subsidence measurements in roads and implementation in land use plan optimisation in areas affected by deep coal mining this paper presents a study of 12 year monitoring of ground subsidence along a selected road affected by subsidences trough induced by underground black coal mining in the largest mining district in the czech republic the major scientific contribution of this study is that it suggests a new methodology that involves independent observation of a subsidence trough in the linear direction a road permitting determination of the ground deformation parameters and related building site categories in areas affected by deep coal mining it is vital to update the current status of the building site categories which represent the zones of potential hazard posed to the existing structures or future development it is possible to identify the actual conditions in the localities using systematical measurements along roads which are in any case required for periodical maintenance in areas of underground mining prognoses may be subsequently optimised in this way and investors property owners and mining companies may benefit through saving on costs associated with subsidence damage in fact there are two eventualities i e the conditions either improve or deteriorate the latter occurred in the case of the study area in the beginning the majority of the study area i e 91 belonged to the most suitable category of building sites which means that development was possible without any restrictions at the end of the observation the measurements showed a prominent fall of the subsidence trough and as much as 19 of the area fell into the least suitable categories i or ii where development is prohibited the publication recommends that mining companies use road monitoring as an independent monitoring tool to determine the hazard in regions affected by deep coal mining it is possible to conveniently verify the prognostic maps in land use planning in this way

tektites in cretaceous tertiary boundary rocks on haiti and their bearing on the alvarez impact extinction hypothesis relic tektites are associated with a pt group metal abundance anomaly and shocked minerals in a thin marl bed that marks the k t boundary on haiti the presence of these three impact produced materials at the precise k t boundary enormously strengthens the alvarez impact extinction hypothesis the tektites occur in smectite spherules that have external shapes typical of tektites their chemical and physical properties are broadly similar to those of other tektite groups except that the haitian tektites have lower si and higher fe ca and na on average they contain more sc v cu zn ga sr sn and ba and less cr ni co b mn and hf than other tektite groups amounts of rare earth elements ree in the tektites indicate that their progenitor materials were not melted mafic or ultramafic oceanic crust rather they were sedimentary deposits having a bulk composition of andesite rare tektites contain unusually high amounts of cao 20 and s 0 4 and these data suggest that some target materials consisted of caso4 anhydrite beds occur in the subsurface at two candidate impact sites chicxulub and manson sm nd isotopic data for the tektites indicate that the melted precursor sediments were most likely deposited less than 400 m y between the late cretaceous and silurian periods major chemical changes accompanied the diagenetic change of glass to smectite the haitian tektites are the first datable impact products in k t boundary rocks and 40ar 39ar ages of the glass show that the k t boundary and impact event are coeval at 64 5 0 1 ma

study of automated top coal caving in extra thick coal seams using the continuum discontinuum element method abstract in order to investigate top coal drawing regularity and automated top coal caving technology in extra thick coal seams an approach coupling the particle element and the block element is presented based on the continuum discontinuum element method cdem then the constitutive model of hydraulic support is introduced into the cdem to simulate the top coal drawing process meanwhile the bergmark roos model for coal drawing of single support is extended into the collaborative coal drawing of multiple supports to optimize the automated top coal caving technology finally cdem models of hydraulic support armored face conveyer and coal rock strata are established according to the field conditions of the tongxin coal mine then the top coal drawing mechanism is analyzed and an automated top coal caving technology is proposed the results show that under the interaction between hydraulic support and surrounding rocks the final drawing body of initial top coal drawing appears as an irregular deflected ellipsoid shape during different support moving cycles the coal rock structure affects the coal drawing amount and support resistance a statistical comparison of the coal rock drawing amount based on 100 drawing openings indicates that the standard deviation of the coal drawing amount in automated one round coal caving is 1 83 m2 less than that in traditional coal caving 8 23 m2 and the coal drawing amount from each drawing window is more uniform for multi round coal caving techniques the average recovery rate remains at 79 4 and the rock mixed rate is less than 1 based on a comparison of several coal caving techniques automated four round coal caving technology is the optimal technology in which the change rate of the standard deviation of the coal drawing amount as well as the top coal recovery rate are both largest

chemical characteristics of the crater lakes of popocatetetl el chichon and nevado de toluca volcanoes mexico abstract three crater lakes from mexican volcanoes were sampled and analyzed at various dates to determine their chemical characteristics strong differences were observed in the chemistry among the three lakes nevado de toluca considered as dormant el chichon at a post eruptive stage and popocatepetl at a pre eruptive stage not surprisingly no influence of volcanic activity was found at the nevado de toluca volcano while the other volcanoes showed a correlation between the changing level of activity and the evolution of chemical trends low phs so 4 2 and f decreased irregularly at el chichon from 1983 until 1997 major cations concentrations also diminished at el chichon a 100 increase in the so 4 2 content was measured at popocatepetl between 1985 and 1994 an increase in the mg cl ratio between 1992 mg cl 0 085 and 1994 mg cl 0 177 was observed at popocatepetl before the disappearance of the crater lake in 1994 it is concluded that chemical analysis of crater lakes may provide a useful additional tool for active volcano monitoring

