fluid inclusion and stable isotope study of yulekenhalasu copper molybdenum deposit in northern margin of junggar xinjiang the yulekenhalasu medium size porphyry copper molybdenum deposit occurs in the diorite porphyry with some mineralization also observed in the porphyroid biotite quartz monzonite and volcanic rocks of the beitashan formation mineralization occurs as veinlets veinlet disseminations and stockworks wall rock alteration is well developed and mainly comprises k feldspathization biotitization quartzification sericitization magnetitization gypsification chloritization and epidotization according to cutting relationships of the ore veins mineral assemblages paragenetic sequence and ore fabrics the ore forming process can be divided into three metallogenic periods porphyry shear deformation and supergene periods the sulfides k silicate stage and the molybdenite stage in the porphyry period constituted the main stages for copper mineralization and molybdenum mineralization respectively two types of fluid inclusions namely h2o nacl and h2o co2 ch4 n2 nacl types have been recognized in quartz and calcite homogenization temperatures of fluid inclusions in the sulfides k silicate stage vary from 141 to 500 concentrated from 200 to 340 salinity w nacleq ranges from 2 96 to 14 97 ore fluid densities range from 0 60 to 0 98 g cm3 fluids of the carbonate stage are characterized by medium low temperatures 140 to 320 and low salinities 2 74 to 10 61 34s values of sulfides associated with mineralization range from 4 5 to 0 1 with the peak being 3 5 indicating that sulfur was derived from deep seated magma 18osmow values of quartz and calcite range from 9 1 to 13 2 with the corresponding 18oh2o values between 2 05 and 6 28 and d values of fluid inclusions vary between 120 and 97 the combined isotopic data imply that the ore forming fluids of the sulfides k silicate stage in the yulekenhalasu cu mo deposit were mainly derived from magmatic fluids with a minor part from the meteoric water and the fluids of the carbonate stage were mainly derived from the meteoric water with a minor part from magmatic fluids cu mo mineralization in yulekenhalasu took place in middle devonian 373 9 2 2 ma related to the diorite porphyry the decrease of temperature and pressure the boiling of local ore forming fluid the water rock exchange and the compositional variation of ore fluids played important roles in ore forming processes of the cu mo ore bodies

characteristics and profile asymmetry properties of waves breaking over an impermeable submerged reef abstract in the present study a 3d two phase flow cfd model that solves the unsteady incompressible reynolds averaged navier stokes equations has been used to simulate breaking waves over an impermeable submerged reef the level set method is used to capture the complex free surface and the turbulence is described by the k turbulence model the numerical model was evaluated by comparing the computed results with the experimental data by blenkinsopp and chaplin 2008 and the computed results are in good agreement with the measured data the computed results over the submerged reef clearly depict the flow features associated with the breaking process such as the complex interface deformation the formation of the plunger vortex and the downstream vortex the splash up phenomenon and the movement of the enclosed air pocket the main aim of the study was to investigate the effect of the offshore wave steepness and the water depth above the reef crest on the characteristics and the profile asymmetric properties of waves breaking over a submerged reef the computed results suggest that the water depth over the reef crest affects the prominent characteristics of waves breaking over a reef such as breaker type water depth at breaking breaker indices and geometric properties

contrasting styles of mineralization in the chinese altai and east junggar nw china implications for the accretionary history of the southern altaids abstract the chinese altai east junggar collage in the southern altaids hosts three metallogenic belts which are from north to south 1 a volcanogenic massive sulphide vms cu pb zn belt 2 a belt of shear zone related gold deposits 3 a porphyry cu au mo belt the vms deposits formed in two pulses c 405 ma and c 375 ma in the chinese altai arc the porphyry deposits developed in three pulses in the east junggar arc the first two synchronous with the vms mineralization and the third at c 330 ma the shear zone related gold deposits developed in the late carboniferous to permian at the contact between the chinese altai and east junggar arcs time space distributions of diverse ore deposits across the altai east junggar collage indicate that the collage developed from two independent arcs the chinese altai and the east junggar the vms and porphyry deposits developed in the chinese altai and east junggar arcs respectively the chinese altai arc is interpreted to be a japanese type arc and the east junggar arc a mariana type arc during the latest palaeozoic the two arcs were juxtaposed by the erqis fault when many shear zone related lode gold deposits were emplaced these metallogenic distributions were a likely response to spatially localized mechanisms of crust growth and to the tectonic evolution of the altai east junggar collage and they are consistent with interpretation of the altaids as a multiple subduction accretion collage

mo deposits in northwest china geology geochemistry geochronology and tectonic setting abstract northwest china covering northern xinjiang northern gansu and westernmost inner mongolia mainly includes junggar basin and its surrounding mountains such as chinese altay junggar chinese tianshan and beishan it lies at the junction of siberia tarim and kazakhstan plates and is a key sector of the central asian orogenic belt caob characterized by multistage phanerozoic continental growth herein at least nine mo only or mo dominated fourteen cu mo two w mo and one be mo deposits have been discovered these 27 deposits occur in altay west jungar west tianshan east tianshan and beishan areas and have been formed during accretionary or collisional orogenies the majority of the deposits are porphyry type followed by the skarn and quartz vein types the orebodies occur mainly as veins lens pods in the positions from inner intrusions through contact zones to the hostrocks distal to causative intrusions the host rocks are variable in lithologies including granites porphyries volcanic breccias and tuffs and sedimentary rocks outward from orebodies to hostrocks the wallrock alteration is zoning from potassic k feldspar quartz mica through phyllic quartz sericite chlorite epidote to propylitic or argillic alterations with skarn specifically occurring in skarn type systems hydrothermal mineralization generally includes four stages from early to late represented by 1 potassic feldspar quartz veins or veinlets 2 quartz molybdenite stockworks 3 quartz polymetallic sulfide stockworks and 4 quartz carbonate fluorite veins or veinlets the ore forming fluids were initially magmatic in origin and shew high temperature and high salinity containing daughter mineral and or co2 bearing fluid inclusions and eventually evolved to low temperature low pressure low salinity and co2 poor meteoric water the porphyry mo deposits can be further subdivided into two subtypes i e dabie and endako types the endako type mo deposits e g suyunhe and hongyuan together with all the cu mo systems were formed in the palaeozoic subduction related magmatic arcs the dabie type porphyry mo deposits represented by giant donggebi and baishan together with the mo only mo dominated and w mo or be mo deposits were formed in syn to post collisional tectonic setting with isotope ages ranging 260 213 2 ma with the kumutage skarn type mo system being an exception aged 319 ma the dabie type porphyry mo deposits are characterized by the co2 bearing fluid inclusions that cannot be observed in the endako type porphyry mo systems the re contents in molybdenites from porphyry and porphyry skarn cu mo systems are mainly 100 ppm suggesting a source significantly contributed by the mantle whereas the re contents in molybdenites from the mo only or w mo deposits are mainly

