bluuebunny/crossref_metadata_2025 huggingface dataset:
Ghost-busting fashion: Symbolic boundaries and the politics of time in fashion journalism
Authors: Van de Peer Aurélie
Published: August 2014

This article examines the rhetorical tools that leading fashion journalists have used over the past 60 years when they seek to protect the idea of impenetrable temporal boundaries between contemporary fashionable dress and its history. Journalists have always taken a dim view of fashion practices that recycle historical styles in contemporary fashion design. Yet in the late 20th century they intensified this repudiation by the previously unseen use of negatively connoted temporal fashion words, like ‘retro’ and ‘nostalgia’. Journalists further combined such fashion words, declaring specific styles as passé or fashion-dead, with chronological designations to evoke the idea that such styles belong to an irretrievable chronological past. In doing so, they are ‘ghost-busting’ the presence of fashion history for the benefit of a cultural industry that is centred on a rhythmic transcendence of its own past in order to convince consumers of the apparent newness of fashion products.
When they don’t die: Prognosis ambiguity, role conflict and emotion work in cancer caregiving
Authors: Olson Rebecca E , Connor James
Published: August 2014

Informal carers of cancer patients have high rates of burden, stress, anxiety and unmet needs; yet, some describe caregiving as fulfilling. Building on the work of Thomas and colleagues, this study takes a sociology of emotions approach to understanding variations in carers of cancer patients’ emotional experiences, using interview data with 32 carers of a spouse with cancer. Analysis indicates that a clearly terminal (negative) prognosis facilitates clear priorities, unambiguous emotion management and improved social bonds. A more ambiguous (positive) prognosis, that includes a greater chance of survival, fosters role conflict, clashing feeling rules and ongoing guilt within spousal carers. This study highlights the importance of a prognosis to emotion management, underscoring a phenomenon that is likely to grow as survival rates continue to improve and explaining some of the variation in carers’ experiences.
Phosphodiesterase 5 inhibitors augment UT-15C-stimulated ATP release from erythrocytes of humans with pulmonary arterial hypertension
Authors: Bowles Elizabeth A , Moody Gina N , Yeragunta Yashaswini , Stephenson Alan H , Ellsworth Mary L , Sprague Randy S
Published: August 2014

Both prostacyclin analogs and phosphodiesterase 5 (PDE5) inhibitors are effective treatments for pulmonary arterial hypertension (PAH). In addition to direct effects on vascular smooth muscle, prostacyclin analogs increase cAMP levels and ATP release from healthy human erythrocytes. We hypothesized that UT-15C, an orally available form of the prostacyclin analog, treprostinil, would stimulate ATP release from erythrocytes of humans with PAH and that this release would be augmented by PDE5 inhibitors. Erythrocytes were isolated and the effect of UT-15C on cAMP levels and ATP release were measured in the presence and absence of the PDE5 inhibitors, zaprinast or tadalafil. In addition, the ability of a soluble guanylyl cyclase inhibitor to prevent the effects of tadalafil was determined. Erythrocytes of healthy humans and humans with PAH respond to UT-15C with increases in cAMP levels and ATP release. In both groups, UT-15C-induced ATP release was potentiated by zaprinast and tadalafil. The effect of tadalafil was prevented by pre-treatment with an inhibitor of soluble guanylyl cyclase in healthy human erythrocytes. Importantly, UT-15C-induced ATP release was greater in PAH erythrocytes than in healthy human erythrocytes in both the presence and the absence of PDE5 inhibitors. The finding that prostacyclin analogs and PDE5 inhibitors work synergistically to enhance release of the potent vasodilator ATP from PAH erythrocytes provides a new rationale for the co-administration of these drugs in this disease. Moreover, these results suggest that the erythrocyte is a novel target for future drug development for the treatment of PAH.
“It’s Their World, so You’ve Just Got to Get Through”
Authors: Opsal Tara
Published: August 2014

This article brings together research on parole governance with women’s experiences of reentry. In particular, drawing on longitudinal qualitative interviews with a group of women leaving prison and returning to their communities, the present study highlights the way parole structures women’s reintegration efforts post-incarceration. The women’s experiences highlight how parole governance intersects, conflicts with, and complicates their efforts to return to their communities and transition out of the gaze of the penal state.
Parental Bonding
Authors: de Cock T. Paul , Shevlin Mark
Published: August 2014

Estimating the early parent–child bonding relationship can be valuable in research and practice. Retrospective dimensional measures of parental bonding provide a means for assessing the experience of the early parent–child relationship. However, combinations of dimensional scores may provide information that is not readily captured with a dimensional approach. This study was designed to assess the presence of homogeneous groups in the population with similar profiles on parental bonding dimensions. Using a short version of the Parental Bonding Instrument (PBI), three parental bonding dimensions (care, authoritarianism, and overprotection) were used to assess the presence of unobserved groups in the population using latent profile analysis. The class solutions were regressed on 23 covariates (demographics, parental psychopathology, loss events, and childhood contextual factors) to assess the validity of the class solution. The results indicated four distinct profiles of parental bonding for fathers as well as mothers. Parental bonding profiles were significantly associated with a broad range of covariates. This person-centered approach to parental bonding has broad utility in future research which takes into account the effect of parent–child bonding, especially with regard to “affectionless control” style parenting.
A 3-D current system of an ionospheric dynamo including a skin effect in an anisotropic plasma
Authors: Plotkin V. V.
Published: August 2014