utilization of engineering geology in geo tourism few case studies of subsidence influence on historical churches in ostrava karvina district czech republic this article studies a set of historical churches influenced by subsidence induced by underground coal mining in the karvina part of the upper silesian coal basin in the czech republic the research made use of engineering geological tools to assess the influence of underground mining on the ground in the cases of the churches in question variations in time of the existing subsidence have also been evaluated the herein applied method in determination of the building site categories transforms the measured macroscopically visible vertical tilts of buildings churches into horizontal tilts and it is new horizontal tilts are important characteristics expressing differential settlement however these are not measurable as the building begins in the foundation soil and the foundations would have to be exposed building site categories i e categories of hazard to determine the mining influence on buildings based on horizontal tilt were used to determine the influence of underground mining onto a building due to the fact that the churches under observation find themselves at diverse stages of subsidence we identified a great variability of subsidence and building site categories this way the churches become unique landmarks in the cultivated landscape as they frequently remain the only historical buildings in the subsidence trough thanks to rehabilitation and repeated repairs churches survive as the memorials of human life in subsidence troughs induced by underground coal mining for example in the ostrava karvina coal district coal has been mined for 200 years the fundamental argument for the nomination of the church set onto the unesco world heritage list is the fact that historical churches may remain the only traces left by people living in localities affected by underground coal mining the article would also like to point at the application of engineering geology for other than construction or environmental purposes geo tourism has this scientific and economic potential for the future

experimental constraints on shock induced microstructures in naturally deformed silicates abstract planar deformation features pdfs in various minerals have long been accepted as evidence of impact induced deformation the uniqueness of this association was challenged in the context of the k t boundary extinction debate after mosaicism and microstructures similar to pdfs were reported from the products of explosive volcanism as a result of this debate a significant volume of new experimental and observational data on the development of shock induced microstructures has become available over the last ten years the results reveal that factors such as pre shock temperature pulse duration and crystallographic orientation of target minerals to the shock wave have a primary influence on how these microstructures develop data from diamond anvil cell and high pressure friction experiments reveal that the same solid state amorphization process that produces shock induced pdfs at low temperatures also occurs at much lower strain rates in static experiments the experimental data indicate that the amorphization process is thermally activated and that the character of the resulting pdfs is a function of the applied strain rate shock induced amorphization occurs along those crystallographic planes that are most readily transformed to the high pressure phase during very short pulse durations and produces pdfs that are visible at the optical scale lower strain rate deformation produces tem scale amorphization with orientations that are more homogeneously distributed throughout the target mineral and produces no optically visible pdfs the data confirm the uniqueness of multiple intersecting sets of optically visible pdfs as a diagnostic indicator of hypervelocity impact the data also support the hypothesis that the amorphization process can occur at a wide range of strain rates and that the limiting pressure for the process is controlled by the phase stability of the target mineral under the applied loading conditions not by the hel the data also suggest that the onset pressure the maximum pressure and the pressure range for producing optically visible pdfs decrease with increasing temperature and decreasing strain rate as the pressure range for optically visible pdf formation decreases it is replaced by homogeneous amorphization as observed in the anvil cell experiments thus the uniqueness of multiple intersecting sets of optically visible pdfs to hypervelocity impact is not due to a unique process but rather to a specific set of loading conditions that produce an optically visible microstructure likewise single sets of microdeformations observed in volcanic rocks are produced by the same process but at different loading conditions that preclude the development of multiple intersecting sets of pdfs the data also indicate that shock mosaicism which occurs above the hel represents a plastic response of the target mineral to loading rates that are too large to be accommodated by crystal plastic mechanisms observational data for some naturally deformed samples from the k t boundary the vredefort dome and volcanic rocks along with the experimental observations are used to constrain the range of conditions under which the natural microstructures form and to understand the differences between microstructures produced by impact volcanic and other natural processes finally some possible mechanisms for producing the microstructures observed in volcanic rocks are proposed

mitigation of geohazards during deep excavations in karst regions with caverns a case study karst landscapes are widely distributed and different characteristics are displayed in different regions due to the effect of various natural environmental factors which occur throughout china buried karst cavern systems covered by sandy strata which are widely distributed in guangdong province possess the following features high fissure water content high rock permeability susceptibility to collapse variability in shape and an irregular distribution socket diaphragm walls are usually adopted to retain soil and to cut off groundwater during deep excavations in guangdong province for the safety of the excavation and to reduce the impact on the surroundings however geohazards often occur during the construction of diaphragm walls in karst regions causing problems such as diaphragm wall collapse water or mud ingress ground collapse and long term instability an eight step treatment technique is proposed which involves filling the karst caverns before the construction of diaphragm walls a case study using the treatment technique in maanshan park station on guangdong metro line 9 is also presented leakage of the diaphragm wall was observed during the excavation and grouting failed to seal the leakage the mechanism of the leakage process was analysed and countermeasures were undertaken

unique documentation analysis of origin and development of an undrained depression in a subsidence basin caused by underground coal mining kozinec czech republic this article aims to explain and demonstrate the origin and development of a subsidence basin caused by coal mining as well as to point out important aspects of this phenomenon in engineering geology engineering geology needs to deal with a number of issues related to the origin and development of subsidence basins in areas affected by deep coal mining an interesting case study from the upper silesian basin in the northeast of the czech republic near the polish border is presented in this paper there is a clear time chronological succession in the ground surface changes manifested by a ground subsidence gradation both in their absolute values as well as in their spatial distribution the phenomenon is documented by aerial photo time series which optimally depict the origin and development of the subsidence in the study area there are changes in the landscape elements and it is essential to be considered in future land use plans the marginal conditions of the quaternary geological structure and hydrogeological conditions are responsible for an unconfined aquifer which manifests there as a water body in an undrained depression in the course of the ground subsidence

