bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lunar cratering chronology: Statistical fluctuation of crater production frequency and its effect on age determination
Authors: Morota Tomokatsu , Haruyama Jun’ichi , Honda Chikatoshi , Yokota Yasuhiro , Ohtake Makiko , Ogawa Yoshiko , Matsunaga Tsuneo 
Published: August 2014

Abstract
The crater frequency is often used to determine ages of planetary surfaces. In this study, we evaluate the statistical fluctuation of the crater frequency and its effect on age determination using a Monte Carlo simulation prior to the SELENE (KAGUYA) / Terrain Camera acquiring extensive high-resolution images over the entire Moon. We found that the ages estimated between 2.5 and 3.5 Gyr tend to be too young when there are not enough craters. Age determination for Eratosthenian units is least accurate. The errors defined with 1σ are 0.7 Gyr for units of 100 km2, 0.5 Gyr for units of 1000 km2, and 0.4 Gyr for units of 2500 km2. The maximum error exceeds 20% and is comparable with the error due to the cratering asymmetry.
Complexities of gamma-ray line intensities from the lunar surface
Authors: Yamashita Naoyuki , Hasebe Nobuyuki , Miyachi Takashi , Kobayashi Masanori , Okudaira Osamu , Kobayashi Shingo , Ishizaki Takeshi , Sakurai Kunitomo , Miyajima Mitsuhiro , Reedy Robert C. , d’Uston Claude , Maurice Sylvestre , Gasnault Olivier 
Published: August 2014

Abstract
Assuming different abundances of the Apollo lunar soil samples and the average spectrum of galactic cosmic ray protons, energy spectra of neutrons and gamma rays and emission rates of gamma-ray lines from major elements have been estimated by using the reviewed Monte Carlo simulation library Geant4 and nuclear data. Previously, such libraries were not able to reproduce gamma-ray lines properly for the planetary application. Results clearly show that the emission rate of gamma rays heavily depends not only on the chemical abundance but also neutron flux within the lunar subsurface. While the intensities of gamma-ray lines are mostly proportional to elemental abundances, the intensity per unit elemental abundance can vary. Such a complex correlation is attributed to the change in neutron flux within the lunar subsurface and petrological restriction of elemental variation.
Instrumentation and observation target of the Lunar Radar Sounder (LRS) experiment on-board the SELENE spacecraft
Authors: Ono Takayuki , Kumamoto Atsushi , Yamaguchi Yasushi , Yamaji Atsushi , Kobayashi Takao , Kasahara Yoshiya , Oya Hiroshi 
Published: August 2014

Abstract
The Lunar Radar Sounder (LRS) on-board the SELENE lunar orbiter is currently being equipped to provide the data of subsurface stratification and tectonic features in the shallow part (several km deep) of the lunar crust, by using an FM/CW radar technique in HF (∼5 MHz) frequency range. Knowledge of the subsurface structure is crucial to better understanding, not only of the geologic history of the Moon, but also of the Moon’s regional and global thermal history of the Moon and of the origin of the Earth-Moon system. In addition to the subsurface radar experiment, LRS will provide the spectrum of plasma waves and solar and planetary radio waves in a wide frequency range from 10 Hz to 30 MHz. This paper provides the basic function parameter of the LRS system based on the final function test and proposes observation targets and data analysis that will provide important information leading to a greater understanding of the tectonics and thermal history of the Moon.
Equivalent source mapping of the lunar crustal magnetic field using ABIC
Authors: Toyoshima M. , Shibuya H. , Matsushima M. , Shimizu H. , Tsunakawa H. 
Published: August 2014

