bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric drag effects on the KOMPSAT-1 satellite during geomagnetic superstorms
Authors: Kim K.-H. , Moon Y.-J. , Cho K.-S. , Kim H.-D. , Park J.-Y.
Published: August 2014

We examine the atmospheric drag on the low earth-orbiting satellite, KOMPSAT-1 in a sun-synchronous orbit at ~685-km altitude starting in 1999, during a 3-month (October-December) period in 2003. This 3-month interval includes the October 29-30 and November 20 magnetic superstorms and weak to moderate storms. We observed that the daily KOMPSAT-1 drag acceleration transiently responses to transient storm-time disturbances. That is, there is an one-to-one correspondence between the KOMPSAT-1 drag accelerations and the storm events. We find that the drag acceleration correlates strongly with the level of geomagnetic disturbance. This indicates that the trajectory of KOMPSAT-1 is significantly perturbed during extremely disturbed intervals because of atmospheric density increase. The main contributor to the density increase is Joule heating associated with the geomagnetic activity rather than the solar EUV radiation, as reported by previous studies. We suggest that understanding how the upper atmosphere responses to the geomagnetic-associated heating is important to predict space weather impacts on low earth-orbiting satellites.
The seismicity, fault structures, and stress field in the seismic gap adjacent to the 2004 Mid-Niigata earthquake inferred from seismological observations
Authors: Imanishi Kazutoshi , Kuwahara Yasuto , Takeda Tetsuya , Haryu Yoshikatsu
Published: August 2014

We investigate the seismicity, fault structures, and stress field in the southern seismic gap adjacent to the source region of the 2004 Mid-Niigata earthquake based on precise earthquake locations and focal mechanism solutions. The double-difference earthquake locations reveal detailed fault structures including five discrete clusters. A stress tensor inversion method indicates that, at the southern ends of the Muikamachi and the Tokamachi faults, the stress state changes from thrust faulting to a strike-slip faulting regime. We show two possibilities for the deep-fault geometry of the southern part of the Muikamachi fault. Our preferred fault geometries of the Muikamachi fault differ from that of the mainshock, especially for the geometry of the dip direction. It is likely that the Muikamachi fault is divided into two segments whose boundary corresponds to the southern end of the source region of the 2004 event, and that the rupture area was terminated due to this fault segment boundary. The Coulomb failure stresses that are induced by the mainshock and the largest aftershock increase at the southern part of the Muikamachi faults. Furthermore, the angle between the maximum principal stress and the preferred fault planes implies that the shear stress resolving along the planes are large. This evidence suggests a high seismic risk in the seismic gap.
High-resolution aftershock observations in the source region of the 2004 mid-Niigata Prefecture Earthquake
Authors: Kato Aitaro ,   The Research Team of aftershock observations for the 2004 mid-Niigata Prefecture Earthquake
Published: August 2014

We deployed an extremely dense temporal seismic network in the source region of the 2004 mid-Niigata Prefecture Earthquake (thrust fault) on October 23, 2004, Japan. The seismic network consisted of 145 temporary seismic stations within a 30 km squared and had been kept within approximately a month after the mainshock. High accurate hypocenters of 708 events were determined by inverting the arrival times using double-difference earthquake location algorithm. The aftershocks along the mainshock (M
w = 6.6) and the largest aftershock (M
w = 6.3) rupture zones are distributed on two 60° westward-dipping planes, located approximately 5 km apart. Conversely, the Oct. 27 aftershock (M
w = 5.8) occurred on an eastward dipping plane with a dip angle of 25° that was conjugate to the mainshock fault plane. Most of aftershocks at both northeastern and southwestern edges occurred at shallow depths with eastward-dipping planes. Epicenters of aftershocks in the southwestern region are aligned along N15°E, and rotate approximately 20° counterclockwise from the strike of the mainshock fault. This rotation of the aftershock alignments coincides with the rotation of anticline axes in the southwestern area of the source region. Furthermore, distributions of station corrections for a one-dimensional velocity model suggest that the seismic velocity at the western side of the Muikamachi-fault is lower than that at the eastern side. It is also inferred that the velocity structures in the hangingwall vary along the fault strike. The average velocity in the mainshock rupture area is higher than the periphery in the hangingwall, especially compared with the southwestern side of the hypocenter.
Source model of the 2005 Miyagi-Oki, Japan, earthquake estimated from broadband strong motions
Authors: Suzuki Wataru , Iwata Tomotaka
Published: August 2014

We estimate the source model of the 2005 Miyagi-Oki earthquake, which consists of two source patches called “strong motion generation areas (SMGAs)”, to explain the broadband strong motions. The location of the first SMGA is determined from the arrival time differences between the first motion and the first pulse in theP-wave portion. Based on the broadband waveform modeling obtained using the empirical Green’s function method, we estimate the parameters of the two SMGAs. The estimated location of the two SMGAs coincides with the two major large slip areas inferred from the inversion of strong-motion and teleseismic waveforms, which implies that the broadband strong motion of the 2005 Miyagi-Oki earthquake mainly radiates from the asperities. The deeper SMGA has a larger stress drop (34.1 MPa) than the shallower one (17.6 MPa). Comparison of the locations of SMGAs between the 2005 and 1978 Miyagi-Oki earthquakes suggests that they do not overlap with each other. The interplate earthquakes, including this event, were found to have smaller SMGAs than those predicted from the relationship of crustal earthquakes for a given seismic moment. This implies that the stress drop of the SMGAs for interplate earthquakes is larger than that for crustal earthquakes.
Day-to-day variability in the occurrence characteristics of Sq focus during d-months and its association with diurnal changes in the Declination component
Authors: Alex S. , Jadhav M. M.
Published: August 2014