first study of the heat and gas budget for sirung volcano indonesia with at least four eruptions over the last 20 years sirung is currently one of the more active volcanoes in indonesia however due to its remoteness very little is known about the volcano and its hyperacid crater lake we report here on the first measurements of gas and heat emissions from the volcano notable is the substantial heat loss from the crater lake surface amounting to 220 mw in addition 17 gg of so2 representing 0 8 of indonesian volcanic so2 contribution into the atmosphere 11 gg of h2s 17 gg of co2 and 550 gg of h2o are discharged into the atmosphere from the volcano annually the volatiles degassed from sirung magmas are subjected to hydrothermal fluid rock interactions and sulfide depositions initiated by the disproportionation of so2 these processes lead to distinct gas compositions and changing lake water chemistry in the sub craters and the main crater lake however the occurrence of so2 rich fluids and strong gas flux appear to highlight a rapid fluid transfer to surface avoiding re equilibration with lower temperature rocks fluids in the conduits

a review of the structure petrology and dynamic deformation characteristics of some enigmatic terrestrial structures abstract we review three categories of enigmatic terrestrial structures that have a variety of macroscopic and microscopic dynamic deformation features the first category includes the midcontinent united states cryptoexplosion structures they are of shallow origin and illustrate the effects that might be expected from a meteorite impact on a sedimentary rock terrane the second category includes the well known vredefort and sudbury plutons or basement uplifts the lesser known precambrian basement uplifts at steen river manson and carswell and the diatreme breccia dikes at the slate islands they are of relatively deep seated origin and illustrate the effects that might be expected from deep crustal or mantle processes of an explosive nature the third category includes the large landslides in areas of crystalline rocks at koefels and langtang the dynamic deformation features at these latter locations appear to be related to high strain rate tectonic processes associated with the landslide itself we conclude that microscopic dynamic deformation features which occur in natural materials may have originated from meteorite impacts from internal explosions or from high strain rate tectonic process

new links between the chicxulub impact structure and the cretaceous tertiary boundary the 200 km diameter chicxulub structure1 3 in northern yucatan mexico has emerged as the prime candidate for the cretaceous tertiary k t boundary impact crater3 6 concentric geophysical anomalies associated with enigmatic occurrences of upper cretaceous breccias and andesitic rocks led penfield and camargo1 to suspect that this structure was a buried impact basin more recently the discovery of shocked quartz grains in a chicxulub breccia3 and chemical similarities between chicxulub rocks and k t tektite like glasses3 6 have been advanced as evidence that the chicxulub structure is a k t impact site here we present evidence from core samples that chicxulub is indeed a k t source crater and can apparently account for all the evidence of impact distributed globally at the k t boundary without the need for simultaneous multiple impacts or comet showers shocked breccia clasts found in the cores are similar to shocked lithic fragments found worldwide in the k t boundary ejecta layer7 8 the chicxulub melt rocks that we studied contain anomalously high levels of iridium up to 13 5 parts per 109 also consistent with the iridium enriched k t boundary layer9 our best estimate of the crystallization age of these melt rocks as determined by 40ar 39ar analyses is 65 2 0 4 1 myr in good agreement with the mean plateau age of 64 98 0 05 myr recently reported10 furthermore these melt rocks acquired a remanent magnetization indicating that they cooled during an episode of reversed geomagnetic polarity the only such episode consistent with40ar 39ar constraints is chron 29r which includes the k t boundary

volcano hydrothermal system and activity of sirung volcano pantar island indonesia abstract sirung is a frequently active volcano located in the remote parts of western timor indonesia sirung has a crater with several hydrothermal features including a crater lake we present a timeseries of satellite images of the lake and chemical and isotope data from the hyperacid hydrothermal system the fluids sampled in the crater present the typical features of hyperacidic systems with high tds low ph and 34s h s o 4 34s s 0 among the highest for such lakes the cations concentrations are predominantly controlled by the precipitation of alunite jarosite silica phases native sulfur and pyrite which dominate the shallow portions of the hydrothermal system these minerals may control shallow sealing processes thought to trigger phreatic eruptions elsewhere sparse mg cl and so4 cl ratios and lake parameters derived from satellite images suggest gradual increase in heat and gas flux most likely so2 rich prior to the 2012 phreatic eruption an acidic river was sampled 8 km far from the crater and is genetically linked with the fluids rising toward the active crater this river would therefore be a relevant target for future remote monitoring purposes finally several wells and springs largely exceeded the world health organization toxicity limits in total arsenic and fluoride

investigation of non explosive expansion material in roof caving field application abstract effective roof caving plays a significant role in mining safety a spatiotemporal coupling fracturing method using a non explosive expansion material neem is proposed in this paper this method depends on the high fracturing capacity of the neem and a change from vertical charging to inclined charging aimed at producing new free surfaces step by step until the integrity of the entire rock is destroyed from a space time perspective the expansion stress and water adsorption of the neem were studied to determine the optimum stress increase interval and soak time with respect to the space aspect the charging sequence of boreholes was negatively correlated to their incline angles bringing the neem s superiority into full play based on the generation of new free surfaces in steps with respect to the time aspect the charging intervals of the inclined boreholes were designed to obtain the best stress compensation and highest fracturing efficiency a field trial was carried out in pingdingshan no 2 mine the results of which showed that some radial cracks were produced around the charging boreholes and that they propagated to the pilot boreholes moreover four main cracks were formed and were approximately parallel to the direction of the borehole rows in a fracturing group a fracture network was eventually generated which verified the expansion capacity of the neem and the feasibility of the spatiotemporal coupling fracturing method for field application

