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21.
Roger Antabe Kilian N. Atuoye Vincent Z. Kuuire Yujiro Sano Godwin Arku Isaac Luginaah 《社会与自然资源》2020,33(3):368-385
AbstractDespite the impact of mining-induced environmental change on community livability, we know little about how disparities in knowledge of health risks associated with mining influence residents’ response, especially in an already environmentally stressed context. Guided by theoretical insights from solastalgia, we examined residents’ decision to relocate due to increasing gold mining activities in the fragile Northern Savannah Ecological Zone of Ghana. Fitting complementary log-log regression models to cross-sectional data from the Upper West Region (UWR) of Ghana, we found that residents with limited knowledge of potential health impacts of mining and those who believe mining activities were not meeting environmental standards were more likely to consider relocating. Given the centrality of land in community health and wellbeing in the UWR, Ghana’s mining guidelines should promote local participation in the regulation of mining activities and guarantee the rights of indigenes to livable native lands. 相似文献
22.
Mitsunori Ozaki Satoshi Yagitani Isamu Nagano Yujiro Hata Hisao Yamagishi Natsuo Sato Akira Kadokura 《Polar Science》2008,2(4):237-249
In order to estimate the dynamic structure of the VLF ionospheric exit point, we conducted multipoint ground-based observation of the natural VLF emissions at three unmanned sites: West Ongul (69°01′ S, 39°30′ E), Skallen (69°40′ S, 39°24′ E), and H100 (69°18′ S, 41°19′ E) around Japanese Syowa station, Antarctica, during a whole year of 2006. In this observation, we developed three sets of unmanned autonomous observation systems for natural VLF emissions. Each observation system consists of two crossed vertical loop antennas to pick-up North–South (NS) and East–West (EW) magnetic components, a multi-channel analyzer, and a data logger. The intensity and polarization of NS and EW magnetic components are obtained in 4 spaced frequency (0.5, 1.0, 2.0, and 6.0 kHz) channels by the multi-channel analyzer.The VLF emissions observed at the three sites exhibit an interesting difference in the wave intensity as well as the polarization that allows important information about the locations of their ionospheric exit point to be determined. Firstly, to find the distinct exit point, we have theoretically calculated the spatial distributions of the wave intensity and the polarization on the Earth for VLF whistler mode waves coming down from the magnetized ionosphere, by using the full-wave analysis. Then, we have compared the calculated results with the observed data, to evaluate the possible locations of the ionospheric exit point for the auroral hiss events.As an example, the direction of the estimated ionospheric exit point for the auroral hiss event at 31 March 2006 was found to be consistent with a bright aurora region. However, in this case, the estimated ionospheric exit point was located a few hundred kilometers equatorward of the associated aurora. This would suggest that the ray paths for the auroral hiss could be different from the directions of the geomagnetic field lines for auroral precipitation. 相似文献
23.
Direct measurements using a free-falling micro-profiler were conducted on the northeast coast of Hokkaido in the summer of 2007 to clarify the mixing process in the Soya Warm Current (SWC) region in terms of microstructure. The distribution of the Turner angle (Tu) showed that these regions have a high potential for double diffusive convection, but direct measurements of the turbulent dissipation rate (ε) and dissipation of temperature variance ( $ \chi_{T} $ ) did not necessarily correspond to each other in the SWC region, especially in the offshore front of SWC and farther offshore. The mixing efficiency indicated that, even though the Turner angle (Tu) indicated a high potential for double diffusive convection, turbulent mixing was the main contributor to the mixing process in this region, and double-diffusive convection only contributed partially and sparsely, especially in the boundary off SWC water. The bottom mixed layer (BML) is known to thicken off the SWC. The vertical diffusivity coefficient was enhanced near the bottom (10?4–10?3 m2 s?1) off the SWC, and these results support that turbulence near the bottom off the SWC contributed to the thickening of the BML. 相似文献
24.
Based on the geological tectonics, aftershock activity, earthquake surface rupture and peak ground motion, the geometric and
dynamic characteristics of seismogenic tectonics about the 1995 Hanshin earthquake are analysed. Nojima fault and Rokko fault
have the same trending direction, but opposite dips. Their rising and falling plates are in symmetrically diagonal distribution.
The two faults can be defined as thrust-strike slip faults and constitute a pivotal strike-slip fault. The earthquake just
occurred at the pivot, which is the seismotectonics for the earthquake to develop and occur. The pivotal movement along a
strike-slip fault often leads to the occurrence of large earthquakes, whose dynamic process can be demonstrated by the stress
analysis on the torsion of a beam with rectangle section. The displacement of earthquake surface rupture, aftershock density
and peak acceleration change in a certain range of epicentral distance just similar as the shear stress changes from the center
to the sides in the rectangle section.
The distribution characteristics of the heaviest damage areas are also discussed in the article from the aspects of special
geological tectonics and seismotectonic condition. The result obtained from the article can be applied not only to realizing
the potencial earthquake sources in middle-long time, but also to build reasonably the prediction model about earthquake hazard. 相似文献
25.
Yujiro Ogawa 《Tectonophysics》1978,47(3-4)
Consideration of the paleogeography and large and small structures in the outer part (the Sakawa Fold Belt) of the Paleozoic—Mesozoic geosyncline of Japan suggests that the main part of the Japanese Islands has grown up not from an arc—trench system but from a marginal sea basin—microcontinent system: the Chichibu Geosyncline and the Kurosegawa — Ofunato Island Arc, Minor structures are superposed in a complicated way and they are analyzed in terms of the concepts of tectonic level and multiple deformation.Stratigraphic evidence shows that an early deformation was pre-middle Triassic in the Chichibu Terrain but northwards in the Sambagawa terrain it may have continued until early Cretaceous in relation to minor scale subduction within the marginal basin. A late Cretaceous phase of deformation produced the greatest crustal shortening in the microcontinent area of the Kurosegawa Tectonic Zone and was nearly contemporaneous with the intrusion of granitic rocks in the Ryoke Zone Younger secondary eugeosynclines were developed by progressive encroachment on the arc—trench gap south of the Kurosegawa zone from late Permian times onwards. 相似文献
26.
