surface rupture during the 2010 mw 7 1 darfield canterbury earthquake implications for fault rupture dynamics and seismic hazard analysis the september 2010 m w 7 1 darfield canterbury earthquake in new zealand is one of the best recorded earthquakes of this magnitude the earthquake occurred on a previously unidentified fault system and generated a 29 5 0 5 km long surface rupture across a low relief agricultural landscape high accuracy measurements of coseismic displacements were obtained at over 100 localities along the greendale fault maximum net displacement d max 5 3 0 5 m and average net displacement d avg 2 5 0 1 m are anomalously large for an earthquake of this m w d max surface rupture length srl and d avg srl ratios are among the largest ever recorded for a continental strike slip earthquake geologically derived estimates of moment magnitude m w g are less than the seismologically derived m w derived using widely employed srl m w scaling regressions m w g is greater than m w using d max and d avg m w regressions the geologically derived static stress drop of 13 9 3 7 mpa provides a context with which to compare this earthquake rupture to interplate and intraplate ruptures of similar m w this data set provides fundamental information on fault rupture processes relevant to seismic hazard modeling in this region and analogous settings globally

strong vertical mixing in the urup strait 1 microstructure measurements were conducted in one of the kuril straits in the summer of 2007 over the course of 1 day of repeated observations across the pacific side of the steep sill of the urup strait extremely strong mixing was observed during periods of pacific ward down sill flows and during the transition from pacific ward to okhotsk ward up sill flows with a turbulent energy dissipation rate of 10 6 to 10 5 w kg 1 and vertical diffusivity of 10 1 to 5 10 1 m2 s 1 during the period of strong mixing we observed homogeneous layers with a thickness of 300 600 m and potential density of 26 6 26 7 occupying the entire water column in one case high values of within this layer indicate the injection of diapycnal flows from the upper and lower layers possibly contributing to southward intrusion of intermediate water into the subtropical gyre

investigation on the characteristics of overlying strata caving in the chengchao iron mine china in this study a comprehensive assessment of the overlying strata caving characteristics of mental mines is conducted for the non pillar sublevel caving method especially considering the geological features and rock mass characteristics in general the overlying strata caving process can be divided into four stages the intermittent roof caving stage the crack extension and surface subsidence stage the karst collapse stage and the mining induced collapse stage roof caving is an intermittent process with higher caving occurring in stronger rock masses and occurs more easily in weaker rock masses due to gaps generated in the overlying rock mass the bulking coefficient of the overlying strata is much greater than the laboratory measured value it also varies with the mining advance lines during the crack extension and surface subsidence stage the surface deformation is less extensive when the rock strength is greater and the gradient of surface deformation is lower when the rock mass integrity is lower thus higher mining height and lower rock mass quality result in greater surface deformation furthermore weak planes such as faults and joints can help to generate fissures in weathered rock masses these fissures create passageways for groundwater flow which accelerates crack extension and connection in reverse in addition surface collapses can be divided into karst collapses and mining induced collapses because a large number of fissures and a high karst rate create favorable conditions for karst collapse significant variations in groundwater levels can induce karst collapse at the surface with high negative pressure forming in the karst caves mining induced collapses are mainly related to the mining depth mining height and the properties of the overlying rock mass underground mining is a major factor in surface collapse and heavy rainfall can induce a delayed but sudden collapse

anticyclonic rings in the gulf of mexico abstract using the historical data set this study describes the anticyclonic rings that separated from the loop current in the eastern gulf of mexico six quasi synoptic data sets are used to describe the evolving circulation of the gulf of mexico from october 1966 to september 1967 showing the separation and movement into the western gulf of three anticyclonic rings the historical data are used to determine that these rings typically translate to the west at a mean speed of 2 1 km day 1 their length scale as defined by their rms radii is 183 km an estimate of ring life span as defined by an e folding time is one year within the context of the gulf s water property distributions these rings appear as warm salty bodies the heat and salt added by one of these rings after separation are estimated to be 7 109 j m 2 and 17 g cm 2 respectively the heat and salt added by one of these features play an important role in the heat and salt budget of the western gulf the latter indicates that about one r

engineering geology and ground collapse mechanism in the chengchao iron ore mine in china abstract the engineering geological and hydrogeological conditions in the eastern mining area of the chengchao iron mine are analyzed in detail the results are combined with the results of site investigations and in situ monitoring data allowing the characteristics of the ground surface collapse events to be summarized the mechanism by which ground surface collapse is induced by underground orebody extraction or de watering activity was then investigated the results show that the ground surface in the mining areas experienced three collapse processes karst collapse mixed collapse and mining induced collapse karst collapse sinkholes were found during the construction stage of the mine and are generally formed in the marble part of the marble granite contact zone these sinkholes show a bead on a string distribution and lines connecting their centers are consistent with the strike of the marble such sinkholes are mainly formed due to changes in the dynamic conditions of groundwater caused by de watering activity furthermore the development level of the collapse mainly depends on the location and scale of the karst caves within the marble mixed collapse occurs in the initial mining stage and mainly results from the combined effect of underground orebody excavation and de watering activity mining induced ground surface collapse pits mostly develop in the diorite and hornstone and generally show a zonal distribution along the strike of the orebodies from east to west mining induced collapse occurs in the form of chimney caving first a caved pipe is formed where the rock masses above the caved zone are highly fractured then the rock masses around the caved pipe gradually cave and finally a large caved zone is formed above the mined out area mixed collapse is of particular interest as it is a peculiar type of subsidence involving the superposition of collapse processes related to both mining and karst cavities and it can provide some instructive insight into the collapsing behavior of the ground surface

earthquake faulting as a structural process abstract structural geology is concerned with the history of movement in the earth s crust and the processes by which displacements occur in the upper one third to one half of deforming continental crust displacement is accommodated largely by seismic slip increments on existing faults it follows that earthquakes and related processes are an integral part of structural geology traditionally structural geologists have been preoccupied with the complexity of the finite deformation within fault zones and with the stress states prevailing at the initiation of faults in intact crust future structural work should be directed more towards understanding the dynamic character of fault reactivation during incremental slip and related effects questions of interest include rheological and geometrical controls on the initiation perturbation and termination of ruptures directivity effects associated with rupture propagation the recognition of structures resulting from repeated stress cycling within seismogenic crust and identification of structural features diagnostic of shear stress levels during faulting structures arising from the inter relationships between slip episodes and induced fluid flow are of special importance because these dynamic fault processes appear influential in the development of much fault hosted mineralization mesothermal gold quartz lodes hosted in high angle reverse shear zones of mixed brittle ductile character form illustrative examples of structures that arguably can only be interpreted by seismo structural analysis embodying the concepts listed above

unusual cases of mining subsidence from great britain germany and colombia subsidence involves sinking of the ground surface the movement generally is localised and may or may not involve some amount of horizontal movement it may be rapid or take place gradually over a period of time subsidence may be brought about by natural causes as for example when the roof of a cavern in limestone is weakened to the extent that it is no longer self supporting and so collapses other more exotic examples are associated with volcanism and earthquakes perhaps however subsidence is more frequently associated with movements caused by mining activities that is the removal of mineral deposits be they in solid liquid or gaseous form from within the ground mining is one of the earliest activities of man and has taken place in every continent subsidence also can result from subsurface excavations such as tunnels caverns cellars and sewers one of the added problems of some forms of subsidence is that it is impossible to predict this coupled with the fact that the presence of potentially collapsible voids may be unknown unrecorded or simply forgotten about further complicates the problem the objectives of this paper are to document and draw attention to a number of unusual examples of subsidence these have been generated due to the mining of chalk in southern england the collapse of slate mines and caverns in germany the underground extraction of evaporites in northern ireland fault reactivation in wales and northern england and the extensive extraction of pumice on the flanks of galeras volcano in colombia

