laboratory earthquakes the sub rayleigh to supershear rupture transition we report on the experimental observation of spontaneously nucleated supershear rupture and on the visualization of sub rayleigh to supershear rupture transitions in frictionally held interfaces the laboratory experiments mimic natural earthquakes the results suggest that under certain conditions supershear rupture propagation can be facilitated during large earthquake events

spectrum of pore types and networks in mudrocks and a descriptive classification for matrix related mudrock pores matrix related pore networks in mudrocks are composed of nanometer to micrometer size pores in shale gas systems these pores along with natural fractures form the flow path permeability network that allows flow of gas from the mudrock to induced fractures during production a pore classification consisting of three major matrix related pore types is presented that can be used to quantify matrix related pores and relate them to pore networks two pore types are associated with the mineral matrix the third pore type is associated with organic matter om fracture pores are not controlled by individual matrix particles and are not part of this classification pores associated with mineral particles can be subdivided into interparticle interp pores that are found between particles and crystals and intraparticle intrap pores that are located within particles organic matter pores are intrap pores located within om interparticle mineral pores have a higher probability of being part of an effective pore network than intrap mineral pores because they are more likely to be interconnected although they are intrap om pores are also likely to be part of an interconnected network because of the interconnectivity of om particles in unlithifed near surface muds pores consist of interp and intrap pores and as the muds are buried they compact and lithify during the compaction process a large number of interp and intrap pores are destroyed especially in ductile grain rich muds compaction can decrease the pore volume up to 88 by several kilometers of burial at the onset of hydrocarbon thermal maturation om pores are created in kerogen at depth dissolution of chemically unstable particles can create additional moldic intrap pores

hiatal duration of correlative sequence boundaries from oligocene pliocene mixed carbonate siliciclastic sediments of the south florida platform abstract sequence boundaries defined by regional unconformities in mixed carbonate siliciclastic sediments have a variable duration from the margin to the interior of the florida platform factors controlling the timing and duration of these unconformities include a combination of global eustatic and regional mechanisms sediment supply current intensification integrated chronostratigraphies developed from a transect of continuous cores in the south central interior to the southern margin of the florida platform show an increase in duration of the hiatal gaps along correlative sequence boundaries toward the platform edge two sequence boundaries are correlated across the south florida platform and mark formation contacts the lower sequence boundary sb a marks the suwannee limestone arcadia formation contact and is of significantly less duration in the platform interior southwest peninsular florida 2 0 m y than at the south platform margin middle florida keys 8 1 m y the hiatal gap along the upper sequence boundary sb b marking the arcadia formation overlain by miocene pliocene sediments that vary in age and composition regionally records the same increase from the central part of the platform southwest florida arcadia fm peace river fm 1 6 m y to the south platform edge lower florida keys arcadia fm stock island fm 11 5 m y eustatic fluctuations affected the relative sedimentation rates of the mixed sediments in the platform interior and at the margin most notably the large eustatic fall at the end of the early oligocene terminated carbonate deposition of the suwannee limestone sb a sediment accumulation on the platform interior was more temporally continuous than at the margin because of greater siliciclastic input from the north the strengthening of marine currents beginning in the middle miocene limited sediment accumulation across the southern platform margin sb b and possibly caused erosion of the margin carbonates increasing the duration of the hiatal gap on top of the arcadia formation

evolution of a deep water carbonate platform upper cretaceous to pleistocene sedimentary environments on the west florida margin abstract deep water carbonates have been accumulating on the west florida margin since the early late cretaceous although the depositional style and sediment types have changed through time seven coreholes drilled by exxon record the establishment of two gently dipping aggradational ramps the first in the late cretaceous to oligocene and the second in the middle to late miocene to the present these dominantly pelagic depositional environments followed episodes of downslope transport of shallow water grains diluting background pelagic sedimentation and producing progradational ramps that built seaward this study traces the evolution of the deep water west florida sedimentary systems and contrasts the older aggradational ramp characterized by both foraminiferal and radiolarian oozes as well as volcanic ash with the late neogene ramp whose biogenic components are mainly foraminifera and coccoliths the cycles of progradation separated by periods of ramp aggradation developed as eustasy interacted with prolonged subsidence of the margin early late cretaceous as well as oceanographic changes caused by closure of the suwannee strait late oligocene to early miocene and of the isthmus of panama middle to late miocene the major transitions in environments recorded in the west florida ramp platform thus resulted from the superposition of climatic tectonic and oceanographic events on global sea level changes

