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

green s functions of coseismic strain changes and investigation of effects of earth s spherical curvature and radial heterogeneity summary a set of green s functions is presented for calculating the coseismic strain caused by four independent seismic sources in a spherically symmetric non rotating perfectly elastic and isotropic snrei earth model corresponding expressions are derived assuming that the seismic sources are located at the polar axis the proper combination of these expressions allows calculation of the coseismic strain components resulting from an arbitrary seismic source at any earth position calculations of strain components are made for the near field resulting from the four independent sources at a depth of 32 km inside the 1066a earth model results agree well with those calculated for a half space earth model thus confirming the validity of the theory presented in this research a case study is performed and earth model effects are investigated furthermore this paper investigates effects of spherical curvature and the stratified structure of the earth in computing coseismic strain changes curvature effects are small for three types of seismic sources but extremely large for the horizontal tensile opening on the vertical fault plane because a general coseismic deformation comprises four independent solutions the large curvature effect on the horizontal tensile opening source contributes to the general result effects of earth s stratified structure are large for all depths and epicentral distances they reach a discrepancy greater than 30 per cent almost everywhere and 100 per cent in a very far field results show that effects of crustal structure mainly exist in the near field they do not affect results for a far field

geometric analysis of fold development in overthrust terranes abstract fault bend folding fault propagation folding and detachment or decollement folding are three distinct scenarios for fold thrust interaction in overthrust terranes simple kink hinge models are used to determine the geometric associations implicit in each scenario bedding maintains constant thickness in the models except in the forelimb of the fold the forelimb is allowed to thicken or thin without limit the models address individual folds and the calculated fold geometries are balanced structures each mode of fold thrust interaction has a distinct set of geometric relationships final fold geometry is adequate in itself to discern many fault bend folds this is not the case for fault propagation and detachment folds these two fold forms have very similar geometric relationships some knowledge of the nature of the underlying thrust or decollement zone is usually needed to distinguish between them the geometry of a fold is altered in a predictable fashion by transport through an upper ramp hinge and by fault parallel shearing of the structure the shearing results in a tighter fold whereas transport through the ramp hinge produces a broader fold the viability of the geometric analysis technique is demonstrated through its application to a pair of detachment folds from the canadian cordillera the geometric analysis is also used to evaluate cross sections through subsurface structures in an example from the turner valley oil field the analysis indicates how the interpretation should be altered so as to balance the cross section the analysis reveals hidden assumptions and specific inconsistencies in structural interpretations

green s functions for post seismic strain changes in a realistic earth model and their application to the tohoku oki m w 9 0 earthquake based on a spherically symmetric self gravitating viscoelastic earth model we derive a complete set of green s functions for the post seismic surface strain changes for four independent dislocation sources strike slip dip slip and horizontal and vertical tensile point sources the post seismic surface strain changes caused by an arbitrary earthquake can be obtained by a combination of the above green s functions the post seismic surface strain changes in the near field agree well with the results calculated by the method in a half space earth model wang et al in comupt geosci 32 527 541 2006 which verifies our green s functions with an increase in the epicentral distance the effect of the curvature on both the co and post seismic strain changes clearly increases revealing the importance of our spherical theory for far field calculations next we use our green s functions to simulate the post seismic surface strain changes that were caused by the viscoelastic relaxation of the mantle over the 6 year period after the tohoku oki mw 9 0 earthquake based on continuous global positioning system gps observations around honshu island of japan northeastern china south korea and the russian far east we also deduce the post seismic strain changes caused by the tohoku oki mw 9 0 earthquake overall the distributions of the calculated and gps derived strain changes agree well each other finally we compare the relative error between the observed and simulated strain changes over the 3 0 4 5 year period after the earthquake in both the near and far field we find that the relative errors decrease as the epicentral distance increases which validates our green s functions for research in the far field

implications of the 26 december 2004 sumatra andaman earthquake on tsunami forecast and assessment models for great subduction zone earthquakes results from different tsunami forecasting and hazard assessment mod els are compared with observed tsunami wave heights from the 26 december 2004 indian ocean tsunami forecast models are based on initial earthquake information and are used to estimate tsunami wave heights during propagation an empirical forecast relationship based only on seismic moment provides a close estimate to the observed mean regional and maximum local tsunami runup heights for the 2004 indian ocean tsunami but underestimates mean regional tsunami heights at azimuths in line with the tsunami beaming pattern e g sri lanka thailand standard forecast models developed from subfault discretization of earthquake rupture in which deep ocean sea level observations are used to constrain slip are also tested forecast models of this type use tsunami time series measurements at points in the deep ocean as a proxy for the 2004 indian ocean tsunami a transect of deep ocean tsunami amplitudes recorded by satellite altimetry is used to constrain slip along four subfaults of the m 9 sumatra andaman earthquake this proxy model performs well in comparison to observed tsunami wave heights travel times and inundation patterns at banda aceh hypothetical tsunami hazard assessments models based on end member estimates for average slip and rupture length m w 9 0 9 3 are compared with tsunami observations using average slip low end member and rupture length high end member m w 9 14 consistent with many seismic geodetic and tsunami inversions adequately estimates tsunami runup in most regions except the extreme runup in the western aceh province the high slip that occurred in the southern part of the rupture zone linked to runup in this location is a larger fluctuation than expected from standard stochastic slip models in addition excess moment release 9 deduced from geodetic studies in comparison to seismic moment estimates may gen erate additional tsunami energy if the exponential time constant of slip is less than approximately 1 hr overall there is significant variation in assessed runup heights caused by quantifiable uncertainty in both first order source parameters e g rupture length slip length scaling and spatiotemporal complexity of earthquake rupture

