| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2015-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume22 |
| Issue | issue1 |
| Content Type | Others |
| JaLCDOI | 10.18926/ESR/54119 |
|---|---|
| Title Alternative | Facies analysis of the Jito Formation ( Upper Triassic Nariwa Group ) in Jito Area, Kawakami, Okayama Pref., SWJapan. |
| FullText URL | esr_022_1_031_039.pdf |
| Author | Masaoka, Yuto| Suzuki, Shigeyuki| |
| Abstract | Facies analysis and analysis of stratigraphy together with folded structure of the Norian Jito Formation were studied in Jito Area, Kawakami, Okayama Pref., SW Japan. Results of regional mapping and measured sections reconstruct three-dimensionally distribution of the Jito Formation. The Jito Formation is sub-divided into the four new members; the Shimohira Muddy Sandstone Member, the Otofuji Coarse-grained Turbidite Member, the Misawa Fine-grained Turbidaite Member, and the Ide Conglomerate Sandstone Member in ascending order. The shimohira Muddy Sandstone Member is interpreted to be deposited in an inner-bay. The Otofuji Coarse-grained Turbidite Member and The Misawa Fine-grained Turbidite Member are considered to be deposited on a continental shelf. The Ide Conglomerate Sandstone Member is inferred to be a shallow marine deposit. As a result, the Jito Formation is regarded as one transgressive-regressive package. |
| Keywords | Jito Formation Nariwa Group Norian facies analysis turbidite |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2015-12-27 |
| Volume | volume22 |
| Issue | issue1 |
| Start Page | 31 |
| End Page | 39 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2015 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005728631 |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2015-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume22 |
| Issue | issue1 |
| Content Type | Others |
| JaLCDOI | 10.18926/ESR/54117 |
|---|---|
| Title Alternative | Petrography of foundation stones of the Bizen Kokubunji Temple, Okayama Prefecture, Japan ―an attempt to identify their collected site― |
| FullText URL | esr_022_1_025_030.pdf |
| Author | Suzuki, Shigeyuki| Nishimura, Norihide| Ariga, Yuji| |
| Abstract | The Bizen Kokubunji Temple was constructed in the 8th century, in Maya, Akaiwa City, Okayama. Only foundation stones are preserved. Geological characteristics of the foundation stones suggest that they are collected from mountain area of Maya, about 300 to 800m west from the site. The similarity of the foundation stones and the rocks Maya are identified by the following characteristics. 1) Assemblage of rock types (high grade welded tuff breccia, tuff breccia, tuffaceous sandstone and conglomerate) are the same. 2) Lithology of the 3 rock type of the foundation stones and the rocks from Maya are the same. 3) Rheomorphic flow structures are developed in both high grade welded tuff breccia. 4)Mudstone fragments are contained in both high grade welded tuff breccia tuff breccia. |
| Keywords | Bizen Kokubunji Temple foundation stone collected site Okayama |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2015-12-27 |
| Volume | volume22 |
| Issue | issue1 |
| Start Page | 25 |
| End Page | 30 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2015 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005728630 |
| JaLCDOI | 10.18926/ESR/54116 |
|---|---|
| Title Alternative | Application of simulated annealing to focal mechanism determination |
| FullText URL | esr_022_1_009_023.pdf |
| Author | Komatsu, Masanao| Takenaka, Hiroshi| |
| Abstract | Simulated annealing (SA) is known as one of the efficient methods for global optimization. It allows for getting an optimal solution by jumping out of local minimum. In this paper, we apply the simulated annealing to determination of focal mechanism solution. To investigate the feasibility of the application, we determine focal mechanism solution of the 14 March 2014 Iyo-Nada intermediatedepth earthquake. The computation of SA method is then 1278 times faster than that of the grid search method. |
| Keywords | focal mechanism solution |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2015-12-27 |
| Volume | volume22 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 23 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2015 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005728632 |
| JaLCDOI | 10.18926/ESR/54115 |
|---|---|
| Title Alternative | The effect of the seismic attenuation on the S-wave polarization anisotropy |
| FullText URL | esr_022_1_001_007.pdf |
| Author | Oda, Hitoshi| |
| Abstract | We investigate the effect of the seismic attenuation on the shear-wave polarization anisotropy by numerical experiments. For the experiments, the P-wave receiver functions are synthesized by assuming that a plane P wave is incident on an anisotropic multi-layer structure with anelastic properties. The synthetic receiver function shows smooth Ps phase waveforms with small amplitudes due to the attenuation of high-frequency spectral components, compared to that calculated for a multi-layer structure with perfect elasticity. From the shear-wave splitting of the Ps converted phases in the synthetic receiver functions, the S-wave polarization anisotropies for the anisotropic layers are measured as a function of propagation direction of the incident P wave. Consequently, we conclude that the seismic attenuation has a minor influence on the measurements of the S-wave polarization anisotropy. |