improvements to field and remote sensing methods for mapping discontinuity persistence and intact rock bridges in rock slopes abstract discontinuity persistence and intact rock bridges are critical factors that influence the stability of rock slopes persistence influences the extent of pre existing potential failure surfaces and intact rock bridges can add cohesion and tensile strength to an incipient failure surface which must be destroyed before slope failure can occur despite continued research and improvements in mapping technology computing power and numerical modelling codes there is no standard recommended methodology for field characterisation of intact rock bridges or their incorporation into stability analysis we use observations from remote sensing and field mapping investigations at three open pit mines and one natural rock slope to recommend improvements to field and remote sensing methods for mapping discontinuity persistence and intact rock bridges in rock slopes we apply a fracture network engineering approach to discontinuity trace mapping using new intensity factors to describe intact rock bridge trace intensity r 21 and blast induced fracture intensity b 21 we emphasize the importance of multi scale characterisation of discontinuity persistence and rock bridges in rock slopes and we distinguish between different classes of intact rock bridges based on scale and geometry with particular attention given to the distinction between laboratory sample scale intact rock bridges on incipient discontinuities and larger rock mass bridges which represent metre or larger scale intervals of fractured rock mass that may exist between very high persistence joints and faults

permeability of sub critical carbon dioxide in naturally fractured indian bituminous coal at a range of down hole stress conditions abstract understanding reservoir dynamics from a geotechnical and petrophysical perspective is essential for safe and steady fluid extraction transport or injection in the reservoir the recent approach on storage of anthropogenic greenhouse gases ghg for mitigation of climate change in the deep geologic reservoirs has led to fast paced research on resolving storage related issues a coal seam is one such target reservoir where co 2 may be injected for storage this may be coupled with the enhanced extraction of coalbed methane cbm it is known that the interaction of co 2 with coal induces hydro mechanical changes however detailed investigation is mandatory for site specific operation the lack of such studies on indian coal is the motivation for this research a naturally fractured coal specimen was chosen and the subcritical co 2 flow was maintained by monitoring the injection pressures and ambient temperature the variations in permeability under various scenarios were also investigated the results indicate that initial co 2 injection caused coal matrix swelling which took nearly 5 6 h of flow related sorption for maximum closure of the natural fractures linear variation in flow rate with the pressure gradient across the sample indicated laminar or darcian flow of co 2 through the coal fractures deeper coal seams have high confinements the co 2 permeability results for such in situ conditions indicated an exponential decline in naturally fractured coal due to increasing confining pressures the observed reduction of co 2 permeability with increase in gas inlet pressure is debated and may be attributed fully to matrix swelling or partly to the klinkenberg effect this study is vital for successful ghg sequestration in coal seams and for better understanding of the gas flow behaviour in the seams

premonitory acoustic emissions and stick slip in natural and smooth faulted westerly granite 1 a stick slip event was induced in a cylindrical sample of westerly granite containing a preexisting natural fault by loading at constant confining pressure of 150 mpa continuously recorded acoustic emission ae data and computer tomography ct generated images of the fault plane were combined to provide a detailed examination of microscale processes operating on the fault the dynamic stick slip event considered to be a laboratory analog of an earthquake generated an ultrasonic signal that was recorded as a large amplitude ae event first arrivals of this event were inverted to determine the nucleation site of slip which is associated with a geometric asperity on the fault surface ct images and ae locations suggest that a variety of asperities existed in the sample because of the intersection of branch or splay faults with the main fault this experiment is compared with a stick slip experiment on a sample prepared with a smooth artificial saw cut fault surface nearly a thousand times more ae were observed for the natural fault which has a higher friction coefficient 0 78 compared to 0 53 and larger shear stress drop 140 compared to 68 mpa however at the measured resolution the ultrasonic signal emitted during slip initiation does not vary significantly between the two experiments suggesting a similar dynamic rupture process we propose that the natural faulted sample under triaxial compression provides a good laboratory analogue for a field scale fault system in terms of the presence of asperities fault surface heterogeneity and interaction of branching faults

