Thematic Section: Bridging the gap separating geological studies and disaster mitigation countermeasures for earthquakes and tsunami
Preface     

Kazuhisa Goto  Osamu Fujiwara  Shigehiro Fujino 《Island Arc》2010,19(3):371-373

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Shaking Maps for Scenario Earthquakes by Applying the Upgraded Version of the Strong Ground Motion Prediction Method ��Recipe��     

Nobuyuki Morikawa  Shigeki Senna  Yuzuru Hayakawa  Hiroyuki Fujiwara 《Pure and Applied Geophysics》2011,168(3-4):645-657

The strong ground motion prediction method ??Recipe?? was published by the Headquarters for Earthquake Research Promotion (HERP) of Japan. HERP has applied this method to prepare shaking maps for scenario earthquakes in specific active faults. Recently, Recipe was updated following its verification by simulations of strong ground motions associated with the Mw?=?6.6 off-shore earthquake west of Fukuoka prefecture in 2005, which occurred in the northwest part of the Kego fault zone located in northern Kyushu, Japan. One of the prominent changes in the upgraded version of Recipe is the inclusion of a procedure to evaluate seismic intensities on the ground surface from waveforms of S-wave velocity of 400?m/s on the engineering bedrock. By applying the upgraded version of Recipe, we have made shaking-maps for earthquakes in the southeast part of the Kego fault zone, which is located directly below the mega-city of Fukuoka. We assume four source models for scenario earthquakes; the locations of the asperities and the hypocenters vary between the models. The results show that in all cases, disastrous seismic intensities can strike a wide area of Fukuoka city. Differences in the distributions of seismic intensities among the four cases can be clearly observed in the area located on the extension of the source fault. Furthermore, we construct a velocity-layer structure model on the engineering bedrock for the central area of Fukuoka city. We assess not only the distribution of seismic intensities but also waveforms on the ground by using an equivalent linear method for the central area of Fukuoka city.  相似文献   

An empirical analysis of the impact of a bus rapid transit system on the concentration of secondary pollutants in the roadside areas of the TransJakarta corridors   总被引：1，自引：1，他引：0  

Sudarmanto Budi Nugroho  Akimasa Fujiwara  Junyi Zhang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(5):655-669

A bus rapid transit (BRT) system began operation in Jakarta City, Indonesia, in January 2004 and led to a modal shift from private to public modes of transport. This modal shift from car and motorcycle to BRT reduced the emission intensity of primary pollutants, such as NO_x and CO. We applied a combined structural equation model and an artificial neural network to evaluate the impact of the BRT system on the concentration of secondary pollutants in the roadside areas in the BRT corridors. An empirical analysis was carried out using data collected at five continuous ambient air quality monitoring stations located near to the BRT TransJakarta corridors in 2005. The establishment of our structural equation model gives a better understanding of the cause–effect relationship among the factors influencing roadside ambient air pollution, and was useful in simplifying the complexity of our artificial neural network model for predicting the modal shift’s impact on the PM₁₀ values and concentration of O₃. The introduction of the BRT system, and the modal shift it produced, had a greater influence on rapidly decaying pollutants, such as PM₁₀, than on O₃ because of the exposure to near-source microenvironments, such as the roadside of the TransJakarta corridors.  相似文献   

Geodynamics and Tectonics of Central Asia: Continental Growth in Vendian-Paleozoic Time     

M.M. Buslov  T. Watanabe  Y. Fujiwara  K. Iwata  Yu.I. Saphonova  O.T. Obut  Y. Sugai 《Gondwana Research》2001,4(4):587

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Strong motion uncertainty determined from observed records by dense network in Japan   总被引：2，自引：1，他引：1  

Nobuyuki Morikawa  Tatsuo Kanno  Akira Narita  Hiroyuki Fujiwara  Toshihiko Okumura  Yoshimitsu Fukushima  Aybars Guerpinar 《Journal of Seismology》2008,12(4):529-546

The variation of ground motions at specific stations from events in six narrow areas was inspected by using K-NET and KiK-net records. A source-area factor for individual observation stations was calculated by averaging ratios between observed values for horizontal peak acceleration and velocity, as well as acceleration response spectra for 5% damping, and predicted values using a ground-motion model (usually known as an attenuation relation) by Kanno et al. (Bull Seismol Soc Am, 96:879–897, 2006). Standard deviations between observed and predicted amplitudes after the correction factor are less than 0.2 on the logarithmic scale and decrease down to around 0.15 in the short-period range. Intra-event standard deviation clearly increases with decreasing distance due to differing paths around near source area. Standard deviations may increase with amplitude or decrease with magnitude; however, both amplitude and magnitude of the data are strongly correlated with distance. The standard deviation calculated in this study is obviously much smaller than that of the original ground-motion model, as epistemic uncertainties are minimized by grouping ground motions at specific stations. This result indicates that the accuracy of strong ground motion prediction could be improved if ground-motion models for specified region are determined individually. For this to be possible, it is necessary to have dense strong-motion networks in high-seismicity regions, such as K-NET and KiK-net.  相似文献   

