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Ogata, Manabu; Komatsu, Tetsuya; Nakanishi, Toshimichi*
Earth, Planets and Space (Internet), 76, p.123_1 - 123_11, 2024/09
Times Cited Count：0 Percentile：0.00(Geosciences, Multidisciplinary)Marine terraces developed along the southeastern coast of Kii Peninsula, southwestern Japan, face a seismogenic region along the Nankai Trough. We determined the emergence age of one of these marine terraces by using feldspar OSL dating of the marine terrace sediments. The target marine terrace has previously been correlated with MIS 5e on the basis of morphostratigraphy. Samples for pIRIR dating were obtained from foreshore deposits of the marine terrace. pIRIR signals were measured at 150 
C (pIRIR
) and 225 C (pIRIR
). These results show that the surface of the marine terrace corresponds to MIS 5e rather than MIS 5c or 7, which is consistent with the chronological framework based on the morphological features of the terraces in this study area.
Zwingmann, H.*; Niwa, Masakazu; Todd, A.*; Saunders, M.*
Earth, Planets and Space (Internet), 76(1), p.27_1 - 27_16, 2024/02
Times Cited Count：0 Percentile：0.00(Geosciences, Multidisciplinary)Atera fault zone clay gouges were collected for age dating from a river section near Kawaue, Nakatsugawa city, central Japan and the results integrated within its complex geological history. The results from the Atera Fault form an internally consistent data set with constraints from existing geochronological data (AFTA, ZFTA, CHIME) and demonstrate the application of gouge dating in providing new data to constrain timing of brittle deformation in Central Japan.
Nakajima, Toru; Sueoka, Shigeru; Nagata, Mitsuhiro; Kohn, B. P.*; Ramos, N. T.*; Tsutsumi, Hiroyuki*; Tagami, Takahiro*
Earth, Planets and Space (Internet), 75(1), p.176_1 - 176_11, 2023/12
Times Cited Count：1 Percentile：24.68(Geosciences, Multidisciplinary)Geo- and thermochronological methods were applied to dioritic rocks from the Cordillera Central, Luzon, Philippines, to understand their emplacement and exhumation history in the island arc mountains. Zircon U-Pb ages range from 32.54 
0.70 to 6.11 0.15 (2SE) Ma, indicating that dioritic magmas intruded the middle and upper crust intermittently during Tertiary magmatism. Zircon fission-track (ZFT) pooled ages range from 35.63 2.17 to 6.91 0.36 (2SE) Ma, and are generally comparable with the U-Pb ages at each locality. These results suggest that the diorites cooled rapidly below 250-350 degree, (i.e. through the partial annealing zone of the ZFT system), following their intrusion. On the other hand, the zircon and apatite (U-Th-Sm)/He (ZHe and AHe) weighted mean ages, ranging from 11.71 0.36 to 8.82 0.26 and 9.21 0.52 to 0.98 0.088 (2SE) Ma respectively, indicate a decrease in cooling rates at a lower temperature range, especially through the partial retention zone of the AHe system. This observation suggests that the ZFT ages reflect initial cooling of the dioritic magma, whereas the AHe ages reflect the cooling history associated with regional exhumation following the initial cooling phase. Spatial distribution of the AHe ages suggest that rapid exhumation of the Cordillera Central during the Quaternary resulted from the block-like uplift of the entire mountain range.
Sueoka, Shigeru; Iwano, Hideki*; Danhara, Toru*; Niwa, Masakazu; Kanno, Mizuho; Kohn, B. P.*; Kawamura, Makoto; Yokoyama, Tatsunori; Kagami, Saya; Ogita, Yasuhiro; et al.