the west central florida inner shelf and coastal system a geologic conceptual overview and introduction to the special issue abstract this paper provides an overview for this special publication on the geologic framework of the inner shelf and coastal zone of west central florida this is a significant geologic setting in that it lies at the center of an ancient carbonate platform facing an enormous ramp that has exerted large scale control on coastal geomorphology the availability of sediments and the level of wave energy in order to understand the holocene geologic history of this depositional system a regional study defined by natural boundaries north end of a barrier island to the apex of a headland was undertaken by a group of government and university coastal geologists using a wide variety of laboratory and field techniques it is the purpose of this introductory paper to define the character of this coastal inner shelf system provide a historical geologic perspective and background of environmental information define the overall database present the collective objectives of this regional study and very briefly present the main aspects of each contribution specific conclusions are presented at the end of each paper composing this volume

suwannee channel of the paleogene coastal plain support for the carbonate suppression model of basin formation a recently proposed model postulates that a basin separating a carbonate from an adjacent terrigenous clastic depocenter is a consequence of the neighboring depocenters rather than a precondition for their coexistence a test of the model is provided by comparison with the well studied carbonate terrigenous clastic transition of the united states coastal plain in general the model is substantiated although deviations caused by changes in sea level terrigenous clastic input and tectonism are noted

morphodynamics of the barrier inlet system west central florida the barrier inlet system along the gulf coast of peninsular florida has one of the most diverse morphologies of any barrier system in the world the delicate balance between tidal and wave generated processes on this low energy coast permits only slight changes in either of these processes to result in significant and rapidly developing morphologic responses some of these responses are the result of natural phenomena such as hurricanes opening tidal inlets closure of inlets due to longshore transport of sediment and changes in the availability of sediment tidal prism is the primary factor in controlling inlet morphology and is greatly influenced by anthropogenic activities in the backbarrier area human activity has also modified the coast in many ways over the past several decades beginning with the construction of the first causeways in the 1920s the various modifications by development have resulted in important morphodynamic changes in the barrier inlet system these include hardening the coast on the beach and at inlets dredging and filling in backbarrier environments and construction of fill type causeways connecting the islands to the mainland construction of seawalls and jetties has inhibited normal coastal processes examples include the downdrift erosion at blind pass and big sarasota pass construction of fill type causeways between the barriers and the mainland has created artificial tidal divides that reduce the tidal prism at some inlets thereby resulting in instability or closure such as blind pass and dunedin pass this is further exacerbated by dredge and fill construction that reduces tidal prism by reducing the area of open water in the backbarrier dredging of the intracoastal waterway also results in a negative impact on selected inlets by channeling tidal flux away from some inlets impacts of these changes inhibit the barrier inlet environments from responding to open coast processes