Hirohisa YAMADA Kenji TAMURA Shingo YOKOYAMA Yujiro WATANABE 《《地质学报》英文版》2006,80(2):290-295
Lath-shaped and highly crystalline trioctahedral smectites were synthesized under hydrothermal conditions. The quenched glasses with stoichiometrically dehydrated Na-smectite compositions were treated at （a） 500℃ and 100 MPa for 1 and 11 days; and （b） 300℃ and 100 MPa for 7 days. The crystallinity and particle size of products were dependent on the chemical composition of the starting glass, synthetic temperature and duration of hydrothermal treatment. The high structural ordering and large dimensions of the products were confirmed from the sharpness of XRD peaks; and hydration behavior under controlled relative humidity. Transmission electron microscopy was also performed for the characterization of the particle size of product. Particle sizes vary from ca. 10 nm to a few pm by changing the chemical compositions of the starting materials. The product with the highest structural ordering and largest dimension was obtained from Nao.33（Mg1.83Al0.67）Si4O11 glass treated at 500℃ and 100 MPa for 1 day. The obtained results also confirmed the metastability and compositional dependency in the formation of highly crystalline trioctahedral smectite at hydrothermal conditions. 相似文献
27.
Takehiro Koyaguchi Kiyokatsu Ochiai Yujiro J. Suzuki 《Journal of Volcanology and Geothermal Research》2009,186(1-2):68
During an explosive volcanic eruption, tephra fall out from the umbrella region of the eruption cloud to the ground surface. We investigated the effect of the intensity of turbulence in the umbrella cloud on dispersion and sedimentation of tephra by performing a series of laboratory experiments and three dimensional (3-D) numerical simulations. In the laboratory experiments, spherical glass-bead particles are mixed in stirred water with various intensities of turbulence, and the spatial distribution and the temporal evolution of the particle concentration are measured. The experimental results show that, when the root-mean-square of velocity fluctuation in the fluid (Wrms) is much greater than the particle terminal velocity (vt), the particles are homogeneously distributed in the fluid, and settle at their terminal velocities at the base of the fluid where turbulence diminishes. On the other hand, when Wrms is as small as or smaller than vt, the particle concentration increases toward the base of the fluid during settling, which substantially increases the rate of particle settling. The results of the 3-D simulations of eruption cloud indicate that Wrms is up to 40 m/s in most of the umbrella cloud even during a large scale plinian eruption with a magma discharge rate of 109 kg/s. These results suggest that relatively coarse pyroclasts (more than a few mm in diameter) tend to concentrate around the base of the umbrella cloud, whereas fine pyroclasts (less than 1/8 mm in diameter) may be distributed homogeneously throughout the umbrella cloud during tephra dispersion. The effect of the gradient of particle concentration in the umbrella cloud explains the granulometric data of the Pinatubo 1991 plinian deposits. 相似文献
28.
Monitoring using a thermistor array and an acoustic Doppler current profiler was carried out in the outer part of Tokyo Bay
from May 20 to November 30, 2006. Current fluctuations with tidal periods were amplified during the maximum temperature period
in early September. The strong current interfered with fishing operations using set nets. Although the current fluctuation
was speculated to be baroclinic motion from a phase relationship among fluctuations of temperature, current and sea level,
empirical orthogonal function analysis showed the dominance of a barotropic structure. Such a discrepancy in the current structure
was explained by an internal tide propagating along a deep canyon in the outer part of Tokyo Bay. Furthermore, amplification
of the semidiurnal internal tide and the warming of the temperature field were found to be induced by the intrusion of Kuroshio
warm water. The amplification mechanism was examined using a two-dimensional model with idealized topography. It was concluded
that the large amplitude of the semidiurnal internal tide is resonantly generated in the deep canyon in the outer Tokyo Bay
when stratification becomes strong and the period of the internal seiche approaches the semidiurnal period. 相似文献
29.
30.
Vincent Renard Kazuaki Nakamura Jacques Angelier Jacques Azema Jacques Bourgois Christine Deplus Kantaro Fujioka Yozo Hamano Philippe Huchon Hajimu Kinoshita Pierre Labaume Yujiro Ogawa Tetsuzo Seno Akira Takeuchi Manabu Tanahashi Akinori Uchiyama Jean-Louis Vigneresse 《Earth and Planetary Science Letters》1987,83(1-4)
Leg 2 of the French-Japanese 1984 Kaiko cruise has surveyed the trench triple junction off central Japan, where the Japan, Izu-Bonin and Sagami Trenches intersect. The Izu-Bonin Trench is deeper than the Japan Trench and filled by a thick turbiditic series. Its anomalous depth is explained by the westward retreat of the edge of the northwestward moving Philippine Sea plate. On the contrary to what happens in the Japan Trench, horst and graben structures of the Pacific plate obliquely enters the Izu-Bonin Trench, suggesting that the actual boundary between these two trenches is located to the north of the triple junction. The inner wall of the Izu-Bonin Trench is characterized in the triple junction area by a series of slope basins whose occurrence is related to the dynamics of this area. The northernmost basin is overthrust by the edge of the fore-arc area of the Northeast Japan plate. The plate boundary is hardly discernible further east, which makes it impossible to locate precisely the triple junction itself. These features suggest that large intra-plate deformation occurs there due to the interaction of the plates involved in the triple junction and the weak mechanical strength of the wedge-shaped margin of the overriding plates. 相似文献