mechanical model for single thrust sheets part i taxonomy of crystalline thrust sheets and their relationships to the mechanical behavior of erogenic belts crystalline thrust sheets cts are those partially or wholly composed of metamorphic and or igneous rocks they have been known for more than a century we have recognized several types 1 thin skinned basement cover sheets 2 ophiolites 3 tectonic slides 4 basement uplifts and 5 composite thrust sheets the overthrust index ratio b may be obtained by dividing the total estimated displacement on cts by the distance from the 0 mgal contour on the prominent gravity gradient in an orogen to the last thrust in the foreland a fundamental property of cts is that the largest crystalline thrust sheet is always larger than the largest foreland thrust sheet in the same orogen this property is doubtlessly related to then relative strengths because they generally contain no pre existing subhorizontal weak zones cts are probably generated within the ductile brittle transition zone thicknesses of cts are thus determined by the geo thermal gradient and crustal lithology a mechanical model primarily for types 1 2 and 5 cts relates cross strike width x of thrust sheets to the compressive stress c friction b and dip of the basal thrust thickness of the thrust sheet at the hinter end t and average thickness t the model based upon an energy conservation argument predicts x c t b g t where g is gravity 980 gal and is average density of the allochthonous mass this equation can be used to relate data from ancient deeply eroded orogens to processes that were active during emplacement of cts for observed widths and thickness the model requires emplacement of composite type 5 thrust sheets by tectonic compression c 50 mpa and low friction thrusts b b 50 mpa

geometrical modeling of fault related folds a pseudo three dimensional approach abstract area balanced cross sections of ramp anticlines and tip line folds in thin skinned fold thrust belts can be quantitatively constructed using plane strain fault bend and fault propagation fold models cross sections alone however are somewhat inadequate for interpreting along strike changes in thrust related fold geometry complex interplay between along strike changes in fault slip and fault shape determines a range of geometric configurations which are difficult to visualize without the aid of quantitative three dimensional models we extend conventional two dimensional folding theories into the third dimension by allowing for continuous variations in fault slip and fault shape along strike geometric equations relating map view angles between fold axial surface traces are derived for a case assuming a uniform fault geometry and an along strike displacement gradient the resulting folds possess no unique fold axis but rather are characterized by multiple fold hingelines each corresponding to bends in the fault for typical displacement gradients observed in the field analysis of the models suggests that discernible differences exist between map patterns of fault bend folds and fault propagation folds whereas little difference exists between map patterns of similar and parallel fault bend folds map view angles between axial surface traces for parallel fault bend folds and fault propagation folds are a function of both ramp cutoff angle and fault slip whereas these same angles for similar fault bend folds are solely a manifestation of fault slip examples assuming uniform shortening and continuously varying fault geometry along strike are also presented fault geometry is varied along strike to simulate oblique and lateral ramps depending upon model type and fault shape parameter modified resulting folds exhibit either cylindrical or non cylindrical fold geometries closure is generated by a decrease in fold amplitude where there is a decrease in ramp cutoff angle along strike or where a fault laterally cuts up section in either instance closure develops without varying shortening along strike model map patterns resemble actual thrust related fold geometries and can be compared to maps of real structures to help predict subsurface geology

upper crustal basement involved folding in the east range of the sudbury basin ontario inferred from paleomagnetic data and spatial analysis of mafic dykes tilting of crystalline basement rocks associated with folding strain at uppermost crustal levels is difficult to recognize if basement rocks are devoid of traceable marker planes here we use the spatial variation in strike of paleoproterozoic mafic dyke segments complemented by compiled paleomagnetic data to identify tilting in archean basement rocks associated with kilometre scale folds of the eastern sudbury basin ontario spatial analysis of the strike of dyke segments is consistent with generation of the ne lobe and a newly identified anticline referred to as the west bay anticline in the layered sudbury igneous complex sic this anticline accounts better for the structural characteristics of the eastern sudbury basin than a previously proposed anticline with west plunging hinge line the west bay anticline is characterized by abrupt plan view thickness variations in the lower sic and curved faults displaying significant strike separations of sic contacts these structural characteristics are co