hangingwall surface subsidence at the kiirunavaara mine sweden large scale surface subsidence has been experienced at the kiirunavaara mine since sublevel caving was implemented as a mining method surface disturbances are affecting part of the city of kiruna the railway and the power station continuous and discontinuous subsidences characterize the hangingwall deformation which is periodically monitored using surveying techniques and mapping of surface cracks a historic review of subsidence prognoses has been carried out and the results compared with the actual condition of the hangingwall the review showed discrepancies between different prognoses in addition limit equilibrium analyses indicated that break angles flatten while the mining depth increases however this tendency is not clear in the field where break angles show a large dispersion of values by using surveying data two different analyses have been performed the time dependent movements of the hangingwall have been described using time displacement curves and strain analysis has been performed for different sections of the hangingwall three different stages of the time displacement behavior have been identified and described it has been concluded that extension strain can reach values which may damage civil structures before surface crack can be observed

in situ monitoring and analysis of the mining induced deep ground movement in a metal mine abstract an extra deep multiple point borehole extensometer applicable up to 300 m depth of cover is introduced for the deformation monitoring of the deep rock masses i e the rock mass below the ground surface in the eastern area of jinshandian iron ore mine and the in situ monitoring results collected over eight years are analysed combined with the deformation monitoring results on the ground surface collected by using a global positioning system gps level monitoring technique and a three dimensional laser scanning system leica hds 880 the ground movement mechanism of the deep rock masses induced by underground mining is investigated results show that the extra deep multiple point borehole extensometer can capture the deformation information pertaining to deep rock masses in metal mines with complex geological conditions such as jinshandian iron ore mine the moment that the deformation of the monitoring point starts to increase significantly can be used to determine whether the major deformation has transferred to the deep rock mass at the monitoring points or not the monitoring results from such critical moments indicate that the major deformation of the overburden strata gradually develops from the lower part to the upper part consistent with the results from a physical modelling experiment in jingshandian iron ore mine the second caving of the deep rock masses reaches the ground surface above the centre of the mined out area and then causes the ground collapse under the combined effect of the underground mining in jinshandian iron ore mine and the remaining private mined out areas large scale ground surface collapses and cracks can be observed in mining affected areas the deep rock masses surrounding the mined out areas are in a state of global deformation and the boundary line of the deep break zone is a fold line currently the rock masses in the major deformation zone move downwards under gravity on the shear surfaces in jingshandian iron ore mine

the influences of mining subsidence on the ecological environment and public infrastructure a case study at the haolaigou iron ore mine in baotou china the scope and extent of mine subsidence caused by exploitation of metal ores are usually low however in some cases owing to such factors as special geological conditions in ore body backward mining technology and unsound management systems exploitation of metal ores would also lead to a large area of mine subsidence causing great damages to the mining environment and infrastructure a serious mine subsidence happened in january 2007 at the haolaigou iron ore mine has caused a huge collapse pit on the earth s surfaces this provides a suitable place to study the influence of mine subsidence based on former research results a 3d geological model is constructed using the rock model software developed by authors group based on in situ geological conditions the range of orebody mining and the physical and mechanical parameters of rock and soil mass were determined by inverse analysis creep analysis of the collapse pit was also performed furthermore the elastoplastic and creep of the secondary collapse were computed and the final range of the collapse pit was predicted finally the influences of mining subsidence on the ecological environment and public infrastructure are discussed and control measures were proposed the results indicate that the collapse pit would not affect the road even if creep is considered however the secondary collapse would influence the road so the collapse pit should be dealt with as soon as possible

a double thermostad warm core ring of the gulf stream abstractan unusual double thermostad warm core ring of the gulf stream was discovered in the slope sea south of georges bank during the r v endeavor cruise 578 in may 2016 the ring s stratificat

investigation on the distribution characteristics of ground cracks in the chengchao iron mine china in this study a comprehensive assessment of the distribution characteristics of ground cracks in the chengchao iron mine was conducted by field investigation and monitoring in general ground cracks are initially distributed around collapse pits and subsequently extend outwards centered on the mined out area greater ground deformation leads to more developed ground cracks ground cracks can be divided into cut through crack deep crack and shallow crack based on their downward extension depths furthermore the formation of ground cracks is controlled by both underground mining and geological structures ground cracks can be divided into mining induced crack and tectonic crack based on their main influencing factors moreover many types of ground cracks are caused by different failure modes including tensile failure shear failure and mixed failure ground cracks can be divided into vertical shear crack vertical shear and horizontal tensile crack horizontal tensile crack horizontal shear crack and mixed crack based on their formation mechanisms in particular the movement line and the break line defined as e 2 mm m and 6 mm m respectively can be reasonably regarded as disturbance boundary and crack boundary in a metal mine the disturbance zone caused by underground mining can be divided into collapse zone break zone and movement zone based on the size of ground deformation and the characteristics of ground cracks increases in ground crack width and length exert different degrees of stress release on the rock masses outside and inside the crack thus increasing their deformation difference in addition the extension of ground cracks is related to the ground topography and the strength and integrity of the rock masses and soil cracks on hilltop are more developed than those on flat land and cracks will initially appear in rock mass and soil rather than on a concrete structure due to the lower strain resistance of the rock mass and soil however concrete structures are more sensitive to cracking than rock mass and soil because of the better integrity of concrete structures

numerical experiments on the movement of a warm core ring with the bottom slope of a western boundary numerical experiments are performed to investigate the effects of the bottom slope of a western boundary on realistic warm core rings using a primitive equation sigma coordinate model warm core rings which initially have baroclinic velocity near a steep bottom slope gradually move northward but those with barotropic velocity do not barotropic velocity on the slope immediately disperses as a topographic rossby wave while baroclinic velocity is retained since the northward movement is caused by an effect very much like the image effect which is originally the effect of a free slip wall the authors term this effect the equivalent image effect the equivalent image effect increases as a slope becomes steeper and bottom friction becomes weaker and vice versa it seems that a steep slope acts like a wall and the bottom friction of a steep slope corresponds to the lateral viscous effect of a wall however the effect of a slope on a warm core ring is different from that of a wall in that ring slope interactions take place at the lower part of the ring because the velocity of a warm core ring is weak in deep layers ring slope interactions are moderate and the leakage of the interior fluid of a ring seen in ring wall interactions is not apparent while the viscous effect is weaker than that of a no slip wall as well these results are applied to the northward movement of kuroshio warm core rings and to warm eddies in the gulf of mexico

impacts of mesoscale activity on the water masses and circulation in the coral sea the climatological vision of the circulation within the coral sea is today well established with the westward circulation of two main jets the north caledonian jet ncj and the north vanuatu jet nvj as a consequence of the separation of the south equatorial current sec on the islands of new caledonia vanuatu and fiji each jet has its own dynamic and transports different water masses across the coral sea the influence of mesoscale activity on mean flow and on water mass exchanges is not yet fully explored in this region of intense activity our study relies on the analysis of in situ satellite and numerical data indeed we first use in situ data from the bifurcation cruise and from an argo float jointly with satellite derived velocities to study the eddy influence on the coral sea dynamics we identify an anticyclonic eddy as participating in the transport of nvj like water masses into the theoretical pathway of ncj waters this transfer from the nvj to the ncj is confirmed over the long term by a lagrangian analysis in particular this numerical analysis shows that anticyclonic eddies can contribute up to 70 90 of the overall eddy transfer between those seemingly independent jets finally transports calculated using s adcp measurements 0 500 m show an eddy induced sensitivity that can reach up to 15 sv i e the order of the transport of the jets

water mass structure of warm and cold anticyclonic eddies in the western boundary region of the subarctic north pacific vertical profile data of temperature and salinity from various sources were analyzed together with satellite altimeter data to investigate the water mass characteristics of warm and cold anticyclonic eddies in the western boundaryregionof the subarctic north pacific a densedistributionof anticyclonic eddieswith warm and saline core water occurred near the kuroshio extension and the distribution extends northward northeastward into the western subarctic gyre along the japan and kuril kamchatka trenches eddies with cold and fresh core water are found mainly around the oyashio southward intrusions and farther north near the kuril islands based on the heat content anomaly integrated over 50 200 dbar 85 of the anticyclonic eddies within the study area 358 508n 1408 1558e have a warm and saline core and 15 have a cold and fresh core warm and saline eddies around the japan and kuril kamchatka trenches have a double core structure with a cold and freshwater mass located below the warm core the northward propagation of these eddies along the trench line results in a large northward heat salinity transport in the upper 400 dbar 250 dbar and a negative salinity transport below 350 dbar the lower core water is colder and fresher on isopycnal surfaces at around 26 70sucompared with the climatology given that the 26 70su isopycnal surface does not outcrop in the open north pacific an alignment process is suggested to occur between the warm and saline and the cold and fresh anticyclonic eddies in the upper and intermediate layers respectively

