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151.
Kenji Notsu Toshiya Mori Sandie Chanchah Do Vale Hiroyuki Kagi Takamori Ito 《Pure and Applied Geophysics》2006,163(4):825-835
Since the 8th century, more than seventeen eruptions have been recorded for the Mt. Fuji volcano, with the most recent eruption
occurring in 1707 (Hoei eruption). For the past 300 years the volcano has been in a quiescent stage and, since the early 1960s,
has exhibited neither fumarolic nor thermal activity. However, the number of low-frequency earthquakes with a hypocentral
depth of 10–20 km increased significantly beneath the northeastern flank of Mt. Fuji in 2000–2001, suggesting a possible resumption
of magmatic activity. In this study, diffuse CO2 efflux and thermal surveys were carried out in four areas of the volcano in 2001–2002 in order to detect possible signs of
the upward movement of deep magma. At all survey points, the CO2 efflux was below the detection limit with the exception of a few points with biological CO2 emission, and ground temperatures at a depth of 20–30 cm were below ambient, indicating no surface manifestations of gas
or heat emission. Should magma rise into the subsurface, the diffuse CO2 efflux would be expected to increase, particularly along the tectonically weakened lineation on the Mt. Fuji volcano, allowing
for the early detection of pre-eruptive degassing. 相似文献
152.
Kaiki Taro Inoue Kenji Tomita Naoshi Sugiyama 《Monthly notices of the Royal Astronomical Society》2000,314(4):L21-L25
The effect of a non-trivial topology on the temperature correlations of the cosmic microwave background (CMB) in a small compact hyperbolic universe with volume comparable to the cube of the curvature radius is investigated. Because the bulk of large-angle CMB fluctuations are produced at the late epoch in low-Ω0 models, the effect of a long-wavelength cut-off owing to the periodic structure does not lead to significant suppression of large-angle power as in compact flat models. The angular power spectra are consistent with COBE data for Ω0 0.1. 相似文献
153.
154.
155.
David Gubbins Peter Molnar J. G. Olliver Petr Vanīček Kenji Satake Allan M. Rubin Waclaw M. Zuberek Janusz Niewiadomski Leszek Czechowski David J. Steveson Jacek Leliwa-Kopystyński Yu. N. Korenkov Fred Lipschultz Marek Jerczyński Krzysztof E. Haman Jerzy Radziwill Maciej Sadowski Maciej Sadowski 《Pure and Applied Geophysics》1990,132(3):599-637
156.
David M. Jenkins Juan Carlos Corona William A. Bassett Kenji Mibe Zhongwu Wang 《Physics and Chemistry of Minerals》2010,37(4):219-226
The compressibilities of two synthetic glaucophane samples were measured over the range of 0–10 GPa at ambient temperature
in a diamond-anvil cell at the Cornell High-Energy Synchrotron Source (CHESS). The pressure–volume data were fitted to the
Birch–Murnaghan equation of state taking care to include only data with a minimum of deviatoric stress. When using a second-order
truncation, both samples yielded essentially identical values of the bulk modulus K
0, which had an average value of 91.8 ± 1.3 GPa. Maximum compression was observed approximately along the a* axis as shown by the strain ellipsoid and supported by the a axis showing the highest compressibility. These results agree closely with the earlier study of a natural glaucophane single-crystal
by Comodi et al. (Eur J Mineral 3:485–499, 1991), suggesting that the substitution of about 20–30 mol.% of Fe for Mg and Al in the structure may not significantly change
its compressibility. 相似文献
157.
We measured the electrical resistivity of face-centered-cubic (fcc) structured iron hydrides at high pressures up to 65 GPa and high temperatures in a laser-heated diamond anvil cell. The results indicate that the resistivity of stoichiometric fcc FeHx (x ~ 1.0) is smaller than that of fcc Fe at the same pressure and temperature conditions. The same behavior was also observed in fcc FeNiHx (x ~ 1.0). On the other hand, hydrogen-poor fcc FeHx (x < 0.77) showed a resistivity comparable to that of the fcc phase of pure iron. Therefore, we conclude that the stoichiometric fcc Fe (–Ni) hydride is more conductive than Fe (–Ni) with the same crystal symmetry, and the impurity resistivity of hydrogen in Fe is vanishingly small. Even if hydrogen is the major light element in the Earth's core, it would have little influence on the electrical and thermal conductivity of Fe–Ni alloys, and hence the thermal evolution of the core. 相似文献
158.