photoelastic and numerical investigation of stress distributions around fault models under biaxial compressive loading conditions abstract this paper presents the results of a photoelastic and numerical study of stress distributions contours and trajectories around fault models of various geometries submitted to a biaxial compressive load it aims to describe typical biaxial stress behaviours and emphasize the existing differences with the well known uniaxial compressive load case stress trajectories are sometimes shown by joint sets acting as markers of a paleostress field and they can be interpreted by particular shallow tension compression situations at depth fractures can be reactivated or can dilate under conditions of triaxial compression and behaviour is essentially controlled by a high stress ratio high 3 1 ratio in spite of the potential importance of such stress states on fracture permeability and fluid flow and although they are frequently found at depth in a reservoir context such stress conditions are poorly investigated particularly in terms of stress perturbations the presented analogue experiments consisted of compression tests done on polymethylmethacrylate pmma plates this material has mechanical properties comparable to those of brittle rocks in the upper crust and presents birefringence the samples contained open defects acting as faults and the stress trajectories around these faults were investigated using a photoelastic device comparable numerical experiments were realised with a finite element code franc 2d using frictionless fault models first the effect of an increasing biaxial compressive load ratio 3 1 on stress trajectories around an isolated open defect was explored it was shown that the stress trajectories were drastically modified when 3 1 increased from 0 2 to 0 4 this result being consistent with previous studies in particular when 3 1 was superior or equal to 0 4 external isotropic points around where trajectories diverged called repulsive isotropic points appeared near the tips but away from the defects they tended to move away from the defects towards the main load direction when 3 1 increased the described isotropic points were points of stress trajectory divergence i e points where stress decreased implying that zones around them were strongly unfavourable to shear reactivation second stress trajectories around fault models of various geometries oblique isolated defect dilational jog compressive jog and complex patterns were studied the applied biaxial compressive load ratio being 0 7 these biaxial stress trajectories were compared with similar uniaxial stress trajectories in order to explore the existing differences between the two regimes it enabled new stress trajectory geometries to be described and interpreted in particular numerous external repulsive isotropic points were observed and defect tips were shown to be zones of high convergence of stress trajectories furthermore in contrast to the uniaxial compressive load case stress trajectories and stress contours were geometrically similar within dilational and compressive jogs under biaxial compressive load for both jog types the centre of the overlapping zone and the areas along the wall of a jog defining fault and facing the overlapping tip of the other fault proved to be zones of low mean stress implying that fluids may migrate towards them from the tips of the faults in response to mean stress gradients furthermore the centre of the jogs exhibiting a high differential stress was a favourable area in terms of fracture reactivation which may facilitate fluids transfer and storage it was also observed that for both the uniaxial and biaxial compressive loads isotropic zones were localised at the acute angle between branching defects

a unified model for predicting earthquake induced sliding displacements of rigid and flexible slopes abstract permanent sliding displacement represents a common damage parameter for evaluating the seismic stability of slopes recently developed empirical models for the sliding displacement of shallow rigid sliding masses have demonstrated that including multiple ground motion parameters in the predictive model e g peak ground acceleration and peak ground velocity improves the displacement prediction and reduces it uncertainty a unified framework is developed that extends these empirical displacement models for application to flexible sliding masses where the dynamic response of the sliding mass is important this framework includes predicting the seismic loading for the sliding mass in terms of the maximum seismic coefficient kmax and the maximum velocity of the seismic coefficient time history k velmax the predictive models are a function of the peak ground acceleration pga peak ground velocity pgv the natural period of the sliding mass ts and the mean period of the earthquake motion tm the empirical predictive models for sliding displacement utilize kmax and k velmax in lieu pga and pgv and include a term related to the natural period of the sliding mass this unified framework provides a consistent approach for predicting the sliding displacement of rigid ts 0 and flexible ts 0 slopes

quantitative visualization methods for continuous evolution of three dimensional discontinuous structures and stress field in subsurface rock mass induced by excavation and construction an overview abstract discontinuous structures such as pores fractures joints and faults govern the physical and mechanical behavior of subsurface rock masses in underground engineering applications the excavation of subsurface energy resources and construction activities extensively change the discontinuous structures and stress distribution in the surrounding rock masses these hidden and dynamic changes are extremely difficult to detect and characterize using conventional methods and techniques and this has greatly impeded the study of the intrinsic mechanisms governing the deformation and failure of rock masses in the past few years discontinuous rock structure imaging methods and three dimensional printing 3dp technology have been successfully applied to replicate rock mass samples for geological and geophysical research purposes the combination of these methods has led to innovative ways to investigate the behavior of complex rock and guide underground engineering applications this review focuses on the characterization and visualization of 1 the interior discontinuities of rock masses and 2 the stress distribution and its continuous evolution in the discontinuous rock masses recent progress in experimental and computational methods in identifying and characterizing the discontinuous structures are presented in particular we discuss the development and process of integrating computed tomography ct 3dp technology transparent rock models and optical mechanics methods to quantitatively and visually present the interior structures and stress evolution inside rock masses

