Simultaneous response of high-frequency geoacoustic emission and atmospheric electric field to strain of near-surface sedimentary rocks

During the period of October 1–18, 2009, 41 km southwest of Petropavlovsk-Kamchatsky, in the intersection zone of tectonic faults of various orders, simultaneous recording of the geoacoustic emission, gradient of the atmospheric electric field’s potential, strains of the Earth’s surface, atmospheric pressure, wind speed, and rain intensity was made. It was found for the first time that anomalous disturbances of high-frequency geoacoustic emission and atmospheric electric field near the Earth’s surface originate as a simultaneous response to extension of near-surface sedimentary rocks. In the case of compression, only disturbances of geoacoustic emission occur. Anomalies were recorded under quiet weather conditions and with rocks strains being two orders greater than those of tidal ones.     

The mechanism of modulation of geoacoustic emission intensity by weak electromagnetic fields in the audio-frequency range

We propose a physical mechanism explaining the mechanism of modulation of the geoacoustic emission intensity by an external electromagnetic field in the audio-frequency range, which was previously revealed as a result of borehole measurements at the Petropavlovsk-Kamchatskii geodynamic testing area. It was established that electric double layers (EDL) at the interface between solid and liquid phases in a fluidsaturated geological medium play a key role in the mechanism proposed.     

Geoacoustic inversion using adaptive neuro-fuzzy inference system

The geoacoustic parameters form significant input for underwater acoustic propagation studies and geoacoustic modeling. Conventional inversion techniques commonly used as indirect approach for extraction of geoacoustic parameters from acoustic or seismic data are computationally intensive and time-consuming. In the present study, we have tried to exploit the advantage of soft computing techniques like, reasoning ability of fuzzy logic and learning abilities of neural networks, in inversion studies. The network model based on the combined approach called adaptive neuro-fuzzy inference system (ANFIS), is found to be very promising in inversion of the acoustic data. The network model once built is capable of invert a few thousand data sets instantaneously, to a reasonably good accuracy. In the case of conventional approaches, repetition of the entire inversion process with each new data set is required. A limited number of sensor’s data are sufficient for simulation of the network model and provides an advantage to use short hydrophone array data. Inversion results of a few hundred test data sets, representing different geoacoustic environments, show the prediction error is much less than 0.01 g/cc, 10 m/s, 10 m and 0.1 against first layer’s density, compressional sound speed, thickness and attenuation respectively for a three-layer geoacoustic model. However, the error is relatively large for the second- and third-layer parameters, which need to be improved. The model is efficient, robust and inexpensive.     

Magma degassing during 7600 14C Kurile Lake caldera-forming eruption and its climatic impact

The main goal of this investigation is estimating volume of volatile emission, atmospheric and climatic impact of the Kurile Lake caldera-forming eruption, one of the Earth’s largest Holocene explosive eruptions. The volatile content of magma before the eruption was estimated by comparing H₂O, S, Cl and F contents in natural quenched glassy melt inclusions trapped by plagioclase phenocrysts. The volatile content of igneous rocks after eruption was estimated by comparing concentrations of degassed matrix glasses. As a result of KO-eruption not more than (3.7–4.2) × 10¹² kg of water, (4.3–4.9) × 10¹⁰ kg of chlorine, (8.6–9.8) × 10⁹ kg of fluorine and (2.6–2.9) × 10¹⁰ kg of sulphur were injected into the atmosphere. This eruption had to produce an important climatic impact.     