planar deformation features in shocked quartz a transmission electron microscopy investigation abstract we present a detailed investigation by transmission electron microscopy tem of the fine structure of planar deformation features pdf in quartz grains within which shock metamorphism has been detected optically and which originate from various sites slate islands la malbaie and manicouagan lake canada ries crater germany the toba caldera sumatra the vredefort complex in south africa and the k t boundary at raton basin colorado pdfs appear on tem micrographs as straight and very narrow tem reveals many more pdfs than are optically detected probably because only concentrations of such defects in narrow areas can induce an optically detectable contrast caution should therefore be exercised when applying criteria based on the optical observation of single or multiple sets of pdfs pdfs in samples from slate islands and raton basin exhibit a peculiar morphology a high density of very tiny bubbles precipitated on the dislocation lines comparison with the behavior of wet quartz strongly suggests that these materials experienced lengthy annealing at moderate pressure and temperature

chemical and isotopic compositions of volcanic gases from the east sunda and banda arcs indonesia the easternmost sunda arc and the banda arc represent a continent arc collision zone where magma genesis is influenced by subducted continent derived material chemical and isotopic studies of volcanic gas samples from this environment provide information on the sources of volatiles in arc magmas these volcanic gases some of which last equilibrated at magmatic temperatures are characterized by anomalous low sup 3 he sup 4 he values but by common arc values of c s approx 2 4 delta sup 13 c approx minus 3 per thousand and delta sup 34 s sub tot approx 5 per thousand abundant helium and high he ar ratios are consistent with the subduction of terrigenous components in local sediments or slivers of continental crust although individual concentration and isotope ratios of volatile components may be explicable by complex fractionation in the recycling process the combined data are in agreement with an important role of subducted sedimentary source components comparison of the authors results with volcanic gas data from other arcs indicates that the carbon and sulfur signals in arc gases are relatively insensitive to the amount and nature of sediment on the subsiding plate hence a contribution to arc volcanic gases from subducted altered oceanic crust cannot be excluded

surveillance of ruapehu crater lake new zealand by aqueous polythionates abstract aqueous sulfur speciation of samples of crater lake water from crater lake collected at mt ruapehu new zealand since 1968 has been determined using high performance liquid chromatography polythionates s x o 6 2 are produced in the lake through reactions between sulfur dioxide and hydrogen sulfide gases from the subaqueous fumaroles their concentrations vary from 0 to a few hundred mg l corresponding to the activity of the volcano the concentration of the total polythionates s x o 6 2 s 4 o 6 2 s 5 o 6 2 s 6 o 6 2 is found to be a good indicator of changes in the subaqueous fumarolic activity at crater lake the molar s x o 6 2 cl ratios of the lake water can be used to divide the volcanic activity of crater lake into four stages 1 stage i period of weak volcanic activity with no hydrothermal explosions this stage is characterized by low total s x o 6 2 with a distribution order of s 5 o 6 2 s 4 o 6 2 s 6 o 6 2 h 2 s is predominant among dissolved gases in the lake water 2 stage iia quiescent period with minor hydrothermal explosions the lake water contains high s x o 6 2 with a distribution order of s 5 o 6 2 s 4 o 6 2 s 6 o 6 2 dissolved h 2 s and so 2 gases are very low 3 stage iib increased fumarolic activity with frequent hydrothermal explosions low s x o 6 2 with a distribution order of s 4 o 6 2 s 5 o 6 2 s 6 o 6 2 sulfur dioxide but no h 2 s is detected in the water 4 stage iii period of phreatomagmatic eruptions with lahars and intensive seismic activity no s x o 6 2 exists but dissolved so 2 is high in the lake water the moderate sized explosion of december 8 1988 which was not preceded by any changes in lake water polythionate chemistry or seismic activity is hypothesized to be a vent cleaning eruption caused by blockage of ascending magmatic gases that was caused by solidification of a molten sulfur pool at the bottom of crater lake

condensation of volatile elements in high temperature gases of mount st helens abstract the cooling of high temperature 675 650 c volcanic gases in silica tubes produces successive condensation of volatile elements as solids on the inner walls of the tubes the chemistry of the solid phases obtained by these reactions varies along the temperature gradient 675 400 c fe3o4 and sio2 occur above 570 c mos2 and fewo4 are mainly enriched between 570 and 480 c nacl and kcl occur in the range 550 450 c and cds occurs at 520 450 c pb and bi sulfides are typical of the low temperature zone 480 400 c thermodynamic calculations performed to define the nature of the stable solid phases in equilibrium with the oxygen sulfur and chlorine fugacities of the gas phase show that the observed solid phases reflect a formation in a low o2 fugacity environment the chemistry of fumarolic incrustations collected around high temperature vents 300 c 5 15 cm below the surface reveals that condensation processes similar to those observed in the tubes occur naturally in the ground these incrustations show marked differences with those generally collected at the outlet of fumarolic vents where reactions with atmospheric gases and wall rocks are the major processes leading to the formation of these incrustations

effect of kcl on melting in the mg2sio4 mgsio3 h2o system at 5 gpa to examine the effect of kcl bearing fluids on the melting behavior of the earth s mantle we conducted experiments in the mg2sio4 mgsio3 h2o and mg2sio4 mgsio3 kcl h2o systems at 5 gpa in the mg2sio4 mgsio3 h2o system the temperature of the fluid saturated solidus is bracketed between 1 200 1 250 c and both forsterite and enstatite coexist with the liquid under supersolidus conditions in the mg2sio4 mgsio3 kcl h2o systems with molar cl cl h2o ratios of 0 2 0 4 and 0 6 the temperatures of the fluid saturated solidus are bracketed between 1 400 1 450 c 1 550 1 600 c and 1 600 1 650 c respectively and only forsterite coexists with liquid under supersolidus conditions this increase in the temperature of the solidus demonstrates the significant effect of kcl on reducing the activity of h2o in the fluid in the mg2sio4 mgsio3 h2o system the change in the melting residues indicates that the incongruent melting of enstatite enstatite forsterite silica rich melt could extend to pressures above 5 gpa in kcl bearing systems in contrast to the behavior in the kcl free system