The numerical two-mode electromagnetic model of an ionospheric dynamo is constructed taking into account a skin effect of a field in an anisotropic plasma, i.e. a non-potential electric field of Sq-variations in the ionosphere. It is shown that a three-dimensional current system generated by the dynamo action of winds is located at altitudes less than about 200 km basically. It does not depend on an ionosphere condition in upper layers and weaker field-aligned currents between the northern and southern hemispheres practically, and an almost complete closed current circuit is generated in the dynamo layer.
Tsunami run-up heights of the 2004 off the Kii peninsula earthquakes
Authors: Koike Nobuaki , Takahashi Tomoyuki , Imai Kentaro , Tanioka Yuichiro , Nishimura Yuichi , Harada Kenji , Suzuki Shingo , Fujima Koji , Shigihara Yoshinori , Namegaya Yuichi , Koshimura Shunichi
Published: August 2014

A tsunami height survey was conducted immediately after the 2004 off the Kii peninsula earthquakes. Results of the survey show that the largest tsunami height was about 4.6 m locally at Kiho-cho, Mie prefecture. Numerical simulation of the tsunami due to the earthquake was carried out using the model parameters estimated by NIED. The distribution pattern of the observed tsunami heights along the coast cannot be explained by the computed heights, because the model equation is linear long-wave theory and the run-up computations with a finer grid system are not included in this simulation. In order to explain tsunami run-up heights, it is necessary that the non-linear and run-up computation model should be used with a finer grid system.
Change of the source mechanism of the main shock of the 2004 off the Kii peninsula earthquakes inferred from long period body wave data
Authors: Hara Tatsuhiko
Published: August 2014

Waveform inversion of long period body wave data was performed to determine the temporal distribution of moment release of the main shock of the 2004 off the Kii peninsula earthquakes. Our result suggests that the source mechanism varied during the rupture, with the first 20 sec dominated by the strike slip component, while a thrust mechanism was predominant between 30–40 sec. The employed dataset has enough resolving power to detect temporal change on such a time scale, and thus our results suggest that this earthquake is a compound event consisting of the two different source mechanisms.
Variation of teleseismic short-period waveforms at Matsushiro Seismic Array System
Authors: Kato Mamoru , Nakanishi Ichiro , Takayama Hiroyuki
Published: August 2014

We investigate the origin of variation of teleseismic P phase waveforms recorded at Matsushiro Seismic Array System. Short-period, vertical component waveforms from three source regions were analyzed separately in the frequency domain. Observed variation is mainly attributed to the site effects, which are frequency dependent and strongly depend on the incoming azimuth. Such variation is not seen for the pre-event noise spectra. The secondary wavefield that is excited by the incident P phase is the likely cause of the observed waveform variation.
Widespread magmatic activities on the angrite parent body at 4562 Ma ago
Authors: Sugiura Naoji , Miyazaki Akiko , Yanai Keizo
Published: August 2014

Mn-Cr chronology of four quenched angrites showed that they formed nearly at the same time (4562 Ma) on the surface of the parent-body. Based on the chemical compositions, the cosmic ray exposure ages, and considerations on the thermal history of an achondrite parent-body, we suggest that the four angrites formed on top of a shallow magma ocean on the angrite parent body.
Earthquake relocations, fault zone geometry and constraints on lateral velocity variations using the joint hypocenter determination method in the Taiwan area
Authors: Kim Kwang-Hee , Chiu Jer-Ming , Pujol Jose , Chen Kou-Cheng
Published: August 2014

Four subsets of earthquakes recorded by an island-wide seismic network from 1991 to 2002 in the Taiwan area are relocated using the joint hypocenter determination (JHD) technique. Relatively large horizontal and vertical shifts are observed during the relocation, which indicates there may be systematic earthquake miss-locations in the Taiwan earthquake catalog due to the over-simplification of complicated earth structures to a simple 1-D velocity model. Generally, earthquakes are more clustered after the JHD relocation. Subsurface structures defined by the relocated seismicity become clearer, while they are not as clear in the initial hypocenters. Significant subsurface structures defined by the relocated seismicity are fault systems beneath the Central Mountain Range, beneath the northern Longitudinal Valley and Coastal Range, beneath the southern Longitudinal Valley and Coastal Range, and beneath the Chao-Chou fault in southern Taiwan. Another set of results from the JHD analysis,P- andS-wave station corrections, provide valuable information on the lateral velocity variations. The JHD station corrections indicate that upper crustal materials in the Central Mountain Range are characterized by higher velocity than those in the Western Foothills and Coastal Plain. The patterns of the observed JHD station corrections are also thoroughly consistent with surface geology observations. Analysis of the four clusters of earthquakes resulted in a remarkable similarity in JHD station corrections, indicating that the overlapping subsurfaces where two or more clusters of rays had traveled through were relatively shallow. These subsurfaces are responsible for the observed patterns of positive and negative JHD station corrections.
Pitch angle diffusion of electrons at the boundary of the lunar wake
Authors: Nakagawa Tomoko , Iizima Masahide
Published: August 2014

