bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crustal movement of Antarctica and Syowa Station based on GPS measurements
Authors: Ohzono Mako , Tabei Takao , Doi Koichiro , Shibuya Kazuo , Sagiya Takeshi 
Published: August 2014

Abstract
In Antarctica, sea level rise and crustal uplift have occurred due to ice sheet melting and mantle response since the Last Glacial Maximum (LGM). The International GNSS Service (IGS) provides continuous data at nine sites on the Antarctic plate, and we analyzed data obtained from these sites between 1998 and 2003. Additional data were acquired by campaign observations around Syowa Station carried out by the Japanese Antarctic Research Expedition (JARE). Five sites around Syowa Station have been repeatedly occupied since 1998. Our analysis of the IGS data demonstrates that the Antarctic continent behaves as a rigid plate. Vertical components indicate an uplift of about 1.3–7.0 mm/year at almost all sites, which are attributed to the postglacial rebound. However, some observed velocities disagree with the predictions of glacial isostatic adjustment (GIA) models. It will be necessary to incorporate our results into the modeling of ice sheet melting. Around Syowa Station, the campaign GPS result is basically consistent with the IGS data analysis, thereby demonstrating that GPS observations properly represent the ongoing crustal movement around Syowa Station. However, the GPS results show some disagreement with the VLBI observations; this discrepancy will need to be sorted out using local tie observations that should be carried out in the near future.
Crustal heterogeneity around the Nagamachi-Rifu fault, northeastern Japan, as inferred from travel-time tomography
Authors: Nakajima Junichi , Hasegawa Akira , Horiuchi Shigeki , Yoshimoto Kazuo , Yoshida Takeyoshi , Umino Norihito 
Published: August 2014

Abstract
An M=5 earthquake occurred on September 15, 1998, in the Nagamachi-Rifu fault (NRF), northeastern Japan. In the aftermath of this event, many seismograph stations were constructed temporarily around the fault, forming a dense network of stations with a spatial separation of 5 km. We report here our estimation of the three-dimensional velocity structures of the P and S waves using arrival-time data recorded at these stations with the aim of understanding the heterogeneous structure around the NRF. Low-Velocity and high Poisson’s ratio anomalies are imaged in the lower crust beneath the volcanic area, which are probably associated with the partially molten materials conveyed through the upwelling flow in the mantle wedge. A distinct low-velocity anomaly, which is explainable by the existence of H2O-filled pores, is observed in the mid crust at the deeper extension of the NRF. Two low-velocity anomalies that are probably associated with the remnants of magmatic activity that formed the Shirasawa caldera and with the existence of thick late-Cenozoic sedimentary layers are observed at depths shallower than 10 km in the hanging wall of the NRF. Our results successfully characterize the major features of the complex velocity structure around the NRF, with implications for the existence of fluid-rich regions in the mid to lower crust.
Oscillating motion of the Jovian Great Red Spot and Numerical Experiments with IG equation
Authors: Asada Tadashi , Miyazaki Isao 
Published: August 2014

Abstract
Position measurements of the Great Red Spot (GRS) on recent digital images of Jupiter were carried out to detect the longitudinal and latitudinal motion of the GRS. Its longitudinal oscillating motion may be interpreted as two types. One has a 57-day period and no latitudinal motion, the other has 86 days and probably has latitudinal motion. In 86 days, oscillation, the GRS seems to locate equatorward when it moves relatively westward, and poleward when it moves eastward. Numerical Experiments of the Intermediate Geostrophic (IG) equation show the same results for the motion of an eddy, and that a kind of wave collides with the eddy when it changes relative longitudinal motion from eastward to westward.
Electron temperature variation associated with the auroral energy input during the DELTA campaign
Authors: Abe Takumi , Oyama Koh-Ichiro , Kadohata Akihiro 
Published: August 2014

