bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental magnetic record and paleosecular variation data for the last 40 kyrs from the Lake Biwa sediments, Central Japan
Authors: Hayashida Akira , Ali Mohammed , Kuniko Yoshiki , Kitagawa Hiroyuki , Torii Masayuki , Takemura Keiji 
Published: August 2014

Abstract
We have conducted paleomagnetic and environmental magnetic analysis of a sediment piston core recovered from Lake Biwa, central Japan. Tephrochronology and AMS radiocarbon dating showed that this core covers the time period since about 40 kyr BP. The variation of paleomagnetic direction shows a good agreement with the PSV record for the last 10 kyrs from the deeper water site (BIWA SV-3; Ali et al., 1999), although the amplitudes are subdued probably due to the relatively lower accumulation rate at the shallower site. Inclination lows of the pre-Holocene interval are correlated to PSV records reported from the marine sediments off Shikoku and in the Japan Sea. In addition, the variation of magnetic mineral concentration reflects environmental changes during the last glacial period. It is suggested that the flux of fine-grained magnetite, probably associated with greater precipitation, was increased during interstadial periods. The variation of anhysteretic remanent magnetization is likely correlated to the Dansgaard-Oeschger (D-O) cycles recorded in Greenland ice cores. An apparent swing of the PSV curve is recognized at about 27 ka, but evidence for the Mono Lake excursion at 32 ka around the D-O events 6 and 7 is unclear. Combination of the detailed paleomagnetic record and the sub-Milankovitch climate cycles thus provides better resolution for understanding geomagnetic secular variation and polarity excursions in space and time.
Impact process of boulders on the surface of asteroid 25143 Itokawa—fragments from collisional disruption
Authors: Nakamura A. M. , Michikami T. , Hirata N. , Fujiwara A. , Nakamura R. , Ishiguro M. , Miyamoto H. , Demura H. , Hiraoka K. , Honda T. , Honda C. , Saito J. , Hashimoto T. , Kubota T. 
Published: August 2014

Abstract
The subkilometer-size asteroid 25143 Itokawa is considered to have a gravitationally bounded rubble-pile structure. Boulders appearing in high-resolution images retrieved by the Hayabusa mission revealed the genuine outcome of the collisional event involving the asteroid’s parent body. Here we report that the boulders’ shapes and structures are strikingly similar to laboratory rock impact fragments despite differences of orders of magnitude in scale and complexities of the physical processes. These similarities suggest the universal character of the process throughout the range of these scales, and the brittle and structurally continuous nature regarding the parent body of the boulders. The similarity was likely preserved because of relatively lesser comminuting processes acting on individual boulders; the close assemblages of similar appearing boulders (a boulder family) represent the impact destruction of boulders on the surface.
Gravity anomalies and the geologic block structures in and around the aftershock area of the 2007 Noto Hanto Earthquake
Authors: Honda Ryo , Hiramatsu Yoshihiro , Kono Yoshiteru , Katagawa Hideki 
Published: August 2014

Abstract
The 2007 Noto Hanto Earthquake occurred on 25 March. We have constructed a detailed gravity anomaly map over the Noto peninsula. Four block boundaries which are identified by morphological/geological studies are also recognized on the gravity anomaly map. Various other observations indicate that the mainshock ruptured only one of the blocks, the Kuwatsuka block, although aftershocks are distributed over two blocks, the Kuwatsuka and the Saruyama blocks. The Bouguer anomalies over the Kuwatsuka block are relatively high compared to those of the Saruyama block, i.e. the basement depth of the Kuwatsuka block is shallower than that of the Saruyama block. This difference in the basement depth is consistent with the deformation pattern observed by SAR interferometry. At the block boundary, an offset is recognized in the aftershock distribution. Based on the relationships among the gravity anomalies, the geologic structures, the aftershock distribution and the source fault, we propose that the rupture size of the earthquake was constrained by the block structure in this region.
Magnetotelluric observations around the focal region of the 2007 Noto Hanto Earthquake (Mj 6.9), Central Japan
Authors: Yoshimura Ryokei , Oshiman Naoto , Uyeshima Makoto , Ogawa Yasuo , Mishina Masaaki , Toh Hiroaki , Sakanaka Shin’ya , Ichihara Hiroshi , Shiozaki Ichiro , Ogawa Tsutomu , Miura Tsutomu , Koyama Shigeru , Fujita Yasuyoshi , Nishimura Kazuhiro , Takagi Yu , Imai Mikihiro , Honda Ryo , Yabe Sei , Nagaoka Shintaro , Tada Mitsuhiro , Mogi Toru 
Published: August 2014