Geoacoustic emission response to deformation processes activation during earthquake preparation

The results of geoacoustic emission investigations carried out on the seismoactive Kamchatka Peninsula since 1999 are presented. The experiments are characterized by the application of broadband piezoceramic sound receivers (hydrophones) for recording the emission. The hydrophones were installed at the bottom of natural and artificial water reservoirs. As compared with the standard hydrophones, such receivers allow us to broaden the registration frequency range up to 0.1 Hz–11 kHz. Three-component vector receivers with the same frequency range were used simultaneously to study the spatial structure of the geoacoustic emission and the mode of the medium particle movement in a wave. In the course of the investigations, it was established that anomalies of the geoacoustic emission in the kilohertz frequency range are recorded 1–3 days before strong earthquakes at a distance of a few hundred kilometers from the epicenter. A sharp increase in the amplitude and frequency of the geoacoustic impulses, which resemble microearthquakes in pattern and last from tens of minutes to several hours, is interpreted as an anomaly. Signals at such frequencies cannot propagate from the epicenters of preparing earthquakes and represent the response of the medium at the registration point to the change of its stress-strain state. The stress field created therein determines the primary orientation of the emission sources, which can be assessed by vector-phase methods. The results of the integrated investigations of the geoacoustic emission and the Earth’s surface deformation revealed that anomalies are observed before earthquakes with a considerable increase in the strain rate during both the compression and extension of the near-surface rocks.     

Dempster–Shafer Theory Applied to Uncertainty Surrounding Permeability

Typically, if uncertainty in subsurface parameters is addressed, it is done so using probability theory. Probability theory is capable of only handling one of the two types of uncertainty (aleatory), hence epistemic uncertainty is neglected. Dempster–Shafer evidence theory (DST) is an approach that allows analysis of both epistemic and aleatory uncertainty. In this paper, DST combination rules are used to combine measured field data on permeability, along with the expert opinions of hydrogeologists (subjective information) to examine uncertainty. Dempster’s rule of combination is chosen as the combination rule of choice primarily due to the theoretical development that exists and the simplicity of the data. Since Dempster’s rule does have some criticisms, two other combination rules (Yager’s rule and the Hau–Kashyap method) were examined which attempt to correct the problems that can be encountered using Dempster’s rule. With the particular data sets used here, there was not a clear superior combination rule. Dempster’s rule appears to suffice when the conflict amongst the evidence is low.     

Church–state relations in Spain: Variations on a National-Catholic theme?

Contrary to the absence of a uniform Spanish identity (a phenomenon that is often referred to as Spain being a ‘nation of nations’), Spain’s confessional map is remarkably homogeneous. From the beginning of its existence as a political conglomeration, Spain has been a mono-confessional Catholic territory. Even at present, Catholicism is an intrinsic feature of Spanish society and – though officially a secular state – of state policy. A closer look at Spain’s religious situation and its corresponding pattern of church–state relations reveals, however, some recent cracks in the century’s old bond between Spain and Catholicism. Particularly secularization and religious pluralism challenge Spain’s mono-confessional Catholic nature, a development that fits well into Spain’s post-Francoist focus on Europe and European (secular) values. This paper discusses Spanish church–state relations from the beginning of its political existence until present times. Special attention will be paid to more recent societal developments and their impact on religious Spain and church–state relations.

Low-mature gases and their resource potentiality

In the 80’s of last century, based on the advances in natural gas exploration practice, the concepts of bio-thermocatalytic transitional-zone gas and early thermogenetic gas were proposed, and the lower limit Ro values for the formation and accumulation of thermogenetic natural gases of industrial importance have been extended to 0.3%–0.4%. In accordance with the two-stage model established on the basis of carbon isotope fractionation involved in the formation of coal-type natural gases, the upper limit Ro ...     

Anthropogenic factor and methane emission on the East-Siberian shelf

Results of data analysis, based on measurement of atmospheric concentrations of methane in the shallow part of the East Siberian shelf (ESS) are presented in this work. It was shown that methane emission in the atmosphere is determined not only by natural factors, but is also sensitive to anthropogenic influences, like the engine mode of a ship. It was determined that the hydraulic impact, which occurs when starting a ship’s engine after drifting through a shallow, can induce a great methane outbreak in the atmosphere. The power of these “short-lived” sources can exceed the power of any one deep-water mud volcano. In the shallow parts of the ESS, the anthropogenic factor can be one of the important factors effecting methane outbreaks in the atmosphere.     