Velocity distribution of the solar wind electrons that penetrate through the lunar wake boundary is investigated by calculating orbits of the electrons injected into model structures of layers of electric fields. Only the electrons with sufficient energy to overcome the potential difference penetrate through the wake boundary. The electrons injected along the magnetic field lines which intersect the model structure undergo pitch angle scattering due to electric field component perpendicular to the magnetic field. After the passage through the electric field, the electrons have significant perpendicular component of velocity as well as the parallel component larger than a lower limit, which is dependent on the electric potential of the wake boundary. The velocity distribution can account for the cyclotron resonance with sunward-propagating whistler mode waves that were detected by GEOTAIL at 27 lunar radii upstream of the moon on October 25, 1994.
A slow slip event in the Tokai area detected by tilt and seismic observation and its possible recurrence
Authors: Yamamoto Eiji , Matsumura Shozo , Ohkubo Tadashi
Published: August 2014

In recent years, some anomalous crustal activities have been detected in the Tokai area, central Japan. First, a seismicity change was detected and was recognized to be the quiescence of microearthquake activities. Anomalous ground deformation was then detected in high-density GPS observations conducted by GSI, and also in tilt observations by NIED at the MKB station. East-southeast upward tilting of about 2 microradians from the middle of 2000 to the present is consistent with the result of the GPS observation. An analysis using the GPS data attributed the ground deformation to a slow slip occurring on the plate boundary beneath Lake Hamana, where distinct seismic quiescence has also been detected. Tilt observation at MKB began in 1981, so we have carefully examined past records to determine whether similar events have ever taken place. An anomalous tilt change of nearly the same direction as the current one and seismic quiescence evidently occurred simultaneously from 1988 to 1990. Apparently, a similar slow slip took place in almost the same place during this epoch. We speculate that slow-slip events beneath Lake Hamana have been repeatedly occurring under the steady subduction of the Philippine Sea plate. However, the magnitude and duration of the current slip now in progress are nearly twice those of the last slip (1988 to 1990). Therefore, a slow slip in this area may not repeat in exactly the same way. Though it is unclear how the ongoing event will proceed, redistribution of stress due to the slow slip may promote the anticipated Tokai earthquake. Careful monitoring and intense observation are necessary.
Candidate main-field models for the Definitive Geomagnetic Reference Field 1995.0 and 2000.0
Authors: Chambodut A. , Langlais B. , Mandea M.
Published: August 2014

Two geomagnetic main-field models for epochs 1995.0 and 2000.0 were proposed as candidate models for DGRF 1995 and DGRF 2000. A main-field model was derived for epoch 2000.0, using the high-quality data provided by the Ørsted satellite around this epoch. Since no high-quality satellite vector measurements of the magnetic field were acquired between 1980 and 1999, our approach was to extrapolate this 2000.0 accurate model back to 1995. To do this we produced a secular-variation model for the time-span 1995-2000, from ground measurements. The models obtained were incorporated into DGRF 1995 and DGRF 2000 as part of the 9th generation of the IGRF in 2003.
Enhancing comprehensive inversions using the Swarm constellation
Authors: Sabaka Terence J. , Olsen Nils
Published: August 2014

This paper reports on the findings of a simulation study designed to test various satellite configurations suggested for the upcoming Swarm magnetic mapping mission. The test is to see whether the mission objectives of recovering small-scale core secular variation (SV) and lithospheric magnetic signals, as well as information about mantle conductivity structure, can be met. The recovery method used in this paper is known as comprehensive inversion (CI) and involves the parameterization of all major fields followed by a co-estimation of these parameters in a least-squares sense in order to achieve proper signal separation. The advantage of coestimation over serial estimation of parameters is demonstrated by example. Synthetic data were calculated for a pool of six Swarm satellites from a model based heavily on the CM4 comprehensive model, but which has more small-scale lithospheric structure, a more complicated magnetospheric field, and an induced field reflecting a 3-D conductivity model. These data also included realistic magnetic noise from spacecraft and payload. Though the parameterization for the CI is based upon that of CM4, modifications have been made to accommodate these new magnetospheric and induced fields, in particular with orthogonality constraints defined so as to avoid covariance between slowly varying induced fields and SV. The use of these constraints is made feasible through an efficient numerical implementation. Constellations of 4, 3, 2, and 1 satellites were considered; that with 3 was able to meet the mission objectives, consistently resolving the SV to about spherical harmonic (SH) degree n = 15 and the lithosphere to a limited n < 90 due to external field leakage, while those with 2 and 1 were not; 4 was an improvement over 3, but was much less than the improvement from 2 to 3. The resolution of the magnetospheric and induced SH time-series from the 3 satellite configuration was sufficient enough to allow the detection of 3-D mantle conductivity structure in a companion study.
Ocean circulation generated magnetic signals
Authors: Manoj C. , Kuvshinov A. , Maus S. , Lühr H.
Published: August 2014