Abstract
On 25 March 2007, a damaging earthquake (M
j 6.9) occurred near the west coast of the Noto Peninsula, Central Japan. A wideband magnetotelluric (MT) survey was carried out in the onshore area of the source region immediately after the mainshock, with the aim of imaging the heterogeneity of the crustal resistivity structure. The final observation network had consisted of 26 sites. As a preparatory step for imaging three-dimensional features of the resistivity around the focal region, we constructed two-dimensional resistivity models along five profiles using only the TM mode responses, in order to reduce three-dimensional effects. Four profiles are perpendicular to the fault strike, and a fifth profile is parallel to the strike through the mainshock epicenter. Significant characteristics of the resistivity models are: (1) beneath the mainshock hypocenter, there is a conductive body which spreads to the eastern edge of the active aftershock region; (2) a resistive zone is located in the gap of the aftershock distribution between the mainshock hypocenter and the largest eastern aftershock; (3) one of the largest aftershock occurred at the boundary of the resistive zone described above. These results suggest that the deep conductors represent fluid-filled zones and that the lateral heterogeneity could have controlled the slip distribution on the fault plane.
Numerical simulation of the tsunami generated by the 2007 Noto Hanto Earthquake and implications for unusual tidal surges observed in Toyama Bay
Authors: Abe Ikuo , Goto Kazuhisa , Imamura Fumihiko , Shimizu Katsuyoshi 
Published: August 2014

AbstractWe conducted a numerical analysis of the tsunami generated by the 2007 Noto Hanto Earthquake (Mj= 6.9) that occurred on 25 March 2007 near the Noto Peninsula on the northwest coast of Honshu Island, Japan. Our numerical simulation reproduced well the behaviors of the tsunami as recorded at the Wajima tidal observatory and showed that the computed tsunami arrived in Toyama Bay more than 1 h after the earthquake. However, a crew of a small boat in the bay felt the shock and, despite calm weather conditions, their boat capsized just 3 min after the earthquake. Although abnormal tidal surges were recorded at several locations around Toyama Bay, the timing of these is inconsistent with the surges being a direct result of the tsunami generated at the source area of the earthquake. We used “backward wave propagation analysis” to estimate the likely source area of the abnormal tidal surges in the bay and carried out the a simulation of landslide-induced tsunami. Our conclusion is that these abnormal tidal surges were likely caused by a submarine landslide on the steep sea floor on the western side of Toyama Bay.
Comparison of early aftershock sequences for the 2004 Mid-Niigata and 2007 Noto Hanto earthquakes in central Japan
Authors: Mori Jim , Kano Yasuyuki , Enescu Bogdan 
Published: August 2014

Abstract
We examined continuously recorded seismograms of the 2004 Mid-Niigata and 2007 Noto Hanto earthquakes to compare the early aftershocks for these two similar earthquakes in central Japan. Although the two mainshocks had similar size, depth, and focal mechanisms, the aftershock levels were quite different, with the Niigata case being much stronger. The results of our analyses show that the early aftershock occurrences for the two events were quite similar for the first several minutes. About 7 minutes after the Niigata mainshock, significantly enhanced aftershock triggering began and continued for the duration of that aftershock sequence. We speculate that the change that occurred in the Niigata region may be due to fluid effects in the fault zone.
Shear-driven kinetic Alfven wave in the plasma sheet boundary layer
Authors: Tiwari B. V. , Mishra R. , Varma P. , Tiwari M. S. 
Published: August 2014