| Keywords | shear-wave polarization anisotropy shear-wave splitting seismic attenuation Psconverted phase P-wave receiver function |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2015-12-27 |
| Volume | volume22 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 7 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2015 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005728633 |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2015-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume22 |
| Issue | issue1 |
| Content Type | Others |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2014-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume21 |
| Issue | issue1 |
| Content Type | Others |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2014-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume21 |
| Issue | issue1 |
| Content Type | Others |
| JaLCDOI | 10.18926/ESR/53196 |
|---|---|
| Title Alternative | Precipitation characteristics and large-scale atmospheric fields on the heavy rainfall days in the eastern part of Japan (Climatological features in midsummer and the supplemental study for the Baiu season) |
| FullText URL | esr_021_1_033_043.pdf |
| Author | Matusmoto, Kengo| Kato, Kuranoshin| Otani, Kazuo| |
| Abstract | Rainfall characteristics and large-scale atmospheric fields on the “heavy rainfall days” (with more than 50mm/day) in midsummer, and so on, at Tokyo in the eastern Japan were examined for 1971 to 2010, succeeding to Matsumoto et al. (2013) The present study firstly examined the rainfall features and the atmospheric fields for the “heavy rainfall days” at Tokyo with rather lower appearance frequency than in the typhoon related patterns in Matsumoto et al. (2013) and so on. In these cases (three cases in total), although the synoptic situations were rather different among each other, they seem to occur under the systems with relatively small zonal scale associated with the great meander of the upper-level westerly wind. Next, the climatological analyses similar to Matsumoto et al. (2013) were performed for the "heavy rain days" at Tokyo in midsummer (1~31 August). The precipitation on the “heavy rainfall days” at Tokyo in midsummer was mainly brought by the intense rainfall with more than 10 mm/h, as in the western Japan in the mature stage of the Baiu season. The detailed examination of the rainfall features for the case on 10 August 2009, with use of the 10-minutes precipitation data and the Radar AMeDAS Composite Data by the JMA, revealed that the organized meso-β-scale convective rainfall systems as often appear in the western Japan in the mature stage of the Baiu season were just to the east of the typhoon, and brought the intense rainfall at Tokyo to result in the large daily precipitation. |
| Keywords | rainfall characteristics in eastern Japan heavy rainfall in eastern Japan in the Baiu and midsummer seasons rainfall climatology |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2014-12-27 |
| Volume | volume21 |
| Issue | issue1 |
| Start Page | 33 |
| End Page | 43 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2014 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005567874 |
| JaLCDOI | 10.18926/ESR/53195 |
|---|---|
| Title Alternative | A preliminary study on the seasonal cycles of the cyclone activity and the large-scale fields in Europe at the viewpoint comparing with those in East Asia |
| FullText URL | esr_021_1_023_032.pdf |
| Author | Takigawa, Yumi| Haga, Yuichi| Matsumoto, Kengo| Kato, Kuranoshin| |
| Abstract | Preliminary analyses on the seasonal cycles of the large-scale atmospheric mean fields and the cyclone activity in Europe were performed based mainly on the NCEP/NCAR re-analysis data, at the viewpoint comparing with those in East Asia. As for the climatological monthly mean fields (1981~2010), the meridional temperature gradient in East Asia presents striking seasonal change with the maximum in winter and the minimum in summer. It is interesting that such transition from winter to summer and that from summer to winter occur rather rapidly accompanied by the great temperature increase around April to June and the decrease around October to November, respectively, in a wide region of 40~70N. On the other hand, the temperature gradient in Europe is significantly smaller with slight seasonal change than that in East Asian winter. By the way, in spite of the above difference of the horizontal temperature gradient between Europe and East Asia, the cyclone activity does not seem to be so weak even around Europe. Thus, the seasonal cycles of the characteristics of the cyclones and their environmental fields around Europe were examined. At the first step, we analyzed the daily cyclone activity in Europe for January and July of 2000. Many low pressure centers at the surface level appeared in both January and July. Referring also to the daily maps of sea level pressure and geopotential height at 500 hPa level, we found that not only the cyclones corresponding to the baroclinic instability waves, but also to the cold vortices which amplitudes increased with height appeared frequently. Moreover, it is interesting that the large-scale cold vortex, which embeds the shortwave trough with the low center at the surface level, appeared in the northern Europe in July as in East Asian winter, when such multi-scale systems sometimes bring the persisting heavy snowfall events in the Japan Sea side of the Japan Islands. |
| Keywords | seasonal cycle cyclone activity Europe and East Asia |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2014-12-27 |
| Volume | volume21 |
