Perceived ambiguity about earthquake and house destruction risks     

Toshio Fujimi  Masahide Watanabe  Ryuji Kakimoto  Hirokazu Tatano 《Natural Hazards》2016,80(2):1243-1256

  相似文献   

Vulnerability of infrastructure to natural hazards and climate change in China     

Wei  Yi-Ming  Wang  Ke  Wang  Zhao-Hua  Tatano  Hirokazu 《Natural Hazards》2014,75(2):107-110

  相似文献   

Coordination of sodium ions in NaAlO2–SiO2 melts: a high temperature 23Na NMR study     

H. Maekawa  T. Nakao  S. Shimokawa  T. Yokokawa 《Physics and Chemistry of Minerals》1997,24(1):53-65

The coordination environment of the sodium ion in the melts of several simple ionic liquids and an Na₂O–Al₂O₃–SiO₂ mixture has been investigated by high temperature ²³Na NMR measurements. A new high temperature NMR probe was utilized for the measurements of the compositional and temperature dependence of the ²³Na NMR chemical shift at temperatures up to 1600?°C. ²³Na NMR spectra of ionic liquids, NaCl, NaBr and NaNO₃, show two peaks at their solid to liquid transition, corresponding to the solid and liquid state, respectively. The ²³Na NMR peak shift in passing from the liquid to the solid is positive. This suggests a decrease in the coordination number for the molten state compared to the crystalline state. The ²³Na peak position for the Na₂O–Al₂O₃–SiO₂ melts of the composition range Na/Al≥1 shifted almost linearly in the positive direction as a function of both the increased degree of depolymerization, NBO/T, and [Al]/([Al]+[Si]). ²³Na MAS-NMR measurement for crystalline silicate compounds of known structure provided a revised relationship between the mean Na–O distances and ²³Na chemical shifts. Comparison of the ²³Na chemical shift of the melts with that of crystalline silicate compounds suggests that the coordination number of Na in those melts is around 6–8 with little compositional dependence. The ²³Na peak position shifted in the negative direction with increasing temperature for sodium silicates, whereas that of aluminosilicates did not show any temperature dependence. The activation energy from the temperature dependence of the ²³Na line width shows little compositional dependence, and the value (51～58?kJ/mol) was close to that of the trace Na ion diffusion in NaAlSi₃O₈ glass.  相似文献   

Spathian to Aegean (upper Lower Triassic to lower Middle Triassic) carbon isotope stratigraphy constrained by the conodont biostratigraphy of carbonates on top of a mid-oceanic seamount formed in the Panthalassic Ocean     

Thuy Thi Nhu Ha  Takumi Maekawa  Hideko Takayanagi  Yasufumi Iryu 《Island Arc》2021,30(1):e12391

The Taho Formation in western Shikoku Island, Japan, consists of Triassic carbonates that formed on a seamount in the Panthalassic Ocean. In order to investigate the stratigraphy and paleoceanography of this carbonate succession, we analyzed the biostratigraphy and chemostratigraphy of a 17.6 m-thick section of the upper Taho Formation at the stratotype area in Tahokamigumi, Seiyo City. This section comprises bioclastic limestone containing Triassic bivalves, ammonoids, and conodonts. We recognized six conodont zones (in ascending order): the Novispathodus pingdingshanensis, Novispathodus brevissimus, Triassospathodus symmetricus, Triassospathodus homeri, Chiosella timorensis, and Magnigondolella cf. alexanderi zones. Thus, the studied carbonate succession is latest Smithian to Aegean in age. A δ¹³C profile of this section shows elevated values during the lowest Spathian followed by a gradual negative excursion, a subsequent positive excursion near the Spathian–Aegean boundary, and relatively constant values during the Aegean. The characteristic series of negative and positive excursions correlates with other δ¹³C records for this period, including the peak of the upper Smithian–lowest Spathian positive excursion (P3), lower to middle Spathian negative excursion (N4), and middle Spathian–lowest Aegean positive excursion (P4). This represents a new high-resolution Spathian–Aegean δ¹³C record of the Panthalassic Ocean, for which ages are constrained by conodont biostratigraphy. The Taho δ¹³C profile exhibits a consistent positive offset of ~2 ‰ as compared with those from other regions (i.e., mostly in the Tethyan Ocean). This can be explained by preferential removal of ¹²C from seawater during photosynthesis and calcification by marine organisms over the platform, and/or the relatively high δ¹³C values of dissolved inorganic carbon in the Panthalassic Ocean due to less influence of ¹²C-enriched terrestrial waters and high marine organic production/burial as compared with the more restricted Tethyan Ocean.  相似文献   

Complexes of activity of the solar cycle and very large scale convection     

Hirokazu Yoshimura 《Solar physics》1971,18(3):417-433

The magnetic field pattern associated with large scale convective motions, which are much larger than the supergranules and have been conceived as a source of maintenance of the solar differential rotation, is calculated in the framework of a slowly and differentially rotating thin spherical shell, including the effects of thermal conductivity and viscosity. The approximations of Boussinesq are used and the initial state of the magnetic field is assumed to be purely toroidal.The resulting magnetic field pattern rotates rigidly on the differentially rotating Sun with some phase delay to the convective pattern, if it is assumed that only the predominant mode with the maximum growth rate is actually realized in the solar convection zone. The obtained magnetic and convective patterns and their properties seem to explain naturally the various aspects of large scale ordering of solar activity such as the existence and behavior of complexes of activity, the rigid body rotation of proton flare active longitudes, their association with UMR's, the existence of ghost and mirror image of UMR's themselves and the fact that the rotational period derived from sunspot data is shorter than that derived spectroscopically from fluid velocity.  相似文献   