Conducting ocean water, as it flows through the Earth’s magnetic field, generates secondary electric and magnetic fields. An assessment of the ocean-generated magnetic fields and their detectability may be of importance for geomagnetism and oceanography. Motivated by the clear identification of ocean tidal signatures in the CHAMP magnetic field data we estimate the ocean magnetic signals of steady flow using a global 3-D EM numerical solution. The required velocity data are from the ECCO ocean circulation experiment and alternatively from the OCCAM model for higher resolution. We assume an Earth’s conductivity model with a surface thin shell of variable conductance with a realistic 1D mantle underneath. Simulations using both models predict an amplitude range of ±2 nT at Swarm altitude (430 km). However at sea level, the higher resolution simulation predicts a higher strength of the magnetic field, as compared to the ECCO simulation. Besides the expected signatures of the global circulation patterns, we find significant seasonal variability of ocean magnetic signals in the Indian and Western Pacific Oceans. Compared to seasonal variation, interannual variations produce weaker signals.
The performance of RTK-GPS for surveying under challenging environmental conditions
Authors: Lee In-Su , Ge Linlin
Published: August 2014

The aim of this paper was to assess the availability of RTK GPS (Real-Time Kinematic Global Positioning Systems) under some challenging environmental conditions. Testing was performed under two of these conditions, i.e. a small tree-covered garden and a pylon for high-voltage electricity supply. The increase in the number of satellites had many benefits for the integer ambiguity resolution, but no significant contribution to the accuracy of RTK positions and PDOP (Precision Dilution of Position). The results of RTK testing were compared against results from Total Station surveying as a further quality check. The results indicate that integrating RTK GPS system with Total Station is favoured for surveying in urban environments.
Strain accumulation in South Korea inferred from GPS measurements
Authors: Jin Shuanggen , Park Pil-Ho
Published: August 2014

Monitoring the variation of the crustal strain is a key issue to understand the physical process of crustal tectonic activities. In this paper, GPS data for the period from March 2000 to February 2004 were analyzed to quantitatively investigate the plate deformation patterns and distributions in the South Korean peninsula. The results show two anomalous rates of strain accumulation in South Korea, a W-E compression accumulation of crustal strain in the East and West parts, and a N-S extension strain accumulation in the middle part along the longitude of about 127.5°E. In addition, the GPS-derived seismic moment accumulation rate is significant and consistent with recent historic earthquakes and fault zones in South Korea. The most anomalous seismic moment rates are in the middle part (about 127.3°E, 35.5°N), North edge (about 128.0°E, 38.0°N) and Northeast part (about 128.5°E, 37.3°N) of South Korea, indicating a high earthquake risk.
A Virtual Global Magnetic Observatory Network: VGMO.NET
Authors: Papitashvili Vladimir O. , Petrov Valeriy G. , Saxena Anshuman B. , Clauer C. Robert , Papitashvili Natalia E.
Published: August 2014

Since the mid-1990s, many geomagnetic datasets began appearing on the World Wide Web. Often these data were not submitted to the World Data Centers as recommended since the International Geophysical Year (1957- 58). As a result, existing data become naturally distributed creating an urgent need for more sophisticated search engines capable of identifying and retrieving the data from Web for scientific analyses. We introduce a Virtual Global Magnetic Observatory concept for “pulling” geomagnetic data distributed worldwide. The VGMO moves information exchange from simple file transfers to a higher level of abstraction, forming the distributed databases through establishment of self-organizing data nodes. We present the first working VGMO prototype: an “on-demand” objects-building Internet application that is transparent in its internal data management to the external users/clients. The VGMO server continuously builds data-objects only from client requests by going through a pre-set list of Web-based data nodes (including WDCs). As the retrieved data are added to the server (or node) database, future requests of the same interval would not force a new Web search. Furthermore, new nodes can be made available to others through the VGMO network, building the worldwide geomagnetic data “fabric” in a platform-independent and location-neutral environment of newly “webbed“ digital data. Application is on a server at http://mist.engin.umich.edu.
Inferred long term trends in lightning activity over Africa
Authors: Price Colin , Asfur Mustafa
Published: August 2014

Global warming is becoming a reality, with growing evidence that anthropogenic activity on our planet is starting to influence our climate (IPCC, 2001). Due to the increase in significant weather-related disasters in recent years, it is important to investigate the role of global warming on such changes. In this paper we attempt to estimate the long term trends in lightning activity over tropical Africa during the past 50 years, using upper tropospheric water vapor as a proxy for regional lightning activity. We use the NCAR/NCEP reanalysis product available for the period 1948 to the present to estimate the long term trends in lightning activity. Similarity between the long term African lightning variability and observed rainfall and river discharge variability are demonstrated. Since 1950 the inferred lightning activity over Africa shows significant variability, reaching a maximum during the 1960s, followed by a decrease in activity during the following 30 years.
Parallel electric field structures associated with the low-frequency oscillations in the auroral plasma
Authors: Reddy R. V. , Singh S. V. , Lakhina G. S. , Bharuthram R.
Published: August 2014

