Analysis of temporal and spatial heterogeneity of magnitude frequency distribution inferred from earthquake catalogues   总被引：11，自引：0，他引：11  

Yosihiko Ogata  Koichi Katsura 《Geophysical Journal International》1993,113(3):727-738

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Thermal diffusivity of silica glass at pressures up to 9 GPa     

Tomoo Katsura 《Physics and Chemistry of Minerals》1993,20(3):201-208

The thermal diffusivity of silica glass was measured at pressures up to 9 GPa and temperatures up to 1200 K. The measurements involve adopting the Ångström method to a cylindrical geometry in a uniaxial split-sphere apparatus. This method can be used to determine thermal diffusivity in samples with dominant conductive heat transfer. The thermal diffusivity of silica glass has a negative first pressure derivative but a positive second pressure derivative. Although the elastic moduli have minima near 3 GPa, the thermal diffusivity does not has minimum up to 9 GPa, which cannot be explained by the model of Kittel (1949). The negative pressure derivative of thermal diffusivity is a feature probably unique in silica glass, and its magnitude should decrease with the addition of Na₂O.  相似文献   

High-temperature emplacement and liquefaction of shallow-water caldera-forming eruption products: Early Miocene Tateyamazaki Dacite in the Oga Peninsula, NE Japan     

Yudai Sato  Kazuhiko Kano  Takeshi Ohguchi  Teiji Yamazaki  Kenshiro Ogasawara 《Sedimentary Geology》2009,220(3-4):218

The Early Miocene Tateyamazaki Dacite infills a 3.2 km diameter caldera. It comprises poorly sorted, massive, biotite-bearing dacite pumice lapilli tuff, in which huge blocks of densely welded dacite lapilli tuff, basaltic andesite lava, and other lithologies are commonly set. Dense blocks are variably cracked and intruded by the host lapilli tuff. Sparse blocks of bedded lapilli tuff and tuff are variably disaggregated to intermingle with the host rocks or are plastically deformed into irregular shapes. Rootless tuff veins millimeters to 30 cm thick are developed within the host rocks, mainly dipping at 10–30°, and are locally branched and mutually cut to form a network. Where thicker, they are stratified and locally carry accidental fragments. Accidental lapilli up to 2 or 3 cm wide and 30 cm long are locally set in near-vertical and variably sinuous arrays. Although poorly defined they are reminiscent of fluid escape structures. The host pumice lapilli tuff, however, retains in part a thermal remnant magnetization (TRM) vector stable at temperatures above 280 °C. Blocks in the caldera fill also retain TRM but the vectors are rotated significantly from those of the host pumice lapilli tuff and the adjacent volcanic rocks. Tateyamazaki Dacite is thus likely to have been emplaced at high temperatures, and intermingled with shattered basement rocks and ambient water to be partly liquefied within the caldera immediately after or during the caldera-forming eruption.  相似文献   

Electrical conductivity of the major upper mantle minerals: a review     

T. Katsura  T. Yoshino  G. Manthilake  T. Matsuzaki 《Russian Geology and Geophysics》2009,50(12):1139-1145

The electrical conductivity of the major upper mantle minerals, namely, olivine, wadsleyite and ringwoodite, is reviewed in this paper. There are mainly three electrical conduction mechanisms for three upper mantle minerals: hopping, ionic and proton conductions. The charge carriers for these conduction mechanisms are an electron hole in Fe ion, a vacancy in Mg site, and a proton, respectively. Hopping conduction is the most essential conduction mechanism for the major upper mantle minerals. Because ionic conduction has high activation energy, it becomes a dominant conduction mechanism only at high temperatures. Proton conduction contributes at relatively low temperatures. If the mantle minerals contain large amount of water (more than 0.1 wt.%), proton conduction can be a dominant conduction mechanism, even at high temperatures.  相似文献   

Petrology of the diamond-grade eclogite in the Kokchetav Massif, northern Kazakhstan   总被引：2，自引：0，他引：2  

K. Okamoto  J. G. Liou and  Y. Ogasawara 《Island Arc》2000,9(3):379-399

Abstract The Kokchetav Massif of northern Kazakhstan is unique because of the abundant occurrence of microdiamond inclusions in garnet, zircon and clinopyroxene of metasediments. In order to determine precise pressure–temperature (P–T) conditions, we have systematically investigated mineral inclusions and the compositions of major silicates in Ti–clinohumite–garnet peridotite and diamond-grade eclogite from Kumdy–Kol. It was found that garnet peridotites from Kumdy–Kol contain assemblages of garnet, olivine, Ti–clinohumite and ilmenite. The garnet contains inclusions that are indicative of both ultrahigh pressure (UHP) and retrograde conditions. Inclusions of hydrous phases such as chlorite, amphibole and zoisite were formed at the post-UHP stage. The study also found that eclogite from Kumdy–Kol contains albite–augite symplectites after omphacitic pyroxene. The core of pyroxene (sodic augite) contains high K₂O (up to 1wt%; average 0.24wt%). Phengite is included in the core. Applying the K₂O-in-augite geobarometry, which is based on recent experiments, and the garnet–clinopyroxene (Grt–Cpx) geothermometer for peak metamorphism, the eclogites yield P–T estimates of > 6 GPa and > 1000 °C, and the diamond-grade eclogites yield lower temperature estimates at 900–1000 °C and 5 GPa.  相似文献   

Interlaboratory comparison of some chemical analyses of Hawaiian Volcanic Rocks     

G. A. Macdonald  H. A. Powers  T. Katsura 《Bulletin of Volcanology》1972,36(1):127-139

The comparability of chemical analyses of Hawaiian volcanic rocks by different laboratories is investigated. The comparability is reasonably good for most purposes, but small differences in compositions of rocks determined by different laboratories should not be used as a basis of classification or to support petrogenic deductions.  相似文献   

Alteration of rock by volcanic gas in Japan     

Iwaji Iwasaki  Mitsuei Hirayama  Takashi Katsura  Takejiro Ozawa  Jyoyo Ossaka  Masaakira Kamada  Hatao Matsumoto 《Bulletin of Volcanology》1964,27(1):65-78

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Nature of volcanic gases and volcanic eruption     

Iwaji Iwasaki  Takejiro Ozawa  Minoru Yoshida  Takashi Katsura  Bunji Iwasaki  Masaakira Kamada 《Bulletin of Volcanology》1963,26(1):73-81

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