remote sensing of breaking wave phase speeds with application to non linear depth inversions abstract a number of existing models for surface wave phase speeds linear and non linear breaking and non breaking waves are reviewed and tested against phase speed data from a large scale laboratory experiment the results of these tests are utilized in the context of assessing the potential improvement gained by incorporating wave non linearity in phase speed based depth inversions the analysis is focused on the surf zone where depth inversion accuracies are known to degrade significantly the collected data includes very high resolution remote sensing video and surface elevation records from fixed in situ wave gages wave phase speeds are extracted from the remote sensing data using a feature tracking technique and local wave amplitudes are determined from the wave gage records and used for comparisons to non linear phase speed models and for non linear depth inversions a series of five different regular wave conditions with a range of non linearity and dispersion characteristics are analyzed and results show that a composite dispersion relation which includes both non linearity and dispersion effects best matches the observed phase speeds across the domain and hence improves surf zone depth estimation via depth inversions incorporating non linearity into the phase speed model reduces errors to o 10 which is a level previously found for depth inversions with small amplitude waves in intermediate water depths using linear dispersion considering the controlled conditions and extensive ground truth this appears to be a practical limit for phase speed based depth inversions finally a phase speed sensitivity analysis is performed that indicates that typical nearshore sand bars should be resolvable using phase speed depth inversions however increasing wave steepness degrades the sensitivity of this inversion method

s wave velocity structure of sediments in anchorage alaska estimated with array measurements of microtremors the array measurements of microtremors were carried out at nine sites to estimate the subsurface s wave velocity structures of the sedimentary deposits beneath the metropolitan area of anchorage alaska the data were recorded by ten three component accelerometers arranged in a triangular manner for three different array sizes the phase velocities c f were estimated at each site from the vertical component of the recorded microtremor data by using the frequency wavenumber technique the c f data from different arrays were combined after checking their consistency for a series of overlapped frequency bands from different arrays and were inverted using a stochastic least squares inversion technique to estimate the 1d structure underneath each site the inversion results show that the engineering basement 750 m sec lies at a relatively shallower depth 40 m in the eastern part of the basin along the foothills of the chugach mountains cm and at deeper depths toward the southcentral 100 m and western 150 m parts of the basin in accord with the general dip of the basin below the engineering basement a well developed low velocity zone lvz with values in the range of 900 1040 m sec is found to be present in the eastern as well as along the knik arm side in the western part of the basin at a depth of 200 m and 900 m respectively moreover the central part of the basin is associated with a weakly developed lvz below the engineering basement depth in the rest of the basin the value increases gradually with depth the spatial variations of in the basin at different depths from 20 to 500 m are represented by using 2d interpolation of the structures obtained from the inversion of c f data the depth to the crystalline basement of the basin however could not be ascertained and it seems to be much deeper than the maximum depth 2000 m resolved by the data gathered in this study to validate the results of inversion the spectral ratio between the horizontal and vertical components h v of the recorded microtremor data at each site has been compared with the computed h v of rayleigh waves based on the respective structure the results showed good agreement in the frequency range of about 0 4 6 0 hz in this frequency range the h v peaks are due to the overall effect of the velocity contrasts between layers representing the subsurface structure

delineation of spatial variation of shear wave velocity with high frequency rayleigh waves in anchorage alaska high frequency rayleigh waves were generated in the frequency range of about 1 100 hz by an electromagnetic vibrator in co operation with the vibration instrument company japan and the ensol corporation north carolina at 36 sites in anchorage from phase delay times between two sensors the phase velocity of the fundamental mode at each site was computed these data were inverted in terms of shear wave velocity structure by a stochastic inversion scheme of the 36 sites values of shear wave velocity as a function of depth were available at seven sites from downhole measurements at these sites the comparison of the results obtained by others between surface and downhole measurements showed reasonable agreement these results were therefore combined with those of the remaining 29 sites obtained in this study the structure of the 36 sites could be subdivided into four groups on the basis of nehrp provision and from the time averaged structures for the uppermost 30 m corresponding to the four groups it has been possible to identify the lateral extent of soil classes c and d in the anchorage area from statistical analysis of the time averaged data it is shown that the lithology of the area in soil class c is distinct from that in d the same is true for the subunits namely glaciofluvial deposits in areas of c and d moreover the areas in soil class d along the knik arm in west anchorage with relatively low values coincide with the areas of high ground failure susceptibility identified by others from observations following the prince william sound earthquake mw 9 2 of 1964

remote sensing of wave roller lengths in the laboratory 1 the optical intensity signals from surf zone waves in a laboratory flume are analyzed using several different phase averaging techniques and a methodology is developed for estimating wave roller lengths and local wave dissipation the intensity signals i e phase averaged intensity profiles of individual breaking waves are compared with the wave profiles measured by in situ wave gauges and the optical signal of the wave roller is shown to ramp up from the toe of the wave roller on the front face of the wave to a maximum intensity at the wave crest the remote sensing observations capture the growth equilibrium and decay phases of the roller as it propagates over a fixed bed arranged in a bar trough morphology next for the regular wave conditions considered here the local maxima of the phase averaged intensities are shown to better indicate the initial onset of wave breaking and the occurrence of wave breaking in the bar trough as compared to the more commonly used time averaged mean intensity in addition the phase averaged profiles are used to measure the size of the roller and these measurements are compared to previous observations of smaller scale rollers in equilibrium the observed roller lengths are shown to agree with predictions from a wave roller model and to provide a new physical link between the remotely sensed signal and roller dissipation finally as an example application of these new data a simple wave height inversion model is presented that allows an estimation of surf zone wave heights from the remotely sensed roller lengths

effects of wave rollers and bottom stress on wave setup 1 setup the increase in the mean water level associated with breaking waves observed between the shoreline and about 6 m water depth on an ocean beach is predicted well by a model that includes the effects of wave rollers and the bottom stress owing to the mean flow over the 90 day observational period the measured and modeled setups are correlated squared correlation above 0 59 and agree within about 30 although rollers may affect setup significantly on beaches with large amplitude several meters high sandbars and may be important in predicting the details of the cross shore profile of setup for the data discussed here rollers have only a small effect on the amount of setup conversely bottom stress calculated using eddy viscosity and undertow formulations based on the surface dissipation and assuming that the eddy viscosity is uniform throughout the water column significantly affects setup predictions neglecting bottom stress results in underprediction of the observed setup in all water depths with maximum underprediction near the shoreline where the observed setup is largest

magmatic sequences in the halasu cu belt nw china trigger for the paleozoic porphyry cu mineralization in the chinese altay east junggar abstract the halasu porphyry copper belt situated in the east junggar is one of the major porphyry copper belts in xinjiang uygur autonomous region northwest china copper and molybdenum mineralization occurs as disseminated sulfides or veinlets mainly in granodiorite porphyry and diorite porphyry with the intense development of zoned alteration from potassic through sericitic to an outer zone of propylitic alteration new la icp ms zircon u pb dating reveals that magmatism in the belt can be divided into three periods during the middle devonian and early carboniferous namely the pre mineralization stage of 390 ma syn mineralization stage of 382 372 ma and post mineralization stage of 350 320 ma the syn mineralization intrusions are calc alkaline whereas pre and post mineralization intrusions are shoshonitic and high k calc alkaline the syn mineralization intrusions are enriched in highly incompatible trace elements but depleted in nb ta hf and ti relative to the pre and post mineralization intrusions zircon trace elements analyses demonstrate a negative correlation between ti in zircon temperatures and oxygen fugacity ore bearing syn mineralization granitoids are characterized by higher water content oxygen fugacity and low temperatures with higher mineralization potential than pre and post mineralization ones these characteristics together with the geochemical signature of the intrusions suggest that the ore bearing porphyries are derived from relative high h2o magma reservoir the remarkably homogeneous hf isotopic compositions ehf t 8 to 13 from syn mineralization intrusions span over 10 m y suggesting the existence of a long lived reservoir beneath halasu belt during the middle devonian all the intrusions have low initial 87sr 86sr values 0 703935 to 0 707172 high end t values 4 7 to 5 5 and young crustal model ages 650 to 750 ma combined with the mantle derived pb isotope characteristics the sr nd hf data suggest that the parental magma was probably derived from flat subduction triggered partial melting of juvenile crust generated during subduction accretionary process with no significant input of old crust whereas pre mineralization and post mineralization intrusions are supposed to emplaced in immature island arc setting and post orogenic setting respectively

