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Wireline logs and vertical seismic profile data were acquired in two boreholes intersecting the main mineralized zone at the Cu–Au New Afton porphyry deposit, Canada, with the objectives of imaging lithological contacts, fault zones that may have acted as conduits that channelled the mineralization, and alteration zones. Log data provide physical rock properties for the main lithologies and alteration zones. Calliper logs reveal many faults and caved‐in zones generally indicating rocks with low integrity at the borehole wall. The preponderance of these zones, as indicated by the logs, suggests that their response may dominate the seismic‐reflection wavefield. Outside fault zones, compressional and shear‐wave velocities exhibit significant variability due to porosity, the heterogeneity of volcanic fragmental rocks and alteration. Distributed acoustic sensing was used to acquire vertical seismic profiling data in the two boreholes surveyed with wireline logs. Straight and helically wound fibre‐optic cables housed standard fibres and a fibre engineered to increase the intensity of backscattering at the distributed acoustic sensing interrogator. Standard and engineered optical fibres placed in the two boreholes were daisy‐chained together to form two 5‐km‐long continuous fibres that were interrogated at once with two interrogators. A new generation of interrogator connected to the engineered fibres provided field data with lower noise level and higher signal‐to‐noise ratio. These data with higher signal‐to‐noise ratio from straight fibre‐optic cable were processed and used for depth imaging. Depth images benefitted from new migration weights that account for the directional sensitivity of the straight fibre‐optic cable and limit the extent of migration artefacts. Migration results show several reflectors with shallow dips to the northwest, some explained by faults intersecting the surveyed boreholes. The main sub‐vertical lithological and alteration contacts at New Afton generated downgoing reflections that were not considered in the migration.

International audience; The editors of JGR: Solid Earth announce that Plain Language Summaries will be required for all manuscripts.

Calderas are major volcanic features with large volcanic and seismic hazards. They also host diverse microbiota, provide heat, energy, mineral and economic benefits. Despite their scientific and socio-economic importance, we still do not completely understand calderas and the interactions between volcanism, tectonism, fluid circulation and the deep biosphere because in-situ and subsurface observations are sparse.The Okataina Volcanic Centre (OVC) in Aotearoa New Zealand, is one of two active giant calderas of the Taupō Volcanic Zone within the rapidly extending continental intra-arc Taupō Rift. This superb natural laboratory has: 1) numerous past eruptions of varied size and style, 2) documented co-eruptive earthquakes, 3) vigorous hydrothermal manifestations, 4) diverse microbial communities in hot springs but unknown in the subsurface.We propose to establish a scientific drilling programme at the OVC to address:What are the conditions leading to volcanic eruptions; and volcano-tectonic feedbacks in intra-rift calderas? What controls fluid circulations in active calderas/rift regions? Does subsurface microbial community composition vary with tectonic and/or volcanic activity? High temperatures complicate drillhole design, restrict data collection and prevent exploration of the biosphere. By targeting the cooler parts of the caldera, this project will use conventional engineering to maximise sampling (drill cores and fluids), downhole logging and establish long-term observatories.Two preliminary drill targets are suggested: (1) in the centre of the caldera; (2) through the caldera margin. Drill data will provide a comprehensive record of past activity, establishing eruption frequency-magnitude relationships and precursors. Combined with well-known fault rupture history, the relative timing of tectonic and magmatic activity will be untangled. Drill data will unravel the relationships between the groundwater and hydrothermal systems, magma, faults and stress, informing thermo-hydro-mechanical regional caldera models with findings applicable worldwide. Drill cores and a dedicated fluid sampler triggered by nearby earthquakes will reveal the composition, function and potential change of microbial activity in response to rock and fluid variations.The programme is informed by indigenous Māori, regulatory authorities and emergency managers to ensure scientific, cultural, regulatory and resilience outcomes. The programme will underpin 1) community resilience to volcanic and seismic hazards; 2) sustainable management of groundwater and geothermal resources, and 3) understanding of subsurface microbial diversity, function and geobiological interactions. At these early stages of planning, we invite the scientific community to contribute to the concept of this project in the exceptional OVC settings and strengthen linkages with other ongoing research and scientific drilling programmes.

