exploring the factors that influence the perception of risk the case of volcan de colima mexico abstract volcan de colima has increased its activity considerably since 1998 with four periods of effusion and since 2003 daily vulcanian explosions during 2005 the magnitude of the explosivity increased producing many pyroclastic flows two of which reached over 5 km from the volcano making them the largest events since the last plinian eruption in 1913 a significant risk is also presented by the lahar hazard with various examples of damage to infrastructure during the last few years and 23 people killed in 1955 nearly 5000 people live in small settlements within 15 km of the volcano since 1997 six studies have been carried out in the region in an attempt to define the relationship that exists between the population and its neighbour although the methodologies used were different each study considered the results of the previous and attempted to contribute further data to define geographical variation in the perception of risk the results of the studies highlight the minor role of increasing activity on risk perception and distance from the volcano was shown to not directly influence risk perception in most cases it is the combination of various socio cultural historical and political factors that defines the perception of volcanic risk within these villages by studying the social representation of the risk such complexity could be better understood the 1997 2000 information campaign evidently improved risk perception however it is clear that this type of program needs to be continued to achieve a long lasting impact increased knowledge however does not guarantee willing participation in official risk mitigation strategies

an inversion strategy for hydraulic tomography coupling travel time and amplitude inversion summary we present a hydraulic tomographic inversion strategy with an emphasis on the reduction of ambiguity of hydraulic travel time inversion results and the separation of the estimated diffusivity values into hydraulic conductivity and specific storage our tomographic inversion strategy is tested by simulated multilevel interference slug tests in which the positions of the sources injection ports and the receivers observation ports isolated with packers are varied simulations include the delaying effect of wellbore storage on travel times which are quantified and shown to be of increasing importance for shorter travel distances for the reduction of ambiguity of travel time inversion we use the full travel time data set as well as smaller data subsets of specified source receiver angles the inversion results of data subsets show different resolution characteristics and improve the reliability of the interpretation the travel time of a pressure pulse is a function of the diffusivity of the medium between the source and receiver thus it is difficult to directly derive values for hydraulic conductivity and specific storage by inverting travel times in order to overcome this limitation we exploit the great computational efficiency of hydraulic travel time tomography to define the aquifer structure which is then input into the underlying groundwater flow model modflow 96 finally we perform a model calibration amplitude inversion using the automatic parameter estimator pest enabling us to separate diffusivity into its two components hydraulic conductivity and specific storage

a bayesian approach for inversion of hydraulic tomographic data 1 hydraulic tomography is a promising methodology that shows the potential to map subsurface hydraulic properties at an unprecedented level of detail by interpreting a suite of hydraulic tests in the present work we apply the hydraulic tomography concept to a multiple pulse multiple receiver mpmr cross well configuration which consists of two boreholes subdivided into intervals by packers a short pressure or flow pulse is applied sequentially to all the intervals and for each perturbation the transient heads are recorded at the remaining intervals the resulting tomograms are inverted within the bayesian framework by using the pilot point approach in addition to the values of the hydraulic conductivity at the pilot points we assume that the stochastic parameters of the spatial variability model the structural parameters are unknown using synthetic two dimensional and three dimensional examples we demonstrate the effectiveness of the mpmr configuration and the inversion procedure for characterizing the spatial variability of the hydraulic conductivity with limited or no prior information we observed that increasing the number of source points the locations at which the pulse is alternatively applied provides more details on the spatial variability and that the parameters of the hydrogeological model of spatial variability are inferred with an acceptable although variable level of accuracy in particular the theoretical variance of the log conductivity is estimated with large errors while the estimate of the anisotropic integral scales depends on the distance between the boreholes inversion preserves the overall spatial pattern of hydraulic conductivity although low conductivity values are less connected in the inferred than in the true conductivity fields

volcanic risk and tourism in southern iceland implications for hazard risk and emergency response education and training abstract this paper examines the relationship between volcanic risk and the tourism sector in southern iceland and the complex challenge emergency management officials face in developing effective volcanic risk mitigation strategies an early warning system and emergency response procedures were developed for communities surrounding katla the volcano underlying the m rdalsjokull ice cap however prior to and during the 2007 tourist season these mitigation efforts were not effectively communicated to stakeholders located in the tourist destination of orsmork despite its location within the hazard zone of katla the hazard zone represents the potential extent of a catastrophic jokulhlaup glacial outburst flood furthermore volcanic risk mitigation efforts in orsmork were based solely on information derived from physical investigations of volcanic hazards they did not consider the human dimension of risk in order to address this gap and provide support to current risk mitigation efforts questionnaire surveys were used to investigate tourists and tourism employees hazard knowledge risk perception adoption of personal preparedness measures predicted behaviour if faced with a katla eruption and views on education results indicate that tourists lack hazard knowledge and they do not adopt preparedness measures to deal with the consequences of an eruption despite a high level of risk perception tourism employees lack knowledge about the early warning system and emergency response procedures results show that tourists are positive about receiving information concerning katla and its hazards and therefore the reticence of tourism employees with respect to disseminating hazard information is unjustified in order to improve the tourism sector s collective capacity to positively respond during a future eruption recommendations are made to ensure adequate dissemination of hazard risk and emergency response information most importantly education campaigns should focus on a increasing tourists knowledge of katla jokulhlaup and other volcanic hazards and b increasing tourist and employee awareness of the early warning and information system and appropriate behavioural response if a warning is issued further tourism employees should be required to participate in emergency training and evacuation exercises annually these efforts are timely given that katla is expected to erupt in the near future and international tourism is an expanding industry in orsmork

different communities different perspectives issues affecting residents response to a volcanic eruption in southern iceland this research investigates residents knowledge and perception of the katla volcano and emergency response procedures in all rural and urban communities located in the eastern and southern katla hazard zones using a questionnaire survey conducted in 2008 we demonstrate that there is an apparent difference between rural and urban communities knowledge and perceptions and identify some of the issues influencing residents perspectives and behaviour all rural and most urban residents have an accurate knowledge of katla the proposed warning system and emergency response plan urban residents perceived the emergency response plan to be appropriate in comparison rural residents did not perceive the emergency response plan as appropriate rural residents stated that they would personally assess the situation before deciding on a course of action independent of the proposed plan livelihood connections and inherited knowledge affect rural residents ability and willingness to comply with the recommended procedures factors such as hazard knowledge sense of community and attachment to place indicate that rural residents are more resilient to volcanic hazards based on our findings we recommend that emergency management agencies consider issues such as personal responsibility neighbourliness and community involvement and cooperation to develop and implement more appropriate volcanic risk mitigation strategies in light of the recent eyjafjallajokull eruptions we provide a brief discussion on the 2010 emergency response although our findings are iceland specific our recommendations may be applied internationally to other volcanic and disaster prone regions

identification of groundwater basin shape and boundary using hydraulic tomography abstract shapes and boundary types of a groundwater basin play essential roles in the analysis of groundwater management and contaminant migration hydraulic tomography ht a recently developed new approach for high resolution characterization of aquifers is not only an inverse method but a logical strategy for collecting non redundant hydraulic information in this study ht was applied to synthetic 2 d aquifers to investigate its feasibility to map the irregular shapes and types of the aquifer boundaries we first used the forward model of vsaft2 to simulate hydraulic responses due to ht surveys in the aquifer with irregular geometry and predetermined constant head conditions at some boundaries and no flow conditions at others the simsle simultaneous successive linear estimator inverse model in vsaft2 was then used to interpret the simulated ht data to estimate the spatial distribution of hydraulic properties of the aquifer using a domain with a wrong geometry surrounded by boundaries of a constant head condition the inverse modeling experiment used steady state and transient states data from the ht forward simulations and it used the same monitoring network as in the aquifer with irregular geometry to assess the ability of ht for detecting types and shapes of the boundary as well as heterogeneity in the aquifer results of the experiment show that no flow boundaries which were incorrectly treated as constant head boundaries in inverse models were portrayed as low permeable zones of the aquifer near the boundaries overall the results show that ht could delineate not only the irregular shape of the aquifer in general but also heterogeneity in the aquifer improvements of the estimation with prior information of transmissivity and storage coefficient was also investigated the study shows that using homogeneous initial guess parameters resulted in a slightly better estimate than others moreover this study employs monte carlo simulations to ensure statistically meaningful conclusions