Abstract
Shear-driven kinetic Alfven waves (KAWs) at the plasma sheet boundary layer (PSBL) were investigated for substorm events in the presence of a parallel electric field using the general loss-cone distribution function. Using a kinetic approach, we derived the expressions for dispersion relation and growth length of the KAW in the presence of the parallel electric field using the general loss-cone distribution function for both, weak and strong shear regimes. The frequency of the KAW obtained is in agreement with observed values of 0.1–4 Hz in the PSBL. The results explain the generation of the energetic KAWs at the PSBL by the shear at substorm onset. The parallel electric field associated with the energetic KAWs at substorm onset may heat the field-aligned electrons, leading to parallel electron energisation that ultimately causes an intense aurora. The electric field along magnetic field lines enhances the frequency of KAW but decreases the growth length in the case of weak shear. We also found that the parallel electric field can reflect KAW towards the PSBL. The loss-cone distribution index changes the profiles of frequency and growth length plots of the shear-driven KAW. Hence, the loss-cone distribution function is an important factor in the excitation of KAW in the active region of the magnetosphere, such as the PSBL and the auroral acceleration region.
Analytic model of upper tropospheric clouds in the tropical Hadley cell
Authors: Tanaka Kyoko K. , Yamamoto Tetsuo , Watanabe Sei-ichiro , Nakajima Kensuke 
Published: August 2014

Abstract
We have developed a two-dimensional analytic model that describes the behavior of upper tropospheric clouds in the tropical Hadley cell. The behavior of the model is characterized by two dimensionless parameters: one is proportional to the temperature lapse rate, and the other is relevant to the initial altitude of the cloud particles. We derived analytic expressions for the motion and evaporation of the cloud particles and calculate various cloud properties, such as the cloudiness and the column water content. We found that the outflow from the convective regions spreads out and generates a cirrus layer whose coverage has a maximum at the tropopause: the cloudiness is as large as 0.5–1 in the vicinity of the tropopause for small cloud particles with radii of less than 5 μm. We suggest that the thin cirrus clouds observed near the tropopause in the tropic region are formed by the advection of cloud particles supplied from the ITCZ. Because of its simpleness, the present model may play a role in diagnosing cloud properties in climate models that are used to study climate changes over a long time span.
Instrumentation and performance evaluation of the XRS on SELENE orbiter
Authors: Shirai K. , Okada T. , Yamamoto Y. , Arai T. , Ogawa K. , Shiraishi H. , Iwasaki M. , Arakawa M. , Grande M. , Kato M. 
Published: August 2014

Abstract
The x-ray fluorescence spectrometer (XRS) on board Japanese lunar polar orbiter SELENE (Kaguya) will provide global distribution of major elemental composition on the lunar surface in energy range of characteristic K-α x-ray line emission for Mg, Al, Si, Ca, Ti, and Fe. These measurements will contribute to research of lunar origin and its evolution. The XRS shows a good energy resolution within 200 eV at 5.9 keV relying on charge coupled device (CCD) as photon energy dispersive detector. Total collective area of 100 cm2 for main detector facing the lunar surface is composed of 16 CCD chips. Instrumentation of the XRS and its performance evaluated in laboratory are presented.
Ground calibration of the high-sensitivity SELENE lunar magnetometer LMAG
Authors: Shimizu Hisayoshi , Takahashi Futoshi , Horii Naoki , Matsuoka Ayako , Matsushima Masaki , Shibuya Hidetoshi , Tsunakawa Hideo 
Published: August 2014

Abstract
Ground calibration experiments of the SELENE high sensitivity fluxgate Lunar Magnetometer (LMAG) have been performed in order to determine the alignment, sensitivity, and offset of the sensors (MGF-S). It is checked out that the sensors are orthogonal to each other within 0.4 degrees, and the linearity of the ambient magnetic field and the output from the sensors are confirmed. Also, the temperature dependences of the offset and sensitivity are examined but no clear signatures of temperature dependencies can be seen. SELENE has an in-flight calibration system in order to determine the direction of the magnetometer routinely. The magnetic fields generated by the sensor alignment monitor coil (SAM-C) system are used for the in-flight calibration. The magnetic field distributions generated by SAM-C are determined and the accuracy of determination of the magnetometer position and direction is estimated. Multiple measurements will allow us to determine the direction of MGF-S with about 0.1-degree accuracy. Appropriate corrections from the results of the ground and in-flight calibrations will allow us to recover the magnetic field near the moon with accuracy about 0.1 nT.
A new model of lunar crust: asymmetry in crustal composition and evolution
Authors: Arai Tomoko , Takeda Hiroshi , Yamaguchi Akira , Ohtake Makiko 
Published: August 2014