International audience

Project HOTSPOT, the Snake River Scientific Drilling Project (International Continental Scientific Drilling Program), tested for deep geothermal resources and examined the petrology of volcanic rocks with three drillholes in the central and western Snake River Plain (western USA). The MH-2 drillhole targeted fractured crystalline and hydrothermally altered basalt in the area of the Mountain Home Air Force Base (Idaho) to a total depth of 1821 m. At 1745 m depth the drillhole encountered flowing artesian hydrothermal fluids of at least 150 °C. We integrate geological analyses of core, image log, and borehole geophysical data, and in situ stress analyses to describe the structural environment that produces permeability for artesian flow. The rocks in the lower 540 m of the drillhole consist of basalt flows as much as 30 m thick, altered basalt, and thin sedimentary horizons. The mechanical stratigraphy is defined by nine mechanical horizons that are in three ranges of rock strength on the basis of experimentally determined strength data, core logging, and geophysical log signatures. Hydrothermal alteration products and mineralization in the core are associated with three highly faulted sections; the lowermost section is associated with the zone of flowing thermal water. Shear slip indicators on faults observed in core indicate slip ranging from pure strike slip to normal failure mechanisms in the stronger horizons. The borehole breakouts indicate that the maximum horizontal stress, SH, is oriented 047° ± 7°, and drilling-induced tensile fractures indicate that SH is oriented at 67° ± 21°. The in situ stress orientations exhibit little variation over the depth of the measured interval, but the SH magnitude varies with depth, and is best explained by an oblique normal fault stress regime. The geomechanical model indicates that if pore pressures at depth are elevated above the normal hydrostatic gradient, as observed here, the system has the potential to deform by mixed normal and strike-slip failure. Our observations and interpretations suggest that the MH-2 borehole was drilled into oblique normal faults that intersect a buried 300°-trending fault block masked by the basaltic volcanic complex. These data indicate that the transition from the central to western Snake River Plain is characterized by complex structures developed in response to a transitional stress state related to Snake River Plain and western Basin and Range stress regimes. The western Basin and Range stress and tectonic regime may extend from northern Nevada into western Idaho and may enhance the potential for geothermal resources by creating interconnected fracture and fault-related permeability at depth.

The change in seismic reflectivity from a reservoir — during in situ bitumen recovery processes such as SAGD — can be substantial due to the combined effects of increased temperature, pore pressure and effective stress changes, and the substitution of bitumen with water and steam. These physical property changes can be observed with time lapse seismic monitoring e.g. 4D seismology. The proper interpretation of geophysical observations, however, requires a solid understanding of the saturated reservoir rock’s behavior and pore fluid’s properties under changing conditions. Our first suite of ultrasonic measurements with bitumen saturated carbonate show the P- and S-wave velocities decrease by ~11.5% and ~8.5% for a temperature increase from 10°C to 102°C, respectively at a constant effective pressure of 5 MPa. In the next effort, direct measurements with bitumen show ~29% decrease of P-wave velocity for 10°C to 130°C change in temperature. Different slopes in velocity versus temperature plot may also indicate the possible states of quasi solid and liquid in bitumen. The change in fluid bulk modulus with temperature drives the drop in the P-wave velocities. We may also infer that the decline in S-velocity in core sample is due to greatly lowered viscosity of the fluid with temperature. We also attempt to simulate numerically the ultrasonic pulse-transmission through rock saturated with viscous fluid, which exhibits similar trends of P-wave velocity drop with temperature. However, the decrease in velocity is not quite large as experimental studies with bitumen saturated carbonates; may be due to the difference in pore structure and fluid properties. In addition, the dynamic moduli of saturated rocks at seismic frequencies on core scale using the strain-stress method indicate its strong dependency on viscosity of pore fluid and (or) the frequency.

Fluid injection is known to induce seismic events if the injection causes fracturing of the surrounding rock or if resulting pressure changes reactivate pre-existing faults and fractures. Carbon dioxide (CO2) storage projects where CO2 is injected into deep geological formations for permanent containment are one sector where induced seismicity has been observed. The Aquistore storage project in Saskatchewan, Canada began CO2 injection into the basal Cambrian sandstone at ∼3.2 km deep in April 2015 and the site has been extensively monitored for seismicity. Passive seismic monitoring instrumentation includes a small network of broadband seismometers, a continuously recording array of near-surface geophones and temporary deployments of downhole geophones at depths from 2950 m to 3010 m in an observation well. To date no injection-related induced seismicity has been observed. The seismic arrays are functioning as expected and local mine blasts, orientation shots and perforation shots have been detected using standard detection algorithms. Data stacking algorithms have also been tested on short-periods of data. Using synthetic data added to noise models, the estimated minimum detectable event local magnitude is −0.8 for the broadband stations and between −1.6 and −0.6 for the near-surface geophones. Thus far, small volumes of CO2 have been injected at Aquistore (∼140 kt) and injection has generally occurred below the fracture pressure. As a result, predicted pore pressure changes are small and periods without injection have allowed relaxation of the pressure plume. Geomechanical modelling suggests insignificant effective stress changes at an identified fault near the Aquistore injection well. It is therefore not surprising that no induced seismicity has been detected. With further injection, continued seismic monitoring is essential to provide warning of any fault reactivation and thus any potential increase in seismic risk or CO2 leakage risk.