An approximate analytical solution for measuring air permeability of asphalt samples partially saturated with water

In coastal areas, abnormally high pressure may be caused by the tide-induced water table variation under extensive pavements, particularly during rainfall. To simulate the rainfall infiltration effects on the air permeability of asphalt pavements in coastal area, column-shaped asphalt sample was fixed in the upper part of a steel cylinder with its upper surface saturated with ponding water (depth < 5 mm) and open to the atmosphere. The cylinder’s lower part formed an air chamber. The chamber was pressurized and then the air therein was released naturally through the sample. The pressure variation with time in the chamber was recorded for analysis. Based on the Green–Ampt piston model for the surface water infiltration, an approximate analytical solution was derived to describe the pressure–time relationship in the chamber. A new parameter called the escape pressure was introduced to describe the air pressure needed for the chamber air to break through the capillary pressure induced by the ponding water. The analytical solution gave good estimations of both the escape pressures and the harmonic averages of the permeabilities of the wet and dry parts of 14 samples in the sense that excellent fittings were obtained between the observed and predicted air pressures in the air chamber. The estimated escape pressure ranges from 0.0 to 1.74 kPa. The harmonic average of the permeabilities of the wet and dry parts is 5–94% of the dry sample’s permeability.     

Is counselling a feminist practice?

Women’s efforts to influence policies have complex effects, which are often difficult to evaluate. This paper identifies four themes in feminist politics through which to analyse whether a particular intervention involving substantial numbers of women – that of counselling in the UK – can be understood as a feminist practice. These themes are concerned with gender equality, women’s autonomy, recognition of diversity among women and the deconstruction of gender norms. In its early post-war origins prior to the emergence of second wave feminism, and in the stories recounted by women practitioners at the turn of millennium, counselling emerges as contradictory and ambivalent in relation to these themes in feminist politics.     

High-latitude supergiants: Anomalies in the spectrum of LN Hya in 2010

High-spectral-resolution observations with the Special Astrophysical Observatory 6-m telescope obtained in 2003–2011 are used to study features of the optical spectrum and the velocity field in the atmosphere of the semiregular variable LN Hya in detail. The weak, symmetric, photospheric absorption lines indicate radial-velocity variations from night to night (by as much as 3 km/s), resulting from small pulsations. Peculiarities and profile variations were found for strong lines of FeI, FeII, BaII, SiII, etc. The profiles of these lines were asymmetric: their short-wavelength wings were extended and their cores were either split or distorted by emission. During the 2010 observing season, the position and depth of the Hα absorption component, the intensities of the short- and long-wavelength emission components, and the intensity ratio of the latter components varied from spectrum to spectrum. Weak emission lines of neutral atoms (VI, MnI, CoI, NiI, FeI) appeared in the spectrum of June 1, 2010. These spectral peculiarities, recorded for the first time, suggest that we have detected rapid changes in the physical conditions in the upper atmospheric layers of LN Hya in 2010.     

The phase boundary between wadsleyite and ringwoodite in Mg2SiO4 determined by in situ X-ray diffraction

The phase boundary between wadsleyite and ringwoodite in Mg₂SiO₄ has been determined in situ using a multi-anvil apparatus and synchrotron X-rays radiation at SPring-8. In spite of the similar X-ray diffraction profiles of these high-pressure phases with closely related structures, we were able to identify the occurrence of the mutual phase transformations based on the change in the difference profile by utilizing a newly introduced press-oscillation system. The boundary was located at ~18.9 GPa and 1,400°C when we used Shim’s gold pressure scale (Shim et al. in Earth Planet Sci Lett 203:729–739, 2002), which was slightly (~0.8 GPa) lower than the pressure as determined from the quench experiments of Katsura and Ito (J Geophys Res 94:15663–15670, 1989). Although it was difficult to constrain the Clapeyron slope based solely on the present data due to the kinetic problem, the phase boundary [P (GPa)=13.1+4.11×10⁻³×T (K)] calculated by a combination of a P–T position well constrained by the present experiment and the calorimetric data of Akaogi et al. (J Geophys Res 94:15671–15685, 1989) reasonably explains all the present data within the experimental error. When we used Anderson’s gold pressure scale (Anderson et al. in J Appl Phys 65:1535–1543, 1989), our phase boundary was located in ~18.1 GPa and 1,400°C, and the extrapolation boundary was consistent with that of Kuroda et al. (Phys Chem Miner 27:523–532, 2000), which was determined at high temperature (1,800–2,000°C) using a calibration based on the same pressure scale. Our new phase boundary is marginally consistent with that of Suzuki et al. (Geophys Res Lett 27:803–806, 2000) based on in situ X-ray experiments at lower temperatures (<1,000°C) using Brown’s and Decker’s NaCl pressure scales.     