Earth, Planets and Space (Internet), 75(1), p.177_1 - 177_24, 2023/12
Times Cited Count：0 Percentile：0.00(Geosciences, Multidisciplinary)Fluid-inclusion and thermochronometric analyses have been applied to hydrothermal alteration zones and their host rocks outcropping in the Hongu area of the Kii Peninsula, southwestern Japan in an attempt to detect thermal anomalies related to hydrothermal events and quantify the thermal effects on the host rocks. Hydrothermal events at ca 150 deg. C and ca 200 deg. C were identified by fluid-inclusion microthermometry of quartz veins in the alteration zones. For the host rocks and alteration zones, in the youngest population zircon yielded U-Pb dates ranging between ca 74.7-59.2 Ma, fission-track dates of ca 27.2-16.6 Ma, and (U-Th)/He single-grain dates of ca 23.6-8.7 Ma. Apatite yielded pooled fission-track ages of ca 14.9-9.0 Ma. The zircon U-Pb dates constrain the maximum depositional ages of the sedimentary samples. However, the fission-track and (U-Th)/He dates show no clear trend as a function of distance from the alteration zones. Hence, no thermal anomaly was detected in the surrounding host rocks based on the thermochronometric data patterns. The fission-track and (U-Th)/He dates are rather thought to record regional thermal and exhumation histories rather than a direct thermal imprint of fluid flow, probably because the duration of such activity was too short or because fluid flow occurred before regional cooling events and were later thermally overprinted. Apatite fission-track ages of ca 10 Ma may reflect regional mountain uplift and exhumation related to the obduction of the SW Japan lithospheric sliver onto the Shikoku Basin, or the rapid subduction of the Philippine Sea slab associated with the clockwise rotation of the Southwest Japan Arc.
Minami, Saki*; Nagata, Mitsuhiro; Sueoka, Shigeru; Fukuda, Shoma; Kajita, Yuya*; Ogita, Yasuhiro; Kagami, Saya; Yokoyama, Tatsunori; Tagami, Takahiro*
Earth, Planets and Space (Internet), 73(1), p.231_1 - 231_7, 2021/12
Times Cited Count：1 Percentile：5.16(Geosciences, Multidisciplinary)Saito, Susumu*; Wickramasinghe, N. K.*; Sato, Tatsuhiko; Shiota, Daiko*
Earth, Planets and Space (Internet), 73(1), p.57_1 - 57_10, 2021/12
Times Cited Count：7 Percentile：41.20(Geosciences, Multidisciplinary)By using an flight trajectory generation algorithm and the global effective dose rate (EDR) distribution calculated WASAVIES, the economic impacts of SEP events on aircraft operation, namely the flight path length, flight time, and fuel consumption, are estimated. The flight path length, flight time, and fuel consumption for a flight route from New York, US to Tokyo, Japan are estimated with constraints in flight routes to avoid the hazard of radiation and compared with those of the reference case without the SEP effects. Setting more flexible constraints in the flight route and generating optimal flight trajectories with minimal economic impacts by fully utilizing the global EDR distribution is the next step.
Ishii, Mamoru*; Shiota, Daiko*; Tao, Chihiro*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Ishii, Takako*; Ichimoto, Kiyoshi*; Kataoka, Ryuho*; Koga, Kiyokazu*; Kubo, Yuki*; et al.
Earth, Planets and Space (Internet), 73(1), p.108_1 - 108_20, 2021/12
Times Cited Count：10 Percentile：55.47(Geosciences, Multidisciplinary)We surveyed the relationship between the scale of space weather events and their occurrence rate in Japan and we discussed the social impact of these phenomena during the Project for Solar-Terrestrial Environment Prediction (PSTEP). The information was compiled for domestic users of space weather forecasts for appropriate preparedness against space weather disasters. This paper gives a comprehensive summary of the survey, focusing on the fields of electricity, satellite operations, communication and broadcasting, satellite positioning usage, aviation, human space activity, and daily life on the Earth's surface, using the cutting-edge knowledge of space weather. Quantitative estimations of the economic impact of space weather events on electricity and aviation are also given.
Barucci, M. A.*; Reess, J.-M.*; Bernardi, P.*; Doressoundiram, A.*; Fornasier, S.*; Le Du, M.*; Iwata, Takahiro*; Nakagawa, Hiromu*; Nakamura, Tomoki*; Andr
, Y.*; et al.