effects of spatial distribution of fault slip on calculating co seismic displacement case studies of the chi chi earthquake mw7 6 and the kunlun earthquake mw7 8 1 this study presents a segment summation scheme for calculating co seismic deformations caused by a seismic model with spatial distribution of fault slip the basic idea is to divide such a fault plane into limited sub faults so that the co seismic deformations caused by each sub fault can be evaluated by applying okada s formulation okada 1985 and summing up the individual contributions from the whole sub faults two case studies of the chi chi earthquake mw7 6 1999 and the kunlun earthquake mw7 8 2001 show that there exists a big discrepancy between the results calculated for the two dislocation models it implies that the mean dislocation model remarkably affect the calculating results the results of rms errors show that the co seismic displacements calculated by the fault with spatial distribution of fault slip improve the results by over 50 compared to the mean dislocation results

three dimensional geometry and interference of fault bend folds examples from the ponga unit variscan belt nw spain abstract examples of the three dimensional geometry and interference patterns between fault bend folds occur in the ponga unit of the variscan cantabrian foreland thrust and fold belt of nw spain the ponga unit consists of several e directed thrust sheets with a cumulative displacement of 93 km which were emplaced during upper westphalian stephanian time two major lateral ramps developed in the basal thrust of the ponga unit reaching 15 and 20 km in length respectively and some 3 km in height lateral structures are also common within the hangingwall thrust sheets the three dimensional staircase trajectories of thrust faults together with the tectonic superposition of thrust sheets has produced a complex interference pattern of fault related folds most map scale folds formed as fault bend folds related to interference between frontal and lateral ramps fold geometry and size varies depending on the geometry and size of the associated thrust ramp and flat the axial traces are grouped into lateral and frontal sets which are sub parallel or sub perpendicular to the tectonic transport direction respectively corner folds form with plunging axes at the intersections of frontal and lateral ramps and generally link pairs of frontal lateral folds they have relatively short axial traces that are oblique to the tectonic transport direction fold plunge varies due to the superposition of lateral and frontal structures of a thrust fault and also depends on the geometry of subsequent thrusts in the footwall the final geometry of frontal folds in the ponga unit are not only the result of the bending mechanism but have been modified by simple shear parallel to the emplacement direction major lateral structures have been reactivated as reverse faults and are locally overturned due to post emplacement north south compression

fold interference structures in thrust systems abstract the accommodation problems associated with the generation of interference folds in thrust belts are examined there are several ways in which interference folds may grow in thrust systems such as moulding on to non planar ramps or via the interaction of non coaxial structures the geometries of interference folds from thrust belts in spain and pakistan are described and form the basis of an analog model the model is used to quantify the volume of rock which must be accommodated during the growth of these structures mechanisms which might solve the inherent space problem are discussed the simplest geometrical solution would involve a mechanism which caused thickening in the fold hinges but this was not observed in the field field evidence is used to construct a linked fold and fault model which reconciles the absence of thickening in the interference fold hinge with the volume of material which must be accounted for

sliding thrusting tectonics caused by thermal uplift in the yunmeng mountains beijing china abstract a ductile shear zone analogous to a normal fault with a low dip angle occurs on the southeastern flank of the yunmeng anticlinorium north of beijing in huairou county the southeast dipping shuiyu ductile shear zone is composed of mylonitic granitic gneiss and has an average width of about 1 km the structures in the area show a symmetrical pattern this pattern may be generated by a process of sliding and thrusting caused by thermal uplift an alternative possible model for the area is that for the north american cordilleran regions

general formulations of global co seismic deformations caused by an arbitrary dislocation in a spherically symmetric earth model applicable to deformed earth surface and space fixed point summary based on the authors previous work co seismic deformations for a spherical symmetric earth model are summarized and reformulated unified expressions presented herein accommodate physical deformations displacement potential gravity geoid and strain changes the corresponding green s functions are derived by combining spheroidal and toroidal deformations sign errors in previous publications are corrected in these new formulas these expressions are developed basically for a deformed earth surface because most traditional geodetic measurements are performed on the terrain surface however through development of space geodetic techniques such as the satellite gravity missions co seismic gravity changes can be detected from space in this case the above dislocation theory e g the co seismic gravity change cannot be applied directly to the observed data because the data do not include surface crustal deformation the free air gravity change correspondingly the contribution by the vertical displacement part must be removed from the traditional expressions for this purpose we present the corresponding expressions applicable to space observations some numerical technical problems are discussed in addition a smoothing technique is necessary to damp the high frequency contribution so that the theory can be applied reasonably global co seismic deformations caused by the 2004 sumatra andaman earthquake m9 3 are studied as an application of the new green s function that earthquake caused a global deformation detected by gps strain metres and even a satellite gravity mission these global deformations are calculated based on the derived green s functions and the seismic wave derived earth model a segment summation scheme is used considering the slip distribution on a limited fault plane the results are useful for interpreting observed deformations especially those in the far field the earthquake reveals global co seismic deformations and effects of spherical curvature and the earth s layered structure comparisons between results for a spherical earth mode and a half space model show a large discrepancy at an epicentral distance of about 1000 km implying that effects of spherical curvature and layer structure are considerably large in addition the theoretical results are compared with the real observed strain steps horizontal displacements and gravity changes caused by that earthquake good agreement validates the results of the current theoretical work finally we discuss the application the above theory to the grace data through several case studies