Tomoki Watanabe Hiroaki Takahashi Masayoshi Ichiyanagi Muneo Okayama Masamitsu Takada Riyo Otsuka Kenji Hirata Shigehiko Morita Minoru Kasahara Hitoshi Mikada 《Tectonophysics》2006,426(1-2):107
Japan Marine Science and Technology Center installed a cabled geophysical observatory system off Kushiro, Hokkaido Island in July 1999. This observatory system comprises three ocean bottom seismographs (OBSs), two tsunami gauges, and a geophysical/geochemical monitoring system. 4 years and 2 months after the installation, a megathrust earthquake (the 2003 Tokachi-Oki earthquake, 26th September in Japan Standard Time (JST), MJMA 8.0) occurred along a plate boundary underneath a forearc basin where the system is located. The system recorded clear unsaturated seismograms just at 28.6 km from the epicenter. This paper demonstrates advantages brought by the cabled observatory to record the megathrust earthquake showing how earthquake detectability is improved dramatically combining permanent OBS and land-based observations around the region, and importance of the in situ monitoring on the seismogenic zone. In the present study, processing OBSs and land-based network together, and comparing magnitudes of common observed earthquakes with national authorized network, event detection level improved down to M 1.5, which is much lower than the previously designed as down to M 2. Comparing detection level before and after installing OBSs, we found dramatic improvement of the earthquake detection level in the interesting region. Real-time continuous observations of microearthquakes since 1999 have brought us tremendous findings. First, a seismic quiescence started about 10 days before the 2003 Tokachi-Oki earthquake. Second, aftershock distribution is not uniform over the focal area and can be divided into several sub-regions, which might indicate an existence of several asperities. We think that the geophysical observations helped to understand the initiation process of the rupture of the 2003 Tokachi-Oki earthquake and that observations including seismological, geodynamic, hydrogeological, and the other multidisciplinary observations would provide a clue to future understanding of seismogenic processes at subduction zones. 相似文献
159.
Toshiyuki Kurihara Kazuhiro Tsukada Shigeru Otoh Kenji Kashiwagi Minjin Chuluun Dorjsuren Byambadash Bujinlkham Boijir Sersmaa Gonchigdorj Manchuk Nuramkhan Masakazu Niwa Tetsuya Tokiwa Gen’ya Hikichi Takafumi Kozuka 《Journal of Asian Earth Sciences》2009,34(2):209-225
Recent mapping projects undertaken in Central Mongolia have revealed the widespread occurrence of radiolarian chert within a Paleozoic accretionary complex. We present the results of the first detailed tectonostratigraphic and radiolarian biostratigraphic investigations of the Gorkhi Formation in the Khangai–Khentei belt of the Central Asian Orogenic Belt.The Gorkhi Formation consists of sandstone shale, alternating sandstone and shale of turbidite affinity and chert with small amounts of siliceous shale, basalt, limestone, and clast-bearing mudstone. Radiolarian chert that is completely devoid of terrigenous clastic material is commonly associated with underlying basalt (sedimentary contact) and with conformably overlying siliceous shale and turbidite deposits. The tectonic stacking of basalt–chert and chert–turbidite successions is the most remarkable structural feature of the formation.The recovery of moderately well-preserved radiolarians and conodonts from red chert led to the recognition of four radiolarian assemblages that have a combined age range from the latest Silurian (Pridolian) to the Late Devonian (Frasnian). No age control exists for the siliceous shale, shale, and sandstone, although they are considered to be latest Devonian or slightly younger on the basis of stratigraphic relationships with underlying chert.The Gorkhi Formation has previously been interpreted as a thick sedimentary basin deposit overlying an unexposed Archean–Neoproterozoic basement; however, the stratigraphy within individual tectonic slices clearly corresponds to that of an ocean plate stratigraphy of an accretionary complex generated by the trenchward movement of an oceanic plate. From the lowermost to uppermost units, the stratigraphy comprises ocean floor basalt, pelagic deep-water radiolarian chert, hemipelagic siliceous shale, and terrigenous turbidite deposits. The biostratigraphic data obtained in the present study provide corroborating evidence for the existence of an extensive deep-water ocean that enabled the continuous sedimentation of pelagic chert over a period of nearly 50 million years. These data, together with structural data characterized by tectonic repetition of the stratigraphy, indicate that these rocks formed as an accretionary wedge along an active continental margin, possibly that of the Angara Craton. The mid-oceanic chert was probably deposited in the Northern Hemisphere portion of the Paleo–Pacific Ocean that faced the Angara Craton and the North China–Tarim blocks. Thus, we propose that subduction–accretion processes along the Paleo–Pacific rim played an important role in the accretionary growth of the active continental margin of the Angara Craton, directly influencing the evolution of the Central Asian Orogenic Belt. 相似文献
160.
Serial data from soil–sawdust column experiments were used to develop a mathematical model to describe the biological sulfate
reduction processes in porous media. The mathematical model numerically solves the equation of solute transport in one-dimensional
saturated state. Solute transport is coupled to sulfate reducing bacteria sub model. Bacterial growth is assumed to follow
double Monod kinetic equation. Two bacterial groups (X1 and X2) were described. Bacterial group X1 uses under aerobic conditions
oxygen and under anaerobic conditions nitrate as electron acceptor. Under anaerobic conditions bacterial groups X2, use sulfate
as an electron acceptor. Sulfate rich wastewater is usually deficient in electron donor and requires external addition of
electron donors in order to achieve complete sulfate reduction. The organic carbon as electron donor is one of the most important
factors that affect sulfate reduction bacterial activity. In this study the possible source of organic carbon is the solid
organic carbon supplied to the system in the form of sawdust. The results of this study indicate that sawdust could be employed
as low-cost materials to enhance the biological sulfate reduction processes in porous media. While the availability of organic
carbon as electron donor is one of the most important factors that affect the sulfate reducing bacterial activity in porous
media, this study demonstrates that using sawdust as a carbon source can improve the bacterial activity and increase the column
permeability. 相似文献