Earth, Planets and Space (Internet), 73(1), p.211_1 - 211_28, 2021/12
Times Cited Count：21 Percentile：81.33(Geosciences, Multidisciplinary)The MMX InfraRed Spectrometer (MIRS) is an imaging spectrometer on board of MMX JAXA mission. MIRS is built at LESIA-Paris Observatory in collaboration with four other French laboratories, collaboration and financial support of CNES and close collaboration with JAXA and MELCO. The instrument is designed to fully accomplish MMX's scientific and measurement objectives. MIRS will remotely provide near-infrared spectral maps of Phobos and Deimos containing compositional diagnostic spectral features that will be used to analyze the surface composition and to support the sampling site selection. MIRS will also study Mars atmosphere, in particular to spatial and temporal changes such as clouds, dust and water vapor.
Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：7 Percentile：41.20(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
Fukuda, Shoma*; Sueoka, Shigeru; Kohn, B. P.*; Tagami, Takahiro*
Earth, Planets and Space (Internet), 72(1), p.24_1 - 24_19, 2020/12
Times Cited Count：6 Percentile：29.87(Geosciences, Multidisciplinary)no abstracts in English
Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.
Earth, Planets and Space (Internet), 71(1), p.9_1 - 9_10, 2019/12
Times Cited Count：10 Percentile：40.82(Geosciences, Multidisciplinary)Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of 
10 keV.
Matsuoka, Moe*; Nakamura, Tomoki*; Osawa, Takahito; Iwata, Takahiro*; Kitazato, Kohei*; Abe, Masanao*; Nakauchi, Yusuke*; Arai, Takehiko*; Komatsu, Mutsumi*; Hiroi, Takahiro*; et al.
Earth, Planets and Space (Internet), 69(1), p.120_1 - 120_12, 2017/12
Times Cited Count：6 Percentile：19.09(Geosciences, Multidisciplinary)We have conducted ground-based performance evaluation tests of the Near-Infrared Spectrometer (NIRS3) onboard Hayabusa2 spacecraft and established a method for evaluating its measured reflectance spectra. Reflectance spectra of nine powdered carbonaceous chondrite samples were measured by both NIRS3 and a FT-IR spectrometer. Since raw data obtained by NIRS3 had considerable spectral distortion caused by systematic offsets in sensitivity of individual pixels, we have established two methods for correcting the NIRS3 data by comparing them with the corresponding FT-IR data. In order to characterize the absorption bands in NIRS3 spectra, the depth of each band component D
is defined for each wavelength (
m). Reflectance spectra of asteroid Ryugu, the target asteroid of Hayabusa2, to be recorded by the NIRS3 are expected to reveal the characteristics of the surface materials by using the evaluation technique.
Sueoka, Shigeru; Tagami, Takahiro*; Kohn, B.*
Earth, Planets and Space (Internet), 69(1), p.79_1 - 79_18, 2017/12
Times Cited Count：10 Percentile：31.81(Geosciences, Multidisciplinary)no abstracts in English
Kubo, Yuki*; Kataoka, Ryuho*; Sato, Tatsuhiko
Earth, Planets and Space (Internet), 67(1), p.117_1 - 117_13, 2015/12
Times Cited Count：13 Percentile：36.03(Geosciences, Multidisciplinary)One of the extreme space weather phenomena are solar energetic particles (SEPs). The huge SEP event causes a radiation dose enhancement to aircrews to be warned as soon as possible. To warn a radiation dose enhancement to aircrew, we have tried to develop warning system for radiation exposure to solar energetic particles. This article describes one component of the system, which calculates temporal evolution of SEP intensity and spectrum just outside the terrestrial magnetosphere.
Kato, Aitaro*; Saiga, Atsushi; Takeda, Tetsuya*; Iwasaki, Takaya*; Matsuzawa, Toru*
Earth, Planets and Space (Internet), 66(1), p.86_1 - 86_8, 2014/12
Times Cited Count：24 Percentile：55.65(Geosciences, Multidisciplinary)To understand the mechanism of an intensive non-volcanic seismic swarm in the Kii Peninsula, Japan, we used a dense seismic linear array to measure fine-scale variations of seismic velocities and converted teleseismic waves. A low-velocity anomaly confined to just beneath the seismic swarm area is clearly imaged, which spatially correlates with an uplifted surface area, and a highly conductive and strong attenuative body. These results suggest that fluids such as partial melt or water are present beneath this non-volcanic seismic swarm area. It is notable that the island arc Moho below the seismic swarm area is at depths of ca. 32 km in the northern part of the seismic swarm area, and shallows to ca. 20 km towards the south, due to an upwardly raised structure of serpentinized mantle wedge. In addition, we show that hydrated oceanic crust of the subducting Philippine Sea slab is characterized by low-velocities with a high Poisson's ratio at depths shallower than 40 km. Water released from the subducting oceanic crust could cause serpentinization of the mantle wedge and infiltration into the forearc base of the overlying plate. The interaction between dehydration of the subducting oceanic crust and hydration of the mantle wedge and overlying plate exerts an important role in driving the non-volcanic seismic swarm activity in the Kii Peninsula.
