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排序方式: 共有191条查询结果,搜索用时 31 毫秒
41.
Building damage characteristics based on surveyed data and fragility curves of the 2011 Great East Japan tsunami 总被引:4,自引:2,他引:2
Anawat Suppasri Erick Mas Ingrid Charvet Rashmin Gunasekera Kentaro Imai Yo Fukutani Yoshi Abe Fumihiko Imamura 《Natural Hazards》2013,66(2):319-341
A large amount of buildings was damaged or destroyed by the 2011 Great East Japan tsunami. Numerous field surveys were conducted in order to collect the tsunami inundation extents and building damage data in the affected areas. Therefore, this event provides us with one of the most complete data set among tsunami events in history. In this study, fragility functions are derived using data provided by the Ministry of Land, Infrastructure and Transportation of Japan, with more than 250,000 structures surveyed. The set of data has details on damage level, structural material, number of stories per building and location (town). This information is crucial to the understanding of the causes of building damage, as differences in structural characteristics and building location can be taken into account in the damage probability analysis. Using least squares regression, different sets of fragility curves are derived to demonstrate the influence of structural material, number of stories and coastal topography on building damage levels. The results show a better resistant performance of reinforced concrete and steel buildings over wood or masonry buildings. Also, buildings taller than two stories were confirmed to be much stronger than the buildings of one or two stories. The damage characteristic due to the coastal topography based on limited number of data in town locations is also shortly discussed here. At the same tsunami inundation depth, buildings along the Sanriku ria coast were much greater damaged than buildings from the plain coast in Sendai. The difference in damage states can be explained by the faster flow velocities in the ria coast at the same inundation depth. These findings are key to support better future building damage assessments, land use management and disaster planning. 相似文献
42.
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
43.
Naoki Shirai Yuzuru Karouji Kazuya Kumagai Masayuki Uesugi Kaori Hirahara Motoo Ito Naotaka Tomioka Kentaro Uesugi Akira Yamaguchi Naoya Imae Takuji Ohigashi Toru Yada Masanao Abe 《Meteoritics & planetary science》2020,55(7):1665-1680
Chemical compositions of materials used for new sample holders (vertically aligned carbon nanotubes [VACNTs] and polyimide film), which were developed for the analysis of Hayabusa2‐return samples, were determined by instrumental neutron activation analysis and/or instrumental photon activation analysis, to estimate contamination effects from the sample holders. The synthetic quartz plate used for the sample holders was also analyzed. Ten elements (Na, Al, Cr, Mn, Fe, Ni, Eu, W, Au, and Th) and 14 elements (Na, Al, K, Sc, Ti, Cr, Zn, Ga, Br, Sb, La, Eu, Ir, and Au) could be detected in the VACNTs and polyimide film, respectively. The VACNT data show that contamination by this material with respect to the Murchison meteorite is negligible in terms of the elemental ratios (e.g., Fe/Mn, Na/Al, and Mn/Cr) used for the classification of meteorites due to the extremely low density of VACNTs. However, for the Au/Cr ratio, even small degrees (1.7 wt%) of contamination by VACNTs will change the Au/Cr ratio. Elemental ratios used for the classification of meteorites are only influenced by large amounts of contamination (>60 wt%) of polyimide film, which is unlikely to occur. In contrast, detectable effects on Ti isotopic compositions are caused by >0.1 and >0.3 wt% contamination by VACNTs and polyimide film, respectively, and Hf isotopic changes are caused by >0.1 wt% contamination by VACNTs. The new sample holders (VACNTs and polyimide film) are suitable for chemical classification of Hayabusa2‐return samples, because of their ease of use, applicability to multiple analytical instruments, and low contamination levels for most elements. 相似文献
44.
Nao Nakanishi Tetsuya Yokoyama Satoki Okabayashi Tomohiro Usui Hikaru Iwamori 《Meteoritics & planetary science》2018,53(5):1051-1065
We report Os isotope compositions of metal grains in two CBa chondrites (Bencubbin and Gujba) determined using a micromilling sampling coupled with thermal ionization mass spectrometry, together with the abundances of major and trace siderophile elements obtained by electron probe microanalysis and femtosecond laser ablation inductively coupled plasma–mass spectrometry. The CBa metal grains presented 187Os/188Os ratios akin to carbonaceous chondrites with limited variations (0.1257–0.1270). Most of the CBa metal grains were scattered along a 187Re-187Os reference isochron of IIIAB iron meteorites, indicating that the CBa metals experienced limited Re-Os fractionation at the time of their formation. The Re/Os ratios of sampling spots for the CBa metals, recast from the observed 187Os/188Os ratios, had a positive correlation with their Os/Ir ratios. In addition, the metal grains showed a positive correlation in a Pd/Fe versus Ni/Fe diagram. These correlations suggest that the CBa metal grains have formed via equilibrium condensation or evaporation from a gaseous reservoir at ~10−4 bar with enhanced metal abundances. Compared to the Bencubbin metals, the Gujba metals are characterized by having systematically lower Pd/Fe and Ni/Fe ratios that span subchondritic values. Such a difference was most likely induced by the compositionally heterogeneous impact plume from which the metals were condensed. 相似文献
45.
Kazuo Abe 《Journal of Oceanography》2008,64(6):961-967
From August 2006 to August 2007, the concentrations of dissolved silica (Si(OH)4) were monitored in the surface water of Urasoko Bay and the mouth of the stream that runs into the bay. Urasoko Bay is located
on the northern coast of Ishigaki Island, Okinawa, Japan, which is in a subtropical area of the North Pacific Ocean and is
surrounded by a relatively poorly developed fringing reef. Added to these samples were freshwater from the upstream area and
brackish water that exudes at the beach site, which were collected from April to June 2007. Rainwater samples were also collected
during the study period. The concentration of Si(OH)4 generally decreased from upstream to the bay site, and, on clear days, Si(OH)4 data from all study sites (the bay, beach, stream mouth, and upstream) plotted against salinity fell on a single straight
line. When the influence of rainwater was, the results were scattered below the straight line, which suggests dilution by
rainwater with a much lower Si(OH)4 concentration. These findings show that offshore seawater, rainwater, and upstream freshwater regulate the concentration
of Si(OH)4 in the surface water of Urasoko Bay. 相似文献
46.
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
47.
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
48.
49.
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
50.
On the basis of the model proposed by Matsui and Abe, we will show that two major factors — distance from the Sun and the efficiency of retention of accretional energy — control the early evolution of the terrestrial planets. A diagram of accretional energy versus the optical depth of a proto-atmosphere provides a means to follow the evolutionary track of surface temperature of the terrestrial planets and an explanation for why the third planet in our solar system is an aqua-planet. 相似文献