Abstract
An objective scheme is presented for estimating the lunar crustal magnetic field from the LMAG (Lunar MAGnetometer) data of the SELENE (“KAGUYA”) spacecraft. Our scheme improves the equivalent source method in three respects. The first improvement is that the source calculation is performed simultaneously with detrending. The second is that a great number of magnetic charges (magnetic monopoles) are used as the equivalent sources. The third is that the distribution of the magnetic charges is detremined by the damped least squares method, and the optimum smoothness is determined objectively by minimizing Akaike’s Bayesian Information Criterion (ABIC). For testing the scheme, we apply it to the Lunar Prospector magnetometer data in the region centered at the Reiner Gamma magnetic anomaly. The magnetic field map at an altitude of 20 km is stably drawn from datasets for different altitudes (18 km and 34 km). The ABIC minimizing criterion successfully controls the smoothness due to the numerical damping and extracts as much information as possible from the given data. This scheme will help produce a coherent lunar magnetic anomaly map by integrating the observations from various altitudes of the SELENE and previous missions.
Simulation analysis of differential phase delay estimation by same beam VLBI method
Authors: Kikuchi Fuyuhiko , Liu Qinghui , Matsumoto Koji , Hanada Hideo , Kawano Nobuyuki 
Published: August 2014

Abstract
The same beam VLBI method (SBV) is newly applied to the multi-frequency VLBI method in the VRAD mission of SELENE (KAGUYA). By simultaneously observing two nearby spacecraft with one antenna, the error sources of VLBI measurement common in two propagation paths can be almost canceled out. In this paper, error estimation and simulation analysis are carried out for a feasibility study to apply the SBV method to the VRAD mission. Differential phase delay can be estimated without cycle ambiguity even if tropospheric fluctuation is large and/or traveling ionospheric disturbance occurs. The sensitivity of the differential phase delay with respect to the average elevation angle and the elongation of two spacecraft is also investigated. Moreover, a method is developed for estimating differential phase delay in switching VLBI observations using the cycle ambiguity derived from SBV observations. This method can be performed in more than 90% of the VRAD mission’s total paths. Precise positioning with SBV contributes to accurate estimation of the low degree coefficients of lunar gravity fields by more than one order of magnitude than previous results.
The absorption-peak map of Mare Serenitatis obtained by a hyper-spectral telescope
Authors: Okuno Hideaki , Yamanoi Yuta , Saiki Kazuto 
Published: August 2014

Abstract
The Mg-number [Mg#=atomic Mg/(Mg+Fe)] serves as an important petrologic discriminator when analyzing and understanding lunar rocks. Variations in the Mg# shift the wavelength of the absorption spectra of ferrous iron, which peak at around 1000 nm. Based on the image cubes of the Moon obtained by the Advanced Lunar Imaging Spectrometer (ALIS), we detected the shift in the absorption spectra of ferrous iron and built up an absorption-peak map of Mare Serenitatis. The wavelength of the absorption peak shows an 11-nm shift in Mare Serenitatis. Since the degree of space weathering can be considered to be almost the same as that within the same lava unit and Ca content cannot change without changing Mg# during magma differentiation, these shifts of the peak absorption spectra suggest that there is Mg# variation in at least the same lava unit.
InSAR-based mapping of surface subsidence in Mokpo City, Korea, using JERS-1 and ENVISAT SAR data
Authors: Kim Sang-Wan , Wdowinski Shimon , Dixon Timothy H. , Amelung Falk , Won Joong-Sun , Kim Jeong Woo 
Published: August 2014

Abstract
Mokpo City, located on the southwestern coast of the Korean Peninsula, has been built on one of the largest areas of reclaimed coastal land in Korea. This reclaimed land is currently experiencing significant ground subsidence due to soil consolidation. We have estimated the subsidence rate of Mokpo City (8 × 8 km) using the synthetic aperture radar interferometry (InSAR) and InSAR permanent scatterer (PSInSAR) techniques to analyze 26 JERS-1 SAR images acquired between 1992 and 1998 and six ENVISAT ASAR images acquired in 2004–2005. Mean subsidence velocity, which was clearly related to reclaimed land, was computed from the JERS-1 PSInSAR analysis. The results indicate a continuous and significant subsidence at three sites (Dongmyung, Hadang and Wonsan), where the subsidence velocity has reached more than 5–7 cm/yr in the area of maximum subsidence. The subsidence rate was found to have decreased in Wonsan and Hadang between 1992 and 1998, while it remained steady or increased in Dongmyung during the same period. The subsidence extended to the period of 2004–2005, and the subsidence rate predicted by the JERS-1 PSInSAR analysis using a linear model was confirmed by the ENVISAT ASAR InSAR results. Our results show that InSAR/PSInSAR-based subsidence maps are useful for the long-term monitoring of soil consolidation and for defining risk zones in coastal reclaimed regions.
Assessing intraplate earthquake hazards from satellite geopotential field observations
Authors: von Frese Ralph R. B. , Kim Jeong Woo , Hernandez Orlando , Kim Hyung Rae , Asgharzadeh Mohammad F. 
Published: August 2014