the terminology of structures in thrust belts abstract a review of structures and geometric relationships recognized in thrust belts is presented a thrust is defined as any contractional fault a corollary being that thrusts must cut up section in their transport direction flats are those portions of a thrust surface which were parallel to an arbitrary datum surface at the time of displacement and ramps are those portions of thrusts which cut across datum surfaces ramps are classified on the basis of their orientation relative to the thrust transport direction and whether they are cut offs in the hangingwall or footwall of the thrust lateral variations in the form of staircase trajectories are joined by oblique or lateral ramps which have a component of strike slip movement an array of thrusts which diverge in their transport direction may form by either of two propagation models these are termed piggy back propagation which is foreland directed and overstep propagation which is opposed to the thrust transport direction an array of thrust surfaces is termed an imbricate stack and should these surfaces anastamose upwards a duplex will result the fault bounded blocks are termed horses a duplex is bounded by a higher roof thrust and a lower floor thrust the intersection of any two thrust planes is termed a branch line thrusts can be classified on the basis of their relationship to asymmetric fold limbs which they cut a further classification arises from whether a particular thrust lies in the hangingwall or footwall of another one the movement of thrust sheets over corrugated surfaces or the local development of thrust structures beneath will fold higher thrust sheets these folds are termed culminations and their limbs are termed culmination walls accommodation of this folding may require movement on surfaces within the hangingwall of the active thrust these accommodation surfaces are termed hangingwall detachments and they need not root down into the active thrust this category of detachment includes dip slip hangingwall drop faults which are developed by differential uplift of duplex roofs and out of the syncline thrusts which develop from overtightened fold hinges back thrusts as well as forming as hangingwall detachments may also form due to layer parallel shortening above a sticking thrust or by rotation of the hangingwall above a ramp

thrusting and duplex formation at mount isa queensland australia large scale repetition of mount isa and haslingden group rocks in the anticline north of mount isa is interpreted as the core of a thrust duplex which has been subsequently folded parallel to the direction of thrusting displacement of mount isa group rocks above the duplex is extremely significant to the regional geology and exploration for more mount isa style pb zn and cu orebodies interpretation of the geometry of the thrust belt indicates thrusting on different stratigraphical levels below and above the duplex during its formation horses formed from a heelwards protruding footwall ridge instead of a trough and the complex effects on stratigraphical cross sections through duplexes of sloping lateral footwall ramps on horses

three dimensional geometry strain rates and basement deformation mechanisms of thrust bend folding abstract models for thrust bend folding of an isotropic medium are used to predict initial basement thrust sheet geometries and sub surface thrust fault shapes from final basement thrust sheet structure predicted strains and strain rates from these models are compared with data on deformation fabrics in an example of a basement thrustbend fold in order to characterise the deformation response to thrust bend folding the glencoul thrust sheet in the moine thrust zone of north west scotland is restored to an initial thrust sheet geometry spatial and orientation distribution data of syn emplacement fractures and cataclastic fault zones from within the glencoul thrust sheet are then compared with the strain and strain rate histories predicted by thrust bend folding models a different set of cataclastic fault seams is demonstrated to have been generated at each frontal thrust bend cataclastic failure is restricted to portions of the thrust sheet that have moved over frontal bends with smaller radii of curvature from model thrust bend geometries and an assumed slip rate of 1 x 10 10 ms 1 estimated minimum critical strain rates required for fracture failure of the lewisian basement are 10 11 to 10 14 s 1 for shear strain rates and 10 12 to 10 15 s 1 for extensional strain rates

new paleomagnetic results from northern china collision and suturing with siberia and kazakhstan abstract we report new results from our paleomagnetic studies of the inner mongolia autonomous region in northeastern china and the xinjiang autonomous region in northwestern china primary magnetizations are isolated in tertiary cretaceous late jurassic and late permian rocks and secondary components of magnetization of late jurassic and recent ages are seen in strata of inner mongolia western junggar basin and part of the tarim block suffered widespread complete tectono thermal remagnetization at about 280 ma permian the paleomagnetic evidence suggests that the sampled areas in inner mongolia have been part of the north china block at least since late permian time and the junggar block collided with the tarim block by late permian time our own paleomagnetic results together with available data from other parts of eastern eurasia suggest a tectonic model in which kazakhstan europe and siberia collided with each other and formed the europe siberia kazakhstan plate eur sib kaz in late permian time to the east mongolia outer mongolia inner mongolia and the north china block were also wedged together forming the mongolia north china plate mon nc by this time these two composite continental plates were not a stable unit in the late permian the geometrical relationship of the paleomagnetic poles for these two plates suggests that collision initially occurred in the late permian near the western end 50 n 75 e of the southern siberian fold belt and progressed eastward as the mon nc plate rotated and clockwise about 117 relative to the eur sib kaz plate during the early mesozoic suturing and rotation were probably complete by the late jurassic significant relative motion between the tarim and siberia blocks continued from early triassic to late jurassic as tarim moved northeastward 1400 km relative to siberia

