A synthetic seismicity model for the Xianshuihe fault, southwestern China: simulation using a rate- and state-dependent friction law   总被引：1，自引：0，他引：1  

Naoyuki Kato  Xinglin Lei  Xueze Wen 《Geophysical Journal International》2007,169(1):286-300

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Estimating groundwater storage changes in the Mississippi River basin (USA) using GRACE   总被引：7，自引：0，他引：7  

Matthew Rodell  Jianli Chen  Hiroko Kato  James S. Famiglietti  Joe Nigro  Clark R. Wilson 《Hydrogeology Journal》2007,15(1):159-166

Based on satellite observations of Earth’s time variable gravity field from the Gravity Recovery and Climate Experiment (GRACE), it is possible to derive variations in terrestrial water storage, which includes groundwater, soil moisture, and snow. Given auxiliary information on the latter two, one can estimate groundwater storage variations. GRACE may be the only hope for groundwater depletion assessments in data-poor regions of the world. In this study, soil moisture and snow were simulated by the Global Land Data Assimilation System (GLDAS) and used to isolate groundwater storage anomalies from GRACE water storage data for the Mississippi River basin and its four major sub-basins. Results were evaluated using water level records from 58 wells set in the unconfined aquifers of the basin. Uncertainty in the technique was also assessed. The GRACE-GLDAS estimates compared favorably with the well based time series for the Mississippi River basin and the two sub-basins that are larger than 900,000 km². The technique performed poorly for the two sub-basins that have areas of approximately 500,000 km². Continuing enhancement of the GRACE processing methods is likely to improve the skill of the technique in the future, while also increasing the temporal resolution.  相似文献   

Application of random walk theory to the first-order Fermi acceleration in shock waves     

T. N. Kato  F. Takahara 《Monthly notices of the Royal Astronomical Society》2001,321(4):642-660

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Expulsion of geopressured hydrothermal system along active faults and its relation to the occurrence of earthquakes in the Shinanogawa seismic belt,Japan   总被引：2，自引：0，他引：2  

Yasue Oki  Osamu Sato 《中国科学D辑(英文版)》2005,48(2):273-281

The 1995 Northern Niigata Earthquake (M 6.0) occurred at a shallow depth in the Niigata seismic gap. The anomaly areas in temperature, electrical conductivity and Cl- concentration of groundwater trend northeast as linear distribution in the epicentral area and are approximately coincident with the area of the seismic intensity 6 (JMA scale). The distributions of seismic intensity 6 and groundwater anomalies convincingly imaged the presence of a buried active fault beneath the epicentral area. The occurrence of this earthquake and the anomalies of groundwater were related to the expulsion of geopressured hydrothermal system (GHS). All epicenters of the destructive earthquakes along the Shinanogawa seismic belt are actually located in the buried active fault zones characterized by the areas of temperature and geochemical anomalies of groundwater. These earthquakes might have been triggered by the activity of GHS. The expulsion of GHS along an active fault in combination with the thermal softening of fault  相似文献   

A deep near-infrared survey around the giant radio galaxy PKS 1343–601     

T. Nagayama  P. A. Woudt  C. Nagashima  Y. Nakajima  D. Kato  M. Kurita  T. Nagata  H. Nakaya  M. Tamura  K. Sugitani  K. Wakamatsu  S. Sato 《Monthly notices of the Royal Astronomical Society》2004,354(4):980-990

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Infall of gas from intergalactic space and soft x-ray background     

Makoto Tosa  Takako Kato 《Astrophysics and Space Science》1972,18(2):504-513

As the origin of the soft X-ray background, emission of soft X-rays from shocks occurred in the accretion of intergalactic gas onto the Galaxy is studied. Infall of discrete gas clouds cannot explain the diffuse component of soft X-rays. If intergalactic gas rich in heavy elements as the cosmic abundance continously flows into the Galaxy and forms a standing shock surrounding the Galaxy, the line emissions by heavy elements from the shocked gas explain the soft X-ray background. Formation of the high velocity cloud by thermal instability in the shocked gas is also discussed briefly.  相似文献   

Inversion of GPS velocity and seismicity data to yield changes in stress in the Japanese Islands     

Takeshi Iinuma  Teruyuki Kato  Muneo Hori 《Geophysical Journal International》2005,160(2):417-434