AbstractSatellite magnetic and gravity field observations provide important constraints on the poorly understood lithospheric properties of intraplate earthquakes because they map lateral long-wavelength contrasts in magnetization and density, respectively, related to petrological, structural, and thermal variations that help control the distribution of lithospheric stress. These anomalies are each a product of the vertically integrated physical property times the layer thickness. Thus, they constrain and enhance the geological utility of near-surface geopotential surveys, as well as seismic, GPS, and other geophysical observations that map the geological and dynamic properties of the lithosphere. To illustrate this synergy, we consider the influence of the US Transcontinental Magnetic Anomaly (TMA) on crustal stress and earthquake activity along the 38thparallel. In another example, we compare crustal earthquake stress constraints from gravity and seismic observations of the US mid-continent and North Andes microplate where starkly contrasting plate tectonic forces operate.
Effects of latitudinal distributions of particle density and wave power on cyclotron resonant diffusion rates of radiation belt electrons
Authors: Summers Danny , Ni Binbin 
Published: August 2014

Abstract
We evaluate cyclotron resonant interactions of radiation belt electrons with VLF chorus, plasmaspheric ELF hiss and electromagnetic ion cyclotron (EMIC) waves. We assume that the Earth’s magnetic field is dipolar and that each wave mode has a Gaussian spectral density. The dependence of the resonant electron diffusion rates on the latitudinal distributions of particle density and wave power is examined. We find that while the diffusion rates can be sensitive to the latitudinal distributions of density and wave power, in general the sensitivity depends on wave mode, equatorial pitch-angle, electron energy and L-shell. We determine the effects of the latitudinal distributions of density and wave power on the electron precipitation loss timescale due to combined scattering by VLF chorus, ELF hiss and EMIC waves. Accurate modeling of radiation belt electron dynamics requires observational data on the global distributions of particle number density and wave power.
Temporal characteristics of high band-pass filtered teleseismic P-waveforms from large shallow earthquakes
Authors: Hara Tatsuhiko 
Published: August 2014

Abstract
We measured time differences between P-wave arrivals and the times at which squared amplitudes of high bandpass (2–4 Hz) filtered P-waves became the largest for large shallow earthquakes that occurred during the period 1995–2007. The time differences were then normalized by twice the centroid time shift for the corresponding earthquakes. We found that most of the seismograms had normalized time differences that congregated at about 50% (corresponding to centroid time shifts). Few normalized time differences were found in the 0–20% range. These results support the use of this time difference to infer the order of the source duration and, thereby, the effectiveness of the duration measurement procedure of the high-frequency energy radiation that we recently developed.
Source parameters of the 2007 Noto Hanto earthquake sequence derived from strong motion records at temporary and permanent stations
Authors: Maeda Takahiro , Ichiyanagi Masayoshi , Takahashi Hiroaki , Honda Ryo , Yamaguchi Teruhiro , Kasahara Minoru , Sasatani Tsutomu 
Published: August 2014

AbstractA large crustal earthquake, the 2007 Noto Hanto earthquake, occurred west off the Noto peninsula in Ishikawa prefecture, Japan, on March 25, 2007. We started temporary strong motion observation at five sites within the aftershock area from about 13 h after the main shock occurrence. We first applied the spectral inversion method toS-wave strong ground motion records at the temporary and permanent stations. We obtained source specta of the main shock and aftershocks,Qs(quality factor forS-wave) values (Qs= 34.5f0.95) and site responses at 22 sites. We then estimated a source model of the main shock using the empirical Green’s function method. The source model consists of three strong motion generation areas and well explains the observed records. Finally, we examined the consistency of the main-shock source models estimated from the above two analyses. The high-frequency level of the acceleration source spectrum based on the main-shock source model is consistent with the source spectrum estimated from the spectral inversion. The combined area of strong motion generation areas is approximately half of the value expected by the empirical relationship, and the high-frequency level of acceleration source spectrum is approximately 2.5 times larger than the empirical relationship for shallow inland and inter-plate earthquakes.
Characterization of the 2007 Noto Hanto, Japan, earthquake
Authors: Horikawa Haruo 
Published: August 2014