Scrutiny of the geomagnetic observations of the Declination component “D” from equatorial and low-latitude locations in the Indian longitude revealed anomalous variations during d-months. Examination of the Quiet day (Ap≤7) variations in the Declination component (Yin nT =HsinD) and Horizontal component (H) during the d-months (November, December, January, February) of the low solar activity year 1977 revealed the salient features associated with the day-to-day changes observed in Sq current system over the latitude chain in the Indo-Russian longitude. Diurnal variations in the east-west componentYand north-south componentHwere used to depict the effect of changes in the Sq current pattern for a selected set of Quiet days, which are classified into normal and abnormal days based on the trend in the variation of the Declination component. Normal days designated in the study clearly showed the expected pattern of variation in ΔY(eastward-directed field) in the morning hours and westward-directed field in the afternoon hours, and diurnal variation of ΔHsimultaneously showed the presence of northern Sq focus within the low-latitude range. In contrast, the abnormal days projected by the variation in ΔYand ΔHon certain days of d-months showed an almost complete absence of the focus formation within the expected latitude extent. Day-to-day variability characteristics of the Declination component discussed in the study are illustrated in relation to modifications in the expected Sq current system by the invasion of the prevalent southern hemisphere current whorl to the northern hemisphere during the winter months. Some of the anomalous changes observed in the day-to-day variation in the latitudinal pattern of ΔYand ΔHcomponents are also interpreted as suggesting an influence of high-latitude magnetospheric current systems on certain quiet days.
Self-generation of phase coherence in parallel Alfvén turbulence
Authors: Nariyuki Y. , Hada T.
Published: August 2014

Nonlinear evolution of Alfvén turbulence is discussed within the framework of the derivative nonlinear Schroedinger equation (DNLS), a subset of the hall-MHD equation set, which includes quasi-parallel propagating right- and left-hand polarized Alfvén wave modes. By numerically time integrating the equation with periodic boundary conditions, we discuss relationship between generation of wave phase coherence and self-organization of the system due to birth of Alfvén solitons.
Co- and post-seismic slip associated with the 2005 Miyagi-oki earthquake (M7.2) as inferred from GPS data
Authors: Miura Satoshi , Iinuma Takeshi , Yui Satsoshi , Uchida Naoki , Sato Toshiya , Tachibana Kenji , Hasegawa Akira
Published: August 2014

A large earthquake with M7.2 occurred on August 16, 2005 along the plate boundary off Miyagi Prefecture. Co- and post-seismic deformations associated with this event were investigated to reveal the causal interplate slips using continuous GPS data and geodetic inversion. The coseismic slip distribution shows good agreement with that estimated by seismic waveform inversions. The major slip area is limited to the southeastern part of the rupture area of the previous 1978 event. The post-seismic slip extended to the southwest of the co-seismic slip area. These distinctive features of both the co- and post-seismic slips might be caused by the existence of the locked plate interface, where seismogenic stress has not released yet, in the northern part of the 1978 rupture area.
Revisiting the three M~7 Miyagi-oki earthquakes in the 1930s: possible seismogenic slip on asperities that were re-ruptured during the 1978 M=7.4 Miyagi-oki earthquake
Authors: Umino Norihito , Kono Toshio , Okada Tomomi , Nakajima Junichi , Matsuzawa Toru , Uchida Naoki , Hasegawa Akira , Tamura Yoshiaki , Aoki Gen
Published: August 2014

Hypocenters of main shocks and aftershocks of the 1933 M=7.1, 1936 M=7.4, 1937 M=7.1 and 1978 M=7.4 Miyagi-oki earthquakes are relocated using S-P times reported in the Seismological Bulletin of the Japan Meteorological Agency (JMA) and those re-read from original smoked-paper seismograms observed at the Mizusawa station of the National Astronomical Observatory of Japan (NAOJ) and the Mukaiyama station of Tohoku University. In order to reduce the error caused by inaccuracies of the arrival times and the small number of seismic observation stations, we determined the hypocenters by using a grid search method that assumed that the events occurred at the boundary between the subducting Pacific plate and the overriding plate. The main shock epicenters of these four earthquakes were determined to be close to each other, while the distributions of their aftershocks seem to disperse on the upper boundary of the Pacific plate. These distributions show that aftershock areas of the 1933, 1936 and 1937 events partly overlap with that of the 1978 event and occupy its easternmost, central and westernmost portions, respectively. This result suggests that the 1933, 1936 and 1937 events possibly ruptured a part of the source area of the 1978 event, i.e., its eastern, central and western portions, respectively.
Aftershock seismicity and fault structure of the 2005 West Off Fukuoka Prefecture Earthquake (MJMA7.0) derived from urgent joint observations
Authors: Shimizu Hiroshi , Takahashi Hiroaki , Okada Tomomi , Kanazawa Toshihiko , Iio Yoshihisa , Miyamachi Hiroki , Matsushima Takeshi , Ichiyanagi Masayoshi , Uchida Naoki , Iwasaki Takaya , Katao Hiroshi , Goto Kazuhiko , Matsumoto Satoshi , Hirata Naoshi , Nakao Shigeru , Uehira Kenji , Shinohara Masanao , Yakiwara Hiroshi , Kame Nobuki , Urabe Taku , Matsuwo Norimichi , Yamada Tomoaki , Watanabe Atsushi , Nakahigashi Kazuo , Enescu Bogdan , Uchida Kazunari , Hashimoto Shin’ichi , Hirano Syuichiro , Yagi Takeo , Kohno Yuhki , Ueno Tomotake , Saito Masaki , Hori Mio
Published: August 2014