Instrumental study of high-frequency seismoacoustic signal modulation in a deep drillhole

For many years we have failed to record instrumentally the background variations in seismoacoustic emission in solid consolidated rocks of the Earth’s crust at great depths (3200 m) and to confirm their relation to lunar-solar gravitation. We managed to fulfill the task only with significantly improved parameters of the recording system measurement channel. As follows from analysis of new data, the amplitudes in the diurnal cycle vary from 1930 to 2100 fm (10⁻¹⁵) for the band of 160 Hz and from 129.5 to 132 fm for the band of 500 Hz, while the energy model correlation coefficients are within 0.737–0.852. Hence, this fact proves once again that background variations related to lunar-solar tides are universal in occurrence, and their frequency and amplitude depend significantly on the host rocks, position, and time of observations, while the energy model fits in these variations.     

Thermodynamic properties and equation of state of fcc aluminum and bcc iron, derived from a lattice vibrational method

We use a lattice vibrational technique to derive thermophysical and thermochemical properties of the pure elements aluminum and iron in pressure–temperature space. This semi-empirical technique is based on either the Mie–Grüneisen–Debye (MGD) approach or an extension of Kieffer’s model to incorporate details of the phonon spectrum. It includes treatment of intrinsic anharmonicity, electronic effects based on the free electron gas model, and magnetic effects based on the Calphad approach. We show that Keane’s equation of state for the static lattice is better suitable to represent thermodynamic data for aluminum from 1 bar to pressures in the multi-megabar region relative to Vinet’s universal and the Birch–Murnaghan equation of state. It appears that the MGD and Mie–Grüneisen–Kieffer approach produce similar results, but that the last one better represents heat capacity below room temperature. For iron we show that the high temperature behavior of thermal expansivity can be explained within the Calphad approach by a pressure-dependent Curie temperature with a slope between –1 and 0 K/GPa.     

Evidence of women’s empowerment in India: a study of socio-spatial disparities

Various national and international communities have addressed women’s issues and taken various efforts to empower them so as to enhance their social and health status and involve them in developmental activities. The Indian DHS survey (National Family Health Survey, 1998–1999) provides an opportunity to study women’s empowerment in India. The survey collected information on several dimensions of women’s empowerment from 90,303 ever-married women (ages 15–49), from all the states of India. Utilizing these data sets, four indices – household autonomy index, mobility index, attitude towards gender index and attitude towards domestic violence index – are constructed to measure the different dimensions of empowerment. Using these indices, the spatial and socio-economic and cultural disparities that exist within India are analyzed. Finally, an attempt is made to identify some important determinants for women’s empowerment using multiple logistic regression analysis. The results show that at the national level, 43% of the women have high household autonomy; 23% of the women have high freedom to move outside their home; 40% of the women have no gender preference attitude; and only 43% of the women defy domestic violence. But there are significant divergences in these indices of women’s empowerment across the different states and socio-economic and cultural settings within India. Women’s educational levels emerged as an important predictor for all the four dimensions of women’s empowerment. Additionally, media exposure and age have emerged as the important predictors for some dimensions of woman’s empowerment. This paper was presented by Prof. Kamla Gupta at the International Geographical Union Conference (IGU), held in Canada, 2002.     