AbstractCharacterization of the 2007 Noto Hanto, Japan, earthquake (MS6.9), a moderate-size crustal event, was performed. The rupture process was firstly inferred from strong motion data. Inversion analysis revealed that the overall rupture finished within 6 s, and the seismic moment of this earthquake was estimated to be 1.1×1019N m (Mw6.6). Two areas of large slip and stress drop (asperities) were inferred on the fault plane. The maximum static stress drop calculated from the derived slip distribution exceeded 16 MPa for the major asperity, and the minor asperity has a similar maximum value. An area of negative stress drop corresponding to the distribution of small slip exists between the two asperities. This strongly suggests that the fault is segmented. A boundary between surface faults was located above the major asperity, but an area of negative stress drop appeared between the asperity and fault boundary. This suggests that the configuration of the surface faults reflects only a shallow part of the causative fault. The ratio of radiated energy to seismic moment was also estimated for the purpose of estimation of fault activity. Comparison of the derived value with those of other Japanese earthquakes suggests that the causative fault of the Noto Hanto earthquake is not very active.
Paleointensity data from Early Cretaceous Ponta Grossa dikes (Brazil) using a multisample method
Authors: Brandt Daniele , Hartmann Gelvam A. , Yokoyama Elder , Catelani Edgard L. , Trindade Ricardo I. F. 
Published: August 2014

Abstract
Definition of the long-term variation of the geomagnetic virtual dipole moment requires more reliable paleointensity results. Here, we applied a multisample protocol to the study of the 130.5 Ma Ponta Grossa basaltic dikes (southern Brazil) that carry a very stable dual-polarity magnetic component. The magnetic stability of the samples was checked using thermomagnetic curves and by monitoring the magnetic susceptibility evolution through the paleointensity experiments. Twelve sites containing the least alterable samples were chosen for the paleointensity measurements. Although these rocks failed stepwise double-heating experiments, they yielded coherent results in the multisample method for all sites but one. The coherent sites show low to moderate field intensities between 5.7±0.2 and 26.4±0.7 μT (average 13.4±1.9 μT). Virtual dipole moments for these sites range from 1.3±0.04 to 6.0±0.2 × 1022 A m2 (average 2.9±0.5 × 1022 A m2). Our results agree with the tendency for low dipole moments during the Early Cretaceous, immediately prior to the Cretaceous Normal Superchron (CNS). The available paleointensity database shows a strong variability of the field between 80 and 160 Ma. There seems to be no firm evidence for a Mesozoic Dipole Low, but a long-term tendency does emerge from the data with the highest dipole moments occurring at the middle of the CNS.
Gilbert-Gauss geomagnetic reversal recorded in Pliocene volcanic sequences from Georgia (Lesser Caucasus): revisited
Authors: Goguitchaichvili Avto , Cervantes Miguel Angel , Rathert Manuel Calvo , Camps Pierre , Sologashvili Jemal , Maissuradze Givi 
Published: August 2014