u pb dating of single detrital zircon grains from mesozoic sandstone in the beipiao basin in the eastern yan liao orogenic belt china provenance and correlation of tectonic evolution single grain u pb ages of sediments from the beipiao basin northeast china were conducted to determine the evolution of basin provenance zircons from a sandstone in the upper triassic laohugou formation yield a wide range of ages and according to their u pb ages fall into four groups 209 3 4 0 304 2 4 9 1565 5 71 2154 50 2400 35 2499 9 2512 11 2557 74 ma these ages indicate that the zircons were principally derived from late archean proterozoic and late paleozoic plutonic rocks intrusions in the mongolian accretion belt and the northern margin of the north china block ncb were probably the main source of the sediments in the basin but the easterly liaodong block also provided minor detrital material with lower u pb ages during the late triassic most of the u pb ages from zircons collected from a sandstone in the lower jurassic beipiao formation range from 194 3 2 9 to 233 8 4 2 ma reflecting the major sediment source during the early jurassic zircons derived from late indosinian plutonic rocks increased which suggests that the detritus was supplied mainly from the interior of the yan liao orogenic belt especially from the liaodong block late indosinian zircons 200 230 ma were eroded and deposited in the lower jurassic beipiao formation and this implies that intensive tectonic activation and uplift of the yan liao orogenic belt in the mesozoic commenced in the late indosinian c 2005 elsevier ltd all rights reserved

numerical simulation of time dependent beach and dune erosion a computational procedure is developed for predicting the time dependent two dimensional beach and dune erosion during severe storms due to elevated water levels and waves the model employs the equation of sediment continuity and a dynamic equation governing the cross shore sediment transport due to a disequilibrium of wave energy dissipation levels these equations are solved numerically by an implicit double sweep procedure to determine the change in position of elevation contours in the profile given sufficient time the profile will evolve to a form where the depth h in the surf zone is related to the distance seaward of the waterline by the relationship h ax23 which is consistent with many natural profiles and in which a depends on sediment characteristics the model is verified qualitatively and quantitatively through application to several idealized cases and through a preliminary simulation of erosion during hurricane eloise in general the time scales for shoreline response were found to be quite long relative to natural storm systems and erosion in the early response stages was found to be sensitive to storm surge height but much less sensitive to wave height the model response characteristics for simulation of erosion due to time varying storm conditions show a lag between the maximum storm surge elevation and maximum erosion with the maximum erosion rate occurring at the time of the peak surge for the simulated erosion due to hurricane eloise reasonable agreement was found between the post hurricane dune profiles and those calculated however the eroded volumes were in better agreement than the profile forms as the steepening of the natural dune profiles was not reproduced in the model

rupture segmentation and process of the 2001 mw 7 8 central kunlun china earthquake field investigations allow us to constrain the coseismic surface rupture zone of 400 km with a strike slip up to 16 3 m associated with the 2001 m w 7 8 central kunlun earthquake that occurred along one of the western segments of the kunlun fault northern tibet the rupture zone may be divided into four segments based on the geological structures tectonic landform features spatial displacement distributions obtained from field observations and analysis of teleseismic waveforms the deformational characteristics of the surface ruptures and focal mechanism solutions reveal that the earthquake had a nearly pure strike slip mechanism the inversion results from seismic data show that the rupture started from the west near the epicentral area bilaterally and rapidly extended to the east in an unilateral manner for 380 km and that the largest slip region was limited in the subsegment 150 280 km east of the epicenter consistent with field observations the average stress drop is estimated to be 7 mpa in the area where the largest displacements occurred a value typical of intraplate earthquakes the geologic evidence and the inversion results from seismic data clearly show that temporal and spatial displacement distributions and the rupture process are restricted by the pre existing geological structures of the kunlun fault

geological control of the eastern great wall mountain basin relationships in the eastern north china craton abstract the e w trending yanshan belt an intraplate fold thrust belt located in the northern north china craton has experienced several episodes of mesozoic deformation which resulted in the widely distributed magmatism and mountain basin tectonics that completely re shaped the topography of the eastern north china craton the eastern part of the famous chinese great wall was built on the high range of the southeastern yanshan mountain belt juxta posed to the plain which directly relates to the bohai bay basin our study focuses on which tectonic processes created such mountain basin couple in mid late mesozoic times the u pb la icp ms dating of zircons yield ages of 114 to 201 ma for various granites and 115 to 116 ma for volcanic rocks from yixian and jiufotang fms the detrital zircons from the lower cretaceous sandstones yield four age groups of 2587 to 2460 ma 2222 to 1828 ma 297 to 190 ma and 187 to 100 ma which are all sourced from the qinglong and surrounding areas and indicating that the qinglong area started to uplift after the middle jurassic the qinglong area underwent multiple deformation by ne sw compression in the middle late jurassic times wnw ese compression in the late jurassic to early cretaceous ene wsw extension in the early cretaceous and nnw sse compression in the late cretaceous during the final stage of the yanshanian orogeny meanwhile widely distributed granite intrusions and emplacement of the upper jurassic lower cretaceous volcanic rocks indicate a large amount of magma input into the area the qinglong area with the great wall along its southern margin close to adjacent plain to the south was uplifted to form the qinglong highland and surrounding related basins by combination of the following three processes the multiple tectonic late jurassic and late cretaceous shortening processes related to yanshanian orogeny early cretaceous regional extension triggered by slab retreat of the paleo pacific ocean and inflation of large amount magma at depth during jurassic and early cretaceous