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藏北高原草甸下垫面近地层能量输送及微气象特征   总被引：61，自引：9，他引：52  

马耀明  塚本修  吴晓鸣  玉川一郎  王介民  石川裕彦  胡泽勇  高洪春 《大气科学》2000,24(5):715-722

利用GAME/Tibet 1998年IOP观测资料,分析研究藏北高原草甸下垫面近地层的地面加热场、地表能量平衡、地面阻曳系数CD及感热通量整体输送系数CH等特征,得到了一些有关藏北高原草甸下垫面近地层能量输送及微气象特征结构的新认识.  相似文献   

Rb–Sr and Sm–Nd isotopic studies of mafic igneous rocks from the Ryoke plutono-metamorphic belt in the Setouchi area, Southwest Japan: implications for the genesis and thermal history     

Osamu Okano  Takeharu Sato †  Hiroo Kagami ‡ 《Island Arc》2000,9(1):21-36

Abstract Rb–Sr and Sm–Nd isochron ages were determined for whole rocks and mineral separates of hornblende‐gabbros and related metadiabases and quartz‐diorite from Shodoshima, Awashima and Kajishima islands in the Ryoke plutono‐metamorphic belt of the Setouchi area, Southwest Japan. The Rb–Sr and Sm–Nd whole‐rock‐mineral isochron ages for six samples range from 75 to 110 Ma and 200–220 Ma, respectively. The former ages are comparable with the Rb–Sr whole‐rock isochron ages reported from neighboring Ryoke granitic rocks and are thus due to thermal metamorphism caused by the granitic intrusions. On the contrary, the older ages suggest the time of formation of the gabbroic and related rocks. The initial ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd ratios of the gabbroic rocks (0.7070–0.7078 and 0.51217–0.51231 at 210 Ma, respectively) are comparable with those of neighboring late Cretaceous granites and lower crustal granulite xenoliths from Cenozoic andesites in this region. Because the gabbroic rocks are considered to be fragments of the lower crustal materials interlayered in the granulitic lower crust, their isotopic signature has been inherited from an enriched mantle source or, less likely, acquired through interaction with the lower crustal materials. The Sr and Nd isotopic and petrologic evidence leads to a plausible conclusion that the gabbroic rocks have formed as cumulates from hydrous mafic magmas of light rare earth element‐rich (Sm/Nd < 0.233) and enriched isotopic (?_Sr > 0 and ?_Nd < 0) signature, which possibly generated around 220–200 Ma by partial melting of an upper mantle. We further conclude that they are fragments of refractory material from the lower crust caught up as xenoblocks by granitic magmas, the latter having been generated by partial melting of granulitic lower crustal material around 100 Ma.  相似文献   

Ugandan geosites          下载免费PDF全文

A. Schumann  A. Muwanga  T. Lehto  M. Staudt  T. Schlüter  V. Kato  A. Namboyera 《Geology Today》2015,31(2):59-67

Geosites are important and/or unique geological or geographical features of significance. Typically they comprise geological, palaeontological, as well as archaeological sites. Geosites should be regarded as deserving to be preserved and protected, either from the elements or from destructive human activities, both for the community and future generations. A good knowledge of geological heritage, and a healthy respect for it, is an important factor in the holistic approach for sustainable development. Very often, these sites bear a multi‐faceted ‘story’, which may date back from very recent times to billions of years ago. As such, geosites are of great educational and scientific value. In Africa, such sites have not been receiving the attention they deserve. Only a few countries on the continent acknowledge their importance. Within the framework of a Sustainable Management of Mineral Resources Project (SMMRP), geological mapping, geochemical surveys and mineral resources assessment in selected areas of Uganda have been completed under the umbrella of the Geological Survey of Finland (GTK), and the Department of Geological Survey and Mines (DGSM, Uganda). Apart from recording ‘hard‐tough’ geology, 62 geosites were documented in 2010 and 2011. For the first time, such sites have been incorporated in the new geological maps of the country (at a scale of 1: 250 000). It is possible that this is the first time that such places have been shown on geological maps of Africa. Currently, the extreme north‐east of the country is being geologically mapped by DGSM, with the eventuality of more possible geosites being discovered.  相似文献