temperature inversions in the subarctic north pacific abstract hydrographic data from the world ocean database 2001 and argo profiling floats were analyzed to study temperature inversions in the subarctic north pacific ocean the frequency distribution of temperature inversions f t inv at a resolution of 1 latitude 3 longitude was calculated temperature inversions seldom occurred around 50 n in the eastern subarctic north pacific but were more common in the northern gulf of alaska and the southeastern subarctic north pacific 42 48 n 140 170 w large temperature inversions occurred throughout the year in the western and central subarctic north pacific north of 42 n and west of 180 except near the aleutian and kuril islands near those islands f t inv was characterized by pronounced seasonal variations forced by surface heating cooling and strong tidal mixing

fine and microstructure observations in the urup strait kuril islands during august 2006 1 for the first time we performed continuous observations of turbulent mixing upon the sill of the urup strait kuril islands for a period of 1 day during august of 2006 time series of velocity profiles water properties and isopycnal depths show variability with a period of about 1 day however the water mass variability is not explained by simple water exchange between the sea of okhotsk and the north pacific empirical orthogonal function eof analysis of isopycnal coordinates extracted variability presumed to represent tidal flows as major eofs in profiles of the residual flow after subtracting the mean flow and major eofs we detected phase propagations consistent with internal gravity waves with an approximate period of 9 1 11 4 h the turbulent energy dissipation rate and vertical diffusivity k ranged from 1 10 9 to 3 10 8 w kg 1 and from 3 10 5 to 2 10 3 m2s 1 respectively occurrences of high dissipation rates generally corresponded to either strong shear or weak stratification a significant contribution of shear s to the dissipation rate was indicated with a relationship of s1 4 s1 8 probably related to propagating internal waves a strong mixing event was observed within the water column with extremely weak stratification and a richardson number below the critical value of 0 25 when the flow direction changed from up sill to down sill

eddy induced heat transport in the subtropical north pacific from argo tmi and altimetry measurements basin scale heat transport induced by mesoscale oceanic eddies is estimated by combining satellite derived sea surface height and temperature temperature data are from the trmm microwave imager tmi data with argo float temperature salinity data in the north pacific ocean subtropical gyre warm cold temperature anomalies of mesoscale eddies are found to be consistently located to the west of high low ssh anomalies the phase misalignment between the temperature and velocity anomalies however is largely confined to the seasonal thermocline causing most of the eddy induced heat transport to be carried in the surface 200 m layer by establishing a statistical relationship between the surface and depth integrated values of the eddy heat transport the basin scale eddy heat transport is derived from the concurrent satellite ssh sst data of the past six years in the kuroshio extension region the meandering zonal jet is found to generate oppositely signed eddy heat fluxes as a result the zonally integrated poleward heat transport associated with the kuroshio extension is at a level o 0 1 pw smaller than the previous estimates based on turbulent closure schemes large poleward eddy heat transport is also found in the subtropical north pacific along a southwest northeast tilting band between taiwan and the midway islands this band corresponds to the region of the subtropical front and it is argued that the relevant temperature field for identifying this band in the turbulent closure scheme models should be that averaged over the seasonal thermocline

the transition region mode water of the north pacific and its rapid modification abstractusing argo float data this study examined the formation region spatial distribution and modification of transition region mode water trmw which is a recently identified pycnostad in the subtropical subarctic transition region of the north pacific the basin scale boundary region between subtropical and subarctic water masses analyses of the formation fields of water masses within and around the transition region reveal that trmw forms in a wide area from the western to central transition region and is separated from the denser variety of central mode water d cmw to the south by a temperature and salinity front trmw has temperatures of 4 9 c and salinities of 33 3 34 0 making it colder and fresher than d cmw trmw has a density range of 26 3 26 6 and thick trmw is widely distributed in the transition region however the range of the t s properties at trmw cores is substantially reduced downstream within 10 20 longitude from the formation region by gradually losing its fresh and c

fault kinematics and surface deformation across a releasing bend during the 2010 mw 7 1 darfield new zealand earthquake revealed by differential lidar and cadastral surveying dextral slip at the western end of the east west striking greendale fault during the 2010 m w 7 1 darfield earthquake transferred onto a northwest trending segment across an apparent transtensional zone here named the waterford releasing bend we used detailed surface mapping differential analysis of pre and postearthquake light detection and ranging lidar and property boundary cadastral resurveying to produce high resolution centimeter scale estimates of coseismic ground surface displacements across the waterford releasing bend our results indicate that the change in orientation on the greendale fault incorporates elements of a large scale releasing bend from the viewpoint of westward motion on the south side of the fault as well as a smaller scale restraining stepover from the viewpoint of southeastward motion on the north side of the fault these factors result in the waterford releasing bend exhibiting a decrease in displacement to near zero at the change in strike and the presence within the overall releasing bend of a nested localized restraining stepover with contractional bulging the exceptional detail of surface deformation and kinematics obtained from this contemporary surface rupture event illustrates the value of multimethod investigations our data provide insights into strike slip fault bend kinematics and into the potentially subtle but important structures that may be present at bends on historic and prehistoric rupture traces

use of an integrated finite discrete element method discrete fracture network approach to characterize surface subsidence associated with sub level caving abstract the lkab kiruna sub level cave mine located in kiruna sweden is one of the most well studied sub level cave mines due to proximity of the city to the hanging wall the mine has developed a comprehensive surface deformation monitoring program which is perhaps unparalleled in the mining industry this surface monitoring scheme provides an excellent data source with which to constrain numerical modelling in this study a finite discrete element modelling approach coupled with a discrete fracture network fdem dfn is utilized to analyse the kiruna hanging wall surface subsidence with an emphasis on investigating the influence of discontinuity persistence and spacing the fdem dfn data interpretation uses a variety of novel approaches including time displacement hanging wall deformation characterization numerical inverse velocity analysis and virtual hanging wall inclinometer simulation to improve our understanding of the extent and mechanism of hanging wall failure with mine advance the simulated displacements correspond closely to the actual field data illustrating the ability of the proposed approach to reproduce sub level cave behaviour three distinct time displacement phases namely regressive progressive and steady state are observed in the fdem dfn models the paper also reviews the potential application of the inverse velocity method and virtual inclinometers in characterizing sub surface brittle failure associated with sub level caving

distribution and modification of north pacific intermediate water in the kuroshio oyashio interfrontal zone abstract a multiship ctd survey was conducted in the kuroshio oyash interfrontal zone in the area of 30 41 n 140 e 180 from may to june 1992 to examine the distribution modification process and formation site of north pacific intermediate water npiw low salinity oyashio water and high salinity kuroshio water merge along the kuroshio extension just off the east coast of japan and together flow eastward eastward geostrophic transport and salinity across the kuroshio strong current indicate that the mixture of the kuroshio and oyashia waters along the kuroshio extension can produce new npiw transport estimate suggests that the new npiw bifurcates into the interfrontal zone and into the recirculation of the subtropical gyre a salinity minimum structure can he also created due to the isopycnal mixing along the kuroshio extension between the oyashio and kuroshio waters which have different salinity and vertical velocity structures the low salinity oyashio water seen along the oyashio branches and t