ground motion in anchorage alaska from the 2002 denali fault earthquake site response and displacement pulses data from the 2002 denali fault earthquake recorded at 26 sites in and near anchorage alaska show a number of systematic features important in studies of site response and in constructing long period spectra for use in earthquake engi neering the data demonstrate that national earthquake hazards reduction program nehrp site classes are a useful way of grouping stations according to site ampli fication in general the sites underlain by lower shear wave velocities have higher amplification the amplification on nehrp class d sites exceeds a factor of 2 relative to an average of motions on class c sites the amplifications are period dependent they are in rough agreement with those from previous studies but the new data show that the amplifications extend to at least 10 sec periods longer than considered in previous studies at periods longer than about 14 sec all sites have motion of similar amplitude and the ground displacements are similar in shape polarization and am plitude for all stations the displacement ground motion is dominated by a series of four pulses which are associated with the three subevents identified in inversion studies the first pulse is composed of p waves from the first subevent most of the high frequency ground motion is associated with the s waves from subevent 1 the pulses from subevents 1 and 2 with moment releases corresponding to m 7 1 and 7 0 are similar to the pulse of displacement radiated by the m 7 1 hector mine earthquake the signature from the largest subevent m 7 6 is more subdued than those from the first two subevents the two largest pulses produce response spectra with peaks at a period of about 15 sec the spectral shape at long periods is in good agreement with the recent 2003 nehrp code spectra but is in poor agreement with the shape obtained from eurocode 8

paragenesis and fluid evolution of the halasu iii porphyry cu deposit east junggar nw china implications for the paleozoic multiphase superimposing mineralization in the central asian orogenic belt abstract the halasu iii deposit an important cu deposit in the southernmost part of the halasu porphyry cu belt is situated in the east junggar block in nw china copper and mo sulfide mineralization commonly occurs as disseminations or veinlets and is mainly associated with devonian granodiorite porphyry our detailed field geological investigation identified late stage high grade cu sulfide bearing veining superimposed on the earlier porphyry cu mo mineralization four hydrothermal alteration and mineralization stages were identified namely the early epidote alteration stage i porphyry style alterations stage ii comprising ii a potassic ii b propylitic and ii c phyllic alteration sub stages late veining stage iii and supergene processes stage iv in the northern and southern mineralization zones at halasu iii multiphase granodiorite and alkali granite dykes intruded the beitashan formation volcanic rocks generating the early epidote alteration potassic alteration stage ii a occurred in and around the nnw treading granodiorite dykes while the propylitic alteration stage ii b occurred in the intrusions or volcanic wall rocks around the potassic zone these early alteration assemblages were overprinted by the subsequent structurally controlled phyllic alteration stage ii c confined within the granodiorite porphyry late veins stage iii include sulfide bearing stage iii a and sulfide barren stage iii b ones supergene process stage iv represented by hematite and jarosite replacing primary sulfides extends tens of meters down depth and is commonly fracture controlled three fluid inclusion fi types were recognized namely type a single phase b liquid vapor two phase and c liquid vapor solid three phase for type b fis those of potassic alteration homogenized at 183 347 c with corresponding salinities of 6 2 17 8 wt nacl equiv the propylitic and phyllic fis homogenized at 172 425 c and 231 352 c respectively with the corresponding salinities of 0 9 14 0 wt nacl equiv and 0 4 10 5 wt nacl equiv the sulfide bearing vein fis homogenized at 243 410 c stage iii a 1 260 362 c stage iii a 2 and 117 235 c stage iii a 3 along with the corresponding salinities of 1 9 9 2 wt nacl equiv 1 1 6 7 wt nacl equiv and 6 5 17 1 wt nacl equiv respectively the sulfide barren vein fis yielded homogenization temperatures of 260 380 c stage iii b 1 and 114 297 c stage iii b 2 with corresponding salinities of 1 7 9 8 wt nacl equiv and 0 2 13 6 wt nacl equiv respectively we suggest that hydrothermal veins at halasu iii may have undergone complex and superimposing alteration due to the episodic reopening of the preexisting veins with stage iii a 3 veining overprinting the phyllic alteration and stage iii a 2 veining stage iii b 2 veining superimposed on the potassic alteration as well as on stages iii a 1 and iii b 1 veining paragenetic sequence and fluid evolution at halasu iii indicate that these complex hydrothermal alteration stages were formed in accordance with the regional tectonic evolution these various alteration and mineralization stages at halasu iii deposit reveal a prolonged history of magmatic and hydrothermal processes extending episodically from the middle devonian to middle permian wherein early mineralization was overprinted by late hydrothermal events such superimposed mineralization may occur commonly in the paleozoic central asia orogenic belt

multiple mineralization events of the paleozoic tuwu porphyry copper deposit eastern tianshan evidence from geology fluid inclusions sulfur isotopes and geochronology the tuwu porphyry cu deposit located in eastern tianshan nw china is hosted by a plagiogranite porphyry and carboniferous qi eshan group volcanic rocks based on crosscutting relationships and mineral assemblages hydrothermal alteration and mineralization processes at tuwu can be divided into four stages early propylitic alteration stage i porphyry mineralization stage ii overprinting mineralization stage iii and post mineralization stage iv the porphyry mineralization stage stage ii contributed to the majority of the cu mo resource with cu mineralization occurring mainly as quartz chalcopyrite veins stage iii also produced minor cu mineralization characterized by chalcopyrite anhydrite chlorite calcite assemblages fluid inclusion fi study reveals that stage ii is characterized by a high temperature high salinity highly oxidized and k rich h2o nacl cacl2 fluid fluid boiling and mixing likely occurred during the porphyry mineralization stage leading to the precipitation of chalcopyrite and pyrite alteration and mineralization in stage iii were derived from a s rich h2o nacl cacl fluid with fluid boiling leading to the precipitation of chalcopyrite the 34s values of chalcopyrite from stages ii and iii are 0 8 0 6 and 1 1 1 3 respectively suggesting magmatic sources for the ore forming components of both stages 40ar 39ar dating indicates that stage ii likely occurred at 328 1 1 4 ma around the age emplacement of the causative plagiogranite porphyry ca 337 7 330 3 ma we suggest the overprinting mineralization event occurred at ca 323 ma spatially and genetically related to the emplacement of the quartz albite porphyry at 323 6 2 5 ma