Single-crystal X-ray diffraction study of cation distribution in MgAl<Subscript>2</Subscript>O<Subscript>4</Subscript>–MgFe<Subscript>2</Subscript>O<Subscript>4</Subscript> spinel solid solution     

A.?NakatsukaEmail author  H.?Ueno  N.?Nakayama  T.?Mizota  H.?Maekawa 《Physics and Chemistry of Minerals》2004,31(5):278-287

Synthesis experiments in the system MgAl₂O₄–MgFe₂O₄ [MgAl_2–xFe_xO₄ (0 x 2)] were carried out using a PbF₂ flux. The crystalline products synthesized in the compositional range of 0.6 <x 1.2 consisted of two spinel phases, whereas those synthesized in the compositional ranges of 0.0 x 0.6 and 1.2 < x 2.0 crystallized as single spinel phases. Structure refinements of the spinel single crystals, which grew in the ranges of 0.0 x 0.6 and 1.2 < x 2.0, show that the degree of randomness of cation distribution between A and B sites increases as x approaches the two-phase region. This means that the degree of the size mismatch among Mg²⁺, Fe³⁺ and Al³⁺occupying each equivalent mixing site increases as x approaches the two-phase region. Consequently, if the coexistence of two spinels observed in the intermediate compositions reveals the existence of a miscibility gap at low temperatures, this increase in the degree of the size mismatch among the three cations is suggested as a factor of energetic destabilization to form the miscibility gap.  相似文献   

Gram Stain Index (GSI) of Bacterial and Archaeal Cells in the Natural Microbial Communities of Slightly and Extremely Saline Environments     

Haruo Saida  Masahiro Kamekura  Wael S. M. El-Sayed  Mohamed Abu-Shady  Yukuo Abe  Tomoharu Yamaguchi  Peiling Yang  Takaaki Maekawa  Humitake Seki 《Journal of Oceanography》2001,57(1):109-113

The use of GSI (Gram Stain Index) was studied for natural microbial cells in slightly and extremely saline environments. The GSI spectra of archaeal cells in an extremely saline environment showed unique profiles, different from those of Bacteria. These profiles can be applied for structural analysis of the microbial communities in aquatic environments.  相似文献   

Economics of climate change and risk of disasters in Asia–Pacific region     

Wei  Yi-Ming  Wang  Ke  Liao  Hua  Tatano  Hirokazu 《Natural Hazards》2016,83(1):1-17

  相似文献   

Estimation of property loss and business interruption loss caused by storm surge inundation due to climate change: a case of Typhoon Vera revisit     

Xinyu Jiang  Nobuhito Mori  Hirokazu Tatano  Lijiao Yang  Yoko Shibutani 《Natural Hazards》2016,84(1):35-53

This paper estimates property loss and business interruption loss under scenarios of storm surge inundation to explore the economic impact of climate change on Ise Bay, Japan. Scenarios-based analyses are conducted with respect to Typhoon Vera, which caused the most severe storm surge in the recorded history of Japan in 1959. Four different hazard scenarios are chosen from a series of typhoon storm surge inundation simulations: Typhoon Vera’s landfall with respect to the condition of the past seawall; Typhoon Vera’s landfall with respect to the condition of the current seawall; intensifying Typhoon Vera, but retaining its original tracks; and intensifying Typhoon Vera, but choosing the worst tracks from various possible typhoon tracks. Our economic loss estimation takes advantage of fine geographical scale census and economic census data that enable us to understand the spatial distribution of property loss and business interruption loss as well as identify the most potentially affected areas and business sectors on a sub-city scale. By comparing the property loss and business interruption loss caused by different hazard scenarios, the effect of different seawalls is evaluated and the economic impact of future climate change is estimated. The results indicate that although the current seawall can considerably reduce the scale of losses, climate change can cause Ise Bay to experience more serious storm surge inundation. Moreover, the resulting economic losses would increase significantly owing to a combination of climate change and the worst track scenario. It is, therefore, necessary to consider more countermeasures to adapt to climate change in this area.  相似文献   

Lake-level changes during the past 100,000 years at Lake Baikal, southern Siberia   总被引：1，自引：0，他引：1  

Atsushi Urabe  Masaaki Tateishi  Hirokazu Matsuoka  Alexsander Dmytriev 《Quaternary Research》2004,62(2):214-222

Lake-level changes inferred from seismic surveying and core sampling of the floor of Lake Baikal near the Selenga River delta can be used to constrain regional climatic history and appear to be correlated to global climate changes represented by marine oxygen isotope stages (MIS). The reflection pattern and correlation to the isotope stages indicate that the topset and progradational foreset sediments of the deltas formed during periods of stable lake levels and warm climatic conditions. During warm stages, the lake level was high, and during cold stages it was low. The drop in the lake level due to cooling from MIS 5 through MIS 4 is estimated to be 33-38 m; from MIS 3 through MIS 2, it fell an additional 11-15 m. Because the lake level is chiefly controlled by evaporation and river input, we infer that more water was supplied to Lake Baikal during warm stages.  相似文献