dating of mining induced subsidence based on a combination of dendrogeomorphic methods and in situ monitoring abstract mining induced subsidence is a worldwide environmental problem that leads to damage to infrastructure and property thus knowledge of its past recent development is critically needed during land use planning moreover the temporal occurrence of subsidence is greatly variable with tendencies for gradual to abrupt movements subsidence rates can currently be achieved via radar interferometry but these data usually cover short time periods and are less accurate in forested areas in such cases dendrogeomorphic dating can provide chronologies of past subsidence activity in addition comparisons of tree ring based data with in situ monitoring may answer the sensitivity and reliability of dating methods in these specific conditions of continuous ground movement geomorphic mapping and dendrogeomorphic dating were performed at two forested landslide sites affected by coal mining subsidence in the upper silesian basin czech republic and the resulting chronology from one site was compared with levelling campaigns occurring from 1998 to 2015 based on 284 increment cores from 71 trees we were able to identify 7 subsidence events at the site dominated by a pioneering forest and 19 subsidence events at the site overgrown by a mature forest with the most frequent responses occurring from 1956 to 1971 and 2005 2011 the occurrence of multiple compression wood growth intervals some occurring in different directions of tree stems more than 30 of sampled trees indicated complex deformations presented by the flow like mechanism of waterlogged surfaces ongoing subsidence spreading and fragmentation of larger blocks and grabens a comparison of tree ring based chronology with in situ monitoring revealed good synchronicity with the periods of increased subsidence rates between 1 and 3 m year 1 thus indicating the high relevance of dendrogeomorphic methods for the determination of the most intense periods of ground subsidence our results show the first comparison of dendrogeomorphic methods with in situ monitoring of human induced subsidence areas and provide an alternative option for reconstructing decadal to centennial development of the affected areas

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

geochemistry of the acid kawah putih lake patuha volcano west java indonesia abstract kawah putih is a summit crater of patuha volcano west java indonesia which contains a shallow 300 m wide lake with strongly mineralized acid sulfate chloride water the lake water has a temperature of 26 34 c ph s tot 2500 4600 ppm and cl 5300 12 600 ppm and floating sulfur globules with sulfide inclusions are common sulfur oxyanion concentrations are unusually high with s 4 o 6 2 s 5 o 6 2 s 6 o 6 2 2400 4200 ppm subaerial fumaroles thermodynamic modeling of the lake fluids indicates that the lake water is saturated with silica phases barite pyrite and various pb sb cu as bi bearing sulfides when sulfur saturation is assumed precipitating phases predicted by the model calculations are consistent with the bulk chemistry of the sulfur rich bottom sediments and their identified mineral phases much of the lake water chemistry can be explained by congruent rock dissolution in combination with preferential enrichments from entering fumarolic gases or brines and element removal by precipitating mineral phases as indicated by a comparison of the fluids volcanic rocks and lake bed sediment flank springs on the mountain at different elevations vary in composition and are consistent with local rock dissolution as a dominant factor and ph dependent element mobility discharges of warm sulfate and chloride rich water at the highest elevation and a near neutral spring at lower level may contain a small contribution of crater lake water the acid fluid induced processes at patuha have led to the accumulation of elements that are commonly associated with volcano hosted epithermal ore deposits the dispersal of heavy metals and other potentially toxic elements from the volcano via the local drainage system is a matter of serious environmental concern

the sirung volcanic boiling spring an extreme chloride rich acid brine on pantar lesser sunda islands indonesia abstract the sirung volcano with a history of phreatomagmatic outbreaks has its present active center within a 1000 m wide subsidence crater the sirung crater lake scl has 15 g l 1 cl and 19 g l 1 so4 ph 0 75 temperature 40 c a highly saline brine sirung boiling spring sbs boils to the surface beside the lake it contains 116 g l 1 cl ph 1 4 chemical geothermometers indicate a reservoir temperature of 240 c the maximum depth of this reservoir is estimated to be 400 m the stable isotope composition is d 12 and 18o 5 0 to 6 0 tritium in the sbs is 0 0 tu in the scl 4 6 tu evidence against invading seawater as a source is the negative d value in addition to the six times higher cl concentration of the sbs evaporites are rejected as a source of the cl because of the geologic setting the average cl h 2 o ratio in sirung volcanic glasses as estimated by microprobe is very close to the cl h 2 o ratio of 0 047 for the sbs the zero tritium level in the sbs its high cl concentration and the acid character are other evidences for magmatic water as source for the sbs the acid sbs is poor in sulphur which may have been precipitated at depth as sulphides theories on porphyry cu formation in volcanic arc environments invoke highly saline brines as the transporting agent the acid saline brines from the sirung and white island new zealand craters and cl rich crater lakes associated with andesitic volcanism in subduction zones indicate that such fluids occur more frequently at the surface than has been possibly realized hitherto

laboratory simulation of explosive volcanic loading and implications for the cause of the k t boundary intense explosive volcanism was simulated by preheating samples to 600 c and subjecting them to dynamic stress pulses of 0 9 and 1 3 gpa the resultant ejecta was examined optically and by transmission electron microscopy tem deformation and failure was entirely by brittle fracture and most fractures were irregular and intergranular none of the features typical of k t boundary sediments and of ejecta from meteorite impact craters planar deformation features amorphization mosaicism were observed there were also no signs of intracrystalline plasticity we conclude that explosive volcanism is incapable of producing the microstructural features seen at the k t boundary and that they must have been caused by impact of a large meteorite