characteristics of high resolution hydraulic head profiles and vertical gradients in fractured sedimentary rocks summary accurately identifying the position of vertical hydraulic conductivity k v contrasts is critical to the delineation of hydrogeologic units that serve as the basis for conceptual and numerical models of groundwater flow high resolution head profiles have identified the position and thickness of k v contrasts in clayey aquitards but this potential has not yet been thoroughly evaluated in sedimentary rocks this paper describes an experiment in which head profiles with the highest technically feasible resolution were obtained using westbay multilevel systems mls installed in 15 cored holes at three sedimentary rock research sites with contrasting geologic and flow system conditions mlss were installed to maximum depths between 90 and 260 m with 2 5 monitoring zones per 10 m head profiles were measured over multiyear periods the vertical component of hydraulic gradient i e vertical gradient was calculated for each pair of adjacent monitoring intervals in every mls and then categorized based on its repeatability to facilitate interpretation of k v contrasts and comparisons within boreholes between boreholes at the same site and between sites the head and vertical gradient profiles from all three sites display systematic i e simple geometric shapes defined by repeatable intervals of no to minimal vertical gradient indicating relatively high k v units bounded by shorter depth intervals with large up to 50 m m vertical gradients indicating relatively low k v units the systematic nature of the profiles suggests flow in regular and interconnected fracture networks rather than dominated by a few key fractures with irregular orientations the low k v units were typically thin with their positions and thicknesses not predicted by lithostratigraphy or detailed lithologic geophysical and horizontal hydraulic conductivity data hence the position and thickness of units with contrasting k v would not be evident if mlss with the conventional number of monitoring zones had been used furthermore the detailed profiles can be strongly diagnostic of hydrogeologic unit boundaries or layers and can be used to improve the quantitative assessment of flow system conditions that is foundational to understanding contaminant plume migration

nh _4 in pegmatitic feldspars from the southern black hills south dakota trace amounts of ammonium ion 0 7 mol nh 4 substitution have been identified from the infrared spectra of alkali feldspars from pegmatites occurring in the southern black hills district south dakota the spectroscopic data indicate that the ammonium is structurally bound most likely in the m site of the microcline these results indicate that ammonium was likely a component of metamorphic fluids present during anatexis of metasedimentary rocks in the southern black hills district

the relative importance of head flux and prior information in hydraulic tomography analysis using cross correlation analysis we demonstrate that flux measurements at observation locations during hydraulic tomography ht surveys carry nonredundant information about heterogeneity that are complementary to head measurements at the same locations we then hypothesize that a joint interpretation of head and flux data even when the same observation network as head has been used can enhance the resolution of ht estimates subsequently we use numerical experiments to test this hypothesis and investigate the impact of flux conditioning and prior information such as correlation lengths and initial mean models i e uniform mean or distributed means on the ht estimates of a nonstationary layered medium we find that the addition of flux conditioning to ht analysis improves the estimates in all of the prior models tested while prior information on geologic structures could be useful its influence on the estimates reduces as more nonredundant data i e flux are used in the ht analysis lastly recommendations for conducting ht surveys and analysis are presented

geomorphology natural hazards vulnerability and prevention of natural disasters in developing countries the significance of the prevention of natural disasters is made evident by the commemoration of the international decade for natural disaster reduction idndr this paper focuses on the role of geomorphology in the prevention of natural disasters in developing countries where their impact has devastating consequences concepts such as natural hazards natural disasters and vulnerability have a broad range of definitions however the most significant elements are associated with the vulnerability concept the latter is further explored and considered as a key factor in understanding the occurrence of natural disasters and consequently in developing and applying adequate strategies for prevention terms such as natural and human vulnerabilities are introduce and explained as target aspects to be taken into account in the reduction of vulnerability and for prevention and mitigation of natural disasters the importance of the incorporation not only of geomorphological research but also of geomorphologists in risk assessment and management programs in the poorest countries is emphasized

aquifer heterogeneity characterization with oscillatory pumping sensitivity analysis and imaging potential 1 periodic pumping tests in which a fluid is extracted during half a period then reinjected have been used historically to estimate effective aquifer properties in this work we suggest a modified approach to periodic pumping test analysis in which one uses several periodic pumping signals of different frequencies as stimulation and responses are analyzed through inverse modeling using a steady periodic model formulation we refer to this strategy as multifrequency oscillatory hydraulic imaging oscillating pumping tests have several advantages that have been noted including no net water extraction during testing and robust signal measurement through signal processing through numerical experiments we demonstrate additional distinct advantages that multifrequency stimulations have including 1 drastically reduced computational cost through use of a steady periodic numerical model and 2 full utilization of the aquifer heterogeneity information provided by responses at different frequencies we first perform fully transient numerical modeling for heterogeneous aquifers and show that equivalent results are obtained using a faster steady periodic heterogeneous numerical model of the wave phasor the sensitivities of observed signal response to aquifer heterogeneities are derived using an adjoint state based approach which shows that different frequency stimulations provide complementary information finally we present an example 2 d application in which sinusoidal signals at multiple frequencies are used as a data source and are inverted to obtain estimates of aquifer heterogeneity these analyses show the different heterogeneity information that can be obtained from different stimulation frequencies and that data from several sinusoidal pumping tests can be rapidly inverted using the steady periodic framework

hydraulic tomography analog outcrop study combining travel time and steady shape inversion summary travel time and steady shape inversions are complementary methods for tomographic aquifer characterization in this work a combined procedure is presented that facilitates determination of spatial hydraulic conductivity and specific storage distributions in heterogeneous groundwater systems the procedure is applied to a highly heterogeneous sedimentary aquifer analog that is implemented as a two and three dimensional case study in a numerical flow model by interpreting the observations from multiple simulated short term pumping tests the main hydraulic features of the analog are successfully reconstructed the final results demonstrate the encouraging potential of the combined procedure for identifying the dominant structural elements and composition of sedimentary aquifers however limits derived from the test design of hydraulic travel time tomography in our synthetic case study prevented us from resolving small scale 10 cm in size variability of hydraulic conductivity with high discrepancies up to 5 orders of magnitude a better reconstruction of the aquifer hydraulic parameters is expected by utilizing a larger amount of measurements which involve more test and observation intervals although such a test design would be less feasible for field applications still this newly combined scheme is very attractive for an up scaled reconstruction on the sub meter scale for the present case study representative parameter values could be estimated in a computationally efficient way

improved predictions of saturated and unsaturated zone drawdowns in a heterogeneous unconfined aquifer via transient hydraulic tomography laboratory sandbox experiments summary interpretation of pumping tests in unconfined aquifers has largely been based on analytical solutions that disregard aquifer heterogeneity in this study we investigate whether the prediction of drawdown responses in a heterogeneous unconfined aquifer and the unsaturated zone above it with a variably saturated groundwater flow model can be improved by including information on hydraulic conductivity k and specific storage s s from transient hydraulic tomography tht we also investigate whether these predictions are affected by the use of unsaturated flow parameters estimated through laboratory hanging column experiments or calibration of in situ drainage curves to investigate these issues we designed and conducted laboratory sandbox experiments to characterize the saturated and unsaturated properties of a heterogeneous unconfined aquifer specifically we conducted pumping tests under fully saturated conditions and interpreted the drawdown responses by treating the medium to be either homogeneous or heterogeneous we then conducted another pumping test and allowed the water table to drop similar to a pumping test in an unconfined aquifer simulations conducted using a variably saturated flow model revealed 1 homogeneous parameters in the saturated and unsaturated zones have a difficult time predicting the responses of the heterogeneous unconfined aquifer 2 heterogeneous saturated hydraulic parameter distributions obtained via tht yielded significantly improved drawdown predictions in the saturated zone of the unconfined aquifer and 3 considering heterogeneity of unsaturated zone parameters produced a minor improvement in predictions in the unsaturated zone but not the saturated zone these results seem to support the finding by mao et al 2011 that spatial variability in the unsaturated zone plays a minor role in the formation of the s shape drawdown time curve observed during pumping in an unconfined aquifer

