High-pressure decompositions in cobalt and nickel silicates     

Eiji Ito 《Physics of the Earth and Planetary Interiors》1975,10(1):88-93

High-pressure stability relations in cobalt and nickel silicates have been studied over the pressure range 130–330 kbar employing a double-staged split-sphere-type high-pressure apparatus.γ-Co₂SiO₄ and γ-Ni₂SiO₄ decompose directly into their constituent oxide mixtures (rocksalt plus stishovite) 175 kbar and 280 kbar, respectively. The result that γ-Ni₂SiO₄ has a wider stability field in pressure than γ-Co₂SiO₄, is consistent with simple crystal-field theory.The experimental precision is high enough to show that the decomposition boundary of γ-Co₂SiO₄ has a positive slope (dP/dT > 0) and a preliminary determination of the boundary curve is P(kbar) = 0.065 T (°C) + 110.No positive evidence for the existence of high-pressure forms of CoSiO₃ and NiSiO₃ has been obtained in these quenching experiments, and they finally decompose into constituent oxide mixtures as in the cases of orthosilicates.  相似文献   

Synthesis of γ-Mg₂SiO₄     

Eiji Ito  Yoshito Matsui  Kaichi Suito  Naoto Kawai 《Physics of the Earth and Planetary Interiors》1974,8(4):342-344

Magnesium orthosilicate with spinel structure (γ-Mg₂SiO₄) was synthesized at about 250 kbar and 1000°C. Unit cell dimension was established to be 8.076 ± 0.001Å. X-ray powder diffraction pattern revealed a significant difference between γ-Mg₂SiO₄ and other γ-M₂SiO₄ spinels (M = Fe, Co, and Ni) in the intensities of (111) and (331) reflections, both of which are virtually absent in the Mg₂SiO₄ spinel. This feature could be thoroughly understood by the calculation of the intensities for several silicate spinels.  相似文献   

Earthquake-induced rapid long-traveling flow phenomenon: May 2003 Tsukidate landslide in Japan   总被引：3，自引：2，他引：1  

Hiroshi?Fukuoka  Gonghui?WangEmail author  Kyoji?Sassa  Fawu?Wang  Tatsunori?Matsumoto 《Landslides》2004,1(2):151-155

  相似文献   

Overview of the MITI Nankai Trough Wells: A Milestone in the Evaluation of Methane Hydrate Resources   总被引：4，自引：0，他引：4  

Yoshihiro Tsuji    Hisashi Ishida    Masaru Nakamizu    Ryo Matsumoto  Satoshi Shimizu 《Resource Geology》2004,54(1):3-10

Abstract. Bottom-simulating reflectors suggestive of the presence of methane hydrates are widely distributed below the ocean floor around Japan. In late 1999, drilling of the MITI Nankai Trough wells was conducted to explore this potential methane hydrate resource and a Tertiary conventional structure. The wells are located in the Northwest Pacific Ocean off Central Japan at a water depth of 945 m. A total of six wells were drilled, including the main well, two pilot wells, and three post survey wells at intervals of 10–100 m. All wells except the first confirmed the occurrence of hydrates based on logging-while-drilling, wire-line logging and/or coring using a pressure and temperature coring system in addition to conventional methods. Based on the various well profiles, four methane hydrate-bearing sand-rich intervals in turbidite fan deposits were recognized. Methane hydrates fill the pore spaces in these deposits, reaching saturation of up to 80 % in some layers. The methane hydrate-bearing turbiditic sand layers are less than 1 m thick, with a total thickness of 12–14 m. The bottom depth of high hydrate concentration correlates well with the depth of the bottom-simulating reflector. Based on these exploration results, the Japanese government inaugurated a 16-year methane hydrate exploitation program in 2001.  相似文献   

Surface Heat Balance and Spatially Distributed Ablation Modelling at Koryto Glacier, Kamchatka Peninsula, Russia   总被引：1，自引：0，他引：1  

Keiko Konya  Takane Matsumoto  Renji Naruse 《Geografiska Annaler: Series A, Physical Geography》2004,86(4):337-348

To investigate the characteristics of ablation at Koryto Glacier, a mountain glacier under maritime climate in Kamchatka Peninsula, Russia, we made field observations from August to early September 2000. At a site near the equilibrium line, the 31‐day average net radiation, sensible heat flux, and latent heat flux were 43, 59 and 31 W^?2, respectively. We developed a new distributed ablation model, which only needs measurements of air temperature and global radiation at one site. Hourly ablation rates at this site obtained by the energy balance method are related to measured air temperature and global radiation by linear multiple regression. A different set of multiple regression coefficients is fitted for snow and ice surfaces. Better estimates of ablation rate can be obtained by this approach than by other temperature index models. These equations are then applied to each grid cell of a digital elevation model to estimate spatially distributed hourly melt. Air temperature is extrapolated using a constant temperature lapse rate and global radiation is distributed considering topographic effects. The model enables us to calculate the hourly spatial distribution of ablation rates within the glacier area and could well provide a realistic simulation of ablation over the whole glacier.  相似文献   