In October 2006, three-component zero-offset vertical seismic profile data were acquired from a deviated well in the Flin Flon mining camp in Manitoba, Canada, using a dynamite source. These vertical seismic profile data were processed to reveal reflections originating from the 85.5 Mt Flin Flon-Callinan-777 volcanogenic massive sulphide ore system. From drill records, mine plans, surficial maps, and seismic data, 3D voxel models of the local geology and known ore zones were built, which were then used in 3D finite-difference modelled simulations of the vertical seismic profile surveys. The number of geological units partitioning the model was incrementally increased to study the effects of the massive sulphide ore and the major rock units on the seismic response. The simulations and field data were jointly visualized, and reflections originating at some of the known ore zones were identified. These reflections were observed in each of the three components in both the real field and the forward modelled data and indicate a strong mode-converted component of the reflected wavefield.

Stratigraphic drilling from the McMurdo Ice Shelf in the 2006/2007 austral summer recovered a 1284.87 m sedimentary succession from beneath the sea floor. Key age data for the core include magnetic polarity stratigraphy for the entire succession, diatom biostratigraphy for the upper 600 m and 40Ar/39Ar ages for in-situ volcanic deposits as well as reworked volcanic clasts. A vertical seismic profile for the drill hole allows correlation between the drill hole and a regional seismic network and inference of age constraint by correlation with well‐dated regional volcanic events through direct recognition of interlayered volcanic deposits as well as by inference from flexural loading of pre‐existing strata. The combined age model implies relatively rapid (1 m/2–5 ky) accumulation of sediment punctuated by hiatuses, which account for approximately 50% of the record. Three of the longer hiatuses coincide with basin‐wide seismic reflectors and, along with two thick volcanic intervals, they subdivide the succession into seven chronostratigraphic intervals with characteristic facies: 1. The base of the cored succession (1275–1220 mbsf) comprises middle Miocene volcaniclastic sandstone dated at approx 13.5 Ma by several reworked volcanic clasts; 2. A late-Miocene sub-polar orbitally controlled glacial–interglacial succession (1220–760 mbsf) bounded by two unconformities correlated with basin‐wide reflectors associated with early development of the terror rift; 3. A late Miocene volcanigenic succession (760–596 mbsf) terminating with a ~1 my hiatus at 596.35 mbsf which spans the Miocene–Pliocene boundary and is not recognised in regional seismic data; 4. An early Pliocene obliquity-controlled alternating diamictite and diatomite glacial–interglacial succession (590–440 mbsf), separated from; 5. A late Pliocene obliquity-controlled alternating diamictite and diatomite glacial–interglacial succession (440–150 mbsf) by a 750 ky unconformity interpreted to represent a major sequence boundary at other locations; 6. An early Pleistocene interbedded volcanic, diamictite and diatomite succession (150–80 mbsf), and; 7. A late Pleistocene glacigene succession (80–0 mbsf) comprising diamictite dominated sedimentary cycles deposited in a polar environment.