evaluation of rock anisotropy using 3d x ray computed tomography abstract the anisotropic nature of fabric and internal structures plays a significant role in fluid flow heat transfer and geomechanical behavior in rock the existence and orientation of anisotropy in various rocks have been evaluated using laboratory experiments and image analyses to characterize anisotropic pore networks micro fractures mineralogy grain fabric and stiffness from micro to macro scales we present an assessment of anisotropy in rock by systematic and planar clustering of three dimensional x ray attenuation values and associated statistical analysis on the basis that x ray ct numbers directly represent the internal density of the mineral fabric in the rock mass variation in voxel values across the slicing plane for a given orientation enables identification of the unique orientation of anisotropy in rock the proposed concept is validated using a 3d virtual structure and is applied to four different rock types the sensitivity of anisotropic features and the image noise effect are further explored to highlight the robustness of the proposed method for evaluating the anisotropy of rock fabrics

experimental investigation of strong ground motion due to thrust fault earthquakes thrust fault earthquakes are studied in a laboratory earthquake setup previously used to investigate analog strike slip seismic events dynamic mode ii ruptures are generated along preexisting faults in an analog material homalite h 100 and their interaction with the free surface is studied for both sub rayleigh and supershear rupture speeds high speed digital photography and laser velocimeter diagnostics are used synergistically to identify and study the ground velocity signatures caused by the various features of the generated ruptures the obtained surface normal motions of both sub rayleigh and supershear ruptures show substantial asymmetry between the hanging and footwall with the hanging wall experiencing much larger velocity amplitudes the main features of the surface velocity traces at various stations can be explained by the calculated arrivals of various waves and fronts mach cones pand s waves and sub rayleigh features in both the sub rayleigh and supershear cases the arrival of the rupture tip generates a prominent rayleigh wave traveling along the simulated earth s surface supershear events feature larger amplitudes of ground shaking profiles all signatures in the surface motion records attenuate and broaden with increasing distance from the fault trace the signatures corresponding to the arrival of the mach fronts attenuate with distance at a slower rate than those from sub rayleigh ruptures the arrival of the updip supershear rupture at the free surface creates a downdip propagating slip feature with its own mach cone these additional mach fronts further amplify ground shaking on the hanging and footwalls

mixed siliciclastic carbonate systems and their impact for the development of deep water turbidites in continental margins a case study from the late jurassic to early cretaceous shelburne subbasin in offshore nova scotia progradation of deltaic systems that reach the shelf edge is considered a primary mechanism to deliver sand to continental margins sediment bypass processes can dominate the outer shelf to upper slope transition causing poor preservation of reservoir quality sandstones turbidites can carry the bulk of the coarse fraction downdip where a thicker sand pile can be deposited once the channel to lobe transition is reached predicting this lateral and vertical variability along the slope is challenging this configuration can be further complicated when mixed siliciclastic carbonate systems are present the roseway missisauga case study from nova scotia is used here to explore potential implications associated with the development of deep water turbidites that are time equivalent to outer shelf mixed siliciclastic carbonate units two scenarios are possible 1 the carbonate factory is dominant and the development of carbonate reefs and pinnacles on the outer shelf prevents the passage of siliciclastic systems beyond the shelf break in this case the siliciclastic component is sequestered within the inner outer shelf 2 favorable conditions for carbonate production gradually deteriorate by the activation of fluviodeltaic systems that prograde outboard reaching the slope region in this last scenario low relief and lateral discontinuous carbonate shoals are ubiquitous in the outer shelf representing the last outboard remnants of the carbonate factory shelf edge deltas circumvent or breach these carbonate shoals establishing sedimentary pathways on the shelf break region that connect with deep water turbidites observations suggest that this last scenario is the most likely in this part of the scotian margin during the late jurassic to early cretaceous