On March 20, 2005, a large M
JMA7.0 earthquake occurred in the offshore area, west of Fukuoka prefecture, northern Kyushu, Japan. A series of joint observations were carried out by teams from several universities in Japan with the aim of investigating the aftershock activity. Six online telemetered and 17 offline recording seismic stations were installed on land around the aftershock area immediately followed the occurrence of the mainshock. Because aftershocks were located mainly in offshore regions, we also installed 11 ocean bottom seismometers (OBSs) just above the aftershock region and its vicinity in order to obtain accurate locations of hypocenters. The OBS observation was carried out from March 27 to April 13, 2005. We further conducted temporary GPS observations in which ten GPS receivers were deployed around the aftershock region. The aftershocks were mainly aligned along an approximately 25-km-long NW-SE trend, and the hypocenters of the main aftershock region were distributed on a nearly vertical plane at depths of 2–16 km. The mainshock was located near the central part of the main aftershock region at a depth of approximately 10 km. The largest aftershock of M
JMA5.8 occurred near the southeastern edge of the main aftershock region, and the aftershock region subsequently extended about 5 km in the SE direction as defined by secondary aftershock activity. Enlargement of the aftershock region did not occur after the peak in aftershock activity, and the aftershock activity gradually declined. The distribution of hypocenters and seismogenic stress as defined by aftershocks suggest that the 2005 West Off Fukuoka Prefecture Earthquake occurred on the fault that is the NW extension of the Kego fault, which extends NW-SE through the Fukuoka metropolitan area, and that the largest aftershock occurred at the northwestern tip of the Kego fault.
Seismic moment of the 1891 Nobi, Japan, earthquake estimated from historical seismograms
Authors: Fukuyama Eiichi , Muramatu Ikuei , Mikumo Takeshi
Published: August 2014

The seismic moment of the 1891 Nobi, Japan, earthquake has been evaluated from the historical seismogram recorded at the Central Meteorological Observatory in Tokyo. For this purpose, synthetic seismograms from point and finite source models with various fault parameters have been calculated by a discrete wave-number method, incorporating the instrumental response of the Gray-Milne-Ewing seismograph, and then compared with the original records. Our estimate of the seismic moment (Mo) is 1.8×1020N m corresponding to a moment magnitude (Mw) 7.5. This is significantly smaller than the previous estimates from the distribution of damage, but is consistent with that inferred from geological field survey (Matsuda, 1974) of the surface faults.
The daily variations of the vertical (Z) element of the geomagnetic field around the coast of mainland Australia
Authors: Stening R. J. , Reztsova T.
Published: August 2014

Use is made of an array of magnetic stations spread across the Australian mainland to examine the daily variation of the vertical element Z of the magnetic field. On sections of the west and east coasts visual inspection of Z variations shows that they respond mainly to the onshore component of the horizontal field as predicted by Bennett and Lilley, though only south of about 22°S on the east coast and south of 20°S on the west coast. On the north and south coasts this “coast effect” is not clearly seen at periods corresponding to the daily variation, though it sometimes appears on shorter time scales. On the north and south coasts Z appears to be mainly controlled by the decrease with latitude of the overhead eastward ionospheric currents as measured by the latitude gradient in the northward field, X. By subtracting the vector Z variation at an inland station from Z at a coastal station, the anomalous coastal effect in Z is calculated at periods of 12 and 24 h. These data show that the coastal effect is not just related to the horizontal onshore component but that some phase change is also required. An increase with latitude of the overhead eastward currents is sometimes found in morning hours corresponding to the morning current system identified in earlier work.
A tectonic interpretation of the Marmara Sea, NW Turkey from geophysical data
Authors: Ates Abdullah , Bilim Funda , Buyuksarac Aydin , Bektas Özcan
Published: August 2014