kinematics around a large scale oblique ramp southern pyrenees spain the gavarnie thrust sheet of the southern pyrenees is bound to the east and west by 40 km long transverse zones producing a rectilinear thrust sheet within the boltana region the northwest corner of the gavarnie thrust sheet is well exposed the locale is used to characterize the strain and kinematic patterns and detailed geometry of an oblique ramp over a variety of scales the hanging wall of the gavarnie thrust fault in the area was transported toward 200 and contains two regional scale north south trending anticlines in the vicinity of the oblique ramp the strike of the gavarnie thrust fault and the trend of hanging wall fold axes are 0 180 the magnitude of shortening accommodated by regional scale fold and fault development is constant at 25 along the length of the ramp the orientation of instantaneous and finite shortening axes on meso and grain scales was inferred from the attitudes of cleavage mesoscale folds and faults carbonate mechanical twins and the geometry of finite strain finite and instantaneous shortening axes are subhorizontal and remain perpendicular to the gavarnie thrust ramp within a 10 km wide zone in the footwall and a 20 km wide zone in the hanging wall outside of the halo of footwall and hanging wall ramp deformation the principal shortening directions consistently trend 200 parallel to thrust transport directions throughout the south pyrenean thrust belt the parallelism of instantaneous and finite principal strain axes suggests that grain scale deformation was rionrotational total shortening measured within the footwall of the gavarnie thrust fault decreases from 60 adjacent to the thrust ramp to 10 approximately 10 km away from the ramp while principal shortening directions determined over scales ranging from millimeters to kilometers show a consistent pattern in the boltana region they differ by as much as 90 from tectonic convergence directions between iberia and eurasia during the alpine orogeny 80 18 ma determined from magnetic anomaly patterns in the central atlantic and bay of biscay divergence between plate convergence directions and alpine south pyrenean shortening directions suggests that 200 km of nw se convergence was apparently partitioned into the north and south pyrenean thrust zones which were shortened 167 km the iberian range which accomodated 30 km of shortening 10 km of shortening accomodated in the catalan coastal range and 100 km of right lateral strike slip accomodated within the internides

relation of dislocation love numbers and conventional love numbers and corresponding green s functions for a surface rupture in a spherical earth model summary this study was undertaken to complete the dislocation theory presented by sun et al for a spherical earth model with special treatment of coseismic deformations for a surface rupture the previous theory is valid only for inner sources but the coseismic deformations for a surface rupture source remain unsolved therefore this study deals with the special case of coseismic deformations for a surface rupture dislocation for this purpose we first derive the relation between the dislocation love numbers and the conventional love numbers that is the tidal press and shear love numbers based on the okubo reciprocity theorem then we derive the corresponding green s functions for coseismic displacement potential geoid gravity and strain changes using okubo asymptotic solutions finally we present numerical results of those green s functions for four independent seismic sources then we discuss the computation of coseismic deformations at the singular point epicentre as a case study the computations of the coseismic deformations caused by the 2011 tohoku oki earthquake mw 9 0 with considering the new green s functions as a constrain validates the theoretical model established in this study

co seismic strike slip and rupture length produced by the 2001 ms 8 1 central kunlun earthquake field investigations show that the surface wave magnitude ms 8 1 central kunlun earthquake tibetan plateau of 14 november 2001 produced a nearly 400 kilometer long surface rupture zone with as much as 16 3 meters of left lateral strike slip along the active kunlun fault in northern tibet the rupture length and maximum displacement are the largest among the co seismic surface rupture zones reported on so far the strike slip motion and the large rupture length generated by the earthquake indicate that the kunlun fault partitions its deformation into an eastward extrusion of tibet to accommodate the continuing penetration of the indian plate into the eurasian plate

sr nd isotopic and geochemical constraints on provenance of late paleozoic to early cretaceous sedimentary rocks in the western hills of beijing north china implications for the uplift of the northern north china craton late paleozoic to mesozoic strata which were deposited in the western hills of beijing north china recorded the contemporary tectonic evolution of the northern part of the north china craton ncc fine grained sandstones and siltstones of these strata were analyzed for their major and trace element concentrations and sr nd isotope compositions their la sc th sc la co th co and cr th ratios are similar to those of sediments derived from felsic source rocks indicating that the original source materials were mostly intermediate to acidic rocks their end 0 values show dramatic shifts implying changes in provenances from the late paleozoic to the early cretaceous the end 0 values of the late paleozoic and the late jurassic to early cretaceous formations are very low whereas the end 0 values of the xingshikou and the xiaoyaopo formations are much higher indicating that a juvenile component has been added into their sources based on the sr nd isotope compositions the late paleozoic and the late jurassic to early cretaceous samples fall in the paleozoic to mesozoic magmatic rocks distributed in the northern part of the ncc however the sr nd isotope compositions of the xingshikou and the xiayaopo formations vary between the xing meng orogenic belt xmob and the north part of the ncc components these changes can be interpreted by the complex uplift and exhumation history of the northern ncc from the late paleozoic to the early cretaceous during the late carboniferous the uplift of the inner mongolia paleo uplift impu which probably commenced at the late carboniferous might supply detrital materials to the late paleozoic strata in the late triassic the uplift of the xmob and impu was responsible for the mixing source of the xingshikou formation after that the northern xmob became the main source of the xiayaopo formation resulting from the uplift of the xmob due to the collision of siberia and north china mongolia plates during the middle to late jurassic finally the uplift of the yftb which occurred from the late jurassic to early cretaceous provided the source materials and blocked the input of the xmob components

