Evaluation of landfill disposal boundary by means of electrical resistivity imaging

This paper deals with an employment of electrical resistivity imaging (ERI) for survey of leachate content on the waste disposal site in Northern Israel. The research consisted of conducting ten ERI lines and drilling investigation wells. Data simulation used a 2D EarthImager inversion program. Analysis of 2D ERI interpretation results shows that determination of the boundary between the landfill body bottom intensively saturated with leachates and underlying layers of highly water saturated fat nonconsolidated clays presents a challenge. However, statistical analysis of ERI data indicates that standard deviation and confidence interval of a set of resistivity data measured in the landfill body are significantly larger than those in underlying clays. Moreover, maximum changes of these parameters are found on the boundary between landfill body and underlying soil, thus reflecting natural differences in scattering of resistivity data measured in these two objects.     

Precise temperature monitoring in boreholes: evidence for oscillatory convection? Part II: theory and interpretation

In the previous part of this work (Cermak, Safanda and Bodri, this volume p.MMM) we have described experimental data and quantified the heterogeneity features of the microtemperature time series. The spectral analysis and the local growth of the second moment technique revealed scaling structure of all observed time series generally similar and suggested the presence of two temperature forming processes. The longer-scale part can be attributed to the heat conduction in compositional and structural heterogeneous solid rocks, further affected by various local conditions. Short-scale temperature oscillations are produced by the intra-hole fluid convection due to inherent instability of water column filling the hole. Here we present how the observational evidence is supported by the results of the computer simulations. The exact modes of intra-hole convection may be different, ranging from quasi-periodic (“quiescent”) state to close of turbulence. As demonstrated by numerical modeling and referred on laboratory experiments, at higher Rayleigh numbers the periodic character of oscillation characteristic for “quiescent” regime is superseded by stochastic features. This so called “oscillatory” convection occurs due to instability within the horizontal boundary layers between the individual convectional cells. In spite of the fact that the basic convective cell motion is maintained and convection is characterized by slow motion, the oscillatory intra-hole flow and corresponding temperature patterns exhibit typical features of turbulence. The idea of boundary layer instability as a source of stochastic temperature fluctuations could explain many distinct features of borehole temperatures that previously cannot be interpreted.     

SO2 degassing from Turrialba Volcano linked to seismic signatures during the period 2008–2012

In 1996, after 150 years of relative calm, Turrialba Volcano was reawakening. A visible plume and serious damage to surrounding vegetation due to acid rain are the most obvious signals. As part of the Network for Observation of Volcanic and Atmospheric Change project, four gas-monitoring stations were initially installed on the west flank of the volcano with the purpose of measuring sulphur dioxide emissions during this period of increased activity using the scanning-differential optical absorption spectroscopy technique. We present here the results of semicontinuous gas flux measurements over a period of 5 years (from 2008 to 2012), providing a novel data set that documents a relatively rapid increase in SO₂ fluxes from around 350 t day^?1 to around 4,000 t day^?1 leading up to an eruptive period, followed by a gradual return to the former baseline values. Gas flux data were also compared with seismic data for selected periods of interest, providing insights into the link between degassing and seismicity. The most important result from this comparison is the identification of an inflexion point in the gas emissions followed by a clearly increasing trend in seismic activity, distinguishable 6 months prior to a phreatic eruptive event that occurred on 5 January 2010. This signal can be interpreted as a possible indicator of future eruptive events. Monitoring of SO₂ thus complements seismic monitoring as a forecasting tool for eruptive events. Such monitoring is critical considering the proximity of Turrialba to the Central Valley, an area inhabited by more than 50 % of Costa Rica’s population.     

The Metal Potential of Carbonate Rocks in Ancient Reef Systems of Northeastern Asia

Carbonate organogenic buildups (reefs) are lithofacies barriers of marine basins separating sedimentation facies zones. Together with seafloor depressions, they make up two-facies systems that are favorable for the formation of stratiform lead, zinc, and copper deposits. Organogenic reefs are formed at the boundary between the littoral zone and the remaining shelf area, as well as on terraces separating the shelf and continental slope zones. The reefs control the stratiform copper mineralization in the first case and the MV-type lead–zinc mineralization in the second case. This work describes the following reef systems of northeastern Asia incorporating base metal deposits: Chencha (Late Riphean) system of the Zhuya–Patom Trough, West Yakutian (Early–Middle Cambrian), Tankhai–Ust'mil (Middle Cambrian), and Lena (Late Cambrian) systems of the Siberian Platform, and Urul'tun (Early Devonian) and Kamenka (Middle Devonian) systems of the Omulev and Kolyma blocks. The two-facies genetic model of the MV-type lead–zinc and stratiform copper deposits is substantiated.     

Comment on “Methane on Mars: A product of H2O photolysis in the presence of CO” by A. Bar-Nun and V. Dimitrov

Bar-Nun and Dimitrov [Bar-Nun, A., Dimitrov, V., 2006. Icarus 181, 320-322] suggested a sequence of reactions to form methane on Mars. These reactions are based on the study of products in the N₂-CO-H₂O mixture irradiated at 185 nm. The suggested scheme was not quantitatively justified by chemical kinetics. One of the key reactions is effectively blocked by O₂ in the martian atmosphere, and another key reaction does not exist. There are no pathways for effective formation of methane in the martian atmosphere.     

Hydrodynamics of aquatic ecosystems: spatial-averaging perspective

Hydrodynamics of aquatic ecosystems is a relatively new, emerging multidisciplinary research area dealing with two key inter-connected issues: (i) physical interactions between flow and organisms (e.g., due to drag forces); and (ii) ecologically relevant mass-transfer-uptake processes (e.g., due to molecular and turbulent diffusion). Owing to physical and biological complexity of boundary conditions in aquatic systems, the conventional hydraulic methodologies are often impracticable and new approaches are required. One of such approaches, the double-averaging methodology, is discussed with particular focus on flows over biologically-modified beds.     

Experimental estimate of a relation between sea wave energies and the Earth’s crust microdeformations

The experimental data in the microseismic frequency range obtained using the seismo-acoustic-hydrophysical measurement complex are analyzed. The emphasis is put on estimating the ratio between the energy of surface sea wind waves in the area of the Japan Sea where the complex was located and the Earth’s crust microdeformations in this frequency range. The experimental evaluate obtained allow us to estimate the energy re-distribution at the hydrosphere-lithosphere boundary.