Modeling the potential distribution of shallow-seated landslides using the weights of evidence method and a logistic regression model： a case study of the Sabae Area, Japan   总被引：5，自引：0，他引：5  

Ru-Hua SONG  Daimaru HIROMU  Abe KAZUTOKI  Kurokawa USIO  Matsuura SUMIO 《国际泥沙研究》2008,23(2):106-118

A number of statistical methods are typically used to effectively predict potential landslide distributions. In this study two multivariate statistical analysis methods were used （weights of evidence and logistic regression） to predict the potential distribution of shallow-seated landslides in the Kamikawachi area of Sabae City, Fukui Prefecture, Japan. First, the dependent variable （shallow-seated landslides） was divided into presence and absence, and the independent variables （environmental factors such as slope and altitude） were categorized according to their characteristics. Then, using the weights of evidence （WE） method, the weights of pairs comprising presence （w^＋（i）） or absence （w^-（i））, and the contrast values for each category of independent variable （evidence）, were calculated, Using the method that integrated the weights of evidence method and a logistic regression model, score values were calculated for each category of independent variable. Based on these contrast values, three models were selected to sum the score values of every gird in the study area. According to a receiver operating characteristic curve analysis （ROC）, model 2 yielded the best fit for predicting the potential distribution of shallow-seated landslide hazards, with 89% correctness and a 54.5% hit ratio when the occurrence probability （OP） of landslides was 70%. The model was tested using data from an area close to the study region, and showed 94% correctness and a hit ratio of 45.7% when the OP of landslides was 70%. Finally, the potential distribution of shallow-seated landslides, based on the OP, was mapped using a geographical information system.  相似文献   

Climate control on Venus: Comparison of the carbonate and pyrite models     

George L. Hashimoto  Yutaka Abe 《Planetary and Space Science》2005,53(8):839-848

We review two models describing the Venus climate system: the carbonate and pyrite models. It has been argued carbonate and pyrite are potentially important minerals controlling the climate of Venus, though existence of either minerals has not been confirmed. Although it used to be proposed that carbonation reaction might explain the Venus’ atmospheric CO₂ abundance, it is unlikely Venus’ surface is reactive enough to control the Venus’ massive CO₂ atmosphere. Venus’ surface carbonate is also able to affect the climate through the reaction with atmospheric SO₂ to form anhydrite. Under the carbonate model the climate state is not in equilibrium and would be unstable due to the reaction between carbonate and SO₂. On the other hand, pyrite-magnetite reaction is proposed to explain the Venus’ atmospheric SO₂ abundance. Under pyrite-magnetite reaction, however, the climate would be stabilized such that the existing climate state is maintained over a geological timescale, while some observational facts such as atmospheric abundance of SO₂ and surface temperature could also be reasonably explained.  相似文献   

Effect of temperature on the methyl chloride production rate in a marine phytoplankton, <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis>     

Minami?Abe  Takahiro?Nagai  Michiko?Kurihara  Shinya?HashimotoEmail author 《Journal of Atmospheric Chemistry》2017,74(2):157-169

Methyl halides such as methyl chloride (CH₃Cl) are known to be important carriers of halogen from the ocean to the atmosphere, and the halogens they release into the stratosphere by photolysis catalyze ozone depletion. Marine phytoplankton have been reported as a source of CH₃Cl, but the effects of environmental temperature on the CH₃Cl production by phytoplankton have not been investigated. In this study, we investigated the effects of temperature on the production of CH₃Cl in the culture of a marine diatom, Phaeodactylum tricornutum CCMP 630, incubated at 10, 15, 20, 25, and 30 °C. CH₃Cl concentrations in cultured samples were determined using purge and trap gas chromatograph–mass spectrometry. Phytoplankton growth was monitored by measuring the chlorophyll a concentrations. CH₃Cl production was observed for several weeks at four different temperatures ranging from 10 to 25 °C. The CH₃Cl production from P. tricornutum was increased with increasing temperature from 10 to 25 °C, and the maximum production rate for CH₃Cl was 0.21~0.26 μmol (g chlorophyll a)^?1 d^?1 at 25 °C, which was several times higher than that at 10 °C (~0.03 μmol (g chlorophyll a)^?1 d^?1). The Arrhenius equation was successfully used to characterize the effects of temperature on the production rates of CH₃Cl in the culture of P. tricornutum. Our results suggest that water temperature directly affects CH₃Cl production derived from P. tricornutum and that water temperature would be a significant factor for estimating the emissions of CH₃Cl from marine environments.  相似文献   