evolution and progressive geomorphic manifestation of surface faulting a comparison of the wairau and awatere faults south island new zealand comment zinke et al 2015 documented a flight of saxton river terraces deformed by the awatere fault south island new zealand they concluded that the manifestation of off fault deformation ofd is a cumulative effect and therefore may not be immediately apparent on younger terraces with implications for slip rate determinations i argue that they did not adequately consider the detailed structural setting of elements of ofd within the saxton river releasing bend on the awatere fault the surface deformation at saxton river is probably controlled by the coincidence of terraces with structural zones within the bend and i contest the authors conclusion that off plane deformation is simply hidden in younger terraces the influence of structural complexity on the width and geometry of ofd is well established e g milliner et al 2015 zinke et al s figure dr2 in gsa data repository 2015341 shows that ofd along the awetere fault occurs at bends or steps in the fault plane including at saxton river where the fault bends right relative to the main trace by 5 10 50 m east of the t2 t3 riser this gives rise to a graben t1 tread and two pressure ridges t2 tread and bedrock spur that define and bound an overall 150 m wide releasing bend mason et al 2006 figs 1a and 1b the paired pressure ridge and graben geometry is predicted when the wall rocks on either side of a strike slip fault approach and interact with a fault bend during an earthquake sibson 1989 and has been reported on the hope cowan 1990 and greendale duffy et al 2013 faults in new zealand and the san andreas fault in california ben zion et al 2012 among others

investigation of the ground movement due to underground mining at the jinshandian iron mine in china to investigate the mechanism responsible for mining induced ground movement at the jinshandian iron mine in china the vertical and horizontal deformations of the ground surface were monitored in situ over a period of 8 years the results were analyzed and combined with subsidence results derived from laser scanning measurements and collapse cracking behavior of the ground the results show that the horizontal displacement mainly occurs in the rock masses surrounding the mined voids moreover several obvious onset points can be found in the displacement time curves that are indicative of rapid increases in displacement currently the scope of the ground movement of the footwall is larger than that of the hanging wall this behavior is distinctive and distinguishes the jinshandian iron mine from others it can be attributed to the sliding toppling failure of the column shaped rock masses in the footwall under the combined effect of the in situ horizontal stress and high dip angles of the discontinuities

analysis of the surface deformation characteristics and strata movement mechanism in the main shaft area of chengchao iron mine the surface deformation and strata movement caused by underground mining in a metal mine often exceeds the designed range which can destroy main shafts and other key structures causing huge economic losses and affecting production safety here the main shaft area of chengchao iron mine affected by tectonic stress is analyzed detailed monitoring data from the past 11 years were used to analyze the surface deformation characteristics and the strata movement mechanism the results show that the surface deformation in the main shaft area shows s shaped curve characteristics comprising a stable deformation stage a rapid deformation stage and a stable deformation stage the surface horizontal displacement vector in the main shaft area points to the western mining area indicating that the surface deformation in the main shaft area is mainly affected by underground mining in the western area from december 2007 to december 2009 the expansion of the movement line varepsilon 2 mm m was small in december 2009 the expansion of the movement line increased significantly the expansion law of the break line varepsilon 6 mm m was similar to that of the movement line furthermore the movement angle decreased significantly from december 2009 to december 2011 and the break angle sharply decreased from december 2010 to december 2012 the cantilever beam mechanics model revealed that the fractured width of footwall in the direction of the main shaft area was 266 m when exploitation reaches a horizontal depth of 600 m the fracture width is predicted to reach 402 m

a methodology based on strain analysis for identifying potential discontinuous deformation zones in sublevel caving mines abstract underground mining operations using the sublevel caving method often result in discontinuous ground deformations involving surface cracks determining the limit of the discontinuous deformation zone is important for the relocation of neighbouring residential areas mining infrastructure and the planning of underground mining operations the limit of the discontinuous deformation zone is characterised by the outermost surface crack which is a tensile crack when it occurs and is correlated with the horizontal ground tensile strain in this study a mathematical procedure combining the horizontal displacement as periodically monitored by total station and gps multiquadric radial basis function mq rbf interpolation and continuum mechanics is provided to calculate the strain state at any point on the ground then the relationship between a new tensile crack and horizontal ground tensile strain is studied to determine the criterion representing the presence of a new tensile crack this means that when the criterion at any point on the ground is satisfied the point will have the potential to crack based on this the potential discontinuous deformation zone where surface cracks may occur can be identified potential break angles at representative sections can then be determined a case study is presented to illustrate the results given by the above methodology the result shows that when major principal horizontal ground strain e1 at any point on the ground reaches the potential cracking major principal strain pcmps 6 mm m in this case study the point will have the potential to crack subsequently the area within the outermost contour of the pcmps can be defined as the potential discontinuous deformation zone moreover the approximate matching of the limits of potential discontinuous deformation zones and surface cracks verifies the reliability of the mathematical procedure and the rationality of the pcmps in identifying the discontinuous deformation zone additionally in this case study the potential break angles at two respective sections are significantly different indicating that the break angles should be further studied and care taken in design of works in these two zones respectively

the development of surface steps during mining subsidence not due to fault reactivation abstract in spite of the voluminous literature which has been collated over the past ca 150 years regarding the occurrence prediction and control of the various phenomena associated with mining subsidence the behaviour of geological faults during such subsidence is still poorly understood it is generally appreciated that the reactivation of faults during mining events and the consequent formation of a step in the surface topography is complex and variable and can result in extensive and spectacular structural damage within the past ca two yearsevidence from the british and ukrainian coalfields has been correlated which suggests that the surface steps formed and effected in the topography may be centred over contrasting lithological contacts such as bedding planes joints unconformities and the outcrop of fold axes

baroclinic eddy interactions with continental slopes and shelves abstract the evolution and propagation of large anticyclonic eddies similar to the loop current eddies found in the gulf of mexico are studied in a two layer intermediate equation numerical model it is found that the propagation of these eddies is governed primarily by the effect lower layer flow driven by the surface eddies and the image effect as the eddies move westward under the influence of the effect they drive deep circulation that typically includes a cyclone near the eddies trailing edge this cyclone accelerates the eddy southward leading to a path substantially different from that found in reduced gravity models of similar surface eddies when the eddy encounters a continental slope the lower layer flow is dispersed by topographic rossby waves and the eddy loses its southward propagation component if the continental slope is backed by a shelf that is wider than the eddy s radius a deep anticyclone will form over the shelf as the eddy approaches the shelf break this anticyclone w

numerical analysis of a large landslide induced by coal mining subsidence mining induced subsidence is one of the challenging problems in geotechnical engineering the surface topography of the ground over mining excavations plays a key role in the mechanism of subsidence when a mining operation is performed beneath mountainous or hilly terrain it may trigger landslides this study therefore aims to analyse the impacts of underground mining on the stability of slopes by using numerical modelling a coal mining induced landslide at nattai north australia is investigated as a typical case study in this area mining operations beneath the sydney basin escarpments initiated the largest contemporary landslide and mass movement known in australia cunningham 1988 discontinuous numerical modelling is employed to analyse the mechanisms of the ground movements leading to this landslide the role of geological and geotechnical factors such as rock mass characteristics bedding and joints are discussed through the numerical modelling the outcomes of the analyses reveal that mining induced stresses lead to the shear and compressive failure of weak strata at the escarpment base particularly around its toe the failure of the base materials as well as the caving of the overlaying bedded rocks into the extracted panel facilitated the detachment of the massive sandstone this rock column ahead of the escarpment was overlaying the weak strata the numerical results also indicate that the aforementioned rock column remained almost unaffected during mining however the failure of the weak strata at the toe of the escarpment initiated the simultaneous forward sliding and toppling of the rock column this mode of failure which is known as ski jump type of failure was previously observed and explained by pells et al 1987

geometrical control of subduction related magmatism the mesozoic and cenozoic plutonic history of western colombia radiometric age data from western colombia combined with geological evidence allow five main plutonic episodes ranging in age from triassic to tertiary to be recognized it is suggested that variation in the convergence angle of the oceanic plate relative to the continental edge was an important factor affecting the timing and spatial distribution of plutonic activity on a regional scale major breaks in activity are probably best attributed to either low angle parallel convergence or periods of accretion along the convergent margin