processes and behaviors of block topple avalanches resulting from carbonate slope failures due to underground mining major rock landslides are the main type of geological hazards in the mountainous areas of southwestern china in which failure modes and behaviors are compounded in this study field surveys centrifuge modelling and numerical simulations were utilized to analyze the failure process of a steep dip and layered carbonate slope which was induced by underground goaf these included gravitational bending interlayer faulting topple failure of the upper blocks due to underground mining shearing through the underlying slide resistant rocks and catastrophic avalanches it was concluded that the bending and compaction of the weak interbedded coal seam had occurred on the slope with the effects of gravity the support for the overburden rocks was lost following the underground mining activities which led to bedding separation and the generation of cracks the upper blocks acted on blocks at the toe and shear failure at the toe was initiated when the force along the joints exceeded the anti shear strength which gradually formed an intact failure surface then a rock slide took place which transformed into a catastrophic rock avalanche the failure process was validated using a flac3d simulation and centrifuge testing

crater lake and post eruption hydrothermal activity el chichon volcano mexico abstract explosive eruptions of volcan el chichon in chiapas mexico on march 28 and april 3 4 1982 removed 0 2 km3 of rock to form a 1 km wide 300 m deep summit crater by late april 1982 a lake had begun to form on the crater floor and by november 1982 it attained a maximum surface area of 1 4 105 m2 and a volume of 5 106 m3 accumulation of 4 5 m of rainfall between july and october 1982 largely formed the lake in january 1983 temperatures of fumaroles on the crater floor and lower crater walls ranged from 98 to 115 c by october 1983 the maximum temperature of fumarole emissions was 99 c in january 1983 fumarole gas emissions were greater than 99 vol h2o with traces of co2 so2 and h2s the water of the lake was a hot t 52 58 c acidic ph 0 5 dilute solution 34 046 mg l 1 dissolved solids cl s 20 5 sediment from the lake contains the same silicate minerals as the rocks of the 1982 pyroclastic deposits together with less than 1 of elemental sulfur the composition and temperature of the lake water is attributed to 1 solution of fumarole emissions 2 reaction of lake water with hot rocks beneath the lake level 3 sediments washed into the lake from the crater walls 4 hydrothermal fluids leaching sediments and formational waters in sedimentary rocks of the basement 5 evaporation and 6 precipitation

influence of underground mining activities on the slope deformation genesis doubrava vrchovec doubrava ujala and staric case studies from czech republic abstract one the most important manifestation of underground mining activities is its potential influence on the initiation and reactivation of the slope movements however an adequate attention has not yet been paid to these problems the goal of this study is to analyze the possible influence of present and former mining activities on the selected set of model slope deformations in the ostrava karvina coalfield and also to describe a methodology for their observation for the application to similar conditions and influence three different methodologies applied in three different case studies of slope deformations where the subsidences are still active in the first case study doubrava vrchovec inclinometer was not used in the second doubrava ujala case study only one inclinometer was installed in landslide body and in the third case study sta ic two inclinometers were installed as one of them was inside of the landslide body while the other inclinometer was outside for evaluation of the impact isocatabase maps terrain deformation parameters calculated for the point lying on the slope deformation surface length measurement by zone extensometer and dilatometer measurement in cracks was also provided in order to show that inclination of both boreholes is an evidence of underground mining impact localization of inclinometer measurement on boreholes in the active part as well as in the near vicinity was found as very important thus the study contributed to a more objective knowledge of these problems of interest for the professional public and also for the state administration to solve problems associated with the utilization and settlement of such affected areas

variations in the building site categories in the underground mining region of doubrava czech republic for land use planning abstract in terms of demands and needs of ground investigation and foundation engineering the engineering geological conditions in the underground mining territories represent anthropogenically influenced areas in the most complicated manner since they suffer the impacts from the underground mining of mineral resources the subjects of observation are the so called building site categories which represent a certain risk factor that must be taken into consideration during foundation engineering and engineering geological studies in the undermined territories it is necessary to realise that underground mining is an anthropogenic geodynamic process which significantly varies over time due to mining change and consequently with variations in the position shape and size of subsidence in a subsidence basin all the above mentioned variations should be mandatory knowledge for land use planners engineering geologists geotechnicians foundation engineers and designers because of the evident logicality of these needs this work presents a case study ostrava karvina coal district in the north east of the czech republic of variations in the building site categories over time and the results show that the chronology of the changes has a very significant influence in this area of interest the results of the building site category evaluation imply that the majority of the interest area falls within relatively good conditions for founding all kinds of structures however it was then necessary to consider variations over time in the surface area of less suitable building site categories a trend certainly confirmed the existence of the previously presumed mutual relationship between building site categories and subsidence size distribution it is apparent from the analytic results of the relationship between building site categories and planned development that the negative impacts of mining have been only partly considered or completely disregarded in the development planning process consequently future land use planners should carefully consider these particular building site categories as the most important and significant factors in the undermining of a region in this manner development can be successfully planned for present and future safety

volcanic lake systematics ii chemical constraints abstract a database of 373 lake water analyses from the published literature was compiled and used to explore the geochemical systematics of volcanic lakes binary correlations and principal component analysis indicate strong internal coherence among most chemical parameters compositional variations are influenced by the flux of magmatic volatiles and or deep hydrothermal fluids the chemistry of the fluid entering a lake may be dominated by a high temperature volcanic gas component or by a lower temperature fluid that has interacted extensively with volcanic rocks precipitation of minerals like gypsum and silica can strongly affect the concentrations of ca and si in some lakes a much less concentrated geothermal input fluid provides the mineralized components of some more dilute lakes temporal variations in dilution and evaporation rates ultimately control absolute concentrations of dissolved constituents but not conservative element ratios most volcanic lake waters and presumably their deep hydrothermal fluid inputs classify as immature acid fluids that have not equilibrated with common secondary silicates such as clays or zeolites many such fluids may have equilibrated with secondary minerals earlier in their history but were re acidified by mixing with fresh volcanic fluids we use the concept of degree of neutralization as a new parameter to characterize these acid fluids this leads to a classification of gas dominated versus rock dominated lake waters a further classification is based on a cluster analysis and a hydrothermal speedometer concept which uses the degree of silica equilibration of a fluid during cooling and dilution to evaluate the rate of fluid equilibration in volcano hydrothermal systems