The nonlinear evolution of low-frequency electrostatic oscillations in a magnetized plasma consisting of protons, electrons and oxygen ion beams has been studied. The fluid equations have been used for the oxygen beam, whereas the Boltzmann distributions are used for the protons and electrons. The coupled system of equations are reduced to a single nonlinear differential equation in the rest frame of the propagating wave for any direction of propagation with respect to the ambient magnetic field. This nonlinear differential equation is solved numerically for the parameters charateristic of the auroral acceleration region. Depending on the wave Mach number, proton and oxygen ion concentrations, and driving electric field, the numerical solutions show a range of periodic solutions varying from sinusoidal to sawtooth and highly spiky waveforms. The effects of the plasma parameters, in particular the oxygen ion concentration and the proton temperature on the evolution of the nonlinear waves are examined. The results from the model are compared with satellite observations.
Simultaneous DMSP, all-sky camera, and IMAGE FUV observations of the brightening arc at a substorm pseudo-breakup
Authors: Yago K. , Shiokawa K. , Yumoto K. , Baishev D. G. , Solovyev S. I. , Rich F. J.
Published: August 2014

Auroral particles, field-aligned currents, and plasma convections in the vicinity of the brightening arc at substorm onset are still not well understood, since it is very rare to have conjugate satellite measurements above the brightening arc. In this paper, we investigate the characteristics of auroral particles and fields associated with the brightening arc at a pseudo-onset of substorm on October 31, 2000, using ground all-sky TV images, IMAGE FUV auroral images, and particle, magnetic field, and plasma flow data obtained by the DMSP F12 satellite. The arc brightening at Tixie (66.0°MLAT), Russia, occurred at 1004 UT (18.75 MLT) coincident with a coherent Pi 2 pulsation at midlatitudes and with the DMSP crossing above the arc. The brightening arc did not develop on a global scale, indicating that this event is a pseudo auroral breakup, which occurred ≈16 min before the major substorm expansion onset. IMAGE auroral images indicate that the longitude of the brightening center was ≈2.5 h nightside of Tixie. The DMSP data show that the precipitating particles associated with the brightening arc correspond to an electron inverted-V structure at the equatorward edge of the electron precipitation region. The arc was located in the energetic (>1 keV) ion precipitation region, near the equatorward boundary of the upward region 1 field-aligned current, and at the peak of the sunward convection velocity. These facts indicate that the brightening arc at duskside of the onset local time was located in the inner plasma sheet at the inner edge of the region 1 current source in the sunward convection region.
A note on the semidiurnal non-migrating tide at polar latitudes
Authors: Aso Takehiko
Published: August 2014

In the Antarctic upper mesosphere and lower thermosphere around 90 km, meteor radar observations at the South Pole have detected a significant semidiurnal wind component in summer which is found to be non-migrating with zonal wavenumber s = 1. It has been surmised that this component might possibly be excited through the non-linear interaction of the migrating semidiurnal tide with stationary planetary waves with zonal wavenumber s = 1 prevailing at stratospheric heights. The Kyushu University GCM has been successful in elucidating very unambiguously this conjecture. In the present paper, linearized steady tidal modeling is carried out in this connection to reproduce, by a fairly simplified but explicit model, trans-equatorial propagation of non-migrating semidiurnal tide forced in the opposite winter hemisphere and to compare latitudinal structures of migrating and non-linearly excited intermittent tides in view of polar latitudes where non-migrating tide tends to dominate over migrating tide. It is also shown that the re-analysis meteorological data for almost 10 years clearly supports the well-known N-S asymmetry in stationary planetary wave activity in winter polar stratospheric regions, possibly due to the difference in surface topography between two hemispheres. We suggest that there might be significant asymmetry in the summertime enhancement of semidiurnal non-migrating tide between both polar regions. This phenomenon may be in a context similar with the N-S asymmetry of gravity wave activity in the polar regions, possibly giving rise to N-S disparity of cold summertime mesopause temperature. Clarification awaits intensive bi-polar studies by coordinated radar and optical observations which are running both in the Arctic and Antarctic regions.
Determination of ground conductivity and system parameters for optimal modeling of geomagnetically induced current flow in technological systems
Authors: Pulkkinen Antti , Pirjola Risto , Viljanen Ari
Published: August 2014

In this work, methods to determine technological system parameters and the ground conductivity structure from different sets of geomagnetically induced current (GIC), magnetic field and geoelectric field observations are explored. The goal of the work is to enable optimal modeling of induced currents in any technological system experiencing GIC. As an additional product, the introduced methods can also be applied to utilize GIC observations in the imaging of the subsurface geological structures. Here a robust processing scheme and Occam’s inversion technique familiar from magnetotelluric (MT) studies are applied to the determination of the ground conductivity structure. The application of the methods to GIC data from the Finnish pipeline for a storm period of October 24-November 1, 2003 demonstrate that optimal system parameters and ground conductivity structure can be obtained using time series comprising only 8 days worth of data. Importantly, the obtained ground model is in agreement with models obtained in earlier MT studies. Furthermore, it is shown that although in an ideal case the magnetic field data used should be obtained from the immediate vicinity of the GIC observation site, some spatial separation (200–300 km) between the sites can be tolerated.
Formation process of recent fumarolic gases at the Mt. Mihara summit peak of the Izu-Oshima volcano, Japan
Authors: Ohba Takeshi
Published: August 2014