Abstract
Japanese sounding rocket “S-310-35” was launched from Andøya Rocket Range in Norway on December 13, 2004 during Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign, in which the rocket-borne in-situ measurements and ground-based measurements were coordinated to conduct a comprehensive observation of the upper atmospheric response against the auroral energy input. The Fast Langmuir Probe (FLP) was installed on the sounding rocket to study thermal structure and energy balance of the plasma by measuring the electron temperature in the polar lower ionosphere. The FLP observations indicate that the electron temperatures were found to be remarkably high in an altitude range from 106 km to 114 km during the ascending phase of the rocket. The lowest part of this high temperature region might be affected by artificial electron beam which was generated by the N2 temperature instrument on the same rocket. On the other hand, a small increase of the electron temperature was observed at the altitude from 114 to 119 km in the descending phase. This is possibly the first time that both the temperature increase and density fluctuation that may be caused by the Farley-Buneman instability were detected by in-situ observation.
An aspect of the subsurface structure of the Burdur-Isparta area, SW Anatolia, based on gravity and aeromagnetic data, and some tectonic implications
Authors: Dolmaz M. Nuri 
Published: August 2014

AbstractGravity and aeromagnetic analyses were conducted in the Burdur-Isparta area of Turkey in order to identify the subsurface structure and tectonics of the region independent of surface cover. The analytic signal of the aeromagnetic anomalies was first calculated to delineate the source fields of these anomalies. The magnetic signatures were found to correlate well with the intrusives associated with the subduction of the African oceanic lithosphere and with the ophiolitic nappes in the region. The residual aeromagnetic anomalies mostly orientate in the N-S direction, implying the presence of remanent magnetization. Based on the shape analysis of aeromagnetic anomalies, the region appears to have rotated clockwise. The magnetic anomalies were found to continue upward to 5 km a.s.l. The upward continued map shows deep effects of the sub-crustal magnetic sources. Based on the Bouguer gravity anomalies, the thickness of the crust in the study area is between 33 and 37.5 km. Major extensive NE- and NW- as well as N-trending faults are identified that coincide with the Lake Burdur, Lake Beysehir and Kovada grabens, respectively. Lake Egirdir is also devoid of any magnetic sources. As a final step, the maxima of the horizontal gradient of the gravity data were calculated. The maxima show that the major geological formations and the structural trends in the area are remarkable. The boundaries of the various geological formations can be identified based on the boundary analysis of the gravity and the analytic signal of the aeromagnetic data. The change in the nature of the anomalies reflects the imprints of intense deformation associated with major tectonic activity of the African-Eurasian plate convergence zone.
Moment release budget at oblique convergence margin as revealed by the 2004 Sumatra-Andaman earthquake
Authors: Oishi Makiko , Sato Tamao 
Published: August 2014

Abstract
Based on the model of oblique convergence, we predicted the slip rate on the megathrust plate boundary in the western Sunda arc and compared it with the slip distribution of the 2004 M
w 9.0 Sumatra-Andaman earthquake. The slip directions on the megathrust plate boundary, which are necessary for predicting the slip rate, were determined using the fault plane solutions of medium-sized earthquakes occurring for the last 30 years in the 2004 rupture zone. At long wavelengths the predicted slip rate correlates well with the latitudinal variation of the coseismic slip, suggesting that kinematics described by the model of oblique convergence operated over a long interseismic period and that the seismic coupling coefficient has been generally uniform along the strike of the rupture zone. Using the data for the same period of time, we estimated the total seismic moment released by the earthquakes on the Sumatra fault and its submarine continuation located on the backarc side of the Nicobar and Andaman islands. The ratio of the observed seismic moment to the seismic moment predicted from the model of oblique convergence is small. The residual may either be stored for generation of future earthquakes or was taken up by the fault creep at shallow depths.
Cathodoluminescence and fluid inclusion analyses of mineral veins within major thrusts in the Shimanto accretionary complex: evidence of hydraulic fracturing during thrusting
Authors: Mukoyoshi Hideki , Hirono Tetsuro , Sekine Kotaro , Tsuchiya Noriyoshi , Soh Wonn 
Published: August 2014