Abstract
Earlier models of lunar crustal formation as a simple flotation of ferroan anorthosites (FAN) do not account for the diverse crustal composition revealed by feldspathic lunar meteorites and granulites in the Apollo samples. Based on the integrated results of recent studies of lunar meteorites and global chemical and mineralogical maps, we propose a novel asymmetric crust model with a ferroan, noritic, nearside crust and a magnesian, troctolitic farside crust. Asymmetric crystallization of a primordial magma ocean can be one possibility to produce a crust with an asymmetric composition. A post-magma-ocean origin for a portion of the lunar crust is also possible and would account for the positive eNd value for FAN and phase equilibria. The formation of giant basins, such as the South Pole-Aitken (SPA) basin may have significant effects on resurfacing of the early lunar crust. Thus, the observed surface composition of the feldspathic highland terrane (FHT) represents the combined results of magma ocean crystallization, post-magma-ocean magmatism and resurfacing by basin formation. The Mg/(Mg+Fe) ratios, rock types, and mineral compositions of the FHT and the South Pole-Aitken basin Terrane (SPAT) obtained from the KAGUYA mission, coupled with further mineralogical and isotopic studies of lunar meteorites, will facilitate an assessment of the feasibility of the proposed crust model and improve understanding of lunar crustal genesis and evolution.
A new index to monitor temporal and long-term variations of the equatorial electrojet by MAGDAS/CPMN real-time data: EE-Index
Authors: Uozumi T. , Yumoto K. , Kitamura K. , Abe S. , Kakinami Y. , Shinohara M. , Yoshikawa A. , Kawano H. , Ueno T. , Tokunaga T. , McNamara D. , Ishituka J. K. , Dutra S. L. G. , Damtie B. , Doumbia V. , Obrou O. , Rabiu A. B. , Adimula I. A. , Othman M. , Fairos M. , Otadoy R. E. S. ,   MAGDAS Group
Published: August 2014

Abstract
A new index, EE-index (EDst, EU, and EL), is proposed to monitor temporal and long-term variations of the equatorial electrojet by using theMAGDAS/CPMN real-time data. The mean value of the H component magnetic variations observed at the nightside (LT = 18–06) MAGDAS/CPMN stations along the magnetic equatorial region is found to show variations similar to those of Dst; we defined this quantity as EDst. The EDst can be used as a proxy of Dst for the real-time and long-term geospace monitoring. By subtracting EDst from the H component data of each equatorial station, it is possible to extract the Equatorial Electrojet and Counter Electrojet components, which are defined as EU and EL, respectively.
Relation between structure and low-temperature geothermal systems in Fukuoka city, southwestern Japan
Authors: Saibi Hakim , Nishijima Jun , Hirano Tomohiro , Fujimitsu Yasuhiro , Ehara Sachio 
Published: August 2014

Abstract
The Fukuoka area is located in the southwestern part of Japan. The Yokote-Ijiri area, located in the southern part of Fukuoka city, has several low-temperature geothermal systems, including eleven hot springs. From 1996 to 2008, the Fukuoka area was investigated by gravity survey, using Scintrex CG-3 and CG-3M gravimeters, in an attempt to delineate its subsurface structure. The surveys were intended to improve the understanding of the relation between the geothermal systems and the subsurface structure as well as to locate the active faults in the surveyed area, which are responsible for generating large earthquakes. The gravity data were analyzed using integrated gradient interpretation techniques, such as the Horizontal Gradient (HG), Tilt Derivative (TDR), and Euler deconvolution methods. With these techniques, many faults were detected, including the famous Kego fault, which is an active fault in Fukuoka city. A 2-D gravity model was constructed to show the relationship between the faults and the geothermal systems. The results of the present study will hopefully lead to an understanding of the relationships between the interpreted faults and the location of the low-temperature geothermal systems and possibly aid in future geothermal exploration of the area.
Resistivity structure around the focal area of the 2004 Rumoi-Nanbu earthquake (M 6.1), northern Hokkaido, Japan
Authors: Ichihara Hiroshi , Honda Ryo , Mogi Toru , Hase Hideaki , Kamiyama Hiroyuki , Yamaya Yusuke , Ogawa Yasuo 
Published: August 2014