parameterization of nearshore wave front slope abstract this study presents an empirical parameterization of wave front slope angle used in the characterization of shoaling and breaking waves in nearshore environment a large amount of experimental datasets is analyzed for determining possible values of the wave front slope angles results indicate that the slope angle increases with wave shoaling and decreases when wave breaks for the data used here the maximum slope angle is around 0 8 rad at the breakpoint two empirical formulas developed based on data analysis establish relationships between the wave front slope angle and other parameters of engineering interest specifically the first formula expresses the local wave front slope angle as a function of the local wave parameters the applicability of this formula to regular and random shoaling and breaking waves is verified using extensive datasets the second formula defines the critical wave front slope angle for wave breaking as a function of the relative water depth and bed slope this formula is shown applicable to both the first and second breakpoints for regular wave breaking over sloping and barred beaches a combination of these two formulas provides estimates of the incipient breaking wave heights which are in good agreement with independent experimental data

modeling the alongshore current on barred beaches mean alongshore currents observed on two barred beaches are compared with predictions based on the one dimensional time and depth averaged alongshore momentum balance between forcing by breaking waves wind and 10 100 km scale alongshore surface slopes bottom stress and lateral mixing the observations span 500 hours at egmond netherlands and 1000 hours at duck north carolina and include a wide range of conditions with maximum mean currents of 1 4 m s including rollers in the wave forcing results in improved predictions of the observed alongshore current structure by shifting the predicted velocity maxima shoreward and increasing the velocity in the bar trough compared with model predictions without rollers for these data wave forcing balances the bottom stress within the surfzone with the other terms of secondary importance the good agreement between observations and predictions implies that the one dimensional assumption holds for the range of conditions examined despite the presence of small alongshore bathymetric nonuniformities with stronger bathymetric variations the model skill deteriorates particularly in the bar trough consistent with earlier modeling and laboratory studies

estimation of strong ground motion from the great 1964 mw 9 2 prince william sound alaska earthquake we are generating physically plausible near field synthetic ground motions for the great 1964 prince william sound alaska earthquake compatible with available seismological data tectonic information and eyewitness accounts the first objective of this study is the simulation of the low frequency i e f 0 03 hz strong ground motions on selected locations and on a dense grid of observation points extending over the shallow dipping causative fault of the 1964 alaska earthquake in order to accomplish this task we are utilizing the slip model proposed by johnson et al 1996 based on a joint inversion of tsunami waveforms and geodetic data the calculations are carried out using the discrete wavenumber representation method bouchon and aki 1977 bouchon 1979 and the generalized transmission and reflection coefficient technique luco and apsel 1983 the second objective of this study is the reconstruction of the strong ground motion time histories and response spectra that the city of anchorage experienced during the 1964 alaska earthquake the low frequency i e f 0 03 hz ground motions are generated using the methodology described previously the intermediate frequency i e 0 03 f 0 50 hz ground motions are simulated by convolving green s functions generated by the discrete wavenumber representation method with far field radiation pulses of circular cracks sato and hirasawa 1973 dong and papageorgiou 2002a the high frequency i e 0 5 f 8 0 hz ground motions are simulated using the stochastic modeling approach the three independently derived ground motion components are then properly combined to generate synthetic broadband ground motion time histories and response spectra for the city of anchorage due to the 1964 prince william sound earthquake the third objective of this study is the validation of the synthetic strong ground motions for the 1964 alaska earthquake against observed tectonic deformation ground motion estimates inferred from descriptions of structural damage and eyewitness accounts in summary the analysis presented in this study contributes to a better understanding of the seismological aspects of the 1964 alaska earthquake and provides synthetic time histories and response spectra for engineering applications compatible with all available information i e seismological tectonic and eyewitness accounts it should be noted however that the generated strong ground motions are not necessarily unique nor do they reflect the entire uncertainty that characterizes the problem under investigation

parameterization and simulation of near bed orbital velocities under irregular waves in shallow water a set of empirical formulations is derived that describe important wave properties in shallow water as functions of commonly used parameters such as wave height wave period local water depth and local bed slope these wave properties include time varying near bed orbital velocities and statistical properties such as the distribution of wave height and wave period empirical expressions of characteristic wave parameters are derived on the basis of extensive analysis of field data using recently developed evolutionary algorithms the field data covered a wide range of wave conditions though there were few conditions with wave periods greater than 15 s comparison with field measurements showed good agreement both on a time scale of a single wave period as well as time averaged velocity moments

three dimensional imaging of shear wave velocity in the uppermost 30 m of the soil column in anchorage alaska summary the main aim of this paper is to obtain an overall view of the shear wave velocity structure of the anchorage metropolitan area and to analyse in detail the extent of various soils types both laterally and vertically for this purpose a stochastic scheme has been used to invert the rayleigh wave phase velocity data to obtain 1 d shear wave velocity structure in the uppermost 0 30 m at 36 sites in the anchorage basin located in south central alaska on the basis of these 1 d velocity models we have applied an imaging technique aimed at volumetric modelling and data visualization based on an interpolation algorithm involving finite differences we present a 3 d representation of the s wave velocity structure of the anchorage area obtained through spatial prediction these velocity images are shown as horizontal slices at gradually increasing depths vertical cross sections at various latitudes and longitudes and 3 d blocks as defined by characteristic velocity ranges they enable us to understand in detail the different soil classes by their characteristic shear wave velocities the images are in good agreement with the available geological information about the area

stability of phlogopite in granitic melts an experimental investigation water saturated and water undersaturated experiments ah2o 1 0 and 0 5 were performed in the temperature range 780 1040 c at 2 and 5 kbar in order to determine the upper thermal stability of phlogopite in granitic melts starting compositions were a subaluminous mixtures of 20 wt synthetic phlogopite and 80 wt synthetic anhydrous haplogranitic glass b peraluminous mixtures normative corundum 4 of 20 wt synthetic phlogopite and 80 wt synthetic anhydrous peraluminous haplogranitic glass the molar quartz albite orthoclase ratio of the glasses of the 2 kbar runs was 35 39 26 and that of the 5 kbar runs 30 42 28 in the subaluminous system phlogopite is stable up to 820 c at ah2o 1 0 and up to 780 c at ah2o 0 5 at higher temperatures it is replaced by enstatite in the peraluminous system phlogopite has a remarkably higher thermal stability up to 1000 c at 5 kbar and ah2o 1 0 and there is a temperature interval of 80 c at ah2o 1 0 and 90 100 c at ah2o 0 5 between the first appearance of enstatite and the disappearance of phlogopite in the peraluminous system phlogopite is a solid solution ss of phlogopite muscovite talc and eastonite components the crystalline product of the phlogopitess breakdown reaction is an aluminous enstatite the mgo content of the melt depends on the normative corundum content of the starting material and the run temperature it is independent of pressure in the subaluminous system the mgo content ranges between 0 05 and 0 3 wt in the temperature interval 780 880 c at both investigated water activities the mgo content of the peraluminous melts at ah2o 1 0 ranges between 0 4 and 1 7 wt and at ah2o 0 5 between 0 2 and 1 4 wt in the temperature range 780 980 c