In order to assist in the interpretation of previous seismic refraction and reflection surveys, a vertical seismic profile was acquired in the Lake Bosumtwi (Ghana) hard-rock core hole LB-08A. No seismic reflections are seen in the up-going wave field obtained, and this observation is consistent with the lack of reflectivity observed in the corresponding 2-D surface seismic profile obtained in earlier studies. Direct down-going P-waves were found both in the cased sediment column from a depth of 73 m to 239 m below the lake surface and in the open-hole "hard rock" section from a depth of 239 m to 451 m of LB-08A. Analysis of the observed travel times indicates a nearly constant P-wave velocity of 1520 m/s through the soft lacustrine sediments. In the hard-rock, however, the P-wave velocity rapidly increases by nearly 30% from 2600 m/s to 3340 m/s. These values are in good agreement with the gross velocity structure obtained in the earlier joint inversion of seismic reflection and refraction data. These values are low relative to those expected for the metasedimentary protoliths, an observation that has been made at other young impact structures of similar size. The low velocities, together with the fact that they increase so rapidly, is suggestive of a decreasing density of fractures and microcracks with depth. Consequently, the seismic velocity trend may provide a proxy measure of damage, and hence, the decay of the shock pressure from the impact point. Validation of this requires additional detailed studies of the porosity structure in the core.

The compressional and shear wave speeds of a fully CO2 saturated porous ceramic are measured as functions of pore fluid pressure and temperature. The wave speeds show considerable variation dependent upon the phase state of the CO2. The observations are further in good agreement with Biot’s model of wave propagation. The ability to change the CO2’s compressibility, density, and viscosity by relatively modest changes in temperature and pressure provides for a somewhat ‘tunable’ fluid that can be used to study fluid induced variations of wave propagation behavior.

The Trans-Hudson Orogen forms the largest Paleoproterozoic orogenic belt of Laurentia. It is particularly known for its world-class volcanogenic massive sulphide (VMS) deposits, including Flin Flon mining camp.A program of seismic investigations has been implemented as part of the Targetted Geoscience Initiative-3 (TGI-3) to provide a basis for constructing a 3D geological model and refine the current conceptual exploration model for the camp, and ultimately to provide new drill targets. Rock property measurements, downhole geophysical logging and vertical seismic profiles acquired in advance of the main seismic survey demonstrated the expected reflectivity of the mining camp geology. The main seismic survey comprised a total of 75 km of high-resolution 2D seismic profiles and a 3D survey covering approximately 10 km2. The results of processing the vertical-component data for P-wave reflections reveal subhorizontal reflectivity associated mainly with the Missi metasedimentary complex and steeply dipping reflectivity associated with the polydeformed volcanic rocks, including the main rhyolite horizon which hosts the VMS deposits. Some important fault zones are also imaged.

Compressional and shear wave anisotropy, shear wave birefringence, and the anisotropy of magnetic susceptibility were measured on a series of dunites sampled from the Dinardic–Hellenic ophiolites. The densities of these materials ranged from 3330 kg/m 3 to 2620 kg/m 3 and indicate degrees of serpentinization from 2.3% to 87.9%, respectively. Magnetic susceptibility increases and the compressional and shear wave velocities decrease in proportion to the degree of serpentinization as has been observed by other workers. In all cases the magnetic susceptibility tensor is described by an oblate spheroid whose minor axis is closely aligned to the pole of the foliation, but the magnetic anisotropy is not related to the degree of serpentinization. The compressional wave anisotropy e monotonically decays from 12% for nearly pure olivine dunite to less than 2% for the most serpentinized sample; this observation strongly suggests that serpentinization progressively destroys the original anisotropy by consuming the preferentially aligned olivines and replacing them with randomly oriented serpentines. Typical serpentine mesh textures seen in microscopic thin section examinations support this suggestion. This loss of anisotropy with serpentinization may partly explain the apparent relationship between seismic compressional wave anisotropy of the oceanic lithosphere. The more complex geological structure of slow spreading ridges may admit more sea water via faults for deep circulation which increases serpentinization and consequence of which is decreased seismic anisotropy. © 2007 Elsevier B.V. All rights reserved.

Conventional seismic methods are generally not effective for imaging geological structures with very steep dips, a common situation in some mining camps. Deep boreholes provide an alternative acquisition datum for seismic imaging in this type of setting. At the giant Kidd Creek CuZn deposit, the Archean volcanic stratigraphy has been folded and overturned so that most units are nearly vertical. Borehole logging and laboratory measurements conducted here show that certain stratigraphic contacts, especially those where massive-sulphide deposits and felsic host rocks are juxtaposed, are characterized by large impedance contrasts and are thus good candidates as seismic reflectors. To investigate this possiblity, a series of borehole-seismic profiling experiments were conducted in an area of known sulphide mineralization. Several source configurations were used, yielding both vertical and horizontal seismic images of the volcanic stratigraphy. In addition to observing reflections that correlate with stratigraphic contacts, prominent seismic anomalies were detected and have been correlated with a known massive-sulphide deposit.