the microstructural response of quartz and feldspar under shock loading at variable temperatures shock recovery experiments were carried out on westerly granite and hospital hill quartzite targets in the peak pressure range 8 to 25 gpa preshock temperatures of 25 450 and 750 c and pulse durations of 2 to 7 s using internally heated momentum traps and explosive plane wave generators optical and transmission electron microscopy analyses of quartz and feldspar shocked at 25 c revealed the previously documented progression with increasing pressure 1 fracturing 2 planar fractures and shock mosaicism 3 shock mosaicism and planar deformation features pdfs and 4 isotropization this same sequence is observed for experiments at elevated preshock temperature but with specific microstructures occurring at lower pressures than those in previous experiments at room temperature at 750 c strong shock mosaicism partially thermally recovered is characteristic of feldspar shocked to 8 gpa whereas 15 gpa is required for its development in quartz and for the generation of pdfs in both minerals the results suggest that threshold pressures for formation of the various microstructures and phases are expected to vary systematically as a function of the preshock temperature of the target material we suggest that pdfs are generated in the shock transition by progressive heterogeneous phase transformation of the crystal structure to form dense glass or high pressure polymorphs the onset pressures for pdfs in specific crystallographic orientations is not influenced strongly by temperature but the character of the pdfs does change as preshock temperature is increased at the same peak shock stress the change from multiple sets of thin pdfs at low temperature to thicker single sets of pdfs at moderate temperature and finally to complete isotropization at high temperatures reflects a change in the phase transformation mechanism as a function of temperature in contrast development of shock mosaicism in quartz and feldspar occurs throughout the duration of shock loading and is better developed at elevated temperatures where the kinetics are enhanced by the additional thermal energy in the target

distinguishing shocked from tectonically deformed quartz by the use of the sem and chemical etching abstract multiple sets of crystallographically oriented planar deformation features pdfs are generated by high strain rate shock waves at pressures of 12 gpa in naturally shocked quartz samples on surfaces pdfs appear as narrow 50 500 nm lamellae filled with amorphosed quartz diaplectic glass which can be etched with hydrofluoric acid or with hydrothermal alkaline solutions in contrast slow strain rate tectonic deformation pressure produces wider semi linear and widely spaced arrays of dislocation loops that are not glass filled etching samples with hf before examination in a scanning electron microscope sem allows for unambiguous visual distinction between glass filled pdfs and glass free tectonic deformation arrays in quartz this etching also reveals the internal pillaring often characteristic of shock induced pdfs this technique is useful for easily distinguishing between shock and tectonic deformation in quartz but does not replace optical techniques for characterizing the shock features

on reported occurrences of shock deformed clasts in the volcanic ejecta from toba caldera sumatra reports of shock deformed phenocrysts from the toba ignimbrite deposits sumatra have prompted considerable debate over whether shock deformation products are clear evidence of a meteorite impact origin for the cretaceous tertiary k t boundary deposits as well as terrestrial cryptoexplosion structures evidence presented in favor of volcanically induced shock at toba includes kinked biotites and rare occurrences of single sets of lamellae in quartz grains but rests most heavily upon occurrences of mosaic extinction patterns in plagioclase phenocrysts our analysis of several of the same toba samples reveals that these mosaic patterns are related to distinct compositional zoning and cannot be attributed to deformation of the crystal lattice that shock would produce additionally in more than 200 quartz grains examined we detected no occurrences of microdeformation features or mosaic textures similar to those associated with known impact structures and the k t boundary we conclude that evidence of shock deformation in the toba deposits has not been demonstrated

an investigation by transmission electron microscopy of planar deformation features in naturally shocked quartz we have investigated by transmission electron microscopy tem the planar deformation features pdf in quartz from various sites where shock metamorphism has been detected optically impact sites the vredefort complex south africa and the k t boundary at raton basin colorado pdfs are straight narrow bands of glass or microtwins or huge densities of dislocations such contrasting microstructures must reflect different shock scenarios in the vredefort complex the post shock thermal history has strongly overprinted the shock induced defects in the raton basin samples very tiny bubbles have precipitated on the dislocations strongly suggesting a lengthy annealing at moderate pressure and temperature this new information should be taken into account in any model of the origin of the k t transition in any case observation of pdfs by optical microscopy alone is not sufficient to unambiguously conclude on their origin

carbon sources in arc volcanism with implications for the carbon cycle new co2 3 he data from the east sunda arc indonesia confirm earlier observations that arc volcanic gases have higher co2 3 he ratios than mor environments on average 80 of arc volcanic co2 is recycled exogene carbon addition of a few percent of carbonate bearing sediments to the mantle wedge explains much of the carbon abundance andcarbon isotopic data of arc gases but can not explain the he isotope observations the co2 3he in arc volcanoes is not strongly dependent on the composition of modem trough sediments e g deep sea clays vs carbonate rich sequences and calcite veins in the hydrothermally altered subducted slab may provide a contribution to the recycled carbon flux of arcs the sum of globally deep subducted sediment and slab carbon exceeds the estimated arc co2 flux and approximately 3 5 teramole of carbon may return annually to the mantle in convergent zones the modem combined processes of mor volcanism slab alteration and subduction volcanism do not produce a substantial carbon flux into the exosphere and rate changes in ocean floor spreading are unlikely to cause major changes in atmospheric co2 as a result of changes in the volcanic co2 fluxes intense pulses of flood basalt volcanism however may alter the co2 contents of the atmosphere over the course of a millenium or so and influence global climate