direct breaking of large amplitude internal waves in the urup strait abstract observations and model data have been analyzed for the urup strait one of the kuril straits focusing on processes driving the extremely strong vertical mixing observations over 1 day on the pacific side of the sill of the urup strait show the generation of a large amplitude internal wave laiw characterized by the depression of potential density surfaces caused by a strong off sill flow when the laiw developed the potential density surface of 26 7 was depressed downward by more than 300 m and vertical mixing was markedly elevated within the 400 m thick layer 26 6 26 7 with a layer mean maximum energy dissipation rate and vertical diffusivity of 1 2 10 6 7 9 10 6 w kg 1 and 4 0 10 1 2 8 m2 s 1 respectively a three dimensional model simulation of the kuril straits driven by the diurnal barotropic tide reproduces well the observed features relevant to the generation of laiws in and around the urup strait the structure and generation pattern of laiws in the urup strait are consistent with those of the arrested lee waves observed in the hawaiian ridge and luzon strait although the depth at the top of the sill is far shallower in the urup strait it is suggested that barotropic tidal energy with diurnal frequency is converted into laiws through the excitation of topographically trapped waves with hydraulically supercritical velocity near the sill top and it is these waves that are responsible for the extremely strong mixing on the sill flanks of the shallow kuril straits

rapid evolution of a gulf stream warm core ring gulf stream warm core rings form in the slope water between the north american continental shelf and the gulf stream by the separation of a north extending meander1 the initial physical chemical and biological properties of the core of these 100 200 km eddies are often similar to those of its parent water mass the sargasso sea a clockwise rotating remnant of the gulf stream circulates around the core with surface current speeds of 50 200 cm s 1 although warm core rings can slowly change over periods of months through interactions with the surrounding slope water gulf stream meanders continental slope other rings and the atmosphere we have now discovered that major alterations to ring structure can occur during very short periods 2 5 days when an interaction with the gulf stream is particularly intense such short period interactions between a ring and the gulf stream are a major factor governing a ring s evolution

modification of a kenai eddy along the alaskan stream 1 a kenai eddy was studied through analyses of satellite altimeter data and hydrographic data from shipboard and argo float observations this eddy formed in december 2006 south of the kenai peninsula and propagated southwestward along the alaskan stream the eddy held horizontally uniform warm core water in january 2007 in late winter 2007 this core water was cooled from the top and a subsurface temperature maximum was formed around 26 5 two years later in summer 2009 warm and low dissolved oxygen low do water characterized by a temperature maximum around 26 5 was observed again in the eddy core and was likely the remnant of original core water at the same time cold and high do water intrusions occurred in the eddy core suggesting that strong modification of core water was ongoing after summer 2009 the core water was fully changed through interaction with another eddy

mining induced ground deformation in tectonic stress metal mines a case study abstract in situ monitoring data of ground deformation in the western area of chenchao iron mine were collected over eight years results were analysed to conduct a preliminary investigation into the ground movement induced by underground mining 1 in the northeastern area the ratios of horizontal to vertical displacement increase gradually and the horizontal displacement may be as much as an order of magnitude larger than the vertical displacement at a large distance which induces regional horizontal movement curves of the ratio of horizontal to vertical displacement with respect to time can be categorised as fluctuation fallback convergence and increase types 2 in the mine road stack site and southern area around the high voltage tower ground deformation can be divided into two stages stable deformation and rapid deformation while in the southeastern area of the transport tunnel service shaft and road tunnel it can be divided into three stages stable deformation rapid deformation and subsequent stable deformation three categories are found in the time displacement curves folding s and linear types 3 the ground deformation of the footwall underwent a significant change in january 2010 because the large horizontal tectonic stress in the mine was released at that time surrounding rock masses were subjected to toppling deformation along the major structural plane in the northeastern area while tensile deformation occurred perpendicular to the major structural plane in the northern area

surface stepped subsidence related to top coal caving longwall mining of extremely thick coal seam under shallow cover the surface stepped subsidence had badly affected the public infrastructure safety the formation mechanism of the surface stepped subsidence case was explained the surface subsidence profile after the sequent mining activity was predicted the possible controls of the stepped subsidence were lastly proposed

the monitoring and prediction of mining subsidence in the amaga angelopolis venecia and bolombolo regions antioquia colombia abstract amaga angelopolis venecia and bolombolo are small towns located in antioquia in the central cordillera of the colombian andes mining has been practised in this region for a period of at least 100 years this mining has mainly been small scale poorly mechanised and restricted to shallow room and pillar workings recently the semi mechanisation of some mines has enabled coal to be extracted using longwall mining methods however this has resulted in subsidence that has caused severe damage to structures residential property and agricultural land and also induced landslides in the british isles there are several reliable methods that can be used to predict the likelihood and magnitude of mining subsidence the british coal corporation and the university of nottingham have developed one such method the subsidence with influence function technique swift based on mining subsidence observations undertaken in the coalfields of britain over a period of approximately 50 years the swift program was used to predict the magnitude of subsidence above a longwall panel at the industrial hullera mine in colombia the results were then compared with subsidence profiles obtained from precise levelling and field monitoring in each case the swift program overestimated the magnitude of mining subsidence by 0 17 0 20 m however the morphology of the subsidence profile area of influence and location of maximum subsidence were similar this overestimation of the predicted subsidence was attributed to the occurrence of strong igneous rocks such as rhyolite sills in the colombian coal measures these strong competent horizons act as cantilever beams during subsidence causing bed separation and therefore reducing the magnitude of subsidence in spite of these differences mining subsidence can be predicted with a reasonable degree of accuracy and precision using the swift technique provided the software is calibrated and used in conjunction with local expertise

deep intense vertical mixing in the bussol strait 1 to reveal the intensity of deep mixing in the bussol strait we performed the direct observations of turbulence for the first time vigorous vertical mixing with a turbulent energy dissipation rate e above 10 6 w kg and diapycnal diffusivity k above 103 cm2 s were observed at depths of 600 1300 m potential densities of 27 0 27 5 at the western gap of the bussol strait possibly affecting water mass transformation and thermohaline circulation the strong vertical mixing with a diurnal period occurred when the diurnal tidal current flowed toward the okhotsk sea corresponding to a period of enhanced shear consisting of the mean flow with a two layered structure and the large amplitude diurnal tidal current with a vertical structure explained by a low vertical mode topographically trapped wave the empirical relationship ofe 10 1 46 1 91 s2 16 0 72 is obtained between e and the shear sreconstructed from the 50 m scale mean diurnal and semi diurnal tidal currents

how eddies gain retain and release water a case study of a hokkaido anticyclone a lagrangian methodology is elaborated to identify the origin of water masses in the kuroshio oyashio frontal zone where waters of the kuroshio extension and oyashio current and of the japan and okhotsk seas converge it allows one to track the evolution of mesoscale eddies during the satellite altimetry era and to document how they gain retain and release water masses of different origin the methodology is applied to study warm core mesoscale anticyclones propagating along the japan and kuril trenches near the eastern coast of hokkaido island that have been observed from january 1 1993 to december 10 2016 in an altimetry based velocity field the hokkaido eddy sampled by profiling floats and a few cruises in 2003 and 2004 is analysed in detail in order to compare lagrangian simulation results to observations

cold core anticyclonic eddies south of the bussol strait in the northwestern subarctic pacific abstract summer hydrographic surveys from 1993 to 1997 in the area south of the kuril islands in the northwestern subarctic pacific showed the existence of anticyclonic eddies south of the bussol strait at almost the same location but with variable sizes and intensities depending on the year every eddy had a cold low salinity and low potential vorticity core suggesting a strong influence from the okhotsk sea water two formation processes and annual variations were found with satellite data analyses one is the case where eddies are locally formed south of the bussol strait and intensified from summer to fall with the supply of okhotsk sea water as observed in 1993 in the other case kuroshio warm core rings that had translated northeastward are arrested near the bussol strait and amplified with the supply of okhotsk sea water as seen from summer to autumn in 1995 in winter eddies tend to move northeastward with decay the 1992 eddy moved northeastward then northward in winter and was eventually