3 d transient hydraulic tomography in unconfined aquifers with fast drainage response we investigate through numerical experiments the viability of three dimensional transient hydraulic tomography 3dtht for identifying the spatial distribution of groundwater flow parameters primarily hydraulic conductivity k in permeable unconfined aquifers to invert the large amount of transient data collected from 3dtht surveys we utilize an iterative geostatistical inversion strategy in which outer iterations progressively increase the number of data points fitted and inner iterations solve the quasilinear geostatistical formulas of kitanidis in order to base our numerical experiments around realistic scenarios we utilize pumping rates geometries and test lengths similar to those attainable during 3dtht field campaigns performed at the boise hydrogeophysical research site bhrs we also utilize hydrologic parameters that are similar to those observed at the bhrs and in other unconsolidated unconfined fluvial aquifers in addition to estimating k we test the ability of 3dtht to estimate both average storage values specific storage ss and specific yield sy as well as spatial variability in storage coefficients the effects of model conceptualization errors during unconfined 3dtht are investigated including 1 assuming constant storage coefficients during inversion and 2 assuming stationary geostatistical parameter variability overall our findings indicate that estimation of k is slightly degraded if storage parameters must bemore jointly estimated but that this effect is quite small compared with the degradation of estimates due to violation of structural geostatistical assumptions practically we find for our scenarios that assuming constant storage values during inversion does not appear to have a significant effect on k estimates or uncertainty bounds less

risk assessment of residential buildings for an eruption of furnas volcano sao miguel the azores this paper presents the results of a study of the risks to human settlements of a future eruption of the furnas volcano in the azores it makes use of previous geological studies to estimate the likely impact of the volcanic hazards on the surrounding settlements given an eruption comparable with the last major eruption in the island in 1630 it presents the results of a comprehensive building by building survey of the settlements at risk to determine the exposure of the residential building stock to these hazards and it uses data from recent experience of volcanic eruptions elsewhere to estimate the vulnerability of the buildings to each hazard and the likely scale of human casualties and building damage the paper concludes with some recommendations for preparedness and protective measures which could be taken before an eruption to reduce the risk of human casualties from roof and building collapses principal among these are recommendations for strengthening the lateral load resistance of buildings built with the traditional vernacular techniques to better resist groundshaking during eruptions and earthquakes upgrading local building code requirements with view to increasing the live load resistance of roofs to levels similar to those applied in areas of heavy snowfalls to prevent roof collapse from tephra loading other preparedness measures are also discussed with respect to volcanic earthquakes volcanic bomb impact pyroclastic flows and tephra falls many aspects of this paper are relevant to other volcanic areas around the world

theology and disaster studies the need for dialogue abstract in hazard analysis the conventional wisdom holds that disasters are features of either human vulnerability and or de moralised nature the notion of the act of god has been almost completely replaced using examples of volcanic eruptions and christian theology it is argued that many actual and potential victims of hazards continue to explain losses in theistic terms even in societies where individuals are aware of alternative scientific and social explanations in christianity attempts to reconcile god s love justice and omnipotence on the one hand and human suffering on the other is termed theodicy and it is proposed that recent developments allow more fruitful dialogue to take place between hazard analysts and theologians than has been the case hitherto during the international decade for natural disaster reduction 1990 2000 a consensus emerged that if responses to disaster are to be successfully managed then an awareness of local culture is vitally important this consensus has continued as research agendas are currently being formulated for the international strategy for disaster reduction in many disaster prone regions religion is an essential element of culture and must be carefully considered in the planning process and not simply dismissed as a symptom of ignorance superstition and backwardness

experimental monitoring of carbon dioxide by low power ir sensors soil degassing in the furnas volcanic centre azores abstract in october 1993 two experimental carbon dioxide sensors were installed at the furnas volcanic centre sao miguel the monitoring sites are tilt meter stations in furnas village and at castelo branco on the sw caldera rim the selection of these observation sites is meant to record changes in carbon dioxide outgassing close to an active fumarole ground furnas village 3 m deep well and at an outer caldera wall castelo branco 6 m deep well where geothermal processes are definitely absent recording of carbon dioxide was made for one year by hourly readings from october 1993 to october 1994 the experiment revealed carbon dioxide pulses characterised by short rise times hours and fading on the time scale of days interpretation of the data in relation to meteorological conditions is preliminary and suggestive an overall covariation of carbon dioxide outgassing and changes in atmospheric pressure and or precipitation is observed at the calderas fumarole grounds of the furnas village a favoured degassing mechanism is based on increased out diffusion of carbon dioxide from the soil layer at the onset of low pressure intervals due to increased boiling and carbon dioxide release from the shallow local hydrothermal aquifers increased soil degassing after heavy rain is attributed to closure of the porous surface layer resulting in an increased partial pressure of carbon dioxide at the base of the instrument well at the castelo branco station which is located on a narrow ridge some 20 m above the surroundings the opposite effect of barometric pressure is observed on the very low carbon dioxide flux this still unexplained covariation may be related to chemical conditions within the soil during high pressure dry soil and low pressure wet soil periods after every impulsive increase in carbon dioxide flux the normal baseline is slowly reached a periodic effect on soil degassing to a first approximation of tidal origin cannot be excluded at castelo branco it is concluded that the experimental sensors are adequate for detailed long standing evaluation of monitoring sites which needed prior to permanent monitoring of soil degassing

nitrogen in future biosphere studies this article suggests a theme for future nitrogen studies involving the functioning and evolution of the biosphere together with certain aspects of human biology it is hoped that this theme could be developed into a multi authored book at some point in the future although numerous new case studies may be required the biosphere can be considered to be a single interactive system comprised of numerous component parts including the atmosphere rain rivers lakes oceans continental ecosystems marine ecosystems soils and sediments in order to study the internal complexity of each of the components and the relationships that exist between them one can choose a common theme the author believes that nitrogen is a good prospect because of its ubiquitous nature and complex chemistry the burial of sedimentary volatiles in the continental crust has contributed to the long term chemical evolution of the exterior environments of the earth the most marked effects notably the accumulation of atmospheric oxygen have been due to the burial of reduced carbon an understanding of the passage of sedimentary volatiles through the crust will provide important constraints on the evolution of the biosphere and may lead to a more meaningful comparative planetology carbon is difficult to trace through crustal processes because its high temperature form graphite is incompatible with the crystal structures of silicate minerals however the high temperature form of sedimentary nitrogen ammonium readily enters into potassic minerals and it can be easily traced through crustal processes herein the fate of sedimentary nitrogen is traced from wet sediments through metamorphic rocks into granites and other crustal melts without the trapping of nitrogen in the crust and the liberation of oxygen that is a consequence of biological nitrogen fixation the n2 o2 of the atmosphere may have been about 82 9 to 16 3 and the total atmospheric pressure about 1 2 atm most of the changes in the oxygen content is due to dilution by nitrogen with only about 5 of the present atmospheric oxygen being a consequence of nitrogen fixation the ancient continental surfaces would have been volcanic deserts containing little 1 ppm or no nitrogen today nitrogen rich soils support continental ecosystems one can use nitrogen as a window to speculate on the colonisation of the continents by land plants herein nitrogen fixation by legumes is considered in detail and by drawing analogies with the present day the author speculates on the colonisation of the continents by land plants having speculated on the co evolution of the atmosphere soils and continental ecosystems one can place a human being in the centre of a tropical forest and begin to examine how they relate to the modern biosphere the chosen example is the metabolism of plant protein and the roles of glutamate dehydrogenase gdh vitamin b2 and flavin mononucleotide fmn the realisation of this theme would imply numerous new case studies notably those concerning the continental crust where nitrogen studies were linked to mineralogy petrology and other geochemical tracers including sr o al and k and where the short range order of 15n were taken into consideration