particle geochemistry of volcanic plumes of etna and mount st helens particles in volcanic plumes include vapor condensates and reaction products of ash with vapors or condensed liquids in addition to abundant silicate particles in the 1980 mount st helens plume we detected abundant na k cl crystals as well as ca sulfates the latter commonly as overgrowths on ash or anthropogenic particles many of the chloride particles contained zinc and cadmium high temperature fumarolic incrustations showed strong enrichments of arsenic zinc alkalis and iron at etna we did not detect chloride crystals but found abundant al fe and ca sulfates sulfuric acid droplets were ubiquitous in both plumes bulk analyses of fumarole incrustations at etna showed an enrichment in the rare earth elements ree the chemical and textural data of the plume particles indicate that chloride particles form relatively early and react later with sulfuric acid droplets to form sulfates at etna aluminum as well as some ree are probably transported as volatile fluorine compounds the differences in plume chemistry between etna and mount st helens are most likely related to differences in f cl ratios of the vapors based on the abundance of particulate chlorine in plumes we suggest that only a small fraction of the total chlorine released during an eruption might reach the stratosphere in the vapor phase

zoning method for mining induced environmental engineering geological patterns considering the degree of influence of mining activities on phreatic aquifer abstract environmental engineering geological patterns eegps are the generalized manifestation of environmental engineering geology with the protection of phreatic water resources as the core especially in mining areas with fragile eco geological environment based on the formation mechanism of mining induced eegps with the aim of win win between protection of phreatic water resources and exploitation of coal resources this study presents a zoning method for eegps taking the yushenfu mining area in northern shaanxi china as a case study four types of eegps basically unaffected model gradually restored model after destruction gradually deteriorated model and disaster model were defined separately on the basis of the degree of influence of mining activities on phreatic aquifer the zoning method for eegps was proposed firstly the height of water flowing fractured zone wffz and the residual aquifuge thickness were calculated using multivariate linear regression method secondly according to the relationship among phreatic water leakage groundwater recharge and variation in groundwater level the thickness of laterite loess and bedrock as the thresholds between the eegps were separately determined thirdly based on the thresholds between eegps and the linear variation of residual aquifuge thickness combination the zoning criteria for eegps were formulated finally the zoning results were obtained furthermore the verification of the types of eegps in coalfaces and the comparison between the zoning results obtained using variable weight theory and those given in the present study indicated that the zoning results presented in the current study are more accurate and reasonable the research results can provide theoretical basis for solving the contradiction between coal resource exploitation and eco geological environmental protection

fluid immiscibility in volcanic environments volatile components enter the atmosphere oceans and other surface waters through pre syn and post eruptive volcanic processes that involve a variety of fluids aluminosilicate poor fluids include aqueous or carbonic to sulfide sulfate chloride fluoride carbonate and phosphate rich compositions in volcanic environments but other more complex combinations of these constituents may be involved giggenbach 1977 roedder 1984 1992 lowenstern 1995 other rare gases and dissolved constituents e g h2 n2 he ar h3bo3 hg ch4 and other hydrocarbon compounds metals and metalloids are also present but in general they are not sufficiently concentrated to form their own phases or control bulk fluid composition and volcanic processes as a result of their diverse compositions volcanic fluids ranging from vapor to liquid exhibit widely different densities and show strong distinctions in heat capacity dielectric behavior viscosity and other chemical and physical characteristics geiger et al 2006a the density of a saline liquid in the system nacl h2o at 50 mpa and 800 c for example is more than 7 times that of the coexisting aqueous vapor e g 0 2 gm cm3 henley and mcnabb 1978 multiple fluids move mix and or unmix in magma chambers and volcanic conduits in the root zone of fumaroles and in the convective hydrothermal systems that are ubiquitous to volcanic environments hydrothermal systems are typically centered on magmatic intrusions and may include crater lakes at the top of eruptive conduits hydrothermal processes involving two or more fluid phases operate through a variety of geologically relevant shallow crustal pressure temperature composition conditions volcanic fluids occur at supersolidus to subsolidus conditions meaning that the dense aluminosilicate melt that is common to volcanism may or may not be present this chapter addresses the evidence for and occurrence of two or more low density aluminosilicate poor fluids

research on the surface movement in a mountain mining area a case study of sujiagou mountain china landslides caused by underground mining are very common in mountain mining areas and thus threaten human lives and assets under the superposed influence of underground mining and landslides surface movement in mountain areas is different from that in flat areas further understanding of the law of surface movement in mountain mining areas can protect the locals and their assets in this study an improved survey technique called spherical fitting real time kinematic was employed to monitor surface movement regularly and similar material simulation was used as a supplement to reveal the process of strata failure results showed that the ground would uplift during underground mining in the valley bottom areas an action that caused the subsidence velocity curve to appear as a skewed distribution instead of a gaussian distribution to improve the prediction accuracy the prediction model of surface subsidence in mountain mining areas was updated the mountain surface subsidence prediction system was developed using visual basic finally the mechanism of mining landslide was studied this work is of general interest to the professional public and it will contribute to a more objective knowledge of understanding the surface movement in mountain mining areas