quantifying near field and off fault deformation patterns of the 1992 mw 7 3 landers earthquake coseismic surface deformation in large earthquakes is typically measured using field mapping and with a range of geodetic methods e g insar lidar differencing and gps current methods however either fail to capture patterns of near field coseismic surface deformation or lack preevent data consequently the characteristics of off fault deformation and the parameters that control it remain poorly understood we develop a standardized method to fully measure the surface near field coseismic deformation patterns at high resolution using the cosi corr program by correlating pairs of aerial photographs taken before and after the 1992 m w 7 3 landers earthquake cosi corr offers the advantage of measuring displacement across the entire zone of surface deformation and over a wider aperture than that available to field geologists for the landers earthquake our measured displacements are systematically larger than the field measurements indicating the presence of off fault deformation we show that 46 of the total surface displacement occurred as off fault deformation over a mean deformation width of 154 m the magnitude and width of off fault deformation along the rupture is primarily controlled by the macroscopic structural complexity of the fault system with a weak correlation with the type of near surface materials through which the rupture propagated both the magnitude and width of distributed deformation are largest in stepovers bends and at the southern termination of the surface rupture we find that slip along the surface rupture exhibits a consistent degree of variability at all observable length scales and that the slip distribution is self affine fractal with dimension of 1 56

evolution and progressive geomorphic manifestation of surface faulting a comparison of the wairau and awatere faults south island new zealand reply field mapping and lidar analysis of surface faulting patterns expressed in flights of geologically similar fluvial terraces at the well known branch river and saxton river sites along the wairau alpine and awatere strike slip faults south island new zealand reveal that fault related deformation patterns expressed in the topography at these sites are markedly less structurally complex along the higher displacement hundreds of kilometers structurally mature wairau fault than along the awatere fault 13 20 km total slip these differences which are generally representative of the surface traces of these faults provide direct evidence that surface faulting becomes structurally simpler with increasing cumulative fault offset we also examine the degree to which off fault deformation ofd is expressed in the landscape at the saxton river site along the less structurally mature awatere fault significantly greater amounts of ofd are discernible as a wide damage zone 460 m fault perpendicular width in older ca 15 ka more displaced 64 74 m fluvial terraces than in younger ca 1 7 ka less displaced 55 m terraces no ofd is discernible in the lidar data on the least displaced 35 m terraces from this we infer that ofd becomes progressively more geomorphically apparent with accumulating displacement these observations imply that 1 the processes that accommodate ofd are active during each earthquake but may not be evident in deposits that have experienced relatively small displacements 2 structures accommodating ofd will become progressively geomorphically clearer with increasing displacement 3 geomorphic measurements of overall fault zone width taken in deposits that have experienced small displacements will be underestimates and 4 fault slip rates based on geomorphic surface offsets will be underestimates for immature faults if based solely on measurements along the high strain fault core

rates of active faulting during late quaternary fluvial terrace formation at saxton river awatere fault new zealand a flight of faulted fluvial terraces at saxton river on the awatere fault northeast south island new zealand preserves the incremental slip history and detailed paleoearthquake chronology of this major strike slip fault here six fluvial terraces have been progressively displaced across the inland molesworth section of the fault with horizontal displacements ranging from 6 m for an ephemeral channel on the youngest terrace to 81 m for the riser above the oldest terrace new optically stimulated luminescence ages for abandonment of the two oldest terrace treads are 14 5 1 5 and 6 7 0 7 ka when combined with new measurements of incremental horizontal displacements and previous age data these new ages indicate that strike slip on this part of the awatere fault has been occurring at a near constant rate of 5 6 0 8 mm yr since ca 15 ka this rate is similar to recent slip rate estimates for an adjoining section of the same fault to the east which suggests that there is near complete slip transfer across the junction between the two fault strands comparison of the magnitudes and ages of the terrace riser displacements to the timing of paleoearthquakes on the molesworth section allows the mean per event horizontal displacement over the eight most recent surface rupture events to be estimated at 4 4 0 8 m between ca 5 ka and ca 2 ka surface rupturing earthquakes increased in frequency and decreased in their mean coseismic displacements to 2 6 m during this time the sense of local dip slip also shifted from north side up to south side up rapid incision of saxton river in the mid holocene may have caused a perturbation in the near surface stress directions acting on the fault plane beneath the saxton river valley forcing a change in the near surface fault geometry that resulted in the shift in sense of dip slip

sinkhole formation above underground limestone quarries a case study in south limburg belgium abstract historical records were used for the compilation of a database of sinkholes resulted from collapses of abandoned shallow underground limestone quarries mines in two villages in belgian south limburg during the last 350 years the formation of such sinkholes caused at least 38 casualties but more often it caused a change in topography and damage to public and private property the objective of this study is to better understand the spatial and temporal patterns of quarry collapse related sinkholes in the study area apart from sinkhole locations and ages the compiled database provides information on the dimensions of the area affected and the damage caused by sinkhole formation as well as the causal factors of sinkholes one hundred seventy three sinkholes have been reported since 1665 but most 80 reported sinkholes postdate 1965 sinkhole dimensions provided information on the type of collapse seven large sinkholes displacing a total sediment volume of 480 000 m3 resulted from large scale roof breakdown after pillar failure the smaller sinkholes were the result of fall of the overburden into galleries after local roof collapse or suffosion of a solution pipe in total these small sinkholes displaced 12 300 m3 of sediment at present almost all large underground quarries in the study area have been affected by sinkholes these features were caused by natural and anthropogenic factors and occur in zones with thin roofs where pillars were affected by pillar robbing or on locations with inappropriate sewerage systems above quarries the formation of sinkholes was often reported in spring during years with high moisture contents in the overburden caused by high groundwater recharge or above average precipitation with increasing time since quarry abandonment quarries become more susceptible to pillar creep and bending of the roof hence if no appropriate mitigation measures are taken to reduce such deterioration processes the number of sinkholes is expected to increase

the shedding of mesoscale anticyclonic eddies from the alaskan stream and westward transport of warm water abstract the south flowing waters of the kamchatka and oyashio currents and west flowing waters of the alaskan stream are key components of the western sub arctic pacific circulation we use ctd data argo buoys woce surface drifters and satellite derived sea level observations to investigate the structure and interannual changes in this system that arise from interactions among anticyclonic eddies and the mean flow variability in the temperature of the upstream oyashio and kamchatka currents is evident by warming in mesothermal layer in 1994 2005 compared to 1990 1991 a major fraction of the water in these currents is derived directly from the alaskan stream the stream also sheds large anticyclonic aleutian eddies averaging approximately 300 km in diameter with a volume transport significant in comparison with that of the kamchatka current itself these eddies enclose pools of relatively warm and saline water whose temperature is typically 4 c warmer and salinity is 0 4 greater than that of cold core kamchatka eddies in the same density range aleutian eddies drift at approximately 1 2 km d 1 and retain their distinctive warm and salty characteristics for at least 2 years selected westward pathways during 1990 2004 are identified if the shorter northern route is followed aleutian eddies remain close to the stream and persist sufficiently long to carry warm and saline water directly to the kamchatka current this was observed during 1994 1997 with substantial warming of the waters in the kamchatka current and upstream oyashio if the eddies take a more southern route they detach from the stream but can still contribute significant quantities of warm and saline water to the upstream oyashio as in 2004 2005 however the eddies following this southern route may dissipate before reaching the western boundary current region

characteristics of mesoscale eddies in the kuroshio oyashio extension region detected from the distribution of the sea surface height anomaly abstract this study investigates the distribution of the sea surface height anomaly ssha with the aim of quantifying the characteristics of mesoscale eddies in the kuroshio oyashio extension region koer where intense mesoscale eddies are commonly observed during hydrographic surveys dense distributions of both anticyclonic eddies aes and cyclonic eddies ces are detected for the first time in koer with sufficient temporal and spatial coverage using the okubo weiss parameter without smoothing their contribution to the total ssha variance is estimated to be about 50 the zones of highest amplitudes are located north and south of the axis of the kuroshio extension ke for aes and ces which represent warm core and cold core rings respectively the areas extend poleward along the japan and kuril kamchatka trenches especially for aes eddies of both polarities and with moderate amplitudes are also recognized along the subarctic front saf eddies in areas north and south of the ke generally pro