Two recent flowslides in Yamashina area, Kanazawa City, Japan     

Fa-Wu Wang  Tatsunori Matsumoto  Yasuhiro Tanaka 《Landslides》2005,2(3):229-234

Due to a continual rainfall, a flowslide occurred in Yamashina area, Kanazawa City, Japan on November 8, 2002 in the Tertiary mudstone area. The sliding mass was fully fluidized during the motion and moved downward the slope for a long distance. On December 31, 2003, slope failure was triggered by intensive rainfall and snowmelt water at the same site again, and resulted in the second occurrence of flowslide. The total displacement of the slope was recorded with an extensometer. Through field investigation, the difference of the sliding mechanism between the two flowslides was examined.  相似文献   

Fault system of the 2004 Mid Niigata Prefecture Earthquake and its aftershocks     

Naoshi Hirata  Hiroshi Sato  Shin’ichi Sakai  Aitaro Kato  Eiji Kurashimo 《Landslides》2005,2(2):153-157

Data recorded by a seismic network deployed the day after the 2004 Mid Niigata Prefecture Earthquake (M6.8) in central Japan are used to determine the major source faults responsible for the mainshock and major aftershocks. Using this high-resolution seismic data, three major source faults are identified: two parallel faults dipping steeply to the west located 5 km apart, and the other dipping eastward and oriented perpendicular to the west-dipping faults. The analysis also reveals that the lateral variation in seismic velocity observed at the surface extends to a depth of 15 km, encompassing the source area of the mainshock. This strong heterogeneity of the crust, related to the complex geological and tectonic evolution of the area, is considered to be responsible for the prominent aftershock activity following the 2004 Niigata event.  相似文献   

家用电器重复出现的地震前兆异常     

池谷元伺 《华南地震》1998,18(2):53-57

据有关报导,１９９５年神户地震前家用电器出现了奇怪的异常现象。我们在实验室中利用范德格拉夫静电发电机用磨擦生电的方法,证实了这些收音机和电视的噪音以及频道混乱现象的存在。  相似文献   

Seasonal　Transition　of　Summer　Rainy　Season　over　Indochina　and　Adjacent　Monsoon　Region   总被引：10，自引：0，他引：10  

Jun MatsumotoDepartment of Geography  University of Tokyo --  Hongo  Bunkyo-ku  Tokyo  Japan 《大气科学进展》1997,(2)

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Element partitioning between metallic liquid, silicate liquid, and lower-mantle minerals: implications for core formation of the Earth     

Eiji Ohtani  Hisayoshi Yurimoto  Shuji Seto 《Physics of the Earth and Planetary Interiors》1997,100(1-4):97-114

We determined the partition coefficients of 19 elements between metallic liquid and silicate liquid at 20 GPa and 2500°C, and between metallic liquid and silicate perovskite at 27 GPa and 2200°C. Remarkable differences were observed in the partitioning behaviors of Si, P, W, Re, and Pb among the silicate liquid, perovskite, and magnesiowüstite coexisting with metallic liquid, reflecting incompatibility of the elements in the silicate or oxide phase. We could not observe any significant difference in the partitioning behaviors of V, Cr, Mn, Co, Ni, and Cu among the phases coexisting with metallic liquid.

Comparison of the present partitioning data with those obtained previously at lower pressure and temperature suggests that the exchange partition coefficients, K_met/sil, of Co, Ni, Mo, and W decrease, whereas those of V, Cr, and Mn increase and tend to approach unity with increasing pressure and temperature. We also made preliminary experiments to clarify the effect of sulfur on the partitioning behaviors. Sulfur lowers the exchange partition coefficients, K_met/sil, of Mo and W between metallic liquid and silicate liquid significantly at 20 GPa and 2300°C.

The mantle abundances of Co, Ni, Cu, Mo, and W calculated for the metal-silicate equilibrium model are lower than those of the real mantle, whereas P, K, and Mn are overabundant in the calculated mantle. The discrepancies in the abundances of Co and Ni could be explained by the chemical equilibrium at higher pressure and temperature. Large discrepancies in Mo and W between the calculated and real mantles could be accounted for by the effect of sulfur combined with the effects of pressure and temperature on the chemical equilibrium. The mantle abundances of P, K, and Cu could be accounted for by volatile loss in the nebula, perhaps before accretion of the Earth, combined with the chemical equilibrium at higher pressure and temperature. Thus the observed mantle abundances of P, K, Co, Ni, Cu, Mo, and W may be consistent with a model of sulfur-bearing metal-silicate equilibrium in lower-mantle conditions.  相似文献