| Issue | issue1 |
| Start Page | 23 |
| End Page | 32 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2014 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005567874 |
| JaLCDOI | 10.18926/ESR/53194 |
|---|---|
| Title Alternative | Aerosol observation at Okayama with Skyradiometer and LIDAR |
| FullText URL | esr_021_1_013_021.pdf |
| Author | Nagamatsu, Sinpei| Egawa, Daiki| Tsukamoto, Osamu| |
| Abstract | Aerosol is one of the controlling parameter for the global climate and also effects on local health hazards. The measurement of the aerosol was originally carried out as in-situ sampling and mass weight measurement including chemical analysis. Recently, remote sensing method is applied as satellite remote sensing and surface based remote sensing. Skyradiometer and LIDAR are surface based remote sensing system. Skyradiometer measures solar radiation as direct and scattered solar radiation affected by aerosols. LIDAR emit laser beam upward and it is backscattered by overlying aerosols. The backscattered light is received by a telescope and vertical distributions of the aerosols are obtained. These measurements require atmospheric radiation physics. A Skyradiometer and a LIDAR were operated continuously at Okayama University campus and aerosol parameters were obtained from both of the system. Seasonal variations of the AOT (Aerosol Optical Thickness) and Angstrom parameter (α) are evaluated. During some dust events (e.g. yellow sand and PM2.5), time variations of these parameters were identified from both of the measurement system. |
| Keywords | Aerosol Skyradiometer LIDAR Aerosol Optical Thickness (AOT) |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2014-12-27 |
| Volume | volume21 |
| Issue | issue1 |
| Start Page | 13 |
| End Page | 21 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2014 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005567873 |
| JaLCDOI | 10.18926/ESR/53193 |
|---|---|
| Title Alternative | Paleoparadoxia from the middle Miocene of Obara, Misaki-cho, Okayama Prefecture, Japan |
| FullText URL | esr_021_1_007_011.pdf |
| Author | Fukuchi, Akira| Suzuki, Shigeyuki| |
| Abstract | The partially preserved left humerus of the Desmostylia (Mammalia) has been collected from the riverbed in Obara, Misaki-cho, Okayama Prefecture in the western Japan. This specimen can be classified to the genus Paleoparadoxia by the following features: the absence of the supratrochlear foramen; the curved disto-lateral border of the shaft in the antero-posterior view; the medio-laterally expanded flat trochlea of humerus. Moreover, this specimen can be referred to cf. P. media on the basis of its middle-sized dimensions. This is the second occurrence of Palaeoparadoxia from Okayama Prefecture. |
| Keywords | Middle Miocene mammal Desmostylia Paleoparadoxia |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2014-12-27 |
| Volume | volume21 |
| Issue | issue1 |
| Start Page | 7 |
| End Page | 11 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2014 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005567872 |
| JaLCDOI | 10.18926/ESR/53192 |
|---|---|
| Title Alternative | A high precision and high resolution estimation of the spatial distribution of PM2.5 in the south area of Okayama prefecture, Japan |
| FullText URL | esr_021_1_001_005.pdf |
| Author | Omori, Akiho| Yamakawa, Junji| |
| Abstract | A relatively high precision and high resolution spatial distribution of the PM2.5 in the south part of the Okayama prefecture, Japan was estimated by the Universal Kriging method and the FOSS4G GIS softwares. The observation data of the PM2.5 were obtained from the Environmental data service site of the Okayama prefecture. The geospatial open data about the research field that used in the research were served by the government research institutes. The spatial analysis were executed by the R (R core team, 2014) and its spatial libraries, maptools (Bivand and Lewin-Koh, 2014), rgdal (Bivand, Keitt and Rowlingson, 2014) and gstat (Pebesma, 2014). The geospatial representation and qualitative analysis of the estimated distribution were performed by the QGIS (QGIS Development Team, 2014) and the Google earth (Google, 2014). The time variant of the PM2.5 concentration by the each observatories in the area were show some cross correlation factor to the SPM10 concentration data. The estimated PM2.5 distribution seems to show that the relatively tight relation to the geospatial factors in the research area. The estimation of a time variant change of the PM2.5 distribution will be required of the further research.. |
| Keywords | PM2.5 Spatial statistics Kriging R-language gstat FOSS4G Google earth |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2014-12-27 |
| Volume | volume21 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 5 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2014 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005567871 |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2014-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume21 |
| Issue | issue1 |
| Content Type | Others |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2014-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume21 |
| Issue | issue1 |
| Content Type | Others |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2013-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume20 |
| Issue | issue1 |
| Content Type | Others |
| Author | Department of Earth Sciences, Faculty of Science, Okayama University| |
|---|---|
| Published Date | 2013-12-27 |