health hazards and disaster potential of ground gas emissions at furnas volcano sao miguel azores a health hazard assessment of exposure to soil gases carbon dioxide and radon was undertaken in the village of furnas located in the caldera of an active volcano a soil survey to map the area of soil gas flow was undertaken gas emissions were monitored at fumaroles and in eight houses and a preliminary radon survey of 23 houses in the main anomaly area was performed potential volcanic sources of toxic contamination of air food and water were also investigated and ambient air quality was evaluated about one third 41 ha of the houses were located in areas of elevated carbon dioxide soil degassing unventilated confined spaces in some houses contained levels of carbon dioxide which could cause asphyxiation mean indoor radon levels exceeded uk and us action levels in the winter months a tenfold increase in radon levels in one house over 2 h indicated that large and potentially lethal surges of carbon dioxide could occur without warning toxic exposures from the gaseous emissions and from contamination of soil and water were minimal but sulphur dioxide levels were mildly elevated close to fumaroles in contrast evidence of dental fluorosis was manifested in the population of the nearby fishing village of ribeira quente where drinking water in the past had contained elevated levels of fluoride the disaster potential of volcanic carbon dioxide in the area could also be associated with the hydrothermal system storing dissolved carbon dioxide beneath the village felt or unfelt seismic activity or magma unrest especially with a reawakening of explosive volcanic activity 30 probability in the next 100 years could result in an increase in gas flow or even a gas burst from the hydrothermal system a survey of all houses in furnas is advised as structural measures to prevent the ingress of soil gases including radon were needed in some of the study houses evaluations of the human hazards of volcanic gases should be undertaken in all settlements in volcanic and hydrothermal areas associated with soil gas emissions

derivation of site specific relationships between hydraulic parameters and p wave velocities based on hydraulic and seismic tomography derivation of site specific relationships between hydraulic parameters and p wave velocities based on hydraulic and seismic tomography brauchler r 1 doetsch j 1 2 dietrich p 3 sauter m 4 eth zurich department of earth sciences sonneggstrasse 5 8092 zurich switzerland now at earth sciences division lawrence berkeley national laboratory one cyclotron road berkeley ca 94720 ufz helmholtz centre for environmental research department monitoring and exploration technologies permoserstrasse 15 04318 leipzig germany geoscientific centre university of gottingen goldschmidtstrase 3 37077 gottingen germany

characterizing subsurface hydraulic heterogeneity of alluvial fan using riverstage fluctuations strategic environmental research and development program serdp er 1365 environmental security and technology certification program estcp er201212 nsf ear from the united state 1014594 jilin university from department of education china global expert award through tianjin normal university from the thousand talents plan of tianjin city from china taiwan typhoon and flood research institute national applied research laboratories natural science foundation of china 51409029

a field assessment of high resolution aquifer characterization based on hydraulic travel time and hydraulic attenuation tomography 1 in this study the potential of an inversion approach based on hydraulic travel time and hydraulic attenuation tomography was assessed both hydraulic travel time and hydraulic attenuation tomography are based on the transformation of the transient groundwater flow equation into the eikonal equation using an asymptotic approach the eikonal equation allows the calculation of pressure propagation and attenuation along trajectories which is computationally efficient the attenuation and travel time based inversion approaches are naturally complementary hydraulic travel times are determined by the hydraulic diffusivity a combination of hydraulic conductivity and specific storage whereas the attenuation is determined solely by specific storage the potential of our hydraulic tomographical approach was investigated at a well characterized sand and gravel aquifer located in the leine river valley near gottingen germany the database for the hydraulic inversion consists of 392 cross well slug interference tests performed between five wells in which the positions of the sources injection ports and the receivers observation ports isolated with double packer systems were varied between tests the results have shown that the combination of hydraulic travel time and hydraulic attenuation tomography allows the reconstruction of the diffusivity and storage distribution in two and three dimensions with a resolution and accuracy superior to that possible with type curve analysis

volcanic risk perception and adjustment in a multi hazard environment hazard risk perceptions and protective behaviors are examined for wildfires earthquakes and volcanic activity data were gathered in two northern california usa communities that are exposed to all three hazard types it was found that resident risk perceptions approximated the risks calculated by experts personal risks associated with fires were significantly lower than property risks associated with the same threat the discrepancy between person and property risks for earthquakes and volcanic activity was much smaller in general it was found that the number of protective adjustments undertaken for each hazard was small averaging about half of the possible number measured when combined in a regression analysis risk perception was not a statistically significant predictor of number of adjustments for any of the three hazards resident s sense of responsibility for self protection and experience with property damage were significant predictors of adjustment for all three hazards information seeking behavior was significantly related to protective actions for earthquakes and volcanic activity but not for fire hazards in general an insufficient number of residents reported experience with personal injury or harm to make meaningful assessments of the effect of this variable on adjustments

should hydraulic tomography data be interpreted using geostatistical inverse modeling a laboratory sandbox investigation the robust performance of hydraulic tomography ht based on geostatistics has been demonstrated through numerous synthetic laboratory and field studies while geostatistical inverse methods offer many advantages one key disadvantage is its highly parameterized nature which renders it computationally intensive for large scale problems another issue is that geostatistics based ht may produce overly smooth images of subsurface heterogeneity when there are few monitoring interval data therefore some may question the utility of the geostatistical inversion approach in certain situations and seek alternative approaches to investigate these issues we simultaneously calibrated different groundwater models with varying subsurface conceptualizations and parameter resolutions using a laboratory sandbox aquifer the compared models included 1 isotropic and anisotropic effective parameter models 2 a heterogeneous model that faithfully represents the geological features and 3 a heterogeneous model based on geostatistical inverse modeling the performance of these models was assessed by quantitatively examining the results from model calibration and validation calibration data consisted of steady state drawdown data from eight pumping tests and validation data consisted of data from 16 separate pumping tests not used in the calibration effort results revealed that the geostatistical inversion approach performed the best among the approaches compared although the geological model that faithfully represented stratigraphy came a close second in addition when the number of pumping tests available for inverse modeling was small the geological modeling approach yielded more robust validation results this suggests that better knowledge of stratigraphy obtained via geophysics or other means may contribute to improved results for ht

chemistry of waters from furnas volcano sao miguel azores fluxes of volcanic carbon dioxide and leached material abstract the well constrained hydrology of the furnas caldera permits the quantification of the precipitation evapotranspiration runoff and the groundwater discharge out of the volcanic structure chemical composition of the discharge in furnas has been stable for at least a century a hydrogeochemical survey and discharge measurement of the springs and runoff in furnas allow estimates of chemical fluxes from the volcanic structure a tectonically controlled lineament of high carbon dioxide flux has been identified across the caldera floor three water types are encountered in furnas hydrothermal carbonated and cold waters the hydrothermal waters originate from shallow aquifers which derive their heat from local intrusions at shallow depth 100 200 m at about 160 c the carbonated waters some of which are steam heated by discharge from underlying thermal aquifers occurs above the carbon dioxide anomaly across the caldera floor extensive leaching in some cases stoichiometric of glassy volcanic rocks by these mildly acid carbonated waters supplies most of the dissolved solids in furnas waters chemical flux estimates for the volcano show that carbon dioxide 9358 tons yr leached silica 3994 tons yr and leached sodium 2628 tons yr are the dominating mobile components of the system