the western central asian orogenic belt a window to accretionary orogenesis and continental growth abstract the architecture of accretionary orogens is a key to understand continental growth here we present an overview of the orogenic components and their amalgamation in the western central asian orogenic belt caob the caob records the convergence and interactions among various types of orogenic components including the japan type mariana type and alaska aleutian type arc systems as well as the active marginal sequences of the siberia craton which incorporated wide accretionary complexes and accreted arcs and terranes during construction of the caob the kazakhstan arc chain was characterized by multiple subduction whereas the northern fringe of the tarim craton remained mostly as a passive margin the multiple convergence and accretions among these various orogenic components generated huge orogenic collages in the late paleozoic and even in the early triassic involving parallel amalgamation circum microcontinent amalgamation and oroclinal bending the preservation of trapped basins played a significant role in orogenesis with some parts of the oceanic plate being subducted and others behaving as rigid units the orogenesis in the caob was long lived lasting for more than 800 m y involving multiple subduction and long continuous accretion and featuring the complexity of accretionary orogenesis and continent growth

vertical flow structure during sandy duck observations and modeling abstract observations of the vertical distribution of time averaged cross shore and alongshore flows during the sandy duck field experiment are compared with model predictions to assess the parameters governing the flow behaviour the measurements were obtained with a vertical stack of eight two component current meters with the lowest and highest sensor at respectively o 0 1 and o 2 7 m above the bed observations under breaking wave conditions within the surfzone show that the maximum return flow velocities occur in the lower part of the water column consistent with laboratory observations under non breaking conditions outside the surfzone the maximum return flow velocities are observed closer to the water surface again in line with laboratory results analogous to previous observations the measured longshore current velocity profiles are logarithmic under non breaking conditions and become more depth uniform under breaking conditions the model description of the vertical structure of the flow includes the presence of wind stresses wave stresses pressure gradients turbulent eddy viscosity and a wave boundary layer the model utilizes parabolic shape functions to describe the vertical distribution of the turbulent eddy viscosity in the middle layer and within the bottom boundary layer eddy viscosity is enhanced in regions where turbulence is produced i e near the surface in the case of breaking waves and within the bottom boundary layer estimates of the wave breaking induced turbulent eddy viscosity and bottom friction are obtained by minimizing the model measurement discrepancies predictions utilizing calibrated expressions for both the turbulent eddy viscosity and bottom friction are in general agreement with the observations provided the wave transformation and associated mass flux are modeled correctly and a parabolic eddy viscosity distribution is used using a piecewise constant eddy viscosity distribution generally results in a degrading of the agreement between measurements and model results

petrogenesis of early carboniferous adakitic dikes sawur region northern west junggar nw china implications for geodynamic evolution abstract adakitic dikes are widespread in the sawur region northern west junggar northwestern china zircon u pb analyses of the dikes have yielded consistent ages of ca 334 ma the dikes are characterized by relatively high sio 2 55 5 61 8 wt al 2 o 3 14 5 16 3 wt and sr 468 1005 ppm and low y 10 1 14 1 ppm and yb 0 93 1 39 ppm contents with high sr y 34 74 ratios and slight eu anomalies which are analogous to those of slab derived adakites in addition the dikes are relatively mgo rich 1 75 3 57 wt mg 44 56 with high th yb ratios and positive end 334 ma 6 2 to 6 5 and ehf 334 ma 11 3 to 15 8 values the data suggest that the dikes were generated by partial melting of subducted oceanic crust and overlying sediments however these early carboniferous adakitic rocks and associated i type granites in the northern part of west junggar are petrochemically distinct from the late carboniferous adakitic plutons from the southern part of west junggar the latter are associated with charnockites a type granites tholeiites and nb enriched alkaline basalts as well as magnesian dikes which were generated by ridge subduction during the late carboniferous the distinct lithological association of the early carboniferous adakites is consistent with flat slab subduction which was characterized by anomalous heating of the slab and consequential partial melting to generate adakitic magma after generation of the early carboniferous adakites the subducting slab cooled reverted to a more normal subduction angle in the late early carboniferous and was associated with more typical i type granite arc magmatism

a boussinesq model for waves breaking in shallow water abstract a simple description of wave breaking in shallow water is incorporated in the boussinesq equations by using the concept of surface rollers the roller is considered as a volume of water being carried by the wave with the wave celerity the effect of the roller is included in the vertical distribution of the horizontal velocity which leads to an additional convective momentum term the breaking criterion is related to the local slope of water surface and the thickness of the roller is determined from simple geometrical considerations although the model is simple it is capable of representing a variety of processes such as the initiation and cessation of wave breaking the evolution of wave profiles before during and after wave breaking the initial conversion of potential energy into forward momentum flux and the associated horizontal shift between the break point and the point where the setup in mean water level is initiated results are presented for regular and irregular wave trains and comparison with measurements shows good agreement

a laboratory study of longshore currents over barred and non barred beaches abstract a detailed description is given of the results of laboratory experiments on wave driven longshore currents on both barred and non barred beaches the objective is to examine the cross shore distribution of the longshore current velocities for purely wave driven currents with emphasis on the position of maximum current velocity with respect to areas where wave energy is dissipated unidirectional obliquely incident waves both regular and random were used the measurements were performed in a large wave basin with a pump recirculation system to create spatially homogeneous longshore currents the experiments yielded information on wave transformation set up of the mean water level and the cross shore distribution of wave driven longshore current velocity a number of cases are presented and compared with each other the measurements show that in the case of purely wave driven longshore currents the maximum current velocities occur close to areas where wave breaking is most intense the effect of mixing bottom friction and wave rollers on the longshore current velocity profile are examined in more detail with help of numerical modelling existing model equations based on the assumption of alongshore uniformity are used the results for the mean longshore current profile on a barred beach are in close agreement with the measurements

estimation of earthquake source parameters and site response in anchorage alaska from strong motion network data using generalized inversion method abstract generalized inversion of the s wave amplitude spectra from the strong motion network data in anchorage alaska has been analyzed to estimate simultaneously source parameters site response sr and the s wave attenuation qs 1 the data represented 60 earthquakes of magnitudes ml from 3 0 to 6 3 in the hypocentral distance range from 30 to 300 km the source term obtained from inversion was analyzed to estimate various source parameters namely seismic moment mo seismic energy es corner frequency fc apparent stress a and brune s stress drop for each event it is shown that mo and es varies from 1014 to 2 1 1018 n m and form 5 8 108 to 0 8 1014 j respectively while varies from 0 2 to 24 mpa the regressional analysis of the source parameters shows the following 1 es mo is approximately equal to 1 2 10 5 and 2 mo is proportional to fc 3 it is also shown that a and approximately satisfies the relation a 0 23 the sr values obtained for the anchorage basin from the above inversion were averaged for two frequency bands 0 5 2 5 and 3 0 6 3 hz with geometric center frequencies of about 1 0 and 5 0 hz respectively the spatial variation of sr at 1 0 hz shows a gradual increase from 1 0 along the foothills of chugach mountains to 3 5 in the western part of the basin at 5 0 hz the trend of the variation of sr values is from north to south moreover at 1 0 hz the above trend of sr values is in agreement with that of shear wave velocity of the uppermost 30 m of the sedimentary formations of the basin the variation of qs 1 in the region is found to be 0 0066f 1 2 in the frequency range from 0 25 to 20 hz

