent obduction of ophiolites and intracontinental thrusting during the devonian the mesozoic belt appears to be the product of purely intracontinental shallow crustal deformation over a large decollement with at least 100 km of horizontal transport since the devonian both belts have been sliced by huge east west sinistral strike slip faults

flexural behavior of the continental lithosphere in italy constraints imposed by gravity and deflection data a procedure is developed that systematically matches observations of plate flexure and gravity anomalies at simple convergent boundaries to the bestfitting two dimensional flexural geometry obtained by a thin elastic sheet of specified elastic strength the procedure allows analytical solution for three independent variables one of which is the initial preflexure elevation of the reference surface and two of which are related to the vertical forces and bending moments that act on the plate application to four profiles constructed across the apennine convergent system in italy shows that the observed depth of the basal pliocene surface which marks the base of the foredeep basin and the observed bouguer gravity anomalies can be fit by a two dimensional elastic plate model with an effective elastic thickness of about 20 km on three profiles and about 10 km on the fourth profile the initial elevation prior to flexure is determined to have been about 1000 m below sealevel on all profiles large bending moments and or vertical shear forces are required to act at the effective plate ends in order to maintain the observed deflection moments between 0 5 1017 and 3 1017 n and shear forces between 3 1012 and 3 1012 n m gravity modelling indicates that on the two northernmost profiles these terminal forces can not be supplied by a static mass at crustal depths and suggests that on all four profiles the terminal forces are supplied by anomalously dense material present at depths of 75 150 km beneath and west of the west coast of italy this dense material probably corresponds to westward subducted lithosphere of the adriatic plate extending from the northern apennines to the southern apennines and calabria this study suggests that in subduction systems like the apennines that are characterized by backarc extension forces acting on subducted lithosphere at depth can be expressed at the surface in the geometry of the foredeep basin that forms adjacent to the subduction zone

diamond inclusions in garnets from metamorphic rocks a new environment for diamond formation diamonds commonly occur in kimberlites lamproites and alluvial sediments derived from these rocks more recently diamonds or their graphite pseudomorphs have been discovered in ultramafic massifs1 and picrites2 here we report the occurrence of diamonds in situ in crustal rocks highly retrograded high pressure metamorphic garnet pyroxene and pyroxene carbonate garnet rocks biotite gneisses and schists from the kokchetav massif northern kazakhstan ussr the diamonds are cubo octahedral averaging 12 m in size and occur in zircons and with euhedral graphite as inclusions in unzoned garnets we believe that the zircon and garnet matrices protected these diamonds from retrogressive transformation to graphite mica rutile titanite clinopyroxene kyanite and zircon also occur as inclusions in garnet often intergrown with the diamonds equilibration relations of inclusions and host garnets indicate that both diamonds and graphite crystallized from a fluid phase under static conditions at pressures of 40 kbar and temperatures 900 1 000 c

statistical seismic landslide hazard analysis an example from taiwan abstract following the work of lee et al 2008a a statistical approach is applied to seismic landslide hazard analysis for the whole of taiwan all the work is done using new data sets which include a new and carefully mapped chi chi earthquake induced landslide inventory a 5 m dem and a new version of the 1 50 000 scale geologic map of taiwan landslide causative factors used in the susceptibility analysis include the slope gradient slope aspect terrain roughness slope roughness total curvature total slope height and lithology the corrected arias intensity taking topographic amplification into consideration is used as a triggering factor firstly a susceptibility model is built using the 1999 chi chi shallow landslides as a training data set and multivariate logistic regression as the analytical tool this model is validated by using the 1998 jueili earthquake induced landslide data then a probability of failure curve is established by comparing the chi chi landslide data and the susceptibility values after which the spatial probability of landslide occurrence is drawn the temporal probability may be accounted for with the triggering factor the hazard level of the arias intensity which was obtained through regular probabilistic seismic hazard analysis finally the susceptibility model and the probability of failure curve are applied to the whole of taiwan using the topographically corrected 475 year arias intensity as a triggering factor to complete a seismic shallow landslide probability map for ground motions having a 475 year return period

analysis on mechanism of landslides under ground shaking a typical landslide in the wenchuan earthquake a high steep rock hill with two side slopes near national road 213 is used as a prototype in this paper the full process from initial deformation to sliding of the slope during ground shaking is simulated by a new discrete element method continuum based discrete element method then the seismic responses of a high steep rock hill with two side slopes are researched from the base of time frequency and joint time frequency domain using hilbert huang transform and fourier transform the findings are first the stress concentration phenomenon occurs at the top of the sliding mass and then some tension and shear failure points appear which expand from the top toward the toe of the sliding mass along the structural plane at the same time the number of tension failure points gradually increases then the toe of the sliding mass fails and shears out from its toe which results in the landslide if the material parameters are under the same conditions the landslide in the middle of the slope occurs before that at the foot of slope and the starting time of landslide and the arrival time of the peak ground acceleration are synchronous or the former slightly lags behind the latter the difference of distribution and dissipation of earthquake energy in the sliding body and sliding bed is the major influence factor to induce the landslide when the accelerations are small the instantaneous frequency of accelerations between sliding bed and sliding body is generally consistent the energy transmittance coefficients of the sliding structural plane and the controlled frequency band of the energy all range in a limitation with the increase of the seismic intensity the instantaneous frequency and the energy transmittance coefficients gradually decrease and then they are steady within the lower limitation at the same time the controlled frequency band also shifts gradually from high frequency band to the lower one based on the input seismic wave the peak acceleration amplifies as the increase of elevation regardless of the monitoring points on the steep slope gentle slope side or inside of the slope generally speaking amplification of the vertical peak acceleration is stronger than that of the horizontal peak acceleration and amplification of the peak acceleration on a steep slope is stronger than that on a gentle slope and that of inside of the slope is the weakest amplification

performance of piles with different configurations subjected to slope deformation induced by seismic liquefaction abstract liquefaction induced lateral ground deformation has been a common observation during many past earthquakes piles are widely used in liquefaction prone areas and their performance under such circumstances has become an important issue for researchers and engineers previous studies on this issue have focused primarily on piles located behind quay walls or in level ground conditions which have considerably different boundary conditions compared to those of an inclined sloping ground condition that is more common for waterfront structures this study presents a series of shaking table tests modeling the performance of piles subjected to liquefaction induced slope deformation different pile configurations including single piles piles aligned in one row parallel to the direction of the slope piles aligned in one row perpendicular to the direction of the slope and piles in a 3 3 configuration were tested several aspects regarding the behaviors of excess generation of pore water pressure pile bending moment and lateral slope deformation under different pile configurations were revealed and discussed the results obtained in this study can be used for validation of related numerical approaches or as benchmarks that can further facilitate performance based pile designs in liquefaction prone areas