interplay of late cenozoic siliciclastic supply and carbonate response on the southeast florida platform abstract high resolution seismic reflection data collected along the length of the caloosahatchee river in southwestern florida have been correlated to nannofossil biostratigraphy and strontium isotope chemostratigraphy at six continuously cored boreholes these data are interpreted to show a major late miocene to early pliocene fluvial deltaic depositional system that prograded southward across the carbonate florida platform interrupting nearly continuous carbonate deposition since early in the cretaceous connection of the platform top to a continental source of siliciclastics and significant paleotopography combined to focus accumulation of an immense supply of siliciclastics on the southeastern part of the florida platform the remarkably thick 100 m sand rich depositional system which is characterized by clinoformal progradation filled in deep accommodation while antecedent paleotopography directed deltaic progradation southward within the middle of the present day florida peninsula the deltaic depositional system may have prograded about 200 km southward to the middle and upper florida keys where late miocene to pliocene siliciclastics form the foundation of the quaternary carbonate shelf and shelf margin of the florida keys these far traveled siliciclastic deposits filled accommodation on the southeastern part of the florida platform so that paleobathymetry was sufficiently shallow to allow quaternary recovery of carbonate sedimentation in the area of southern peninsular florida and the florida keys

regional stratigraphic framework linking continental shelf and coastal sedimentary deposits of west central florida abstract a regional study of the holocene sequence onlapping the west central florida platform was undertaken to merge our understanding of the barrier island system with that of the depositional history of the adjacent inner continental shelf key objectives were to better understand the sedimentary processes sediment accumulation patterns and the history of coastal evolution during the post glacial sea level rise in the subsurface deformed limestone bedrock is attributed to mid cenozoic karstic processes this stratigraphic interval is truncated by an erosional surface commonly exposed that regionally forms the base of the holocene section the holocene section is thin and discontinuous and north or south of the tampa bay area is dominated by low relief sand ridge morphologies depositional geometries tend to be more sheet like nearshore and mounded or ridge like offshore sand ridges exhibit 0 5 4 m of relief with ridge widths on the order of 1 km and ridge spacing of a few kilometers the central portion of the study area is dominated nearshore by a contiguous sand sheet associated with the tampa bay ebb tidal delta sedimentary facies in this system consist mostly of redistributed siliciclastics local carbonate production and residual sediments derived from erosion of older strata hardground exposures are common throughout the study area regional trends in holocene sediment thickness patterns are strongly correlated to antecedent topographic control both the present barrier island system and thicker sediment accumulations offshore correlate with steeper slope gradients of the basal holocene transgressive surface proposed models for coastal evolution during the holocene transgression suggest a spatial and temporal combination of back stepping barrier island systems combined with open marine low energy coastal environments the present distribution of sand resources reflects the reworking of these earlier deposits by the late holocene inner shelf hydraulic regime

resurrection of a reservoir sandstone from tomographic data using three dimensional printing three dimensional 3 d printing provides an opportunity to build lab testable models of reservoir rocks from tomographic data this study combines tomography and 3 d printing to reproduce a sample of the fontainebleau sandstone at different magnifications to test how this workflow can help characterization of transport properties at multiple scales for this sandstone literature analysis has given a porosity of 11 permeability of 455 md mean pore throat radius of 15 m and a mean grain size of 250 m digital rock analysis of tomographic data from the same sample yielded a porosity of 13 a permeability of 251 md and a mean pore throat radius of 15 2 m the 3 d printer available for this study was not able to reproduce the sample s pore system at its original scale instead models were 3 d printed at 5 fold 10 fold and 15 fold magnifications mercury porosimetry performed on these 3 d models revealed differences in porosity 28 37 compared to the literature 11 and to digital calculations 12 7 mercury may have intruded the smallest matrix pores of the printing powder and led to a greater than 50 increase in measured porosity however the 3 d printed models pore throat size distribution 15 m and permeability 350 443 md match both literature data and digital rock analysis the powder based 3 d printing method was only able to replicate parts of the pore system permeability and pore throats but not the pore bodies other 3 d printing methods such as resin based stereolithography and photopolymerization may have the potential to reproduce reservoir rock porosity more accurately