geostatistical inverse modeling for the characterization of aquitard heterogeneity using long term multi extensometer data abstract the classical aquitard drainage model compac was used to simulate the deformation of a one dimensional vertically heterogeneous aquitard i e heter compac by coupling heter compac with the quasi linear geostatistical inversion approach the vertical heterogeneities of hydraulic conductivity k v elastic specific storage s ske and inelastic specific storage s skp fields could be characterized with the availability of long term multi extensometer data the methodology was first tested through a group of ten synthetic cases with randomly generated k v s ske and s skp fields results of the synthetic cases revealed that a geostatistical model could characterize the variability of aquitard hydraulic parameter fields and yields improved fits of simulated versus observed zone deformation than a geological model that treats each zone to be homogeneous subsequently the methodology was applied to a research site situated in changzhou city jiangsu province china where long term deformation behaviors of the strata within the aquifer aquitard system have been monitored vertical heterogeneities of k v s ske and s skp fields of the investigated aquitard at the site were characterized using the quasi linear geostatistical approach the correlation length of the three fields that yielded the best quality fit was assessed to be approximately 50 m and the fitting quality was slightly improved in comparison with that produced from calibrating a geological or zonation model through monte carlo analysis of aquitard deformation utilizing the inversed parameters and corresponding uncertainties the investigated aquitard is estimated to have compacted 914 8 42 6 mm before the rise in groundwater levels in adjoining aquifers

characterization of aquifer heterogeneity using transient hydraulic tomography 1 hydraulic tomography is a cost effective technique for characterizing the heterogeneity of hydraulic parameters in the subsurface during hydraulic tomography surveys a large number of hydraulic heads i e aquifer responses are collected from a series of pumping or injection tests in an aquifer these responses are then used to interpret the spatial distribution of hydraulic parameters of the aquifer using inverse modeling in this study we developed an efficient sequential successive linear estimator ssle for interpreting data from transient hydraulic tomography to estimate three dimensional hydraulic conductivity and specific storage fields of aquifers we first explored this estimator for transient hydraulic tomography in a hypothetical one dimensional aquifer results show that during a pumping test transient heads are highly correlated with specific storage at early time but with hydraulic conductivity at late time therefore reliable estimates of both hydraulic conductivity and specific storage must exploit the head data at both early and late times our study also shows that the transient heads are highly correlated over time implying only infrequent head measurements are needed during the estimation applying this sampling strategy to a well posed problem we show that our ssle can produce accurate estimates of both hydraulic conductivity and specific storage fields the benefit of hydraulic tomography for ill posed problems is then demonstrated finally to affirm the robustness of our ssle approach we apply the ssle approach to a hypothetical three dimensional heterogeneous aquifer

comparison of aquifer characterization approaches through steady state groundwater model validation a controlled laboratory sandbox study 1 groundwater modeling has become a vital component to water supply and contaminant transport investigations an important component of groundwater modeling under steady state conditions is selecting a representative hydraulic conductivity k estimate or set of estimates which defines the k field of the studied region currently there are a number of characterization approaches to obtain k at various scales and in varying degrees of detail but there is a paucity of information in terms of which characterization approach best predicts flow through aquifers or drawdowns caused by some drawdown inducing events the main objective of this paper is to assess k estimates obtained by various approaches by predicting drawdowns from independent cross hole pumping tests and total flow rates through a synthetic heterogeneous aquifer from flow through tests specifically we 1 characterize a synthetic heterogeneous aquifer built in the sandbox through various techniques permeameter analyses of core samples single hole cross hole and flow through testing 2 obtain mean k fields through traditional analysis of test data by treating the medium to be homogeneous 3 obtain heterogeneous k fields through kriging and steady state hydraulic tomography and 4 conduct forward simulations of 16 independent pumping tests and six flow through tests using these homogeneous and heterogeneous k fields and comparing them to actual data results show that the mean k and heterogeneous k fields estimated through kriging of small scale k data core and single hole tests yield biased predictions of drawdowns and flow rates in this synthetic heterogeneous aquifer in contrast the heterogeneous k distribution or k tomogram estimated via steady state hydraulic tomography yields excellent predictions of drawdowns of pumping tests not used in the construction of the tomogram and very good estimates of total flow rates from the flow through tests these results suggest that steady state groundwater model validation is possible in this laboratory sandbox aquifer if the heterogeneous k distribution and forcing functions boundary conditions and source sink terms are characterized sufficiently

volcanic geology of furnas volcano sao miguel azores abstract furnas is the easternmost of the three active central volcanoes on the island of sao miguel in the azores unlike the other two central volcanoes sete cidades and fogo furnas does not have a well developed edifice but consists of a steep sided caldera complex 8 5 km across it is built on the outer flanks of the povoacao nordeste lava complex that forms the eastern end of sao miguel constructive flanks to the volcano exist on the southern side where they form the coastal cliffs and to the west the caldera margins tend to reflect the regional local tectonic pattern which has also controlled the distribution of vents within the caldera and areas of thermal springs activity at furnas has been essentially explosive erupting materials of trachytic composition products associated with the volcano include plinian and sub plinian pumice deposits ignimbrites and surge deposits phreatomagmatic ashes block and ash deposits and dome materials most of the activity has occurred from vents within the caldera or on the caldera margin although strombolian eruptions with aa flows of ankaramite and hawaiite have occurred outside the caldera the eruptive history consists of at least two major caldera collapses followed by caldera infilling based on 14 c dates it appears that the youngest major collapse occurred about 12 000 10 000 years bp new 14 c dates for a densely welded ignimbrite suggest that a potential caldera forming eruption occurred at about 30 000 years bp recent eruptions

stochastic structure constrained image guided inversion of geophysical data abstractinverse modeling of geophysical data involves the recovery of a subsurface structural model and the distribution of petrophysical properties independent information regarding the subsurface structure is usually available with some uncertainty from the expertise of a geologist and possibly accounting for sedimentary and tectonic processes we have used the available structural information to construct a model covariance matrix and to perform a structure constrained inversion of the geophysical data to obtain a geophysical tomogram m we have considered that the geologic models y were built from random variables and were described with a priori probability density function in the bayesian framework we have explored for the a posteriori probability density of the geologic models i e the structure of the guiding image with the markov chain monte carlo method and we inverted at the same time in a deterministic framework the geophysical data the sampling of the geologic models was performed

hydrous species in feldspars a reassessment based on ftir and sims recent interest in hydrogen incorporation in feldspars has been driven by the potential of this common mineral species to record magmatic water contents accurate measurement of h concentrations in feldspars by fourier transform infrared ftir spectroscopy is hampered by the need to collect polarized spectra in three mutually perpendicular directions which can be impractical for crystals characterized by small dimensions polysynthetic twinning and or chemical zoning sims is an attractive alternative to ftir offering high spatial resolution high precision and the feasibility of attaining low detection limits in this study we compare ftir and sims data for 19 feldspars including plagioclase anorthoclase sanidine microcline and orthoclase we present adjustments to previously published ftir data on some of these samples our new sims and ftir data are well correlated and we demonstrate the feasibility of quantitatively measuring h concentrations as low as 1 2 ppmw h 2o using sims combination of the new data together with re evaluation of the nmr calibration of johnson and rossman 2003 indicates that the ir absorption coefficients for hydrous species in feldspar increase with decreasing frequency of their o h absorptions in accord with theory we derive new molar integral ir absorption coefficients i for feldspars with the following hydrous species as defined by johnson and rossman 2003 type i and ii h 2o microcline and orthoclase i 120 470 11 360 l mol 1 h 2o cm 2 type iib oh sanidine i 150 000 15 000 l mol 1 h 2o cm 2 type iia oh plagioclase and anorthoclase i 202 600 20 260 l mol 1 h 2o cm 2 these absorption coefficients depend on critical assumptions with regards to sims matrix effects if accurate one important implication is that the h concentrations of plagioclase crystals estimated in the literature are too high by up to a factor of two requiring revision of previously estimated plagioclase melt h partitioning coefficients