Dual beam electronic speckle interferometers provide raw data in the form of maps of wrapped relative phase or fringe patterns. Interpretation of such fringe patterns is complicated by aliased and random speckle noise. This noise can result in misidentification of the phase at a given point in the image. Automated determination of the loci of fringe extrema, useful for quantitative evaluation, are particularly affected. A nonlinear image filtering technique referred to as mean curvature diffusion is applied to overcome this difficulty. This technique essentially smooths the image without a substantial reduction in the magnitude of the underlying trends that here represent the fringes. Mean curvature diffusion uses calculations analogous to those for the diffusion of heat with the difference that the diffusion coefficient, reminiscent of thermal diffusivity, varies spatially within the image with a value given by the reciprocal of the local surface gradient. At a given point in the image, the rate of surface diffusion depends only on the average value of the normal curvature in any two orthogonal directions and not on its magnitude; this allows the lower frequency underlying components of the image structure to be retained. The method is tested on both calculated and real speckle interferograms to highlight the effectiveness of this smoothing technique relative to more standard smoothing algorithms.

Soon the new booster for the Zero Gradient Synchrotron (ZGS) will be commissioned at Argonne. Three of its diagnostic systems will be described here: 1) the beam position system, 2) the toroid intensity measuring system and 3) the capacitive intensity measuring system.

Gloveboxes are frequently used for the protection of personnel and containment of an inert atmosphere within which operations upon pyrophoric or physiologically hazardous materials are performed. L...

Two experiments with human subjects investigated the effects of rate of reinforcement and reinforcer magnitude upon choice. In Experiment 1, each of five subjects responded on four concurrent variable-interval schedules. In contrast to previous studies using non-human organisms, relative response rate did not closely match relative rate of reinforcement. Discrepancies ranged from 0.03 to 0.43 (mean equal to 0.19). Similar discrepancies were found between relative amount of time spent responding on each schedule and the corresponding relative rates of reinforcement. In Experiment 2, in which reinforcer magnitude was varied for each of five subjects, similar discrepancies ranging from 0.05 to 0.50 (mean equal to 0.21), were found between relative response rate and relative proportion of reinforcers received. In both experiments, changeover rates were lower on the long-interval concurrent schedules than on the short-interval ones. The results suggest that simple application of previous generalizations regarding the effects of reinforcement rate and reinforcer magnitude on choice for variable-interval schedules does not accurately describe human behavior in a simple laboratory situation.

Subjects could either cooperate or respond on a lower-paying individual task. In Exp. I and II, either subject could make a response that took $1.00 of the other's earnings whenever subjects chose to cooperate. The two experiments differed as to whether taking responses were effective continuously or intermittently. Both experiments showed that the opportunity to take disrupted cooperative behavior. Experiment III indicated that if taking was possible regardless of whether the subjects cooperated or responded on the individual task, subjects either cooperated or terminated the experiment.

The cooperative responses of pairs of human subjects were reinforced under several stimulus conditions in two settings designed to require a “social” response, i.e., where at least one of the two persons is responding to the behavior of the other. The first task, designed by Lindsley and Cohen, required individual responses within 0.5 sec of one another for reinforcement. The second (modified) task required a delay of 3 sec between individual responses. To determine dependence of cooperation on social stimuli, rates of cooperative behavior on these tasks were compared in the presence and absence of a stimulus indicating to each subject the other's response and a stimulus which indicated the duration of the timeout after reinforcement. The results indicated that only in the modified task was a high rate of cooperation always contingent upon the presence of the social stimuli.

In order to assist in determining detailed structure of bedrock nearby the Outokumpu deep drill hole and combine straight measurements done in deep drill hole to surface measurements, a zero-offset vertical seismic profile was acquired near the Outokumpu deep drill hole. In this new survey, 2 m depth increment was applied to obtain high resolution information. Using the first break picking, the interval P-wave velocities were determined and that match the sonics well. And from the stack result, it showed detailed information about sequence structure which also can be used for the interpretation of surface reflection seismic profiles.

The titanium vacuum chambers installed in the ZGS this past summer were equipped with PFW's. In this paper, the operation and monitoring of the windings used to flatten the guide field in the ZGS will be described. The physical and electrical characteristics of the system will be discussed along with a computer program which calculates the magnetic field shape in the vacuum chamber as a function of PFW current and other machine parameters.