We have investigated the chemical and isotopic composition of recently formed gases emitted by three fumaroles on the Mt. Mihara summit peak of the Izu-Oshima volcano in order to assess the formation process of these gases. The CO2/H2O ratio of these gases varied greatly, with the σD and σ18O of the H2O being as low as a vapor phase equilibrated with the local meteoric water. These features are explained by a mixing of the vapor equilibrated with local meteoric groundwater and primary steam, which is a vapor phase generated by the mixing of magmatic gas and a cold meteoric groundwater. We concluded that there was no direct mixing between the magmatic vapor and a vapor phase of meteoric origin in the processes involved in fumarolic gas formation.
Shock-induced anisotropy of magnetic susceptibility: impact experiment on basaltic andesite
Authors: Nishioka Itoyuki , Funaki Minoru , Sekine Toshimori
Published: August 2014

Changes in the anisotropy of the low-field magnetic susceptibility (AMS) of basaltic andesite were induced by decaying stress waves and subsequently quantified. An initial shock pressure of 5 GPa was generated in a block of the target rock through impacting with a cylindrical projectile. Following the impact, the maximum or minimum principal susceptibility axes of the target were reoriented toward the shock direction at low (0.5–3 GPa) or high (>3 GPa) estimated shock pressures, respectively. Subtraction of the initial AMS demonstrated a parallelism between the induced susceptibility axes and the shock direction. These results suggest a potential application of AMS as an indicator of the propagation directions of stress waves generated in rocks at terrestrial impact structures.
The seismological and geodetical roles of strain seismogram suggested from the 2004 off the Kii peninsula earthquakes
Authors: Okubo Makoto , Asai Yasuhiro , Aoki Harumi , Ishii Hiroshi
Published: August 2014

Dynamic strain seismograms obtained by high-speed sampling include not only long-period changes, such as ‘strain-step’, step change in strain, but also short period variations, such as body waves. We studied dynamic strain variations caused by the 2004 off the Kii peninsula earthquakes. Using such strain seismograms, we clarified the relation between dynamic strain and velocity. Our results will contribute greatly to seismology. We also clarified the strain-step formation process. This result and the concept of dynamic strain will bring more information to geodetics.
Estimation of local site effects in Ojiya city using aftershock records of the 2004 Mid Niigata Prefecture earthquake and microtremors
Authors: Yamanaka Hiroaki , Motoki Kentaro , Fukumoto Shun’ichi , Takahashi Toshiyuki , Yamada Nobuyuki , Asano Kimiyuki
Published: August 2014

Aftershock observations of the 2004 Mid Niigata Prefecture earthquake were conducted in the central part of Ojiya city, the Niigata prefecture, central Japan, to investigate local site effects. We installed eight accelerographs in the vicinity of the K-NET and JMA stations in the area. The stations of the aftershock observations are situated under different geological conditions including one installed in a mountainous area on Tertiary layers to serve as a reference site. We examined the ground-motion characteristics of the records for a Mj 6.1 aftershock focusing on local site effects. The amplification, at a period of less than 1 sec, is the largest in the vicinity of the K-NET station. The amplification at periods longer than 2 sec is larger in the western part of the city than those in the east. We estimated theS-wave velocity structure in the sediments above the basement with anS-wave velocity of 3.4 km/sec from the inversion of phase velocities measured by the array observations of vertical microtremors. We discuss the amplification factors using theS-wave velocity profile and show that shallow soils over the layer with anS-wave velocity of 0.49 km/sec are responsible for the amplification at periods shorter than 0.4 sec. Deeper sedimentary layers are needed to explain amplification at periods of 1 sec.
Correlation between gravity and magnetic anomalies of Western Anatolia and its relation to tectonic structures
Authors: Düzgit Z. , Hisarli Z. M. , Sayin N. , Orbay N.
Published: August 2014

In this paper, we apply for the first time the moving-windows application of the Poisson’s theorem to the synthetic gravity and magnetic data, followed by calculations of the correlations of the Bouguer gravity and aeromagnetic data of Western Anatolia. The correlation coefficient, slope and intercept parameters were generated from the internal correlations existing between the gravity and magnetic anomalies. Relative negative correlation values of positive gravity and negative magnetic anomalies were found on the Menderes Massif and in the southern part of the Marmara sea. Higher heat flow values were also obtained from these regions. The negative correlation values can be seen on a profile taken along the 28°E longitude and are sourced from a large graben system which has been generated as a result of lithospheric extension in Western Anatolia since the Early Miocene. The grabens were filled up by approximately 2000-m-thick sediments. The negative correlation coefficients and high heat flow values correspond to relative uplift of the asthenosphere in these regions.
Possible TCRM acquisition of the Kilauea 1960 lava, Hawaii: failure of the Thellier paleointensity determination inferred from equilibrium temperature of the Fe−Ti oxide
Authors: Yamamoto Yuhji
Published: August 2014