sedimentary basins formed and carried piggyback on active thrust sheets small sedimentary basins that formed on the apennine southern margin of the po basin complex northern italy have been studied using borehole and seismic reflection information and their evolution can be dated using the largely marine biostratigraphy of the miocene to quaternary sediments these studies show that the basins formed and were filled while being carried on moving thrust sheets and they are therefore named piggyback basins each of these basins corresponds to the active phase of a different thrust front ramp on the pyrenean northern margin of the ebro basin complex northern spain similar piggyback basins formed between eocene and mid miocene time they have since been uplifted and eroded and may therefore be studied in outcrop in northern spain much of the basin fill sediment was deposited in nonmarine environments

laramide basement deformation in an evolving stress field bighorn mountain front five springs area wyoming discussion new road cuts of u s route 14a along the western flank of the bighorn mountains of wyoming create nearly continuous outcrops through the edge of a laramide uplift exposed granitic basement in the range front area is divided into three large differentially rotated blocks separated by shattered poorly exposed zones within each of these rotated blocks are three populations of faults 1 an early set of dominantly strike slip faults at high angles to the front with either polish or smearing of hematite epidote and or chlorite 2 a slightly younger set of faults with mostly similar motion and mineralization but no smear or polish and 3 a young set composed mostly of thrust faults marked by gouge and pervasive shattering stress tensor analysis on these three fault populations shows that maximum compressive stress sigma 1 acted n25e s25w normal to the local range front but changed plunge with time in the early buckling stages sigma 1 plunged at about 30 degrees in both directions away from the future buckle subsequently sigma 1 assumed a relatively uniform 30 degrees plunge into the range presumably as a result of reduced resistance to buckling finally under extremely brittle conditions associated with regional uplift and erosion sigma 1 assumed a relatively flat plunge through the rotating blocks the exposures support models of basement folding by subhorizontally driven tectonic forces creating an early buckle zone that expanded into a small number of rotated blocks with subsequent bea bag like minor reshaping of the rotating blocks by many small faults

basement balancing of rocky mountain foreland uplifts restorable cross sections of foreland basement uplifts must contain faults whose curvatures are consistent with the relative slip and tilt between adjacent basement blocks cylindrical fault surfaces can explain the uniform dip of strata on the back side of foreland uplifts local zones of shortening and extension occur in hinge zones above transitions in fault curvature high curvature fault splays form fault wedges of basement which ease the transition from thrust and reverse faulting of basement blocks to folding in the sedimentary cover 20 references 4 figures

comparison of fault models of the 2008 wenchuan earthquake ms8 0 and spatial distributions of co seismic deformations article i nfo a proper slip fault model and a reasonable dislocation theory are necessary to compute and investigate co seismic deformations caused by the 2008 wenchuan earthquake ms8 0 to find such a model several comparisons are made of different dislocation theories seismic fault models and earth models results indicate that the fault model determined by combining gps and seismic waveform data is the best the spherical dislocation theory yields better results than that of a half space theory and the results obtained from a revised prem earth model are better than those from prem according to results of earlier investigations co seismic deformations such as the displacement geoid gravity and strain changes caused by the 2008 wenchuan earthquake ms8 0 are computed described and discussed results show that the earthquake generated considerable co seismic deformation in a large area around the epicenter the modeled deformations are applicable as a reference for other researchers to study inter structural inversion crustal deformation etc the effects of the curvature and layer structure are great moreover spherical dislocation theory is necessary for studying co seismic deformations caused by a large event

precambrian basement structure and laramide deformation revealed by seismic reflection profiling in the laramie mountains wyoming the university of wyoming conducted seismic reflection profiling in the laramie mountains of wyoming to investigate the nature of precambrian crustal structure and laramide deformation in the region here the imaging of layering in the laramie anorthosite complex confirms that layered intrusions can be reflective and establishes an analog for interpreting events in other seismic reflection data sets where layered intrusions could be the cause of multicyclic events moreover the presence of prominent primary layering in the complex supports a conclusion that it formed in situ and not as the result of the emplacement of a diapiric crystal mush imaging of laramide thrusts in the laramie mountains adds credence to the idea that brittle faults can be reflective in some situations migrated apparent dips on these faults are 30 westward basement involved compressive structures consisting of monoclinal folding and a fault triple junction demonstrate that compression controlled the style of deformation during the laramide orogen in wyoming west dipping precambrian structures imaged in these data have a similar attitude to the laramide structures suggesting that laramide deformation was influenced by precambrian features these precambrian structures may be subthrust slices of exotic proterozoic terranes