Drift loss cone instability in the ring current and plasma sheet

The drift loss cone instability, propagating nearly transverse to the ambient magnetic field, is studied in the ring current plasma taking into account the relative driftU between electrons and protons due to density gradients. The growth rates attain maxima and then decrease as the wave number parallel to the magnetic fieldk _II increases. The peak values of the growth rates, maximised with respect tok _II, are enhanced by the increase in number density, electron temperature and loss cone index, and by the decrease in β_t, the ratio of the proton thermal pressure to magnetic field pressure. The unstable frequencies fall in the range of 5 to 30Ω_p with the growth rate γ ≥Ω_p. In the ring current region betweenL=4 and 5, the instability will generate a strong turbulence in the frequency range between 5–500 Hz which can produce fluctuating electric fields 0. 5–5 mV/m and magnetic field 0.8–80mγ. This instability can also occur on the auroral field lines, which connect to the region of intense earthward plasma flow in the distant magnetotail and produce a broad band electrostatic noise.     

Evaluation of rock mechanical behaviors under uniaxial compression with reference to assessed weathering grades

Summary  A weathering classification for granitic rock materials from southeastern Brazil was framed based on core characteristics. The classification was substantiated by a detailed petrographic study. Indirect assessment of weathering grades by density, ultrasonic and Schmidt hammer index tests was performed. Rebound values due to Schmidt hammer multiple impacts at one representative point were more efficient in predicting weathering grades than averaged single impact rebound values, P-wave velocities and densities. Uniaxial compression tests revealed that a large range of uniaxial compressive strength (214–153 MPa) exists in Grade I category where weathering does not seem to have played any role. It was concluded that variability in occurrences of quartz intragranular cracks and in biotite percentage, distribution and orientation might have played a key role in accelerating or decelerating the failure processes of the Grade I specimens. Deterioration of uniaxial compressive strength and elastic modulus and increase in Poisson’s ratio with increasing weathering intensity could be attributed to alteration of minerals, disruption of rock skeleton and microcrack augmentation. A crude relation between failure modes and weathering grades also emerged. Correspondence: Prof. T. B. Celestino, Universidade de S?o Paulo, S?o Carlos, Brazil     

Modelling the effects of climate change on methane emission from a northern ombrotrophic bog in Canada

Peatlands are a large potential source of methane (CH₄) to the atmosphere. In order to investigate the effects of climate change on CH₄ emission from northern ombrotrophic peatlands, a simulation model coupling water table dynamics with methane emission was developed for the Mer Bleue Bog in Ontario, Canada. The model was validated against reported values of CH₄ flux from field measurements and the model outputs exhibited high sensitivity to acrotelm thickness, leaf area index, transmissivity and slope of water table. With a 2–4°C temperature rise over the 4-year simulation period, the rate of CH₄ release dropped significantly to under 0.1 mg m⁻² day⁻¹. On the other hand, mean CH₄ emission increased by >26-fold when the increase in precipitation was >15%. When looking at the combined effects, the highest CH₄ release (13.3 mg m⁻² day⁻¹) was attained under the scenario of 2°C temperature rise and 25% precipitation increase. Results obtained in this study highlight the importance of avoiding more extreme climate change, which would otherwise lead to enhanced methane release from peatlands and further atmospheric warming through positive feedback.     

Hydrochemical changes in a small tropical island’s aquifer: Manukan Island, Sabah, Malaysia

Small islands groundwater are often exposed to heavy pumpings as a result of high demand for freshwater consumption. Intensive exploitation of groundwater from Manukan Island’s aquifer has disturbed the natural equilibrium between fresh and saline water, and has resulted increase the groundwater salinity and leap to the hydrochemical complexities of freshwater–seawater contact. An attempt was made to identify the hydrochemical processes that accompany current intrusion of seawater using ionic changes and saturation indices. It was observed that the mixing between freshwater–seawater created diversity in geochemical processes of the Manukan Island’s aquifer and altered the freshwater and seawater mixture away from the theoretical composition line. This explained the most visible processes taking place during the displacement.