AbstractThe Rumoi-Nanbu earthquake (M6.1) occurred in northern Hokkaido, Japan, on December 14, 2004. We conducted MT surveys along three profiles in and around the focal area to delineate and decipher the structural features of the seismogenic zone. The inverted 2-D resistivity images of the three sections comprised two layers: an upper conductive layer and a lower resistive layer. The boundary of these layers lay at a depth of approximately 3–5 km. A comparison with the surface geology and drilling data revealed that the upper conductive layer and the lower resistive layer corresponded to the Cretaceous—Tertiary sedimentary rocks and older basement rocks, respectively. A clear upheaval of the layer boundary was found along the profile at the center of the focal area. In addition, borehole data indicated an obvious increase in the Young’s modulus toward the lower layer. Therefore, the elastic properties with a complex geometry around the focal zone tended to vary; this probably depicts the zone of stress accumulation that triggered the earthquake.
Fault model of the 2007 Noto Hanto earthquake estimated from coseismic deformation obtained by the distribution of littoral organisms and GPS: Implication for neotectonics in the northwestern Noto Peninsula
Authors: Hiramatsu Yoshihiro , Moriya Kazuyoshi , Kamiya Takahiro , Kato Michio , Nishimura Takuya 
Published: August 2014

AbstractWe investigate the coseismic vertical crustal movement along the northern and western coast of the Noto Peninsula caused by the Noto Hanto earthquake on March 25, 2007, from the distribution of supra-, mid- and infra-littoral organisms. The highest uplift of 44 cm is observed at Akakami and the maximum subsidence of 8 cm at Fukami. We construct a rectangular fault model with a uniform slip in elastic half-space using both the coseismic vertical displacement estimated from the distribution of these organisms and the coseismic crustal deformation obtained by GPS. The model shows a reverse fault with a right-lateral slip of 1.3 m in a 18.6 km×14.5 km area. The seismic moment is 1.0×1019 N m (MW6.6) using a rigidity of 30 GPa. The geometry of the source fault is consistent with the distribution of aftershocks and active faults, and the fault is restricted to the central area of the aftershock area. Relationships among the fault, the distribution of aftershocks, active faults, and geological blocks around the source area suggest that geological structures restrict the fault size of the earthquake. By considering an inclined altitudinal distribution of marine terraces and the coseismic vertical crustal deformation detected in this study, we estimate that the recurrence of earthquakes during the past 120 kyr would produce a vertical crustal deformation of ≈12 m and the background tectonic uplift would reach ≈28 m.
An experiment of predicting Total Electron Content (TEC) by fuzzy inference systems
Authors: Akyilmaz O. , Arslan N. 
Published: August 2014

Abstract
The Total Electron Content (TEC) is predicted by fuzzy inference systems for various station-satellite pairs. GPS data from the GRAZ, HFLK, LINZ, MOPI and UZHL permanent stations are processed in order to obtain the vertical total electron content (VTEC) using differenced carrier-smoothed code observations. The quality of the VTEC prediction was studied on 9 and 11 September 2005 (DOY 252 and 254). The predictions were computed for 5, 10 and 15 min intervals. The mean accuracies of predictions are about 0.1, 0.2 and 0.3 TECU for these time intervals. More than 98% of the VTEC is successfully recovered with the proposed prediction method.
Summer-time nocturnal wave characteristics in mesospheric OH and O2 airglow emissions
Authors: Guharay A. , Taori A. , Taylor M. 
Published: August 2014

Abstract
The mesospheric temperature mapper (MTM) measurements on mesospheric OH (6, 2) and O2 (0, 1) band emissions from Maui, Hawaii during July, 2002 show significant day-to-day variability. The nocturnal variability reveals prominent wave signatures with a periodicity ranging from 6 to 13 h. For better characterization of the nocturnal wave in the data, a Krassovsky’s η (∼|η|e

iφ) analysis was carried out. Deduced Krassovsky parameters show significant variability, with ranges of |η| ∼ 1.7–3.9 for the OH data and ∼4.3–13 for the O2 data. The phase values of Krassovsky parameters exhibit larger variability, with variations from approximately −91° to +23° for the OH data and −45° to −10° for the O2 data. Comparison of these values with existing observations and models show large deviations from model values and relatively better agreements with the observed values reported by other investigators. The deduced vertical wavelength from |η| and φ indicates that our data is mostly dominated by upward propagating waves with occasional high values ≥100 km, implying possible evanescent waves.