crustal motions in great britain evidence from continuous gps absolute gravity and holocene sea level data two independent continuous global positioning system cgps processing strategies based on a double difference regional network and a globally transformed precise point positioning solution provide horizontal and vertical crustal motion estimates for great britain absolute gravity and geological information from late holocene sea level data further constrain the vertical motion estimates for 40 cgps stations we estimate station velocities and associated uncertainties using maximum likelihood estimation assuming the presence of white and coloured noise horizontal station velocity estimates agree to 1 mm yr 1 between the two cgps processing strategies and closely follow predicted plate motions residual velocities generally 1 mm yr 1 follow no regular pattern that is there is no discernible internal deformation nor any dependence on station monumentation or time series length vertical station velocity estimates for the two cgps processing strategies agree to similar to 1 mm yr 1 but show an offset of similar to 1 mm yr 1 with respect to the absolute gravity ag estimates we attribute this offset to a bias related to known issues in current cgps results and correct for it by ag alignment of our cgps estimates of vertical station velocity both cgps estimates and ag aligned cgps estimates of present day vertical crustal motions confirm the pattern of subsidence and uplift in great britain derived from holocene sea level data for the last few thousand years ongoing subsidence on shetland uplift in most areas of scotland and subsidence in large areas of england and wales

three dimensional structure and temporal evolution of submesoscale thermohaline intrusions in the north pacific subtropical frontal zone abstract four instances of persistent intrusive deformation of the north pacific subtropical front were tagged individually by a lagrangian float and tracked for several days each feature was mapped in three dimensions using repeat towed observations referenced to the float isohaline surface deformations in the frontal zone included sheetlike folds elongated in the alongfront direction and narrow tongues extending across the front all deformations appeared as protrusions of relatively cold and fresh water across the front no corresponding features of the opposite sign or isolated lenslike structures were observed the sheets were o 10 m thick protruded about 10 km into the warm saline side of the front and were coherent for 10 30 km along the front having about the same thickness and cross frontal extent as the sheets tongues extended less than 5 km along the front all of the intrusions persisted as long as they were followed several days to one week their structures evolved on both inertial

decoding the origins of vertical land motions observed today at coasts in recent decades geodetic techniques have allowed detecting vertical land motions and sea level changes of a few millimetres per year based on measurements taken at the coast tide gauges on board of satellite platforms satellite altimetry or both global navigation satellite system here contemporary vertical land motions are analysed from january 1993 to july 2013 at 849 globally distributed coastal sites the vertical displacement of the coastal platform due to surface mass changes is modelled using elastic and viscoelastic green s functions special attention is paid to the effects of glacial isostatic adjustment induced by past and present day ice melting various rheological and loading parameters are explored to provide a set of scenarios that could explain the coastal observations of vertical land motions globally in well instrumented regions predicted vertical land motions explain more than 80 per cent of the variance observed at scales larger than a few hundred kilometres residual vertical land motions show a strong local variability especially in the vicinity of plate boundaries due to the earthquake cycle significant residual signals are also observed at scales of a few hundred kilometres over nine well instrumented regions forming observation windows on unmodelled geophysical processes this study highlights the potential of our multitechnique database to detect geodynamical processes driven by anthropogenic influence surface mass changes surface loading and glacial isostatic adjustment and tectonic activity including the earthquake cycle sediment and volcanic loading as well as regional tectonic constraints future improvements should be aimed at densifying the instrumental network and at investigating more thoroughly the uncertainties associated with glacial isostatic adjustment models

charts for the mining induced deflection of buildings this study investigates the flexural deformations of buildings induced by mining related subsidence a two stage solution previously applied to the tunnelling problem is used buildings are model

agulhas eddies a synoptic view using geosat erm data abstract warm core rings formed in the agulhas retroflection transfer water from the indian ocean to the south atlantic in an attempt to measure the strength of this exchange a combination of satellite altimeter and hydrographic data are used to examine agulhas eddy paths and decay rates in the south atlantic because the surface dynamic height of a warm core eddy is higher than surrounding waters the rings are visible in satellite altimeter measurements over 20 agulhas eddies have been tracked from maps of anomalous sea surface height ssh derived from the geosat exact repeat mission erm dataset the correlation r2 of dynamic height referenced to 2000 dbar and anomaly ssh for one coincidentally sampled area is 97 within an agulhas eddy dropping to a fraction of that outside of it indicating that the ssh anomaly signal is a reliable measure for strong features like agulhas eddies the sizes and distribution of the agulhas eddies in the erm record compare favorably with those in recent hydrogr

effects of mining subsidence on masonry buildings in zonguldak hard coal region in turkey gallerias are the underground constructed results of mining as these space in underground layers collapse horizontal and vertical ground movements occur and movement which may reach the earth s surface are known as mining subsidence the result of underground displacement may cause surface ground movement which can be detrimental to masonry buildings especially in hard coal regions thorough familiarity with general and regional characteristics of an affected area can assist reduction of the effects zonguldak and the nearby settlement area with a population of 300 000 constitute the centre of a hard coal basin where extensive mining has a history extending through 160 years mining constitutes the main economic activity in this region and consequently influences every aspect of life this study s intent is to identify the effects of mining subsidence on masonry buildings in the mining area of kozlu zonguldak turkey and illustrate them with selected images of damaged masonry buildings also included are satellite and mining galleria images

rings in the ocean certain robust long lived eddy features in t he world s ocean have come to be k nown as rings the nomenclature stems from fuglister 1 1972 who c oined t he name based on the c ircle or ring of gulf stream waters t hat surrounded a class of eddies formed from t he g ulf stream through the pinch off of meanders here it s uffices to define rings as intense eddies or vortices that represent a wrapped up piece of a major ocean c urrent they t ranslate over space scales of hundreds to thousands of k ilometers and exist for periods lasting from months to years rings move t hrough the ocean carrying anomalies s imilar to the contrasts in physical biological and chemical properties observed across the major ocean c urrents while the term ring is t ied to fuglister t he existence ofthese features was evident at least as early as t he 1930s when iselin 2 1936 1940 encountered strong cold anomalies in the region south of the gulf stream that we would identify as c old corc cyclonic rings today iselin fully rec ognized these features as part of the highly time dependent eddy motion in the ocean later iselin fuglister 1948 were the first to survey what is now k nown as a warm core anticyc lonic ring there are tw o types of rings cold core rings are made up of w aters from the poleward s ide of c urrents like the gulf stream that are introduced to

global observations of large oceanic eddies 1 ten years of sea surface height ssh fields constructed from the merged topex poseidon t p and ers 1 2 altimeter datasets are analyzed to investigate mesoscale variability in the global ocean the higher resolution of the merged dataset reveals that more than 50 of the variability over much of the world ocean is accounted for by eddies with amplitudes of 5 25 cm and diameters of 100 200 km these eddies propagate nearly due west at approximately the phase speed of nondispersive baroclinic rossby waves with preferences for slight poleward and equatorward deflection of cyclonic and anticyclonic eddies respectively the vast majority of the eddies are found to be nonlinear

rapid subsidence in damaging sinkholes measurement by high precision leveling and the role of salt dissolution abstract investigations dealing with subsidence monitoring in active sinkholes are very scarce especially when compared with other ground instability phenomena like landslides this is largely related to the catastrophic behaviour that typifies most sinkholes in carbonate karst areas active subsidence in five sinkholes up to ca 500 m across has been quantitatively characterised by means of high precision differential leveling the sinkholes occur on poorly indurated alluvium underlain by salt bearing evaporites and cause severe damage on various human structures the leveling data have provided accurate information on multiple features of the subsidence phenomena with practical implications 1 precise location of the vaguely defined edges of the subsidence zones and their spatial relationships with surveyed surface deformation features 2 spatial deformation patterns and relative contribution of subsidence mechanisms sagging versus collapse 3 accurate subsidence rates and their spatial variability with maximum and mean vertical displacement rates ranging from 1 0 to 11 8 cm yr and 1 9 to 26 1 cm yr respectively 4 identification of sinkholes that experience continuous subsidence at constant rates or with significant temporal changes and 5 rates of volumetric surface changes as an approximation to rates of dissolution induced volumetric depletion in the subsurface reaching as much as 10 900 m3 yr in the largest sinkhole the high subsidence rates as well as the annual volumetric changes are attributed to rapid dissolution of high solubility salts