kinematics and timing of continental block deformation from margins to interiors during the deformation of continental blocks the magnitude of tectonic stress generally decreases with increasing distance from the margin of the block however the timing and kinematics of stress transmission from the margins to the interiors of continents are poorly resolved even though this information is critical to our understanding of the dynamics of continental deformation here we present a case study of mesozoic deformation of the north china craton ncc field investigations of mesozoic thrust faults and folds granitic intrusions and dykes combined with zircon shrimp and la icp ms dating and muscovite 40ar 39ar plateau ages reveal the age of the ne sw trending tectonic belts as 180 155 ma where the deformation of the craton margin occurred 10 20 ma earlier than that of the craton s interior although the kinematics of deformation are similar for the interior and the margin of the ncc strain decreases with increasing distance from the margin notably the bulk of the strain in the cratonic interior was focused in zones of pre existing weakness overall we determined that the ncc deformed under conditions of uniaxial compression a conclusion that is compatible with simple rheological models and that the stress magnitude attained in the cratonic interior was much less than that along its margin

geometric and kinematic evolution of basement cored structures intraplate orogenesis within the yanshan orogen northern china abstract detailed surface mapping lithology facies analysis drillcore data and aeromagnetic interpretation reveal the geometries of the basement involved structures of laowopu nantan liudaohe xinglong and malanyu to have been generated by folding and thrusting the resulting basement cored anticlines are asymmetric with a shallowly dipping top and backlimb and a steep to overturned forelimb and or frontal fault linked with a gently dipping synclinal limb both the fold axes and frontal faults trend roughly east west suggesting north south shortening north to northeast trending faults behave as tear lateral or oblique ramp structures and formed coevally with their frontal faults their trends may have been inherited from proterozoic synsedimentary faults and archaean basement ductile shear zones foliations and mafic dikes thin skinned thrusts and their three dimensional geometry are locally controlled by detachment within mechanically incompetent layers four types of interrelationships between the thick and thin skinned structures occur including 1 lateral changes along the length of a fault 2 displacement transfer between thick and thin skinned structures 3 buttressing of thin skinned thrusts against the basement involved structures and 4 generation of an out of the syncline thrust under thick skinned shortening most of the deformation within the study area involved brittle behaviour but ductile shear zones developed where fluid access was possible both the basement involved structures and the thin skinned structures formed in the early mesozoic as constrained by cross cutting relationships isotopic ages of igneous rock and syntectonic basins the model of geometric and kinematic evolution of the basement involved structures and their relationship with the thin skinned structures defined in this paper provides an alternative to the current metamorphic core complex model used for the yanshan intraplate orogen

geometry and kinematic evolution of passive roof duplexes deduced from cross section balancing example from the foreland thrust system of the southern bolivian subandean zone the subandean zone of bolivia is a foreland fold and thrust belt which forms the eastern edge of the central andes mountains between 19 s and 22 s latitude the construction of five balanced cross sections shows that the n s trending subandean zone is characterized by the existence of passive roof duplexes these complex structures can be distinguished by the lithotectonic unit within which duplexing occurs the five balanced cross sections permit the geometric and kinematic analyses of these passive roof duplexes the sequential restorations of certain cross sections reveal a possible development of a piggy back sequence of three passive roof duplexes apparently these passive roof duplexes propagated toward the foreland from deeper and deeper lithotectonic units while a passive roof duplex was developing the sole thrust stuck and the major horizontal displacements were then transferred either to out of sequence thrusts or to a new sole thrust in a deeper detachment horizon therefore each passive roof duplex would correspond to the orogenic front of the andean range at one very particular time in the history of the subandean zone of southern bolivia from south to north the quantitative analysis by cross section balancing shows a transfer of displacement from the hinterland structures to the passive roof duplex that forms the present orogenic front available data do not permit us to explain completely this phenomenom

source process of the chi chi earthquake a joint inversion of strong motion data and global positioning system data with a multifault model the chi chi taiwan earthquake of 21 september 1999 was a large thrust earthquake that caused disastrous damage the surface fracture trace runs along the chelungpu fault which strikes n5 e along most of the faulting area but turns to the northeast while approaching its northern end it finally presents a horsetaillike faulting system and bends to an east northeast direction at the northern end both strong motion and global positioning system gps data recorded large displace ments in the northern part in this study we use a multifault model to simulate the observed large strong motion and gps data the results of the joint inversion reveal that in the southern part slip occurred mainly in the shallow portion reaching a maximum about 20 m on the ene fault where the rupture propagated to the deep part of the fault there was obviously slip vector rotation from south to north such that the slip on the branched fault plane was almost purely reverse faulting the seismic moment a total of 2 7 10 20 n m was released in less than 40 sec during the mainshock aftershocks occurred mainly in areas where little or no slip occurred slip vector rotation can be explained by the complexity of regional tectonic stress changes in tectonic stress at the northern end of the fault inhibited the northward propagation of the rupture and favored the rupturing of the ene fault