Recent scientific investigations have revealed the deep structure and fault mechanisms in the Marmara Sea and surroundings. However, magnetic and gravity anomalies display interesting features which were not resolved in detail. In this paper, simple two-dimensional magnetic and gravity models are constructed utilizing parameters such as the density contrast and susceptibilities obtained from a borehole, seismic sections and field susceptibility measurements, respectively. The gravity model shows the existence of horst-like structures, as suggested previously. The top of the magnetic bodies in the Marmara Sea is close to the sea bottom. In general, these magnetic bodies are fault-related. The gravity model complies with the seismic base map, which was constructed previously. The magnetic anomalies of anomalous regions of the Cinarcik andWestern Basins demonstrate slight anticlockwise block rotations, while large anticlockwise block rotation is observed in the eastern extremity of the Marmara Sea. Geophysical data and modeling results suggest that the origin and evaluation of the Marmara Sea began with the possibility of emplacement of horst-like structures in the Central Ridge during the Palaeozoic or earlier followed by block rotations and intrusion of the magnetic material into the upper crust with sediment deposition and faulting. It can also be suggested that the horst-like structures in the central Marmara act to diffuse the propagation of the Northern Boundary Fault (NBF). This aspect is correlated with the focal mechanisms of the major earthquakes.
Fine fault structure of a moderate earthquake in the 2007 earthquake sequence of Northern Mie, Japan
Authors: Yukutake Yohei , Takeda Tetsuya , Obara Kazushige
Published: August 2014

A moderate crustal earthquake (M
j = 5.4) occurred in the northern part of Mie Prefecture, Central Japan, 2007. In order to clarify the fault structure of the main shock and its relation to the active faults, we estimated the precise hypocenter locations and focal mechanisms. For the relocation of the hypocenters, we used the differential time obtained by both manual picking and waveform cross-correlation analysis. The estimated detailed fault structure suggests that the main shock ruptured the southwestward dipping fault plane. We found that the faults of the moderate earthquake possessed complex fault segments. Around the largest aftershock hypocenter, a subsidiary fault plane parallel to the main shock fault was identified. This result suggests that the fault structure around the deep part of the active fault is complicated. The hypocenters of the foreshock and main shock were located in the offset part of the aftershock alignment, implying that they did not occur on the same fault plane. The Chisato Fault and Yokkaichi Fault were located around the upward extension of the aftershock alignment. The main shock probably occurred in the deep parts of these faults.
Coulomb stresses imparted by the 25 March 2007 Mw=6.6 Noto-Hanto, Japan, earthquake explain its ‘butterfly’ distribution of aftershocks and suggest a heightened seismic hazard
Authors: Toda Shinji
Published: August 2014

The well-recorded aftershocks and well-determined source model of the Noto Hanto earthquake provide an excellent opportunity to examine earthquake triggering associated with a blind thrust event. The aftershock zone rapidly expanded into a ‘butterfly pattern’ predicted by static Coulomb stress transfer associated with thrust faulting. We found that abundant aftershocks occurred where the static Coulomb stress increased by more than 0.5 bars, while few shocks occurred in the stress shadow calculated to extend northwest and southeast of the Noto Hanto rupture. To explore the three-dimensional distribution of the observed aftershocks and the calculated stress imparted by the mainshock, we further resolved Coulomb stress changes on the nodal planes of all aftershocks for which focal mechanisms are available. About 75% of the possible faults associated with the moderate-sized aftershocks were calculated to have been brought closer to failure by the mainshock, with the correlation best for low apparent fault friction. Our interpretation is that most of the aftershocks struck on the steeply dipping source fault and on a conjugate northwest-dipping reverse fault contiguous with the source fault. Since we found that the Coulomb hypothesis works well for the Noto Hanto sequence, we subsequently computed stress changes on the nearby active faults. Although the calculated stress changes were found to be negligible on the major faults south of the Noto Peninsula, several short active faults near the epicentral area were calculated to have been brought several bars closer to failure. Thus, the probability of strong shaking in and around the epicentral area may still be high due to the transfer of stress to the adjacent faults by a short blind thrust fault.
First optical observation of the Moon’s sodium exosphere from the lunar orbiter SELENE (Kaguya)
Authors: Kagitani M. , Taguchi M. , Yamazaki A. , Yoshikawa I. , Murakami G. , Yoshioka K. , Kameda S. , Ezawa F. , Toyota T. , Okano S.
Published: August 2014

The first successful observations of resonant scattering emission from the lunar sodium exosphere were made from the lunar orbiter SELENE (Kaguya) using TVIS instruments during the period 17–19 December, 2008. The emission intensity of the NaD-line decreased by 12±6%, with an average value of 5.4 kR (kilorayleighs) in this period, which was preceded, by 1 day, by enhancement of the solar proton flux associated with a corotating interaction region. The results suggest that solar wind particles foster the diffusion of sodium atoms or ions in the lunar regolith up to the surface and that the time scale of the diffusion is a few tens of hours. The declining activity of the Geminid meteor shower is also one possible explanation for the decreasing sodium exosphere.
Remote sensing of atmospheric water vapor variation from GPS measurements during a severe weather event
Authors: Song Dong-Seob , Grejner-Brzezinska Dorota A.
Published: August 2014