nd sr isotopic mapping of the chinese altai and implications for continental growth in the central asian orogenic belt article i nfo the chinese altai orogen is a typical domain of the central asian orogenic belt and in previous syntheses was divided into six tectonic units or terranes in this paper 41 new and 36 published whole rock nd and sr isotopic data for granitoid intrusions and mafic dykes within units 2 and 3 of the central altai and units 4 to 6 of the southern altai were used for isotopic mapping the age of the samples used is known from u pb zircon dating end t values range from 4 to 2 in the central altai units 2 and 3 and from 1 4 to 6 in the southern altai units 4 and 5 and up to 8 4 in unit 6 correspondingly nd model ages tdm decrease from 1 6 1 1 ga in the central altai to 1 0 0 5 ga in the southern altai except for a continental fragment in unit 4 isr is elevated in the central units decreasing to b0 705 in the southern units 5 and 6 these results demonstrate that the central altai contains widespread old crustal components in its basement whereas the southern altai comprises a higher proportion of juvenile crust when integrated with published u pb zircon ages our data show that new crust grew southwards in the chinese altai in addition our data suggest that units 2 and 3 are a single tectonic unit whereas the southern altai unit 4 which previously was regarded as a single young accretionary terrane should be subdivided into two units a younger arc and an older continental fragment the granitoids in the chinese altai can be divided into syn and post non orogenic groups the syn orogenic granitoids have ca 50 80 mantle derived component whereas the post non orogenic granitoids contain ca 70 90 the generation of syn and post non orogenic granitoids represents horizontal lateral and vertical crustal growth which contributed ca 18 28 and 7 8 respectively to the area of the chinese altai this work shows that isotopic mapping is an effective approach to elucidate terrane composition in the central asian orogenic belt and thereby better constrain palaeozoic crustal growth

a new breaking wave height direct estimator from video imagery breaker height is a key parameter of nearshore processes and the demand for a continuous remote estimator is pressing in this paper we present a standalone remote video based method that estimates wave height at the breakpoint individual breaking events are first identified from changes in optical properties and wave height is further derived from the optical signature at the onset of breaking an extended validation is performed using a dense wave basin dataset the results show the ability of the method to measure individual breaker heights 9 of mean error 18 rms in addition the unique combination of in situ and remotely sensed data allows the estimation of two other breaking related parameters the height to depth ratio and wave front face slope which show a substantial amount of dispersion because nearshore video systems are rapidly spreading over world coasts this low cost remote breaker height estimator should encounter large interest in coastal engineering studies

accretionary orogenesis of the chinese altai insights from paleozoic granitoids zircon u pb dating and whole rock major oxide trace element and nd sr isotope compositions have been determined for four representative granitic intrusions in the sw chinese altai in order to understand the orogenesis and history of crustal growth in the central asian orogenic belt caob the ashile and halatas bodiesare relatively small intrusions formed in the late carboniferous 318 6ma andpermian 267 4ma respectively thelargertarlang tb andkeketuohaibatholiths kb havemagmaticagesof 359 to 412 ma the granitoids consist chiefly of tonalite granodiorite and granite and are metaluminous to weakly peraluminous in composition asi 0 8 1 1 the ashile pluton is characterized by relatively high mgo 2 73 3 54 wt and sr 395 456 ppm contents with low k2o na2o ratios 0 31 0 42 and mantle like nd sr isotopic compositions endt 2 85 to 3 26 initial 87 sr 86 sr 0 7047 0 7051 it probably formed by fractional crystallization of a mantle derived magma with limited assimilation of oldcrustalmaterial theotherintrusionshavenear zeroornegative endtvalues 0 67to 4 41 andhighersrisotopiccompositions initial 87 sr 86 sr 0 7067 0 7092 indicating a mixture of juvenile and old components in their genesis these intrusions are characterized by relatively low k rb cs contents and low rb sr ratios mostly b0 6 and generally exhibit moderate to high heavy rare earth element hree concentrations ybn 8 26 and weak hree fractionation dy ybnb1 5 with or without negative europium anomalies eu eu 0 5 1 0 these characteristics are consistent with an origin by dehydration melting of a hornblendebearing mid crustal source above the garnet stability field dominated by mafic to intermediate rocks this suggests that the deep crust of the chinese altai may contain a considerable proportion of juvenile material mantle derived magmatism probably in an active extensional continental margin setting played an important role in the formation of the chinese altai acting not only as a heat sourceforcrustalmeltingbutasasourceofjuvenilecomponents therelativelysmallvolumesanddistinctgeochemicalcompositions of the ashile and halatas plutons may imply a substantial change in the geodynamic setting in the late paleozoic 2007 elsevier b v all rights reserved

laboratory study on wave induced setup and wave driven current in a 2dh reef lagoon channel system abstract the nearshore wave action at many barrier reefs or reef atolls can generate wave setup and drive a 2dh reef lagoon channel circulation previous laboratory studies on such reef lagoon channel system focused mainly on the 1dh wave flume experiments without considering the alongshore wave dynamics to better understand the wave induced setup and wave driven current in a reef lagoon channel system a series of laboratory experiments are conducted in a wave basin based on an idealized physical model subject to both regular and irregular waves both the cross shore and alongshore variations of wave setup and mean current are analyzed and the influences of incident wave height wave period and reef flat water level on these wave processes are examined a dimensionless analysis of both wave setup and mean current on the reef flat is conducted and the results are compared with other published laboratory data a quasi 2dh analytical model is improved by incorporating the alongshore wave dynamics in the lagoon to reproduce the present experimental observation the dominant circulation pattern in the system is identified with the analytical model

the effect of relative crest submergence on wave breaking over submerged slopes experiments were performed in a wave flume to measure the intensity transmission and reflection of waves breaking over a submerged reef with an offshore gradient of 1 10 the results demonstrate that the relative water depth over the reef crest hc ho is a dominant factor affecting the breaking characteristics in particular it is found that as the relative crest submergence is reduced there is a considerable increase in the intensity of wave breaking over the reef that can be quantified through measurements of the air cavity enclosed beneath the plunging jet it is also shown that there is a corresponding decrease in wave transmission and reflection as the submergence is reduced

modelling study of wave damping over a sandy and a silty bed abstract laboratory experiments have been carried out to investigate wave damping over the seabed in which the excess pore pressure and free surface elevations are synchronously measured for examining the wave induced soil dynamics and wave kinematics two types of soil namely fine sand and silt are tested to examine the role of soil in the wave damping observation of experiments shows that i soil liquefaction takes place for some tests with silty bed and soil particles suspend into the water layer when the bed is made of silt ii sand ripples can be generated for experiments with sand bed measurements reveal that the wave damping greatly depends on the soil dynamic responses to wave loading and the wave damping mechanism over the silty seabed differs from that over the sand bed on the one hand the wave damping rate is greatly increased when soil liquefaction occurs in the silty bed on the other hand the presence of sand ripples generated by oscillatory flow in the sand bed experiments also increases the wave damping to some extent furthermore experimental results show that soil particle suspension in the silt bed test contributes to the wave damping theoretical analysis is presented to enhance discussions on the wave damping the theoretical calculations demonstrate that the wave damping is mainly induced by the shear stress in the boundary layer for the cases when no liquefaction occurs while for the cases when soil liquefaction takes place the viscous flow in the liquefied layer contributes most towards to the wave damping