Magnetic anomaly lineations from Late Jurassic to Early Cretaceous in the west-central Pacific Ocean   总被引：1，自引：0，他引：1  

Masao Nakanishi  Kensaku Tamaki  Kazuo Kobayashi 《Geophysical Journal International》1992,109(3):701-719

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Spatiotemporal distribution of seismic activity in East Asia and its relation to regional stress field     

Jiren Xu  Zhixin Zhao  Kazuo Oike 《地震学报(英文版)》1992,5(2):263-269

Tectonic forces from the relative movements between plates are transmitted into the continental crust, and then they create the earthquake generating stress field there. The space-time distribution of the seismic activity including the small earthquakes in a region reflects the variation of the stress field in the region. According to this idea, the characteristics of the stress fields in the various regions of East Asia have been analyzed in detail in this paper based on a lot of solutions of focal mechanisms and data of seismic activity during the last 500 years. The results indicate that the tectonic forces from the subduction of the Pacific Ocean plate underneath the Eurasian plate control the stress field in the region from North China to the northern part of the North-South Seismic Belt. The variation of the regional stress field shown by the variation of seismic activity in some regions of Japan has also been discussed based on characteristics of variation of the seimicity of small earthquakes. Synchronous variations of seismicity in the past 100 years or so in West China and in the boundary region between the Indo-Australian and Eurasian plates implicate that there is the transmission of tectonic forces into West China through the collision between the Indo-Australian and Eurasian plates. The active seismic activity in the boundary region between the Indo-Australian and the Eurasian plates and in West China is continuing consistently. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 287–294, 1991.  相似文献   

Effect of oxidation state on Bi mineral speciation in oxidized and reduced granitoids from the Uetsu region,NE Japan     

Yuya Izumino  Teruyuki Maruoka  Kazuo Nakashima 《Mineralium Deposita》2016,51(5):603-618

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Primary productivity at the time-series stations in the northwestern Pacific Ocean: is the subtropical station unproductive?     

Kazuhiko Matsumoto  Osamu Abe  Tetsuichi Fujiki  Chiho Sukigara  Yoshihisa Mino 《Journal of Oceanography》2016,72(3):359-371

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The Cretaceous Ofuku Pluton and Its Relation to Mineralization in the Western Akiyoshi Plateau,Yamaguchi Prefecture,Japan          下载免费PDF全文

Yuka Sasaki  Teruyoshi Imaoka  Mariko Nagashima  Kazuo Nakashima  Takafumi Sonehara  Koshi Yagi  Tetsumaru Itaya 《Resource Geology》2016,66(2):85-113