| Publication Title | Okayama University Earth Science Report |
| Volume | volume20 |
| Issue | issue1 |
| Content Type | Others |
| JaLCDOI | 10.18926/ESR/52167 |
|---|---|
| Title Alternative | Preliminary analyses on the climatological features of precipitation characteristics and large-scale atmospheric fields on the heavy rainfall days in the eastern part of Japan during the mature stage of the Baiu season |
| FullText URL | esr_020_1_025_034.pdf |
| Author | Matsumoto, Kengo| Kato, Kuranoshin| Otani, Kazuo| |
| Abstract | Rainfall characteristics and large-scale atmospheric fields on the “heavy rainfall days” (with more than 50 mm/day) in the mature stage of the Baiu season (16 June ~ 15 July) at Tokyo in the eastern part of the Japan Islands were examined, based on the daily and the hourly precipitation data from 1971 to 2010. Appearance frequency of the “heavy rainfall days” at Tokyo attained only about 1/3 of that at Nagasaki in the western Japan. Furthermore, it is noted that about half of the “heavy rainfall days” at Tokyo were related to the typhoon. In detail, about half of the typhoon cases were associated with the direct approach of a typhoon (referred to as Pattern A, hereafter), the other half corresponded to the situation when the Baiu front also stagnated around Kanto District with a typhoon to the southwest of Kanto (Pattern B). Although the contribution of the intense rainfall with more than 10 mm/h to the total precipitation was large in Pattern A, that with less than 10 mm/h was dominant in Patterns B and C (Pattern C: meso-α-scale cyclone on the Baiu front approaching to the Kanto District). It is noted that about half of the “heavy rainfall days” corresponded to these pattern. In other words, unlike the localized torrential rain in western Japan, the “heavy rainfall days” due to the duration of “not-so-intense-rain” appeared rather frequently in the eastern part of Japan even in the Baiu season. In both Patterns B and C, relatively strong low-level southerly wind associated with the disturbance (a typhoon or a meso-α-scale cyclone) invades into the baroclinic zone in the basic field sustained as the sowthwestern edge of the cool Okhotsk air mass. It is interesting that the “heavy rainfall days” there due to the contribution of the persistent “not-so-intense-rain” occur just in such situation. |
| Keywords | rainfall characteristics in eastern Japan heavy rainfall in eastern Japan in Baiu season rainfall climatology |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2013-12-27 |
| Volume | volume20 |
| Issue | issue1 |
| Start Page | 25 |
| End Page | 34 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2013 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005394595 |
| JaLCDOI | 10.18926/ESR/52166 |
|---|---|
| Title Alternative | A case study on the rainfall distribution over the Japan Islands associated with the approach of Ty0423 in late October (Comparison with that for Ty0418) |
| FullText URL | esr_020_1_013_024_rev.pdf |
| Author | Satake, Ai| Kato, Kuranoshin| Mori, Yoshinori| Goda, Yasuhiro| Ikeda, Shoichiro| Tsukamoto, Osamu| |
| Abstract | Rainfall distribution in the Japan Islands associated with the approach of Typhoon No.23 around 20 October 2004 (referred to Ty0423, hereafter) showed considerably different features from those in late summer of this year. The present study examined the detailed rainfall features around the Japan Islands brought by Ty0423 and the atmospheric processes based on the operational observation data by the Japan Meteorological Agency (JMA), comparing with those in association with Ty0418 around 7 September 2004. During the stage when Ty0423 was approaching or landing on the western part of the Japan Islands, the areal mean precipitation from Kyushu to Kanto District attained much larger than that for Ty0418, with wider extension of the area with the large amount of precipitation. It is interesting that, although the intense rainfall was observed only at the upstream side of the mountain range from Kyushu to Honshu District for Ty0418 except for the area near its center, strong rainfall with 10~30 mm/h persisted in wider regions from the western to the eastern part of the Japan Islands, resulting in the considerably large total rainfall for Ty0423. As for the case for Ty0423, the surface front with stable frontal surface was located just to the east of the Ty0423 center just before its landing at the Japan Islands. Thus, the huge moisture inflow mainly in the eastern region from the typhoon center seems to be redistributed widely over the Japan Islands area associated with the large-scale convergence around the stable frontal surface. In late October, the colder air associated with the high pressure system in the eastern Siberia can cover the northern part of the Japan Sea area as the seasonal march. Such basic field might be favorable for sustaining the synoptic-scale front just around the southern coast of the Japan Islands, even when the strong southerly wind invades associated with the typhoon approach there. |
| Keywords | Ty0423 Ty0418 rainfall in Japan associated with a typhoon in mid-autumn effects of a typhoon on the synoptic climatology in Japan in October |
| Publication Title | Okayama University Earth Science Report |
| Published Date | 2013-12-27 |
| Volume | volume20 |
| Issue | issue1 |
| Start Page | 13 |
| End Page | 24 |
| ISSN | 1340-7414 |
| language | Japanese |
| Copyright Holders | © 2013 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| File Version | publisher |
| NAID | 120005394594 |