The Global Positioning System (GPS) provides a relatively inexpensive method to remotely sense atmospheric water vapor in all weather conditions. In this study, we applied the GPS meteorology technique to monitor the precipitable water vapor (PWV) variation during a severe weather event (typhoon EWINIAR). The Korean weighted mean temperature equation (KWMTE), customized for the Korean Peninsula, was used to improve the accuracy of the GPS PWV estimation. The time series and the comparison with the images of MTSAT/CMAX and the GPS PWV contour maps indicated that the temporal change of GPS PWV was closely related to the progress of the typhoon. The correlation between the maximum GPS PWV and the maximum rainfall caused by the typhoon was also higher than that for the quiet weather period. Furthermore, the peak in the time series of GPS PWV was generally in good agreement with the time when the maximum rainfall was recorded. Our results therefore confirm that GPS meteorology is an efficient PWV sensing technique, capable of capturing the complex characteristics of water vapor distribution and its temporal variation during a period of severe weather events.
Simulation of mode conversion from UHR-mode wave to LO-mode wave in an inhomogeneous plasma with different wave normal angles
Authors: Kalaee Mohammad Javad , Ono Takayuki , Katoh Yuto , Iizima Masahide , Nishimura Yukitoshi
Published: August 2014

We have investigated a linear mode conversion process among UHR-mode, Z-mode, and LO-mode waves by a computer simulation solving Maxwell’s equations and the motion of a cold electron fluid. The characteristics of the wave coupling process occurring in the cold magnetized plasma were examined in detail for the case of an inhomogeneity of plasma density lying perpendicular to the ambient magnetic field. The dependence of the conversion efficiency on the incident wave normal angle, wave frequency, background plasma frequency, and steepness of density gradient was studied. The results show that an efficient mode conversion occurred in the conversion process from Z-mode to LO-mode waves rather than from the coupling between UHR-mode to LO-mode waves. They also show that the highest conversion efficiency was obtained under the specific condition of the wave normal angle for the incident waves. In the specific case of such critical wave normal angles, we found that perpendicular components of refractive indexes became zero at the site of mode conversion, which is consistent with previously published results. We also show that the range of the critical normal angle varied depending on both the plasma frequency and the wave frequency. The simulation results also reveal that, when the steepness of the density gradient was taken into consideration, efficient mode conversion could be expected even in the case of the mismatch of the refractive indexes preventing the close coupling of plasma waves.
In-orbit calibration of the lunar magnetometer onboard SELENE (KAGUYA)
Authors: Takahashi Futoshi , Shimizu Hisayoshi , Matsushima Masaki , Shibuya Hidetoshi , Matsuoka Ayako , Nakazawa Satoru , Iijima Yuichi , Otake Hisashi , Tsunakawa Hideo
Published: August 2014

The high-sensitivity fluxgate Lunar MAGnetometer (LMAG) is mounted on SELENE (KAGUYA) to investigate the near-surface electromagnetic environment and the evolution of the Moon through magnetic field observation. To avoid possible electromagnetic interferences, a triaxial fluxgate sensor (MGF-S) is installed at the far end of a 12-m-long mast. It is critical for the accurate observation to monitor MGF-S alignment in orbit, and thus we have calibrated the sensor alignment by measuring the known magnetic fields generated by the sensor alignment monitor coil (SAM-C) wound onto the mast canister. In-orbit calibration of the MGF-S alignment was performed twice each revolution during the initial check-out phase of the satellite. It is concluded that there is no systematic difference in the sensor alignment between the day-side and night-side. Applying a new technique based on the Davis-Smith method to the observed magnetic field data when KAGUYA was exposed to the solar wind, a zero offset of each axis was quickly and stably determined every month. As a result, LMAG has been calibrated with an accuracy that is sufficient for detection of the lunar magnetic anomaly at an altitude of 100 km and for high-resolution electron reflectometry.
Spectral matrix analysis for detection of polarized wave arrivals and its application to seismic reflection studies using local earthquake data
Authors: Moriya Hirokazu
Published: August 2014

Local earthquakes observed at Sendai, Japan, were analyzed to confirm the validity of a method of polarization analysis using the spectral matrix of seismic wave and its application to seismic reflection studies of the crust using local earthquake data. Reflectors (Bright spots) are known below the Nagamachi-Rifu fault, which caused an M 5.0 class event in 1998. Polarization analysis was applied to earthquake data in and around the fault. Use of the Z-parameter, which is defined using the eigenvalues of the spectral matrix and a statistical value representing the confidence level for the detection of the arrival of polarized waves, allowed detection of linearly and elliptically polarized waves in coda waves. The Z-parameter was also used to image the reflectors by using a migration technique that assumes the P×P and S×S reflection waves travel through a multi-layered velocity structure. Distinct reflectors were detected at depths of around 10 km, 14 km, 17 km, 21–26 km, 35 km and 40 km, that is, from deeper than the fault and the Moho. This study demonstrated the feasibility of using the spectral matrix of three-component seismic signal to detect polarized waves and to image reflectors in the earth’s crust and upper mantle.
Imaging heterogeneous velocity structures and complex aftershock distributions in the source region of the 2007 Niigataken Chuetsu-oki Earthquake by a dense seismic observation
Authors: Kato Aitaro , Sakai Shinichi , Kurashimo Eiji , Igarashi Toshihiro , Iidaka Takashi , Hirata Naoshi , Iwasaki Takaya , Kanazawa Toshihiko ,   Group for the aftershock observations of the 2007 Niigataken Chuetsu-oki Earthquake
Published: August 2014