the coalescence of two east australian current warm core eddies two warm core eddies coalesced in about 20 days as their centers rotated around a point on the contracting line that joined them in the process of forming the new eddy the subsurface isothermal isohaline signature layer of one eddy was uplifted and somewhat depleted while that of the other was depressed

evolution and modulation of a poleward propagating anticyclonic eddy along the japan and kuril kamchatka trenches to investigate the relationships between the movement of an eddy and its interior structure and water properties four profiling floats were deployed in an anticyclonic eddy in the western north pacific in 2013 april october daily float profiles showed rapid changes in temperature and salinity corresponding to strong interactions between eddies north of the subtropical kuroshio extension after the first interaction with a warm core eddy in april the isolation of the winter mixed layer from the surface was observed forming a subsurface remnant layer another interaction with a cold fresh eddy at middepths in may resulted in the formation of a multilayer structure the eddy then moved poleward along the japan and kuril kamchatka trenches indicating changes in its propagation pattern coupled to its interior structure the eddy then moved northward june july stalled july august and moved eastward august october in addition to a general declining trend the properties of the warm saline core changed over a short time period coinciding with changes in propagation a density anomaly at middepths of the eddy changed location during the stalled period however denser waters were continuously observed in the southeast part of the eddy during its northward and eastward movement this unidirectional density anomaly pattern was consistent with the structure of the poleward propagating eddy which interacted with the western topographic boundary meridional exchanges of heat and material were potentially elevated by the eddy s advection and movement as well as by water modifications in the eddy associated with exchanges along its perimeter

anticyclonic eddies in the alaskan stream abstract anticyclonic eddies propagating southwestward in the alaskan stream as were investigated through analysis of altimetry data from satellite observations during 1992 2006 and hydrographic data from profiling float observations during 2001 06 fifteen long lived eddies were identified and categorized based on their area of first appearance three eddies were present at the beginning of the satellite observations another three formed in the eastern gulf of alaska off sitka alaska and four were first detected at the head of the gulf of alaska near yakutat alaska the other five eddies formed along the as between 157 and 169 w and were named as eddies while the eddies that formed in the gulf of alaska mainly decayed before exiting the gulf of alaska the as eddies mostly crossed the 180 meridian and reached the western subarctic gyre four of five as eddies formed under negative or weakly positive wind stress curls which possibly caused as separation from the coast comparison of eddy propag

eddy transport of heat and thermocline waters in the north pacific a key to interannual decadal climate variability abstract high resolution xbt transects in the north pacific ocean at an average latitude of 22 n are analyzed together with topex poseidon altimetric data to determine the structure and transport characteristics of the mesoscale eddy field based on anomalies in dynamic height 410 eddies are identified in 30 transects from 1991 to 1999 including eddies seen in multiple transects over a year or longer their wavelength is typically 500 km with peak to trough temperature difference of 2 2 c in the center of the thermocline the features slant westward with decreasing depth by 0 8 of longitude on average from 400 m up to the sea surface this tilt produces a depth varying velocity temperature correlation and hence a vertical meridional overturning circulation in the mean 3 9 sv sv 106 m3 s 1 of thermocline waters are carried southward by the eddy field over the width of the basin balanced mainly by northward flow in the surface layer corresponding northward heat transport is 0 086 0 012 pw

eddies advected by time dependent sverdrup circulation in the western boundary of the subarctic north pacific 1 it has been reported that several eddies frequently exist along the kuril kamchatka trench k k trench hereafter the western boundary of the subarctic north pacific lagged correlation maps of the altimeter derived sea level anomalies slas along the trench indicate that the southern eddies on the whole move northeastward along the k k trench and the northern eddies on the other hand move southwestward by tracking each anticyclonic eddy its propagating velocity along the trench is calculated the time series of the tracked 7 eddies shows similar seasonal variation to those of the first empirical orthogonal function eof of the sla maps and to those of the sverdrup transport at 40 n in addition when more than two eddies remotely exist in the studied area they show coherent moving patterns these results suggest that the eddies in the western boundary region of the subarctic north pacific are advected by the time dependent wind driven current

geomechanics stability assessment of world war i military excavations at the canadian national vimy memorial site france abstract the canadian national memorial site vimy ridge france commemorates the efforts and loss of life of canadian troops in the first world war wwi the site comprises the monument a visitors centre the grange tunnels and restored trenches and several cemeteries a substantial portion of the battlefield terrain remaining from wwi is preserved at this site including trenches shell holes and military mining craters the ground surface is further disturbed by subsidence of the ground surface into underground excavations left from the war a significant number of subsidence events have been recorded within the last decade there is concern that ground surface subsidence could compromise the safety of visitors or workers at the site the excavations of concern include dugouts headquarters and hospitals and were excavated in chalk possible excavation types dimensions and support were investigated in the historical literature to assess the potential for ground subsidence the geological setting was investigated and the chalk was mapped and sampled to determine the geomechanical characteristics of the material the chalk was accessed in quarry excavations and in tunnels and declines that have been discovered and re opened in recent years finally the influence of excavation geometry and depth chalk condition and effects of weathering on the excavation stability were assessed using numerical simulation using a finite element program and considering voussoir beam stability interpretation of the results of this analysis allow development of general relationships between span depth and possible failure to isolate excavation classes that pose a long term hazard and to reduce the priority for those that are unlikely to fail to surface as well as those that are likely to have failed soon after construction

analysis of the evolution of ground movements in a low densely urban area by means of dinsar technique abstract this paper presents an application example of the use of the differential interferometry synthetic aperture radar technique dinsar for monitoring ground movements in a geologically complex area around the village of suria ebro basin catalonia ne spain associated to underground mining activities and to the presence of a salt dome the analysis has been mostly performed in a rural environment affected by ground movements with different patterns magnitudes and causes a total of fifty sar images recorded between 1995 and 2007 were processed to generate the interferograms in order to study the non linear trends or changes of the ground surface behavior the dinsar technique was applied in two sets of images the interferometric results in the form of vertical displacement rate maps were checked against conventional surveying and gps measurements the results present a significant discrepancy in some location due to the wrapping of the phase when both fast and significant deformations occur in order to avoid the latter effect and improve the accuracy of the results all sar images were reprocessed using topographic leveling and gps data of different monitored points to support the dinsar interpretation a detailed geological reconnaissance of the study area was carried out as well as an inventory of ground movement indicators four different patterns of ground movement have been identified active shifting subsidence associated to the progression of the mining exploitation fronts residual subsidence on abandoned galleries with a decreasing rate of closure uplifting due to the intrusion of the salt dome and sudden ground collapses sinkholes caused by the dissolution of soluble materials laying close to the ground surface

stability of a two layer quasigeostrophic vortex over axisymmetric localized topography abstract the stability of a quasigeostrophic vortex over a radially symmetric topographic feature elevation or depression in a two layer ocean on the f plane is examined this article s concern is with compensated vortices that is those in which the lower layer is at rest the disturbances however are present in both layers through numerical solution of the linear normal mode problem it is demonstrated that a bottom elevation is a stabilizing influence for a cyclone and a destabilizing influence for an anticyclone whereas a bottom depression acts in the opposite way these conclusions are interpreted using an asymptotic theory developed for the case of a thin upper layer it is demonstrated that an elevation moves the critical level of an unstable mode toward the periphery of the cyclone which leads to its stabilization estimates based on realistic oceanic parameters show that stabilization occurs for relatively small topography 5 15 of the lower layer s depth