investigation of shallow sedimentary structure of the anchorage basin alaska using simulated annealing inversion of site response abstract this study deals with shallow sedimentary structure of the anchorage basin in alaska for this purpose inversion of site response sr f data in the frequency range 0 5 11 0 hz from various sites of the basin has been performed using the simulated annealing method to compute subsurface layer thickness shear wave velocity density and shear wave quality factor the one dimensional 1d models for the aforementioned parameters were obtained with preset bounds on the basis of available geological information such that the l 2 norm error between the observed and computed site response attained a global minimum next the spatial distribution of the important parameter was obtained by interpolating values yielded by the 1d models the results indicate the presence of three distinct velocity zones as the source of spatial variation of sr f in the anchorage basin in the uppermost part of the basin the values of fine grain quaternary sediments mainly lie in the range of 180 500 m sec with thickness varying from 15 to 50 m this formation overlies relatively thick 80 200 m coarse grain quaternary sediments with values in the range of 600 900 m sec these two quaternary units are in turn overlain on tertiary sediments with 1000 m sec located at depths of 100 and 250 m respectively in the central and western side along the knik arm parts of the basin the important implication of the result is that the sources of spatial variation of sr f in the anchorage basin for the frequency band 0 5 11 hz besides in the uppermost 30 m are found to be deeper than this depth thus use of commonly considered geological formations in the depth intervals from 0 to 30 m for the ground motion interpretation will likely yield erroneous results in the anchorage basin

genesis of post collisional granitoids and basement nature of the junggar terrane nw china nd sr isotope and trace element evidence the post collisional magmatism of the junggar terrane is characterized by intrusion of large amounts of granitoids and minor basic ultrabasic rocks the granitoids comprise two magmatic suites calc alkaline and alkaline which were emplaced contemporaneously at about 294 ma the calc alkaline rocks are typically sodium rich na2o k2o 1 1 3 5 and metaluminous a nk 1 0 a cnk 0 78 1 04 they show mildly fractionated ree patterns la yb n 15 and spidergrams with strong depletion of nb ti and to a lesser extent sr the alkaline granites have high contents of sio2 75 78 alkalis nb hree y sn f and high feo mgo ratios and huge sr and eu depletion in the spidergrams moreover they display characteristic tetrad ree patterns and non charac trace element behaviour the two rock suites have similar initial nd and sr isotopic compositions with end t in the range 5 2 to 7 1 and isr mostly in the range 0 7031 0 7041 this points to a predominance of juvenile components in their sources the calc alkaline rocks are most probably derived by dehydration melting of a basic lower crust leaving behind a granulite residue the process was probably triggered by underplating of mantle derived basic magmas in an extensional regime the alkaline granites are considered to have formed by differentiation of the calc alkaline granitoids our study argues for a juvenile continental crust for the basement of the junggar terrane which is likely dominated by early paleozoic oceanic crust and arc complex that were deeply buried during the late paleozoic subduction and accretion

relocation of earthquakes in the cook inlet area south central alaska using the joint hypocenter determination method abstract the joint hypocenter determination jhd method was used to relocate 1604 earthquakes that occurred during 1988 to 1993 in the wadati benioff zone wbz beneath the cook inlet in south central alaska the study utilizes both p and s wave arrivals recorded by a recently improved regional seismic network and it provides an improvement over previous studies the jhd locations of the events allowed improved delineation of the geometry of the subducted slab and the detection of a double seismic zone within the wbz in the 40 to 100 km depth range the jhd station corrections obtained correlate with the major surface geological features in the study area slow velocity sedimentary basins as well as with crustal and mantle structure high velocity subducting slab and low velocity anomalies beneath the active volcanoes to investigate the dependence of the jhd relocation procedure on factors such as the hypocentral depths of the events used the velocity model the p s ratio and random and systematic errors in travel time readings synthetic travel times were calculated using an exact raytracing technique a three dimensional tomographic p wave velocity model the present network configuration and the actual seismicity distribution then the synthetic events were located with the jhd algorithm the synthetic experiments showed that the jhd procedure is rather insensitive to the choice of plane layered velocity model and p s ratio preserves relative hypocenter locations well and can handle systematic and large random reading errors effectively

determination of s wave site response in anchorage alaska in the 1 9 hz frequency band site response was estimated at 19 sites in the anchorage basin in south central alaska using 15 local earthquakes recorded with good signal to noise ratio by a temporary weak motion network the receiver function type horizontal to vertical spectral ratios hvsr were computed at 1 9 hz frequency band and the resulting hvsr contour maps at 1 5 and 9 hz are presented here the spatial site response distribution shows considerable variation from the foothills of the chugach mountains in the east to the western part of anchorage the site response increases by a factor of 3 and 3 5 at 1 and 5 hz respectively from the area of older glacial deposits in the eastern part of the city to the area occupied by the bootlegger cove formation particularly in the section adjoining knik arm at 9 hz the variation of hvsr from the east to the west is smaller approximately by a factor of 2 moreover the trend of the hvsr variation at 1 and 5 hz shows good correlation with that of the soil class obtained from surface measurements of s wave velocity in the 0 30 m depth range and available results on ground failure susceptibility of anchorage

can slab melting be caused by flat subduction slab melting has been suggested as a likely source of adakitic arc magmas i e andesitic and dacitic magmas strongly depleted in y and heavy rare earth elements existing numerical and petrologic models however restrict partial melting to very young 5 ma oceanic crust typically at 60 80 km depth paradoxically most of the known pliocene quaternary adakite occurrences are related to subduction of 10 45 ma lithosphere which should not be able to melt under normal subduction zone thermal gradients we propose an unusual mode of subduction known as flat subduction occurring in 10 of the world s convergent margins that can produce the temperature and pressure conditions necessary for fusion of moderately old oceanic crust of the 10 known flat subduction regions worldwide eight are linked to present or recent 6 ma occurrences of adakitic magmas observations from chile ecuador and costa rica suggest a three stage evolution 1 steep subduction produces a narrow calc alkaline arc typically 300 km from the trench above the asthenospheric wedge 2 once flat subduction begins the lower plate travels several hundred kilometers at nearly the same depth thus remaining in a pressure temperature window allowing slab melting over this broad distance and 3 once flat subduction continues for several million years the asthenospheric wedge disappears and a volcanic gap results as in modern day central chile or peru the proposed hypothesis which reconciles thermal models with geochemical observations has broad implications for the study of arc magmatism and for the thermal evolution of convergent margins

surf zone dynamics simulated by a boussinesq type model part i model description and cross shore motion of regular waves abstract this is the first of three papers on the modelling of various types of surf zone phenomena in this first paper part i the model is presented and its basic features are studied for the case of regular waves the model is based on two dimensional equations of the boussinesq type and it features improved linear dispersion characteristics possibility of wave breaking and a moving boundary at the shoreline the moving shoreline is treated numerically by replacing the solid beach by a permeable beach characterized by an extremely small porosity run up of nonbreaking waves is verified against the analytical solution for nonlinear shallow water waves the inclusion of wave breaking is based on the surface roller concept for spilling breakers using a geometrical determination of the instantaneous roller thickness at each point and modelling the effect of wave breaking by an additional convective momentum term this is a function of the local wave celerity which is determined interactively the model is applied to cross shore motions of regular waves including various types of breaking on plane sloping beaches and over submerged bars model results comprise time series of surface elevations and the spatial variation of phase averaged quantities such as the wave height the crest and trough elevations the mean water level and the depth averaged undertow comparisons with physical experiments are presented the phaseaveraged balance of the individual terms in the momentum and energy equation is determined by time integration and quantities such as the cross sectional roller area the radiation stress the energy flux and the energy dissipation are studied and discussed with reference to conventional phase averaged wave models the companion papers present cross shore motions of breaking irregular waves swash oscillations and surf beats part ii and nearshore circulations induced by breaking of unidirectional and multidirectional waves part iii