a temporal sampling strategy for hydraulic tomography analysis 1 this paper investigates optimal sampling times of drawdowns for the analysis of hydraulic tomography ht survey the investigation was carried out by analyzing the spatial and temporal evolution of cross correlations between the head responses at an observation well and transmissivity t and storage coefficient s properties during a pumping test in homogeneous and heterogeneous aquifers the analysis shows that the cross correlation between the head and s values is limited to the region between the observation and the pumping well in the aquifers it reaches the highest value near the early time tm and decays to zero afterwards the time tm is approximately equal to the time t0 at which the extrapolated drawdown from the first straight line portion of an observed drawdown log time plot becomes zero at early times the high cross correlation between the head and t is confined to the region between the observation and the pumping well this region then evolves into two humps one on each side of the circular region encompassing the observation well and the pumping well the size of the two humps expands and their values reach the maximum as flow reach steady state as a consequence we hypothesize that pairs of head data at t0 and those at either the steady state or a late time during an ht survey could yield the best estimates of the heterogeneous t and s fields results from numerical experiments have verified this hypothesis and demonstrated that this sampling strategy is generally applicable even when the boundary condition is unknown we therefore recommend in principle that 1 carrying out pumping tests of ht surveys for sufficiently long period of time such that drawdown reaches the entire area of interest and 2 using a constant head or zero drawdown for all boundaries during the inverse modeling analysis

detection of karst conduit patterns via hydraulic tomography a synthetic inverse modeling study abstract karst aquifers are geologic media that consist of enlarged solution conduits the geometry of such conduits is very difficult to delineate and its hydraulic parameters such as hydraulic conductivity k and specific storage ss are difficult to estimate hydraulic tomography ht shown to successfully map the hydraulic heterogeneity of porous and fractured rock aquifers may also be effective in karst aquifers in this study we utilize two synthetic karst aquifers with the branchwork and network conduit patterns bcp and ncp to explore the ability of ht to map conduit patterns and their hydraulic parameters prior to the ht analysis forward models are built to study groundwater flow through synthetic karst aquifers to generate data and to gain insights into flow patterns forward modeling results reveal that 1 flow rates at the outlet of the bcp model is higher than the ncp model even when the same water injection rates are applied at the wells 2 the location of the injection well has a significant impact on the flow rate at the outlet and 3 flow lines mainly follow the conduit pattern these results suggest that the accurate mapping of karst networks is critical next the ht analysis of these data is conducted using a set of six models bcp and ncp to map the heterogeneity of different conduit systems under steady state and transient flow conditions inverse modeling results reveal that the estimated k maps become more reliable as the number of injection tests and the corresponding monitoring data are increased in the ht analysis moreover the results of the bcp model is closer to the original conduit pattern in comparison to the ncp model a comparative study of three inverse models with different number of observation wells and assuming the availability of geological data has shown that a more reliable pattern of the conduits can be mapped by adding geological information even when a small number of observation wells are available overall our results confirm the feasibility of ht in detecting major conduits as well as being able to differentiate between the bcp and ncp network types

on the importance of geological data for three dimensional steady state hydraulic tomography analysis at a highly heterogeneous aquifer aquitard system abstract hydraulic tomography ht has been shown to map subsurface heterogeneity accurately through the joint interpretation of multiple pumping tests previous research has shown that smooth hydraulic conductivity k estimates are obtained beyond where pumping observation data are available using the geostatistical inversion approach when the inversion begins with a homogeneous k and when data densities are not high however geological data are typically available through outcrops and borehole logs to provide geological variability therefore we investigate the usefulness of geological data for ht analysis at a highly heterogeneous field site by 1 comparing calibrated geological models of two different resolutions to two homogeneous and four highly parameterized geostatistical inverse models in terms of both model calibration and validation performances as well as correspondence of estimated k values with permeameter estimated k profiles along boreholes and 2 using geological models as prior information for the geostatistical inversion approach results reveal that the simultaneous calibration of geological models to seven pumping test data yields k values that correctly reflect the general patterns of vertical distributions of permeameter estimated k we also find that the geostatistical inversion approach using a geological model as prior information performs better for both model calibration and validation than using a homogenous k as a prior and more importantly improves the correspondence of k estimates to permeameter test results along wells as well as in preserving geological features where drawdown measurements are lacking overall our results suggest the joint use of both geological and pumping test data for ht analysis when accurate geological data are available

human vulnerability in volcanic environments the case of furnas sao miguel azores abstract the need to examine the vulnerability of people to natural hazards in addition to the long established requirement to study extreme events of nature is being increasingly recognised within disaster research following a discussion of the nature of human vulnerability we propose a framework for its analysis within the context of volcanic activity and we exemplify our approach by a detailed study of furnas a village located at the centre of a volcano with the same name on the island of sao miguel in the azores the methods used included in depth interviews with permanent residents n 50 analysis of census records and an examination of the socio economic history of the town the vulnerability of an individual to volcanic hazards involves a complex interaction of elements which in addition to the usual factors taken into account in programmes of hazard reduction e g the nature of the physical threat location and economic situation also comprises his or her social context and a number of physiological and psychological considerations it is argued further that both generally and in the case of furnas the root causes of vulnerability lie in the history and development of society individual decision making is fundamental but takes place within and cannot be separated from this social context vulnerability analysis allows the identification of points where intervention may be successful in reducing the likelihood of suffering in a society it avoids the problem of people s unexpected reactions to invention leading to a changing or even increasing level of vulnerability by studying society rather than just one aspect of volcanic hazard in isolation

mapping soil layers using electrical resistivity tomography and validation sandbox experiments abstract knowledge of the geologic structure at a field site is a useful piece of information for hydrologic modeling since it can serve as more site specific prior information about the hydraulic parameter patterns at the site than generic spatial statistics widely accepted electrical resistivity tomography ert survey for mapping subsurface anomalies could be a viable tool for acquiring this information however their ability to delineate geologic structures has not been thoroughly investigated in this study two dimensional ert numerical experiments were first conducted to study the effects of boundary conditions on the dipole dipole and pole pole array configurations an ert setup subsequently was implemented in a sandbox consisting of complex layers of different sands a continuous copper wire was installed along the sides of the sandbox to impose potential boundaries using data collected with the pole pole array in the sandbox under different degrees of drainage and the successive linear estimator sle algorithm we show that ert yields electrical conductivity estimates of complex layer structures with small uncertainties in addition using sle with physically meaningful correlation scales as prior information can lead to an electrical conductivity field that is consistent with visually observed layer structures the correlation scale concept also was demonstrated to provide guidance to the design of the electrode spacing in the surveys moreover the estimated field was validated by predicting electrical potential fields from two independent ert surveys using electrodes at different locations results of this study suggest that the combination of ert and sle is a viable geophysical survey tool for mapping geologic layer structures research significance this study develops a method to implement prescribed potential boundaries for enhancing the pole pole ert survey illustrates the importance of correlation scales and develops an approach for validating ert results

people s behaviour in the face of volcanic hazards perspectives from javanese communities indonesia abstract this paper is concerned with the way in which the indonesian people living on the slopes or near active volcanoes behave in the face of volcanic threats it explores the role of three factors in the shaping of this behaviour e g risk perception cultural beliefs and socio economic constraints the paper is mainly based on field data collected during the last 5 years on four volcanoes in central java namely sumbing sindoro dieng and merapi the common assumption that hazard knowledge risk perception and people s behaviour are closely related and conditional on volcanic activity is debatable in the indonesian context factors that play a role in hazard knowledge e g basic knowledge of volcanic processes personal experience of volcanic crisis time lapsed since the last volcanic eruption etc differ from those that influence risk perception indeed local people often underestimate the scientifically or statistically estimated risk this poor risk perception is characterized by an approximate personal representation of the volcanic processes an excess of trust in concrete countermeasures the presence of a physical visual obstructions or cultural beliefs related to former eruptions in addition the commonly acknowledged factors that influence hazard knowledge and or risk perception may be at odds with the non hazard related factors that prompt or force people to live in or to exploit areas at risk these factors may be either socio cultural e g attachment to place cultural beliefs etc or social and socio economical e g standard of living strength of people s livelihoods well being these factors are fundamental in explaining the short term behaviour in the face of a developing threat during a volcanic crisis