The velocity structure and accurate aftershock distributions in the source region of the 2007 Niigataken Chuetsu-oki Earthquake (thrust type) are obtained by inverting the arrival times from 848 aftershocks observed by a dense seismic network deployed immediately after the mainshock (8 h later). Both the detailed velocity structure and the accurate aftershock distribution show lateral heterogeneity along the fault strike. In the northeast area, aftershocks are aligned along both the NW- and SE-dipping planes. These planes are conjugate to each other. The mainshock hypocenter is located close to the bottom of an approximately 50° NW-dipping plane, which indicates that the mainshock rupture could have initiated on the NW-dipping plane. The high-V

p
body beneath this aftershock alignment shows a convex upward shape. In contrast, from the center to the southwest area, most of the aftershocks are aligned along SE-dipping planes. The high-V

p
body beneath this aftershock alignment shows a convex downward shape. Based on these results, we suggest that the crustal structure in the source region is divided into two segments by a boundary zone situated between the northeast and southwest areas. It should be noted that this segment boundary zone is coincident with the complex aftershock zone where numerous conjugate fault planes exist. We propose that the mainshock rupture initiated near the bottom of the NW-dipping fault plane and ran to the southwest, then transferred at the segment boundary zone which has numerous conjugate fault planes to the SE-dipping plane.
Source process of the 2007 Niigata-ken Chuetsu-oki earthquake derived from near-fault strong motion data
Authors: Aoi Shin , Sekiguchi Haruko , Morikawa Nobuyuki , Kunugi Takashi
Published: August 2014

The 2007 Niigata-ken Chuetsu-oki earthquake generated strong ground motions in Kashiwazaki and Kariwa, where the world largest nuclear power plant was in operation. Due to the complexity of the aftershock distribution, activation of the northwest-dipping fault and/or the southeast-dipping fault is proposed. To explore the fault geometry and source process of the earthquake, we performed multi-time window linear waveform inversions for both the fault planes from near-fault strong motion data. A fault plane model of 30 km in length by 24 km in width was set to cover the region of aftershock distribution within 24 h of the mainshock. Both inverted slip models provided moment magnitudes of 6.7 with a small asperity near the rupture starting point, and a large asperity approximately 10 km southwest of the rupture initiation, which is located in the region of relatively sparse aftershock distribution. Both the small and large asperities are located near the intersection between the two conjugate fault plane models, and the asperities of both models have similar radiation patterns. Therefore, the difference of the residuals between the observed and synthetic waveforms for both models was not significant, indicating that it is difficult to conclude which fault is the rupture.
The effect of non-migrating tides on the morphology of the equatorial ionospheric anomaly: seasonal variability
Authors: England Scott L. , Zhang Xiaoli , Immel Thomas J. , Forbes Jeffrey M. , DeMajistre Robert
Published: August 2014

Recent observations of the low-latitude F-region ionosphere at times near equinox have shown that it varies with a predominant zonal wavenumber-four pattern in a fixed local-time frame. It has been shown that this pattern corresponds well to the non-migrating diurnal eastward wavenumber-three atmospheric tide (DE3) at E-region altitudes simulated by the Global Scale Wave Model (GSWM). Here we present details of the morphology of the F-region ionosphere from TIMED GUVI with simultaneous observations of the non-migrating diurnal tides at E-region altitudes from TIMED SABER. For the case of equinox (March 2002), the correspondence of the SABER and GUVI observations confirms the relationship previously established using the GSWM simulations. There is also a wavenumber-one signature that is present which may be related to the semi-diurnal westward wavenumber-three, possibly in conjunction with changes in the magnetic field with longitude. During July 2002, when the amplitude of the DE3 maximizes, the amplitude of the wavenumber-four pattern in the F-region ionosphere intensifies. There is also evidence of a strong wavenumber-three pattern in the F-region ionosphere, which can be attributed to the strong diurnal eastward wavenumber-two tide during this period. During January 2003, the amplitude of all non-migrating components observed by SABER are either small or asymmetric and the ionosphere does not display either a wavenumber-three or -four pattern. During both solstice periods, a strong wavenumber-one is seen that is attributed to the offset of the subsolar point and the geomagnetic equator that maximizes at solstice, possibly in conjunction with other geomagnetic effects. During all seasons, significant hemispheric asymmetries in the airglow wavenumber spectra are seen. The combined GUVI and SABER observations presented here demonstrate that the large-scale periodic longitudinal structure of the F-region ionosphere responds significantly to changes in the forcing by non-migrating diurnal tides at E-region altitudes.
Asperity along the North Anatolian Fault imaged by magnetotellurics at Düzce, Turkey
Authors: Kaya Tulay , Tank S. Bülent , Tunçer M. Kemal , Rokoityansky I. Igor , Tolak Elif , Savchenko Timur
Published: August 2014