estimation of s wave site response in anchorage alaska from weak motion data using generalized inversion method the generalized data inversion method has been used to estimate the spatial variation of site response sr in the anchorage basin in south central alaska the data analyzed represents weak motion of the horizontal components of s waves for local earthquakes they were recorded by a temporary portable 22 station network iris passcal equipment that was operated for about six months setting the path effect from independent sources the inversion of the data was carried out to determine sr the sr values thus obtained were averaged logarithmically for two frequency bands namely a low frequency band lfb and a high frequency band hfb from 0 5 to 2 5 hz and 3 0 to 7 0 hz respectively with center frequencies of about 1 0 hz and 5 0 hz in lfb sr increases from 1 0 along the foothills of chugach mountains in the east to about 3 5 in the west in and around campbell lake and government hill the areas with sr 3 0 are associated with extensive ground failure during the prince william sound earthquake m w 9 2 of 1964 in hfb there are two small areas adjoining tumagain arm in the southern side of anchorage with sr greater than 3 0 a comparison of the sr values obtained from the inversion with those reported by others for standard spectral ratio ssr and horizontal to vertical spectral ratio hvr showed 1 1 correspondence with the values of ssr but larger hvr values by a factor of about 2 areas of soil class d in the study area are characterized by sr 2 0 while those in c are characterized by sr 2 0 in lfb but soil class and sr lack correlation in hfb

postsubduction porphyry cu au and epithermal au deposits products of remelting of subduction modified lithosphere porphyry cu mo au and some epithermal au deposits are formed from hydrothermal fluids exsolved from cooling water rich calc alkaline magmas emplaced in volcanoplutonic arcs above subduction zones these magmas originate by partial melting of the metasomatized asthenospheric mantle wedge however there is increasing evidence for the existence of a suite of porphyry cu au and epithermal au deposits related to magmas generated after subduction beneath the arc has ceased associated magmas tend to be mildly alkaline relatively sulfur poor and emplaced as isolated complexes rather than in voluminous volcanoplutonic arcs they are likely formed by remelting of previously subduction modified arc lithosphere triggered by postsubduction lithospheric thickening lithospheric extension or mantle lithosphere delamination metasomatized mantle lithosphere or hydrous lower crustal cumulates residual from first stage arc magmatism contain small amounts of chalcophile and siderophile element rich sulfides and constitute a fertile source for hydrous au rich but relatively sulfur poor magmas during later remelting the recognition that porphyry cu au and related epithermal au systems can also form in postsubduction and collisional tectonic settings expands the range of geological environments and geographical terranes that are prospective for such deposits

breaking characteristics and geometric properties of spilling breakers over slopes abstract a two phase flow cfd model based on the reynolds averaged navier stokes rans equations coupled with the level set method lsm and k turbulence model is used to simulate spilling breakers over a sloping bed in order to validate the present numerical model the simulated results are compared with the experimental data measured by ting and kirby 1996 the simulated horizontal velocities and free surface elevations are in good agreement with the experimental measurements moreover the present model is able to model the prominent features associated with the breaking process such as the motion of air pockets in the water formation of a forward moving jet the splash up phenomenon and the mixing of air and water in the breaking region the numerical model has been utilized to study the influences of three important environmental parameters water depth offshore wave steepness and beach slope on the characteristics and geometric properties of spilling breakers over slopes a total of 39 numerical experiment cases are performed to investigate the characteristics of breaking waves such as breaking location incipient breaker height and water depth at breaking incipient breaker indices and geometric properties with different offshore wave steepnesses at different water depths over a wide range of beach slopes the geometric properties associated with breaking waves in shallow water are described using the wave steepness and asymmetry factors introduced by kjeldsen and myrhaug 1978 the computed results appear to give reasonable predictions and consistency with previous studies

predictions of shear wave velocities in southern california using surface geology a new model of the average shear wave velocity in the uppermost 30 m has been generated by extrapolation of discrete velocity profiles using surface geology at several scales statistical methods have been applied to create a map that is no more complicated than is supported by the velocity data several geologic units with similar responses are grouped together the resulting map is simpler than previous ones and yet fits the observed velocity profiles better than earlier more complicated maps analysis within a geographic information system will permit updates and modification of the map as new velocity data are added

petrology of the chilliwack batholith north cascades washington generation of calc alkaline granitoids by melting of mafic lower crust with variable water fugacity calc alkaline granitoid rocks of the oligocene pliocene chilliwack batholith north cascades range from quartz diorites to granites 57 78 sio2 and are coeval with small gabbroic stocks modeling of major element trace element and isotopic data for granitoid and mafic rocks suggests that 1 the granitoids were derived from amphibolitic lower crust having ree rare earth element and sr nd isotopic characteristics of the exposed gabbros 2 lithologic diversity among the granitoids is primarily the result of variable water fugacity during melting the main effect of fh 2 o variation is to change the relative proportions of plagioclase and amphibole in the residuum the ree data for intermediate granitoids quartz diorite granodiorite eu eu 0 84 0 50 are modeled by melting with fh 2 o 1 kbar leaving a plagioclase pyroxene residuum in contrast data for leucocratic granitoids leuco granodiorites and granites eu eu 1 0 0 54 require residual amphibole in the source and are modeled by melting with fh 2 o 2 3 kbar consistent with this model isotopic data for the granitoids show no systematic variation with rock type 87sr 86sri 0 7033 0 7043 end 0 3 3 to 5 5 and overlap significantly with data for the gabbroic rocks 87sr 86sri 0 7034 0 7040 end 0 3 3 to 6 9 the fh 2 o variations during melting may reflect additions of h2o to the lower crust from crystallizing basaltic magmas having a range of h2o contents chillwack gabbros document the existence of such basalts one dimensional conductive heat transfer calculations indicate that underplating of basaltic magmas can provide the heat required for large scale melting of amphibolitic lower crust provided that ambient wallrock temperatures exceed 800 c based on lithologic and geochemical similarities this model may be applicable to other cordilleran batholiths

video imaged surf zone wave and roller structures and flow fields 1 the measurement of mean water levels roller geometries and phase ensemble averaged velocity and turbulence intensity fields under spilling and plunging waves breaking in a two dimensional laboratory surf zone is presented the velocities were measured using digital correlation image velocimetry while water levels and roller geometries were determined through gray scale filtering of video images the phase ensemble averaged horizontal and vertical components of velocity and turbulence intensities are measured throughout the entire flow domain including the wave roller area by utilizing the aerated areas as part of the flow structure the time averaged horizontal velocities undertow turbulence intensities and turbulent kinetic energies are determined by averaging across the wave phase turbulence magnitudes are found to compare favorably with existing laser doppler anemometry measurements below the wave trough level where such measurements have generally been confined because of aeration contamination effects the significantly higher velocity and turbulence intensity magnitudes measured above the trough level in the present experiments highlight the novel nature of the present investigation for describing flow regimes in the surf zone