field evidences for the role of static friction on fracture orientation in extensional relays along strike slip faults comparison with photoelasticity and 3 d numerical modeling fault friction is a parameter that is difficult to assess along fault zones since its determination depends on the knowledge of any factor controlling the state of stress around faults in brittle homogeneous rocks a limited number of these factors such as the shape of the fault surface the vicinity of fault tips or the remote stress ratio are crucial to constrain for this determination in this paper we propose to analyse a field example in which all these properties are met and where the nature of the slipped structure suggest differences in static friction we compare the orientations of branching fractures at strike slip relay zones between en echelon stylolites and en echelon joints both reactivated in shear the field data are compared with both photoelastic and 3 d numerical models that consider the remote stress conditions and the role of the geometry of the strike slip segments based on field observations these analyses quantitatively demonstrate the significant role of fault friction on the local stress field orientation and subsequent fracture formation this work points out that estimations of fault friction based on analyses of fracture patterns or in situ stresses must be accompanied with a thorough investigation of the 3 d fault shape its segmentation and the remote stress state

engineering geology ground surface movement and fissures induced by underground mining in the jinchuan nickel mine the jinchuan nickel mine is the largest underground mine with cut and fill mining in china in 1999 there appeared evident ground surface movement and many ground fissures in jinchuan no 2 mine following an introduction to the engineering geology and mechanical properties of the rock mass in the jinchuan mine areas this paper reveals the features of the measured in situ stresses and puts emphasis on an analysis of the mechanism of surface movement and ground fissures induced by the underground mining with backfill it is indicated that both the fault structures and the alteration contact zones are well developed as the dominant engineering geological characteristics in the jinchuan mine areas the stress redistribution in surrounding rocks resulting from the mining the low stiffness of the filling body the existence of the void space and the influence of on going mining activities is the main reason for the occurrence of surface movement and ground fissures

effects of changes in rock microstructures on permeability 3 d printing investigation rocks are naturally heterogeneous two rock samples with identical bulk properties can vary widely in microstructure understanding how the microstructure and bulk properties of rocks then evolve during experiments and computations simulating diagenesis is inherently a multiscale problem the advent of modern 3 d printing has provided an unprecedented opportunity to link those scales by combining the strengths of digital and experimental rock physics in this study we take a computerized tomography scanned model of a natural carbonate pore space then iteratively digitally manipulate 3 d print and measure the flow properties in the laboratory this approach allows us to access multiple scales digitally and experimentally and test hypotheses about how changes in rock microstructure due to compaction and dissolution affect bulk transport properties in a repeatable manner

quantitative reconstruction of younger dryas to mid holocene paleoclimates at le locle swiss jura using pollen and lake level data abstract pollen and lake level data from le locle in the swiss jura were used to quantitatively reconstruct climatic parameters for the younger dryas event and the first half of the holocene period the younger dryas cold event at le locle was characterized by i a general trend toward a slight increase in summer temperature and a decrease in annual precipitation and ii a marked drying phase at ca 11 900 cal yr b p that occurred between two wetter ones further phases of major deficit in moisture occured at ca 11 500 cal yr b p younger dryas holocene transition 10 800 cal yr b p 8700 cal yr b p and 6500 cal yr b p climatic parameters reconstructed here suggest that phases of higher lake level developing at ca 12 500 12 000 11 750 11 600 11 200 10 900 synchronous with the preboreal oscillation 10 400 8900 8400 8300 possibly related to the 8200 yr event and 7800 7000 cal yr b p coincided with an increase in annual precipitation a decrease in summer temperature and a shorter growing season conversely periods of low lake level corresponded to a decrease in annual precipitation an increase in summer temperature and a longer growing season this general pattern could have resulted from alternate southward northward displacements of the atlantic westerly jet