Natural rock samples may not always be the ideal material for the Thellier-type method as they occasionally result in high paleointensities. The Kilauea 1960 lava, Hawaii, is one such example. Several previous studies have suggested that one of the possible causes for this undesirable behavior is an acquisition of thermochemical remanent magnetization (TCRM) during lava formation. In order to examine this possibility quantitatively, equilibrium temperatures of titanomagnetite grains, which are associated with samples previously subjected to Thellier experiments, are estimated by a Fe−Ti oxide geothermometer. The results show that two specimens from the rock magnetic group giving relatively ideal Thellier paleointensities have clustered equilibrium temperatures of about 800–900 and 700–800°C. In contrast, two swarmed temperatures around 300 and 700°C were observed for the specimen from a group yielding high paleointensities. Although these are semi-quantitative estimates, when the time scales of Fe−Ti interdiffusion and lava cooling are taken into consideration, the last specimen could have acquired the TCRM during its formation. For such specimens, simple calculation predicts that TCRM/TRM (thermoremanent magnetization) ratios could be 1.19–1.72 for the blocking temperature range of 400–480°C, assuming a grain-growth model. The extent of this overestimation (20–70%) is comparable to the magnitude of the observations. It is therefore suggested that attention be paid to titanomagnetite grains with well-developed ilmenite lamellae, as these could be potential sources of overestimations of Thellier paleointensities of up to a few tenths of percentage points.
Berthierine and chamosite hydrothermal: genetic guides in the Peña Colorada magnetite-bearing ore deposit, Mexico
Authors: Rivas-Sanchez M. L. , Alva-Valdivia L. M. , Arenas-Alatorre J. , Urrutia-Fucugauchi J. , Ruiz-Sandoval M. , Ramos-Molina M. A.
Published: August 2014

We report the first finding of berthierine and chamosite in Mexico. They occur in the iron-ore deposit of Peña Colorada, Colima. Their genetic characteristics show two different mineralization events associated mainly to the magnetite ore. Berthierine is an Fe-rich and Mg-low 1:1 layer phyllosilicate of hydrothermal sedimentary origin. Its structure is 7 Å, d
hkl [10 0] basal spacing and low degree structural ordering. The phyllosilicate has been identified by a lack of 14 Å basal reflection on X-ray diffraction (XRD) patterns. These data were supported by High Resolution Transmision Electron Microscopy (HRTEM) images that show thick packets of berthierine in well defined parallel plates. From the analysis of Fast Fourier Transform (FFT), we found around [1 0 0] reflections of berhierine 7.12 Å and corresponding angles of hexagonal crystalline structure. Berthierine has a microcrystalline structure, dark green color, and high refraction index (1.64 to 1.65). Birefringence is low, near 0.007 to null and it is associated to nanoparticles (<15 nm) and microparticles of magnetite (<25 μm), fine grain siderite, and organic matter. Its texture is intergranular-interstratified with colloform banding. The chamosite Mg-rich is of hydrothermal epigenetic origin affected by low-degree metamorphism. It is an Fe-rich 2:1 layer silicate, with basal space of 14 Å, d
hkl [0 0 1]. The chamosite occurs as lamellar in sizes ranging from 50 to 150 μm. It has intense green color and refraction index from 1.64 to 1.65. The birefringence is near 0.008, with biaxial (-) orientation and a 2V small. It is associated mainly to sericite, epidote, clay, feldspar, and magnetite. Chamosite is emplaced in open spaces filling and linings. Mössbauer spectra of berthierine and chamosite are similar. They show the typical spectra of paramagnetic substances, with two well defined unfoldings corresponding to the oxidation state of Fe+2 and Fe+3. Chemical composition of both minerals was obtained by an electron probe X-ray micro-analyzer (EPMA). The radio Fe+Mg+Mn vs Si and Al show similar chemical compositions and different XRD patterns in the crystalline structure provoked by the environmental conditions of emplacement. A hydrothermal environment was predominant, occurring before, during, and after the magnetite mineralization. The identification of magnetite nanoparticles supports the hypothesis of a marine environment, specifically exhalative sedimentary (SEDEX) for the berthierine.
Coexistence of cosmic-ray sidereal anisotropies originating in galactic space and at the heliomagnetospheric nose and tail boundaries, observed with muon detectors in the energy region of 60∼100 GeV
Authors: Nagashima K. , Fujii Z.
Published: August 2014

The coexistence of two kinds of cosmic-ray sidereal anisotropy was found by observations with underground muon telescopes in the energy region (> ∼200 GeV) in 1995: one is the galactic anisotropy with a deficit flux in the direction with right ascension α

G
= 12 hr and declination δ

G
= 20°. The other is the excess flux from the heliomagnetospheric tail direction (α

T
≃ 6 hr) and would be produced on the heliotail boundary where it is considered that the interaction between the galactic and solar magnetic fields could produce the cosmic-ray acceleration. On the other hand, another anisotropy of helioboundary origin from the helionose direction (α ≃ 18 hr), being accompanied by the heliotail-in anisotropy, was found through the observations with neutron monitors in the low energy region (∼20 GeV) in 2005. These observations, however, lack information in the mid-energy region (20∼200 GeV). In order to bridge the absence of information, the cosmic-ray sidereal daily variations in the energy regions (60∼100 GeV) have been derived from the observations with muon telescopes and ion chambers on the ground in the period 1936–2003. It is shown that all the three anisotropies coexist in this energy region and are subject to their respective solar modulations. On the basis of these modulations, the characteristics of the anisotropies are determined through intercomparison with the observations in the high and low energy regions.
Variations in the equatorial ionization anomaly peaks in the Western Pacific region during the geomagnetic storms of April 6 and July 15, 2000
Authors: Lin Chien-Hung , Liu Jann-Yenq , Tsai Ho-Fang , Cheng Chio-Zong
Published: August 2014