an application of hydraulic tomography to a deep coal mine combining traditional pumping tests with water inrush incidents abstract water inrush incidents threaten the safety of coal mining understanding of hydrogeologic parameter distributions is critical for preventing water related hazards in coal mines during the deep mining 1000 m under the north china plain water from water bearing strata discharges into coal seams through geologic conduits i e water inrush due to the fractured zone under the floor of working faces in this study a water inrush incident was exploited as an active stimulus a 3d groundwater flow model was built for the eighth member of the middle ordovician system in xingdong coal mine using this model and an inverse approach we first checked if the data from the incident and an independent pumping test carry non redundant information about the heterogeneity of the mine afterward we combined these datasets to conduct a large scale approximately 10 km hydraulic tomography ht analysis the estimated hydraulic conductivity distribution from the ht analysis is found consistent with the distribution of known geologic faults that is a cluster of faults is characterized as a high conductivity zone a high conductivity zone is identified at locations close to the water inrush location which is the high cement consumption zone during the grouting project finally results of this study promote exploiting the water inrush events as a ht survey for mapping geologic structures over a large area

a survey of hydrous species and concentrations in igneous feldspars the hydrous components in 85 feldspars from various igneous environments spanning the range of naturally occurring compositions were examined with infrared spectroscopy the feldspars contain structural oh 0 512 ppm h 2o h 2o 0 1350 ppm h 2o and nh 4 0 1500 ppm nh 4 groups as well as fluid inclusions and alteration products although composition and structure do influence the type of hydrous species that can be incorporated into a particular feldspar mineral the concentration of these species is not controlled by major element composition coarse perthitic microclines have a heterogeneous distribution of hydrous species and contain h 2o or nh 4 in k rich lamellae and fluid inclusions in na rich areas the structural oh in plagioclase feldspars is not associated with twin boundaries or exsolution lamellae all of the possible structural hydrous species are found in pegmatite feldspars whereas volcanic feldspars contain only structural oh the variation in oh concentration within a given feldspar composition suggests that fluids in the geologic environment play a role in determining the hydrogen concentration of each sample the vast majority of plutonic feldspars have undergone partial or total equilibration with meteoric fluids during low temperature 400 150 c hydrothermal exchange obliterating any structural hydrogen and creating substantial concentrations of fluid inclusions up to 4000 ppm h 2o in the exchanged regions the amount of water stored as fluid inclusions within feldspars in the upper crust 1 10 19 kg is small compared to the 1 35 10 21 kg of water in the oceans but is roughly equivalent to the reservoir of water stored in hydrous minerals in the upper crust

sequential aquifer tests at a well field montalto uffugo scalo italy 1 this paper investigates our ability to characterize an aquifer using a sequential aquifer test in a well field that consists of six wells during the test we pumped water out from the aquifer at one well and monitored the water level changes at the rest of the wells to obtain a set of five well hydrographs by pumping at another of the six wells we obtained another set of five hydrographs this procedure was repeated until each of the six wells was pumped we then analyzed the six sets of hydrographs using the classical drawdown time the drawdown distance and the drawdown distance time methods results of the analysis confirm recent findings that the transmissivity estimates vary significantly at early time and stabilize at late time at late time the estimated values from all hydrographs are similar overall but vary slightly according to the locations of the pumping and observation wells in contrast storage coefficient estimates stabilized rapidly to distinct values associated with the well locations we subsequently used a hydraulic tomography approach to include all hydrographs from the sequential aquifer test to estimate the spatially varying transmissivity and storage coefficient fields the estimated fields appear to be realistic they reflect the geologic setting and the behaviors of the well hydrographs although more definitive confirmation is needed

three dimensional imaging of aquifer and aquitard heterogeneity via transient hydraulic tomography at a highly heterogeneous field site abstract previous studies have shown that geostatistics based transient hydraulic tomography tht is robust for subsurface heterogeneity characterization through the joint inverse modeling of multiple pumping tests however the hydraulic conductivity k and specific storage ss estimates can be smooth or even erroneous for areas where pumping observation densities are low this renders the imaging of interlayer and intralayer heterogeneity of highly contrasting materials including their unit boundaries difficult in this study we further test the performance of tht by utilizing existing and newly collected pumping test data of longer durations that showed drawdown responses in both aquifer and aquitard units at a field site underlain by a highly heterogeneous glaciofluvial deposit the robust performance of the tht is highlighted through the comparison of different degrees of model parameterization including 1 the effective parameter approach 2 the geological zonation approach relying on borehole logs and 3 the geostatistical inversion approach considering different prior information with without geological data results reveal that the simultaneous analysis of eight pumping tests with the geostatistical inverse model yields the best results in terms of model calibration and validation we also find that the joint interpretation of long term drawdown data from aquifer and aquitard units is necessary in mapping their full heterogeneous patterns including intralayer variabilities moreover as geological data are included as prior information in the geostatistics based tht analysis the estimated k values increasingly reflect the vertical distribution patterns of permeameter estimated k in both aquifer and aquitard units finally the comparison of various tht approaches reveals that differences in the estimated k and ss tomograms result in significantly different transient drawdown predictions at observation ports

a travel time based hydraulic tomographic approach 1 hydraulic tomography is a method to identify the three dimensional spatial distribution of hydraulic properties in the subsurface we propose a tomographic approach providing the inversion of travel times of hydraulic or pneumatic tests conducted in a tomographic array the inversion is based on the relation between the peak time of a recorded transient pressure curve and the diffusivity of the investigated system the development of a transformation factor enables the inversion of further travel times besides the peak time of a transient curve as the early travel times of the curve are mainly related to preferential flow features while the inversion based on late travel times are reflecting an integral behavior it can be assumed that the different inversion results reflect the properties of the overall system by comparing the different reconstructions the system interpretation therefore becomes more comprehensive and reliable furthermore the similarity of the proposed hydraulic tomographic approach to seismic travel time tomography allows us to apply the inversion algorithms which are used for seismic tomography we therefore apply the method of staggered grids which enables to refine the grid resulting in a higher nominal resolution to data from a set of interference tests arranged in a tomographic array the tests were conducted in an unsaturated fractured sandstone cylinder in the laboratory the three dimensional reconstructions of the diffusivity distribution are found to be highly reliable and robust in particular the mapped fracture of the sandstone cylinder coincides with our reconstructed diffusivity distribution

steady state hydraulic tomography in a laboratory aquifer with deterministic heterogeneity multi method and multiscale validation of hydraulic conductivity tomograms summary hydraulic tomography potentially is a viable technology that facilitates subsurface imaging of hydraulic heterogeneity to date a comprehensive validation of hydraulic tomography has not been done either at the laboratory or field scales the main objective of this paper is to examine the accuracy of hydraulic conductivity k tomograms obtained from the steady state hydraulic tomography algorithm of yeh t c j liu s 2000 hydraulic tomography development of a new aquifer test method water resources research 36 2095 2105 we first obtain a reference k tomogram through the inversion of synthetic cross hole test data generated through numerical simulations the purpose of reference k tomogram generation is to examine the ability of the algorithm to image the heterogeneity pattern under optimal conditions without experimental errors and with full control of forcing functions initial and boundary conditions as well as source sink terms parallel to the generation of synthetic data we conduct hydraulic tests at multiple scales in a laboratory aquifer with deterministic heterogeneity to generate data that are used to validate k tomograms from hydraulic tomography measurements include multiple k estimates from core slug single hole and cross hole tests as well as several unidirectional flow through experiments conducted on the sandbox under steady state conditions validation of k tomograms involved a multi method and multiscale approach proposed herein which include 1 visual comparisons of k tomograms to the true sand distributions and the reference k tomogram 2 testing the ability of the k tomogram to predict the hydraulic head distribution of an independent cross hole test not used in the computation of the k tomogram 3 comparison of the conditional mean and variance of local k from the k tomograms to the sample mean and variance of results from other measurements 4 comparison of local k values from k tomograms to those from the reference k tomogram and 5 comparison of local k values from k tomograms to those obtained from cores and single hole tests the multi method and multiscale validation approach proposed herein further illustrates the robustness of steady state hydraulic tomography in subsurface heterogeneity delineation