The magnetotelluric (MT) method has been applied to show resistivity variations in the vicinity of the epicenter of the 1999 Düzce earthquake (M
w = 7.2) where a large rupture velocity difference was seen between the western and eastern parts of the epicenter. MT data for frequencies ranging between 320 and 0.0005 Hz were acquired along two parallel profiles to the west and the east of Düzce earthquake’s epicenter. Both profiles crossed the Düzce basin and the Düzce fault in the north and the North Anatolian Fault (NAF) in the south. MT data analysis shows almost two-dimensionality in the region, at the depth starting from 2–3 km beneath the surface. According to two-dimensional MT modeling, a higher resistive layer extends beneath the eastern side of Düzce earthquake epicenter, compared with the western side. This resistivity structure correlates well with the aftershock distribution of the Düzce earthquake.
Application of Mwp to the Great December 26, 2004 Sumatra Earthquake
Authors: Kanjo Kenji , Furudate Tomomichi , Tsuboi Seiji
Published: August 2014

A great earthquake of Mw9.0 (Harvard) occurred off of northwestern Sumatra on December 26, 2004 (UTC), causing an unprecedented tsunami disaster. An earthquake of Mw8.6 (Harvard) then occurred on March 28, 2005 (UTC), about 160 km to the southeast of the December event’s epicenter. The Matsushiro Seismological Observatory of Japan Meteorological Agency determined magnitudes of M8.8 and M8.7 respectively for these events using the Global Seismic Network’s (GSN) Live Internet Seismic Server (LISS) data. The West Coast/Alaska Tsunami Warning Center (WC/ATWC), and the Pacific Tsunami Warning Center (PTWC) both use Mwp to rapidly evaluate moment magnitude. The WC/ATWC calculated a mean Mwp of 8.0 for the multiple event on Decmber 26, 2004. Using data from the IRIS station MAJO, we determined an Mwp of 8.5 by using a distance-dependent apparent P-wave velocity (α = 0.16Δ + 7.9 km/sec.) instead of a constant apparent P wave velocity (α = 7.9 km/sec), for α in the original equation for Mwp. The corrected Mwp value of 8.5 is much closer to the total moment magnitude of the multiple ruptures of the complex December 26 main-shock, and is useful as a first magnitude estimation to evaluate possible tsunami generation.
On exact solution of unsteady MHD flow of a viscous fluid in an orthogonal rheometer
Authors: Rana Muhammad Afzal , Siddiqa Sadia , Noor Saima
Published: August 2014

This paper studies the unsteady MHD flow of a viscous fluid in which each point of the parallel planes are subject to the non-torsional oscillations in their own planes. The streamlines at any given time are concentric circles. Exact solutions are obtained and the loci Γ of the centres of these concentric circles are discussed. It is shown that the motion so obtained gives three infinite sets of exact solutions in the geometry of an orthogonal rheometer in which the above non-torsional oscillations are superposed on the disks. These solutions reduce to a single unique solution when symmetric solutions are looked for. Some interesting special cases are also obtained from these solutions.
Aromatase (Cyp19a1b) in the Pituitary Is Dynamically Involved in the Upregulation of lhb But Not fshb in the Vitellogenic Female Ricefield Eel Monopterus albus
Authors: Zhang Shen , Zhang Yang , Chen Wanping , Wu Yangsheng , Ge Wei , Zhang Lihong , Zhang Weimin
Published: August 2014

Aromatase, encoded by Cyp19a1, is expressed in the pituitary of vertebrates; however, its physiological relevance remains poorly defined. In teleosts, the duplicated cyp19a1b is preferentially expressed in the pituitary where LH and FSH are synthesized in distinct gonadotropes. Our present study demonstrated that Cyp19a1b is colocalized with Lhb, but not Fshb, during vitellogenesis in female ricefield eels. The immunoreactive levels of Cyp19a1b and Lhb, as well as their colocalization frequency, increased during vitellogenesis toward maturation. The expression of lhb but not fshb in the pituitary fragments of female ricefield eels was induced by both estradiol (E2) and testosterone (T). In agreement, the promoter of lhb but not fshb was activated by both E2 and T. T is more potent than E2 in inducing lhb expression, whereas E2 is much more effective in activating the lhb promoter. T-induced lhb expression in the pituitary fragments was abolished by the estrogen receptor (Esr) antagonist fulvestrant and suppressed by the aromatase inhibitor letrozole, suggesting that the effect of T on lhb expression at the pituitary is largely mediated by E2. Furthermore, Lhb was shown to colocalize with Esr1 but not Esr2a. Taken together, results of the present study suggest that Cyp19a1b in LH cells may greatly upregulate lhb expression during vitellogenesis, possibly via E2 and Esr1 in an intracrine manner. The absence of Cyp19a1b in FSH cells and the insensitivity of fshb to sex steroids may contribute to the differential expression of lhb and fshb in ricefield eels and possibly other vertebrates as well.
Aromatase Inhibition Exacerbates Pain and Reactive Gliosis in the Dorsal Horn of the Spinal Cord of Female Rats Caused by Spinothalamic Tract Injury
Authors: Ghorbanpoor Samar , Garcia-Segura Luis Miguel , Haeri-Rohani Ali , Khodagholi Fariba , Jorjani Masoumeh
Published: August 2014