This study utilizes total electron content (TEC) observed by a network of ground-based GPS receivers located in the Western Pacific region (∼120°E) to study the responses of the low-latitude equatorial ionization anomaly (EIA) to the two major magnetic storms that occurred during April 4–10 and July 12–18, 2000. The latitude, time, and TEC (LTT) maps in the northern and southern EIA regions show that both EIA peaks move equatorward along with a pronounced reduction of the TEC values 10–12 h after the storm onset. The variations in the EIA peak TEC values and locations in the northern EIA are highly correlated with those in the southern EIA. The correlation coefficients of the day-to-day variations of peaked TEC between the northern and southern EIA regions are 0.75 in the April storm and 0.83 in the July storm. The correlation coefficients of the day-to-day EIA peak movements between the two hemispheres are 0.98 in the April storm event and 0.88 in the July storm event. The highly correlated peaked TEC and movements between the northern and the southern hemisphere suggest that the storm-produced electrodynamics played a dominant role in affecting the low-latitude ionosphere during the two major storms.
Day-to-day variability of the equatorial electrojet current in the South American sector
Authors: Rastogi R. G.
Published: August 2014

A comparison of the geomagnetic H field data at Ancon, Peru and Buriticupa, Brazil for the period December 1990 and January 1991 revealed the presence of a significant correlation in day-to-day variability in the solar daily variation of H at the two stations, which are separated by about 2000 km. It is suggested that the day-to-day variability in the time as well as in the magnitude of the daily peak of the H field at an equatorial electrojet station is due to the superimposition of a semi-diurnal wave of the electric field over the normal mean daily variation.
The behaviour and detection of partial thermoremanent magnetisation (PTRM) tails in Thellier palaeointensity experiments
Authors: Biggin Andrew J. , Perrin Mireille
Published: August 2014

We analyse the results of Thellier palaeointensity experiments modified so that the measured magnetisation at any stage may be decomposed into components of natural remanent magnetisation (NRM) and laboratory thermal remanent magnetisation (TRM). We demonstrate that the very long high temperature tails of pTRM acquired by multidomain (MD) grains may be detected in Thellier experiments without recourse to explicit pTRM tail check measurements. This can save time in the experimental process and provides a more sensitive indication of how MD behaviour may affect that particular experiment than either pTRM tail checks or the observation of zigzagging in an IZZI experiment. We observe that the action of imparting a pTRM tail also involves some removal of NRM. However, the pTRM tails are not the analogues of classical overprints as may be intuitively expected but instead appear to favour remagnetisation over demagnetisation. This and other observed behaviour is not consistent with any phenomenological model of MD TRM but is consistent with predictions made by kinematic theory.
New K-Ar ages of the Society Islands, French Polynesia, and implications for the Society hotspot feature
Authors: Uto K. , Yamamoto Y. , Sudo M. , Uchiumi S. , Ishizuka O. , Kogiso T. , Tsunakawa H.
Published: August 2014

We report 52 new K-Ar age determinations of volcanic rocks from the Society Islands in French Polynesia. The newly obtained ages range from 0.51 to 4.61 Ma, which are consistent with previously reported ones. The magnetostratigraphy based on 45 data sets combining K-Ar ages and paleomagnetic polarity agrees with the geomagnetic polarity time scale at the 2s level, except for a few age data. Assuming the absolute motion of the Pacific plate, paleopositions of the dated rocks are estimated from the K-Ar ages, showing a narrow distribution in the western part of the easternmost volcano of the active hotspot region. This suggests that a hotspot of a few tens of kilometers in diameter might have been fixed nearly at the eastern margin of the presently active region in the Society archipelago and that the volcanism of each island might have persisted for about 1 myr.
Searching satellites of asteroid Itokawa by imaging observation with Hayabusa spacecraft
Authors: Fuse Tetsuharu , Yoshida Fumi , Tholen David , Ishiguro Masateru , Saito Jun
Published: August 2014

We carried out a search for satellites around Itokawa, the target asteroid of the Japanese Hayabusa mission. An imaging instrument, AMICA, on the spacecraft was used to take four images of Itokawa and its vicinity on September 1, 2005. The distance of the spacecraft from Itokawa was approximately 1,700 km, somewhat longer than the original plan (1,000 km) due to the mission schedule. The field-of-view of AMICA corresponded to 170 km × 170 km around Itokawa. Since the Hill sphere of Itokawa was estimated to be 33 km at the time of the observations, the images completely covered the detectable area of satellites. However, we cannot find the motion of Itokawa satellites between the four images, because the observation period was set to 2 hr due to the mission schedule and the region where satellites would be observable was only within 8 km of Itokawa, which is inside the extensive glare of Itokawa on the images. In addition, high-energy protons produced by a huge solar flare impacted the spacecraft during the observations, and hence the four images suffered from many random spots. Comparing the positions of the spots with catalogued stars, we managed to identify stellar images. No evidence of satellites was found. Additionally, we evaluated the 1-m detection limit of the images from the limiting magnitude of 9.5. The absence of satellites of Itokawa is consistent with past optical and radar observations as well as other results by the Hayabusa spacecraft.