on the importance of geological data for hydraulic tomography analysis laboratory sandbox study abstract this paper investigates the importance of geological data in hydraulic tomography ht through sandbox experiments in particular four groundwater models with homogeneous geological units constructed with borehole data of varying accuracy are jointly calibrated with multiple pumping test data of two different pumping and observation densities the results are compared to those from a geostatistical inverse model model calibration and validation performances are quantitatively assessed using drawdown scatterplots we find that accurate and inaccurate geological models can be well calibrated despite the estimated k values for the poor geological models being quite different from the actual values model validation results reveal that inaccurate geological models yield poor drawdown predictions but using more calibration data improves its predictive capability moreover model comparisons among a highly parameterized geostatistical and layer based geological models show that 1 as the number of pumping tests and monitoring locations are reduced the performance gap between the approaches decreases and 2 a simplified geological model with a fewer number of layers is more reliable than the one based on the wrong description of stratigraphy finally using a geological model as prior information in geostatistical inverse models results in the preservation of geological features especially in areas where drawdown data are not available overall our sandbox results emphasize the importance of incorporating geological data in ht surveys when data from pumping tests is sparse these findings have important implications for field applications of ht where well distances are large

capturing aquifer heterogeneity comparison of approaches through controlled sandbox experiments 1 groundwater modeling has become a vital component to water supply and contaminant transport investigations these models require representative hydraulic conductivity k and specific storage ss estimates or a set of estimates representing subsurface heterogeneity currently there are a number of approaches for characterizing and modeling k and ss heterogeneity in varying degrees of detail but there is a lack of consensus for an approach that results in the most robust groundwater models with the best predictive ability the main goal of this study is to compare different heterogeneity modeling approaches e g effective parameters geostatistics geological models and hydraulic tomography when input into a forward groundwater model and used to predict 16 independent cross hole pumping tests we first characterize a sandbox aquifer through single and cross hole pumping tests and then use these data to construct forward groundwater models of various complexities both homogeneous and heterogeneous distributions two effective parameter models are constructed 1 by taking the geometric mean of single hole test k and ss estimates and 2 calibrating effective k and ss estimates by simultaneously matching the response at all ports during a cross hole test heterogeneous models consist of spatially variable k and ss fields obtained via 1 kriging single hole data 2 calibrating a geological model and 3 conducting transient hydraulic tomography zhu and yeh 2005 the performance of these parameter fields are then tested through the simulation of 16 independent cross hole pumping tests our results convincingly show that transient hydraulic tomography produces the smallest discrepancy between observed and simulated drawdowns

comparative study of transient hydraulic tomography with varying parameterizations and zonations laboratory sandbox investigation the final publication is available at elsevier via http dx doi org 10 1016 j jhydrol 2017 09 045 2017 this manuscript version is made available under the cc by nc nd 4 0 license http creativecommons org licenses by nc nd 4 0

leaving the city for the suburbs the dominance of ordinary decision making over volcanic risk perception in the production of volcanic risk on mt etna sicily abstract the belief that perception plays a central role in the production of risk has tended to dominate research on natural hazards critics have commented on its lack of explanatory power in situations where individuals are heavily constrained in their actions but less has been said about how it might also be a weak form of explanation in contexts where individuals have more choices albeit ultimately bounded on etna italy in the last fifty years the expansion of towns to accommodate the city of catania s population has taken place despite very obvious threats from volcanic activity and alternative safer sites for building being available people are moving into these towns for the same reasons people across the world are moving out of cities to improve their quality of life individuals living in one of these expanded towns trecastagni appear to cognitively diminish their perceptions of volcanic threat within a context of social representations of low risk this is especially true of those who have moved into the town it is concluded that the production of risk within society on etna is strongly related to the socio economic nature of the region and wider european and global contexts that create opportunities and constraints across socio physical space encouraging behaviour and forms of life that are higher risk risk perception appears to play little or no role in this process

alternative paradigms of volcanic risk perception the case of mt pinatubo in the philippines the literature on people s response to volcanic hazards tends to be split between two paradigms the first argues that the choice of adjustment depends on how people perceive rare and extreme volcanic phenomena and the associated risk the second considers that people s behavior in the face of natural hazards is constrained by social economic and political forces beyond their control the present paper addresses both paradigms and demonstrates that in order to understand people s behavior in the face of volcanic threats volcanic risk perception has to be balanced with non hazard related factors and structural constraints these conclusions are based on a case study of mt pinatubo and the lingering threat of lahars from the 1991 eruption drawing on the results of a questionnaire based survey and additional interviews with key informants it is shown that a high perception of risk does not stop people from choosing to forms of living that put them at high threat from lahars furthermore the paper argues that insufficient opportunity for making a livelihood in resettlement centers and strong attachment to native villages push people back to the banks of lahar channels everyday hazards of poverty and the threat to cultural heritage weighed heavier than this seasonal natural hazard in other words in a context of economic and social hardship risk perception of volcanic hazards is necessarily balanced with other risk perceptions this study does not argue that risk perception is unimportant for understanding people s adjustment to volcanic environments but rather stresses the need for placing it in its larger and daily contexts which are independent of volcanic hazards

rapid field application of hydraulic tomography for resolving aquifer heterogeneity in unconsolidated sediments 1 a new framework is introduced for hydraulic tomography application and validation in the field our motivation is the need for methods that are both efficient and expressive for resolving the spatial distribution of heterogeneous hydraulic properties in aquifers the presented strategy involves time efficient field experiments and a computationally efficient inversion scheme by exploiting the early travel time diagnostics of the hydraulic pressure pulses recorded during tomographic cross well tests and new application of attenuation inversion only short term pumping tests are required many of these can be conducted in one day the procedure is developed by a numerical experiment with a highly heterogeneous aquifer analogue and then applied to a field case with a shallow unconsolidated sedimentary aquifer the stegemuhle site in germany it is demonstrated that the performance of a suite of tomographic short term pumping tests data processing and inversion for the reconstruction of heterogeneous diffusivity and specific storage distribution is possible within one day additionally direct push injection logging is performed at the field site and the obtained field data is utilized for successful validation of the hydraulic tomograms we also compare both methods with respect to the necessary requirements time demand in the field and complexity of interpretation

volcanic geology and eruption frequency sao miguel azores six volcanic zones comprise sao miguel the largest island in the azores all are quaternary in age except the last which is partly pliocene from west to east the zones are 1 the trachyte stratovolcano of sete cidades 2 a field of alkali basalt cinder cones and lava flows with minor trachyte 3 the trachyte stratovolcano of agua de pau 4 a field of alkali basalt cinder cones and lava flows with minor trachyte and tristanite 5 the trachyte stratovolcano of furnas and 6 the nordeste shield which includes the povoacao caldera and consists of alkali basalt tristanite and trachyte new radiocarbon and k ar ages augment stratigraphic data obtained during recent geologic mapping of the entire island and provide improved data to interpret eruption frequency average dormant intervals for the past approximately 3000 years in the areas active during that time are about 400 years for sete cidades 145 for zone 2 1150 for agua de pau and 370 for furnas however the average dormant interval at sete cidades increased from 400 to about 680 years before each of the past two eruptions and the interval at furnas decreased from 370 to about 195 years before each of the past four eruptions eruptions in zone 4 occurred about once every 1000 years during latest pleistocene and early holocene time none has occurred for about 3000 years the povoacao caldera truncates part of the nordeste shield and probably formed during the middle to late pleistocene calderas formed during latest pleistocene time at the three younger stratovolcanoes in the sequence outer agua de pau between 46 and 26 5 ka sete cidades about 22 ka inner agua de pau 15 2 ka and furnas about 12 ka normal faults are common but many are buried by holocene trachyte pumice most faults trend northwest or west northwest and are related to the terceira rift whose most active segment on sao miguel passes through sete cidades and zone 2 a major normal fault displaces nordeste lavas 150 250 m and may mark the location of an ancestral terceira rift recent seismicity e g in the 1980s generally has been scattered but some small earthquake swarms have occurred beneath the north eastern flank of agua de pau