Abstract
To elucidate fluid-rock interaction in a seismogenic zone along a plate-subduction boundary, we investigated the occurrence of mineral veins within the major thrusts in the Shimanto accretionary complex and examined their microstructures using a cathodoluminescence technique. We found discriminative structures, for example, a jigsaw-puzzle structure, within the quartz veins in the thrusts, which could indicate that hydraulic fracturing occurred by abnormal pore-fluid pressure during thrusting. Pore pressure values, estimated quantitatively by fluid inclusion analyses, were 3–27 MPa higher than the surrounding parts, which may be direct evidence of abnormal pore-fluid pressure. High pore-fluid pressures and subsequent hydraulic fracturing may play an important role within major thrusts along a plate-subduction boundary.
Automation of absolute measurement of the geomagnetic field
Authors: Auster H. U. , Mandea M. , Hemshorn A. , Pulz E. , Korte M. 
Published: August 2014

Abstract
In this paper a device is presented to measure the geomagnetic field vector absolutely and automatically. In contrast to the standard DI-Flux measurement procedure our automation approach is based on the rotation of a three-component fluxgate magnetometer about precisely monitored axes without using a non-magnetic theodolite. This method is particularly suitable for automation because it only requires exact knowledge of the axes orientations. Apart from this, requirements on mechanical precision are moderate. The design of the facility is presented, and mechanical, optical and magnetic limitations are discussed. First promising results of measuring the Earth’s magnetic field absolutely and automatically with the new device at Niemegk observatory are discussed.
Density distribution in medium-sized icy satellites of giant planets
Authors: Czechowski Leszek , Leliwa-Kopystynski Jacek 
Published: August 2014

Abstract
We discuss processes that determine the distribution of density in the medium-sized icy satellites (MIS). Gravitational differentiation, porosity and phase transitions lead to a spherical distribution, while thermal convection, large impacts and tidal deformation can result in a non-spherical distribution. According to our previous research, convective patterns in MIS can consist of one or two convective cells for radiogenic and tidal heating. The shift of the center of mass ΔrCM and the ratio of moments of inertia IZ/IXY are calculated using a numerical model of convection. A new dimensionless number C is introduced to describe the deformation of the surface. We found that ΔrCM can reach ≈0.5% of the satellite radius for the one-cell pattern. With the two-cell pattern the moment of inertia, IZ, can be reduced by ≈0.4%. The impact cratering could be one cause of significant changes in ΔrCM and IZ /IXY but only for the smallest of the MIS. Tidal deformation could result in the enhancement of mass redistribution caused by other mechanisms.
Interseismic deformation of the Nankai subduction zone, southwest Japan, inferred from three-dimensional crustal velocity fields
Authors: Tabei Takao , Adachi Mari , Miyazaki Shin’ichi , Watanabe Tsuyoshi , Kato Sayomasa 
Published: August 2014

Abstract
We have studied crustal deformation in the Nankai subduction zone, southwest Japan, based on three-dimensional GPS velocity fields. Oblique subduction of the Philippine Sea plate has caused two different modes of deformation of the overriding plate: interseismic crustal shortening in the direction of plate convergence, and permanent lateral movement of the forearc. The block boundary dividing the forearc is the Median Tectonic Line (MTL); however, we assumed that its shallower portion is fully or partially locked to a certain depth. The plate boundary and the MTL are represented by many rectangular faults. We carried out inversion analyses with a priori information to estimate simultaneously slip deficit rates at those rectangular faults, together with the rate of lateral movement of the forearc. The results show that the seismogenic subduction faults at a depth of 5–25 km are strongly locked. As for the transition zone at 25–35 km, the inversion analysis results in stronger locking than shown in previous studies, especially when the vertical velocity data are weighted. The rates of lateral forearc movement and slip deficit at the MTL are nearly comparable but in a reverse sense to each other. This shows that the shallower portion of the MTL is strongly locked but that stationary aseismic slip is occurring in the deeper part.
Geodetic constraint on the slip distribution of the 2006 Central Kuril earthquake
Authors: Takahashi Hiroaki , Kasahara Minoru 
Published: August 2014