The relationship between the magmatism of the Cretaceous Ofuku pluton and mineralization in and around the Akiyoshi Plateau, Yamaguchi Prefecture, Japan was investigated using a combination of field observation, petrographic and geochemical analyses, K–Ar geochronology, and fluid inclusion data. The Ofuku pluton has a surface area of 1.5 × 1.0 km, and was intruded into the Paleozoic accretionary complexes of the Akiyoshi Limestone, Ota Group and Tsunemori Formation in the western part of the Akiyoshi Plateau. The pluton belongs to the ilmenite‐series and is zoned, consisting mainly of early tonalite and granodiorite that share a gradational contact, and later granite and aplite that intruded the tonalite and granodiorite. Harker diagrams show that the Ofuku pluton has intermediate to silicic compositions ranging from 60.4 to 77.9 wt.% SiO₂, but a compositional gap exists between 70.5 to 73.4 wt.% SiO₂ (anhydrous basis). Modal and chemical variations indicate that the assumed parental magma is tonalitic. Quantitative models of fractional crystallization based on mass balance calculations and the Rayleigh fractionation model using major and trace element data for all crystalline phases indicate that magmatic fractionation was controlled mainly by crystal fractionation of plagioclase, hornblende, clinopyroxene and orthopyroxene at the early stage, and quartz, plagioclase, biotite, hornblende, apatite, ilmenite and zircon at the later stage. The residual melt extracted from the granodiorite mush was subsequently intruded into the northern and western parts of the Ofuku pluton as melt lens to form the granite and aplite. The age of the pluton was estimated at 99–97 Ma and 101–98 Ma based on K–Ar dating of hornblende and biotite, respectively. Both ages are consistent within analytical error, indicating that the Ofuku pluton and the associated Yamato mine belong to the Tungsten Province of the San‐yo Belt, which is genetically related to the ilmenite‐series granitoids of the Kanmon to Shunan stages. The aplite contains Cl‐rich apatite and REE‐rich monazite‐(Ce), allanite‐(Ce), xenotime and bastnäsite‐(Ce), indicating that the residual melt was rich in halogens and REEs. The tonalite–granodiorite of the Ofuku pluton contains many three‐phase fluid inclusions, along with daughter minerals such as NaCl and KCl, and vapor/liquid (V/L) volume ratios range from 0.2 to 0.9, suggesting that the fluid was boiling. In contrast, the granite and aplite contain low salinity two‐phase inclusions with low V/L ratios. The granodiorite occupies a large part of the pluton, and the inclusions with various V/L ratios with chloride daughter minerals suggest the boiling fluids might be related to the mineralization. This fluid could have carried base metals such as Cu and Zn, forming Cu ore deposits in and around the Ofuku pluton. The occurrence and composition of fluid inclusions in the igneous rocks from the Akiyoshi Plateau are directly linked to Cu mineralization in the area, demonstrating that fluid inclusions are useful indicators of mineralization.  相似文献   

Impact Of The PROCEEDINGS ON THE ANNUAL MEETING OF THE ASSOCIATION OF AMERICAN GEOGRAPHERS: A COMPARISON OF SCIENTIFIC INFORMATION EXCHANGE AT THE 1967 AND 1969 ANNUAL MEETINGS*     

Carnot E. Nelson  Kazuo Tomica 《The Professional geographer》1970,22(4):221-226

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Current structure and volume transport of the Soya Warm Current in summer     

Masaji Matsuyama  Makiko Wadaka  Taizo Abe  Masaaki Aota  Yoshio Koike 《Journal of Oceanography》2006,62(2):197-205

ADCP, CTD and XBT observations were conducted to investigate the current structure and temperature, salinity and density distributions in the Soya Warm Current (SWC) in August, 1998 and July, 2000. The ADCP observations clearly revealed the SWC along the Hokkaido coast, with a width of 30–35 km and an axis of maximum speed of 1.0 to 1.3 ms⁻¹, located at 20–25 km from the coast. The current speed gradually increased from the coast to a maximum and steeply decreased in the offshore direction. The SWC consisted of both barotropic and baroclinic components, and the existence of the baroclinic component was confirmed by both the density front near the current axis and vertical shear of the alongshore current. The baroclinic component strengthened the barotropic component in the upper layer near the axis of the SWC. The volume transport of the SWC was 1.2–1.3 SV in August, 1998 and about 1.5 SV and July, 2000, respectively. Of the total transport, 13 to 15% was taken up by the baroclinic component. A weak southeastward current was found off the SWC. It had barotropic characteristics, and is surmised to be a part of the East Sakhalin Current.  相似文献