Magnetic polarity stratigraphy of Siwalik Group sediments of Karnali River section in western Nepal     

Pitambar Gautam  Yoshiki Fujiwara 《Geophysical Journal International》2000,142(3):812-824

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The development of Fe-nodules surrounding biological material mediated by microorganisms     

Hidekazu Yoshida  Koshi Yamamoto  Yuki Murakami  Nagayoshi Katsuta  Toru Hayashi  Takeshi Naganuma 《Environmental Geology》2008,55(6):1363-1374

Takashikozo is a phenomenon of Quaternary sediments in Japan. They are cylindrical Fe-oxyhydroxide nodules that form as plaques round plant roots, where Fe is preferentially concentrated to develop a solid wall. Structural features suggest that after the roots have decayed, the central space where the roots were situated acts as a flow path for oxidized water. Analysis of microbial 16S rDNA extracted from the nodules identified iron-oxidizing bacteria encrusted round the roots where they are the likely initiators of nodule formation. Direct microscopic observation revealed an accumulation of Fe-oxyhydroxides that fill the pore spaces and is also likely to be linked with the encrusting microbial colonies. Geological history and nanofossil evidence suggest that these Fe-nodules may have been buried at a depth of up to several tens of meters for at least 10⁵ years in reducing Quaternary sediments. Thus Fe-oxyhydroxide nodules that have formed in a geological environment at the interfaces between water and rock by microbial mediation can persist under reducing conditions. If this is the case, the phenomenon is significant as an analogue of post-closure conditions in radioactive waste repositories, since it could influence nuclide migration.  相似文献   

Atmospheric carbon dioxide variations at coastal site,Sibukawa, in Seto Inland Sea,Japan. 2. observation from 1980 to 1989     

E. Ohtaki  E. Yamashita  F. Fujiwara 《Theoretical and Applied Climatology》1992,45(3):177-181

Summary Atmospheric carbon dioxide variations have been studied by using data between May 1980 and July 1989 from Sibukawa in Seto Inland Sea, sited in the western part of Japan. The power spectrum of carbon dioxide shows that the one-day period was predominant and 4 to 5 days period associated with quasiperiodic variation in weather was also significant. The seasonal variation of daily minimum concentration of carbon dioxide shows a maximum in summer months (July–September), and a minimum in winter months (November–December and January–March). The variation pattern seems to be in opposite phase to the carbon dioxide variations expected in the northern hemisphere. This was probably due to reduced vertical mixing under stable stratification of the air layer prevailing during summer months at Sibukawa station. It is noted that the air layer is in lapse conditions during winter months. The annual rate of increase of carbon dioxide concentration is examined using data obtained during winter months. It is 3.1 ppm/year. This value is about twice the increasing rate of increase on a global scale and in the lower troposphere over Japan.With 5 Figures  相似文献   

Simulation of the Collection of Catch Crops for the Recovery of Agricultural Resources using Geographic and Statistical Data          下载免费PDF全文

Masayuki Matsuoka  Hideaki Nagare  Taku Fujiwara 《Transactions in GIS》2016,20(2):221-239

The cultivation of catch crops has great potential in agricultural areas for the recovery of nutrients, mitigation of groundwater contamination, and secondary utilization of harvestry. To estimate the potential volume of catch crops that can be collected at prospective locations, we simulated the cultivation and collection process at a regional scale using geographic and statistical data. Three types of geographic data, namely the locations of greenhouses, collecting stations and road networks, were used in a geographic information system to compute the volume of collected catch crops and carrying distance between greenhouses and collecting stations. Carbon emission from transportation of the catch crop was calculated using an improved ton‐km method, and the results were compared with the carbon content of the catch crop to evaluate the carbon balance. We found that the total fresh weight of the collected catch crops was 67900 t, of which 70% was collected at the top 15 of 73 stations. Carbon emissions from transportation ranged from >1 to 12% of the carbon content of the catch crop. The analytical method used in this study can readily be applied to other environmental studies concerning the collection of agricultural products and other biomass resources.  相似文献   

Seasonal Variation of Stratification in the Gulf of Thailand     

Tetsuo Yanagi  Suhendar I Sachoemar  Toshiyuki Takao  Shunji Fujiwara 《Journal of Oceanography》2001,57(4):461-470

Intensive hydrographic observations were carried out in the western part of the Gulf of Thailand and the east coastal sea of Peninsular Malaysia in September 1995 and April–May 1996. The characteristics of seasonal variation of oceanic condition in that area are discussed basis of an analysis of observed water temperature, salinity and density distributions in these cruises and NAGA cruises (Yanagi and Takao, 1998a). Stratification is most developed in March–May mainly due to large sea surface heating and weak sea surface wind, which weakened until September–October, vanishing in December–January. The horizontal distribution of bottom cold, saline and heavy water masses, which are found during the stratified season, is governed by the tidal mixing and the water depth. Water exchange between the Gulf of Thailand and the South China Sea becomes large in March–May due to a coupled effect of the intensified estuarine circulation and the Ekman transport by the southwest monsoon. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献