AbstractWe have investigated the slip distribution of the 15 November 2006 Central Kuril earthquake off Simushir Island using continuous GPS data. A dense GPS network on Hokkaido Island, northern Japan, and Sakhalin Island detected coseismic horizontal displacements of ~9 mm despite large epicentral distances of about 900–1200 km. Eastward displacements at the sites decrease to the south, and this spatial distribution feature constrains the slip on the three subfaults. Our data suggest that little slip has occurred in the southern and northern parts, but that a 6-m slip has occurred in the center of the focal region. This interpretation fits well with the detailed slip distribution inferred from teleseismic waveform inversions. The total seismic moment, 2.8 × 1021 N m, is approximately the value indicated using by the Global CMT solution. Our result implies that there remains a seismic gap between this event and the 1952 great Kamchatkan earthquake that is large enough for anM> 8 earthquake.
Calibration of amplification factors using KiK-net strong-motion records: toward site effective estimation of seismic intensities
Authors: Hayashida Takumi , Tajima Fumiko 
Published: August 2014

AbstractEstimated seismic intensities using conventional relationships are not always in agreement with those observed at specific sites. We investigate subsurface amplification factors using the KiK-net strong-motion data recorded both in the borehole and on the ground surface and attempt to estimate more accurate intensities at a given site. Here the amplification factors are evaluated using the ratios of peak velocity amplitudesVsurf/Vborthat are calculated from records on the ground surface and in the borehole. The ratios (amplification factors) decrease with hypocentral distance in general, but the attenuation characteristics vary from station to station. At stations where large amplifications are observed, the ratios show large scatter relative to the empirical amplification formulas. The variation is also affected by the incident direction of seismic waves as well as the hypocentral distance. We derived empirical amplification formulas ofVsurf/VbedwhereVbedis the peak velocity on the engineering bedrock as a function of hypocentral distance at individual stations (i.e. specific sites) in place of the conventionally used amplification constants. The estimated intensities using the site-effective formulas show substantial improvement at most of the stations in comparison with those calculated using conventional formulas.
Evolution of the concept of Sudden Storm Commencements and their operative identification
Authors: Curto J. J. , Araki T. , Alberca L. F. 
Published: August 2014

Abstract
In this paper, we review the evolution of both, the concept and the operative methods of detection of Storm Commencements (SC’s) and we introduce suggestions for future improvements. Finally, a more precise definition of the events with consequences in terminology and detection is proposed.
Hypocenter distribution of plate boundary zone off Fukushima, Japan, derived from ocean bottom seismometer data
Authors: Shinohara Masanao , Hino Ryota , Yoshizawa Takashi , Nishino Minoru , Sato Toshinori , Suyehiro Kiyoshi 
Published: August 2014

Abstract
Microearthquake observation using Ocean Bottom Seismometers (OBSs) was carried out to obtain a detailed distribution of microearthquakes beneath the area off Fukushima, in the middle section of the Japan Trench in the summer of 1997. The observation period spanned approximately one month. Almost all of the well-determined hypocenters occurred in the vicinity of the plate boundary in this region (approximately 100 km landward of the trench axis), while seismicity is markedly lower between this area and the trench itself. The seaward limit of the high seismicity region is close to the western end of the zone of direct contact between the oceanic crust and the overriding landward crust. Twenty-nine earthquakes were recorded within the overriding landward plate. Twelve earthquakes were recorded about 30 km below the plate boundary, and form a landward dipping plane that appears to be an up-dip continuation of the lower plane of the double seismic zone. The microseismicity characteristics of the plate boundary region are interpreted to be controlled by the geometry and physical properties of the plate interface. The seismic activity in the lower seismic plane near the trench is considered to relate to bending of the subducting plate and to dehydration of serpentinized Pacific Plate mantle.
Estimation of picked-up lunar ions for future compositional remote SIMS analyses of the lunar surface
Authors: Yokota Shoichiro , Saito Yoshifumi 
Published: August 2014