Central pain syndrome is characterized by severe and excruciating pain resulting from a lesion in the central nervous system. Previous studies have shown that estradiol decreases pain and that inhibitors of the enzyme aromatase, which synthesizes estradiol from aromatizable androgens, increases pain sensitivity. In this study we have assessed whether aromatase expression in the dorsal horns of the spinal cord is altered in a rat model of central pain syndrome, induced by the unilateral electrolytic lesion of the spinothalamic tract. Protein and mRNA levels of aromatase, as well as the protein and mRNA levels of estrogen receptors α and β, were increased in the dorsal horn of female rats after spinothalamic tract injury, suggesting that the injury increased estradiol synthesis and signaling in the dorsal horn. To determine whether the increased aromatase expression in this pain model may participate in the control of pain, mechanical allodynia thresholds were determined in both hind paws after the intrathecal administration of letrozole, an aromatase inhibitor. Aromatase inhibition enhanced mechanical allodynia in both hind paws. Because estradiol is known to regulate gliosis we assessed whether the spinothalamic tract injury and aromatase inhibition regulated gliosis in the dorsal horn. The proportion of microglia with a reactive phenotype and the number of glial fibrillary acidic protein–immunoreactive astrocytes were increased by the injury in the dorsal horn. Aromatase inhibition enhanced the effect of the injury on gliosis. Furthermore, a significant a positive correlation of mechanical allodynia and gliosis in the dorsal horn was detected. These findings suggest that aromatase is up-regulated in the dorsal horn in a model of central pain syndrome and that aromatase activity in the spinal cord reduces mechanical allodynia by controlling reactive gliosis in the dorsal horn.
Roles of Binding Elements, FOXL2 Domains, and Interactions With cJUN and SMADs in Regulation of FSHβ
Authors: Roybal Lacey L. , Hambarchyan Arpi , Meadows Jason D. , Barakat Nermeen H. , Pepa Patricia A. , Breen Kellie M. , Mellon Pamela L. , Coss Djurdjica
Published: August 2014

We previously identified FOXL2 as a critical component in FSHβ gene transcription. Here, we show that mice deficient in FOXL2 have lower levels of gonadotropin gene expression and fewer LH- and FSH-containing cells, but the same level of other pituitary hormones compared to wild-type littermates, highlighting a role of FOXL2 in the pituitary gonadotrope. Further, we investigate the function of FOXL2 in the gonadotrope cell and determine which domains of the FOXL2 protein are necessary for induction of FSHβ transcription. There is a stronger induction of FSHβ reporter transcription by truncated FOXL2 proteins, but no induction with the mutant lacking the forkhead domain. Specifically, FOXL2 plays a role in activin induction of FSHβ, functioning in concert with activin-induced SMAD proteins. Activin acts through multiple promoter elements to induce FSHβ expression, some of which bind FOXL2. Each of these FOXL2-binding sites is either juxtaposed or overlapping with a SMAD-binding element. We determined that FOXL2 and SMAD4 proteins form a higher order complex on the most proximal FOXL2 site. Surprisingly, two other sites important for activin induction bind neither SMADs nor FOXL2, suggesting additional factors at work. Furthermore, we show that FOXL2 plays a role in synergistic induction of FSHβ by GnRH and activin through interactions with the cJUN component of the AP1 complex that is necessary for GnRH responsiveness. Collectively, our results demonstrate the necessity of FOXL2 for proper FSH production in mice and implicate FOXL2 in integration of transcription factors at the level of the FSHβ promoter.
Guest Editor's Introduction: The Local Intimacies of China's Rural-Urban Divide
Authors: Lai Lili
Published: August 2014

This collection of mostly ethnographic studies of rural China, with some contributions from the rather different discourse world of Chinese anthropology, seeks to bring into visibility the heterogeneity of life in the countryside. They argue that rural China must first and foremost be understood as socially and culturally heterogeneous. On the other hand, there is much resonance in the details among all these articles, reminding us that ethnography in contemporary China can accumulate to give us an anthropology or sociology of the state as it is seen from the point of view of its relatively denigrated or subaltern peripheries, that is, rural China. Many dilemmas and challenges facing the people described in these articles are held in common, and together they allow us to see a broad vision of contemporary China beyond the cities and the dominant mass media. Being rather ethnographic/descriptive, the articles gathered here show that good and attentive description, under some conditions, can also be critique.
Everyday Hygiene in Rural Henan
Authors: Lai Lili
Published: August 2014

The phenomenon of “modernization indoors, dirt and chaos outdoors” (shinei xiandaihua, shiwai zangluancha) is now prevalent all over rural China. This article attends to the political and economic roots and social determinants of “dirty villages,” aiming to show how people's understanding of hygiene is intimately connected with environmental degradation, a perceived “dirtiness” that is not really of their own making. Grounded in anthropological field research in rural Henan, it argues that the lack of any infrastructure to dispose of trash is core to rural environmental problems.

On the other hand, people have an acute understanding of health in relation to the environment. Taking anthropology of embodiment as research methodology, this article formulates questions concerning “environmental health” in rural China as follows: how does the discourse of “rural hygiene and environment” shape people's understanding, perceptions, and living of their body and life, and what escapes this shaping process? This article argues that the recent problem of the excessive production of trash and the nondisposal of garbage exposes a fundamental question of so-called modernization, one that is repressed in only some urban settings. The “dirtiness” of the countryside is directly (and literally) constituted by the dirt of modernization and urbanization that uncannily resists any attempts to disconnect from it. To put it directly, if villagers are “dirty,” so are urbanites.