Abstract
We carried out a detailed paleomagnetic, rock-magnetic, and Thellier paleointensity study of an ~3.6 My Pliocene lava flow succession in southern Georgia. An earlier study (Camps et al., 1996) revealed that several consecutive lava flows record an intermediate polarity direction at the base of the section followed by a thick reverse polarity zone. The transitional field was interpreted as an excursion within chron 2Ar or an upper Cochiti-Gilbert reversal. New paleomagnetic data reported here have been obtained from nearby lava successions. In total, about 170 standard paleomagnetic cores belonging to 22 lava flows were collected during the 2005 sample collection campaign. Rock-magnetic experiments showed that the remanence is carried by Ti-poor titanomagnetite in most of the samples. The fraction of grains with multidomain magnetic structure does not seem to be important. Characteristic remanent magnetization was successfully determined on all samples. The direct correlation with the original (Thoki) sequence, previous preliminary measurements of natural remanent magnetization (Sologashvili, 1986), and field observations allowed us to establish a new magnetic stratigraphy. The lower part of section is characterized by intermediate magnetic polarity followed by thick reversely magnetized lavas. The upper sequence, represented by 18 consecutive flows yielded normal magnetic polarity. The mean paleointensity of the intermediate field is drastically reduced with respect to the post-transitional field strength. Based on all available radiometric ages and new paleomagnetic data, it may be speculated that Gilbert-Gauss (R-N) reversal was recorded at the upper part of sequence. Lower intermediate polarity flows possibly represent a form of precursor of this reversal that is similar to the Matuyama-Brunhes geomagnetic transition.
Anisotropy of magnetic susceptibility analysis of the Cantera Ignimbrite, San Luis Potosi, México: flow source recognition
Authors: Caballero-Miranda C. I. , Torres-Hernández J. R. , Alva-Valdivia L. M. 
Published: August 2014

Abstract
Anisotropy of magnetic susceptibility (AMS) was selected as the key technique to find the source of the widespread Cantera Ignimbrite and to seek its possible relationship with the San Luis Potosí Caldera. Eighteen sites (372 specimens from 155 cores) from the Oligocene Cantera Ignimbrite were sampled. AMS was measured on a KLY2 Kappabridge. AMS data were processed with Anisoft 3 software using Jelinek statistics as well as ‘SpheriStat’ principal components and density distribution. Mean susceptibilities range from 290 to 5026 × 10-6 SI (average = 2526 × 10-6 SI). The anisotropy degree (P
j) ranges from 1.005 to 1.055, with only one site displaying a value of 1.134 (P
j average = 1.031). AMS ellipsoid shapes are mostly oblate, with the T-factor ranging from 0.843 to 0.144 (T average = 0.529), although one site is mainly prolate (T = -0.005), and three additional sites have an important proportion of prolate specimens. Magnetic fabrics of most sites shows k3 axes around nearly circular distributions and k
1-k
2 axes around elongated-girdle distributions defining sub-horizontal foliation planes; exceptions to this are related to sites with a significant percentage of prolate specimens. Flow directions inferred from AMS analysis indicate several ignimbrite sources located along selected NW-SE linear features (faults and fractures such as El Potosino Fault) as well as along the rim of the caldera structure. The geometry of volcanic outcrops, the NW-SE faulting-fracture system, as well as the AMS results suggest that this is a caldera structure resembling the trapdoor-type (Lipman, 1997).
Shear-wave splitting analysis of the upper mantle at the Niigata-Kobe Tectonic Zone with the data of the Joint Seismic Observations at NKTZ
Authors: Iidaka Takashi , Hiramatsu Yoshihiro ,   The Japanese University Group of the Joint Seismic Observations at NKTZ
Published: August 2014

AbstractWe conducted seismic observations with a spatially high density seismic network at the Niigata-Kobe Tectonic Zone, central Japan. The seismic network was used for the analysis of shear-wave splitting. Large lateral variations were found in the polarization direction data: the northern part of the research area yields polarization directions ofNW-SE (Region A), the central part of the research area with the polarization direction of NNE-SSW (Region B), the eastern part of the research area with the polarization direction of NE-SW (Region C), and the southern part of the research area with the polarization direction of E-W (Region D). The polarization directions in Regions B and C could be explained by the preferred orientation of olivine caused by the flow of the subducting Philippine Sea plate. However, the cause of anisotropic region which was related to the heterogeneous structure was also plausible. The polarization direction in Region A might be related to the flow caused by both of the subducting Philippine Sea and Pacific slabs. The polarization direction at the Region D could not be produced by the flow in the wedge and might be related to an anisotropic region beneath the slab. The lateral variation of the polarization direction does not support a model that the NKTZ is a collision region.