Ogawa, Yasuo*; Ichiki, Masahiro*; Kanda, Wataru*; Mishina, Masaaki*; Asamori, Koichi
Earth, Planets and Space (Internet), 66(1), p.158_1 - 158_13, 2014/12
Times Cited Count：81 Percentile：91.19(Geosciences, Multidisciplinary)We have analyzed three-dimensional resistivity structure around Naruko volcano, NE Japan. From the inversion of full tensor components, the following model features are found. Sub-vertical conductors exist at Naruko volcanoes below a depth of few kilometers. The conductor reaches to the surface of Naruko volcano and deepens southward away from the volcano along the backbone ranges. High seismicity in the upper crust is observed above and around the conductors. This implies that the seismicity is fluid-driven and also that the fluid trap is created by the precipitation of quartz due to loss of solubility at shallow depth.
Tanaka, Toshiyuki*; Miyajima, Rikio*; Asai, Hideaki*; Horiuchi, Yasuharu; Kumada, Koji; Asai, Yasuhiro*; Ishii, Hiroshi*
Earth Planets and Space, 65(2), p.59 - 66, 2013/02
Times Cited Count：9 Percentile：24.42(Geosciences, Multidisciplinary)Osawa, Takahito; Hirao, Norie; Takeda, Nobuyori*; Baba, Yuji
Earth Planets and Space, 61(8), p.1003 - 1011, 2009/10
Times Cited Count：4 Percentile：12.37(Geosciences, Multidisciplinary)To verify that kerogen is a carrier phase of Q-noble gases, XAS and XPS using synchrotron radiation were carried on for kerogens (coals) and carbon allotropes that had been bombarded by 3-keV Ar ions, and the Ar retentivities of the two materials were compared. This comparison of the estimated Ar concentrations in the target materials revealed that carbon allotropes (graphite, fullerene, carbon nanotube, and diamond) have a much higher Ar retentivity than kerogens. This unexpected result clearly shows that the terrestrial kerogens tested in our study are not suitable as a carrier phase of Ar and, consequently, that phase Q may not be similar to the terrestrial kerogen tested. If heavy noble gases are really concentrated in carbonaceous components of primitive meteorites, phase Q may have a more ordered structure than terrestrial kerogen based on the fact that the greatest difference between terrestrial kerogen and carbon allotropes is the degree of order of the molecular structure.
Kudo, Takeshi; Yamamoto, Akihiko*; Nohara, Tsuyoshi; Kinoshita, Hirohisa; Shichi, Ryuichi*
Earth Planets and Space, 56(5), p.e5 - e8, 2004/00
Times Cited Count：7 Percentile：19.84(Geosciences, Multidisciplinary)We investigate whether distributions of topographic lineaments in Chugoku district, Japan, may be related to variations of standard deviation (SD) of gravity anomalies. Tectonic movement may disturb lateral continuities of crustal structures at weak zones. These lateral discontinuities of the density structure cause undulations of gravity anomaly fields whose complexities can be an indicator of the past crustal instability. On the other hand, topographic lineaments are formed along weak crustal zones. We would expect therefore that the gravity anomaly complexities have some relations to distributions of surface lineaments. As an index of gravity anomaly complexities in terms of which we interpret spatial distribution of topographic lineaments, we employ Bouguer anomaly SD inside a circular region with adequate radius. The results show that locations of the lineaments, which could be diagnostic of heterogeneity of the previously damaged crust, tend to coincide with those of high SD area
Ito, Hisao; ;
Earth Planets and Space, 54, p.1055 - 1058, 2002/00
Times Cited Count：8 Percentile：23.22(Geosciences, Multidisciplinary)None