Abstract

In situ measurement of Moon-originating ions picked-up in orbit round the Moon is expected to provide valuable information regarding the thin lunar atmosphere and surface. Secondary ions sputtered by the solar wind ions reflect the surface abundance. Global composition mapping of the lunar surface may be thus achieved by measuring the sputtered ions as one would perform laboratory SIMS.We studied the dynamics of picked-up lunar ions when the Moon was exposed to the solar wind. Our model’s source mechanism involved photoionization of the lunar exospheric atoms, photon-stimulated ion desorption, and ion sputtering. We propose that an intense flux of picked-up lunar ions (104 /cm2 sec) exists at an altitude of 100 km, for nearly a quarter of the orbit. The ion flux originating from the lunar surface is mono-directional and mono-energetic, and is distinguishable from that of lunar atmospheric origin whose energy spectra correspond to their spatial distribution. Our calculation suggested that ion measurements in orbit round the Moon enable remote SIMS analyses.
Co-seismic strain-steps associated with the 2004 off the Kii peninsula earthquakes-Observed with Ishii-type borehole strainmeters and quartz-tube extensometers
Authors: Asai Yasuhiro , Okubo Makoto , Ishii Hiroshi , Aoki Harumi , Yamauchi Tsuneo , Kitagawa Yuuichi , Koizumi Naoji 
Published: August 2014

AbstractThe 2004 off the Kii peninsula earthquakes (Mj7.1 and Mj7.4) occurred at the Nankai trough, on 5 September 2004. Clear strain-steps associated with these earthquakes were observed with Ishii-type borehole strainmeters and quartz-tube extensometers in the Tokai and Kinki districts. We investigated the spatial and depth distribution of the observed principal strain changes and compared the observed strain-steps and theoretical calculations at all observatories. The following results were obtained: the observed strain-steps at all observatories are generally consistent with the polarities of the theoretical values, and the observed strain-step increases with depth at the same place. As for the Togari site, the following relationships are obtained: the strain-step and the tidal strains increase with depth and increasing of the modulus of elasticity, namely, hardness of rock. We consider that the geological structure around the observatory may cause a modification of the strain field.
Difference in the initial slopes of the P-wave envelope waveforms of the main shock M7.4 and foreshock M7.1 of the 2004 off the Kii peninsula earthquakes
Authors: Odaka Toshikazu , Nakamura Hiromitsu , Ashiya Kimitoshi 
Published: August 2014

Abstract
We made a close investigation about the initial rising slopes of the envelope waveforms of the P-wave ground motion by using data for recent earthquakes. We have found that the P-wave initial slopes decrease almost linearly with increasing epicentral distance over the wide range of distance. This linear relation looks to be independent of the earthquake magnitudes and focal depths though the dispersion of data is somewhat large. We have found that the P-wave initial slopes of the foreshock M7.1 of the 2004 off the Kii peninsula earthquakes are very sharp. To the contrary, the slope of the main shock M7.4 is quite gentle. The main shock was preceded by a small event that occurred about 6.7 seconds before the main shock. This pre-event was generated near the initiation point of the main fracture. We are speculating that the difference in the initial slope between the foreshock and main shock may reflect the difference in the time variation of the stress drop at the early stage of the fracture and that the small pre-shock may be responsible for the slow rising of the initial P-wave motion of the main shock.
Inversion analysis of the 2004 off the Kii peninsula earthquakes using seismic intensity data
Authors: Kanda Katsuhisa , Takemura Masayuki 
Published: August 2014

Abstract
An inversion analysis has been developed to evaluate short-period radiation zones on an earthquake fault plane using seismic intensity data. It is robust and widely applicable even for historical earthquakes without ground motion, tsunami and geodetic data observed by instruments. It was applied to the 2004 off the Kii peninsula earthquakes that occurred in the Philippine Sea plate along the Nankai Trough. The short-period seismic wave radiation zone of each event during the 2004 off the Kii peninsula earthquakes from the inversion analysis was included in epicenter area of the corresponding aftershocks and slipped fault zone derived from the waveform inversion analysis as well. It may be also found that there were slip areas where little short period energy radiated. It also applied to the 1899/3/7 earthquake whose felt area was similar to that of the 2004 off the Kii peninsula earthquakes. However, it was indicated that the short-period radiation zones of the 1899 earthquake was located near the coast of the Kii peninsula and departed from that of the 2004 earthquake. The 1899 event might be an intermediate-depth earthquake in the Philippine Sea plate or a relative small interplate event at the west margin of the Tonankai earthquake source region.