Dynamical rupture process on a three-dimensional fault with non-uniform frictions and near-field seismic waves   总被引：1，自引：0，他引：1  

Takeshi Mikumo  Takashi Miyatake 《Geophysical Journal International》1978,54(2):417-438

Summary. Dynamical rupture process on the fault is investigated in a quasi-three-dimensional faulting model with non-uniform distributions of static frictions or the fracture strength under a finite shearing pre-stress. The displacement and stress time functions on the fault are obtained by solving numerically the equations of motion with a finite stress—fracture criterion, using the finite difference method.
If static frictions are homogeneous or weakly non-uniform, the rupture propagates nearly elliptically with a velocity close to that of P waves along the direction of pre-stress and with a nearly S wave velocity in the direction perpendicular to it. The rise time of the source function and the final displacements are larger around the centre of the fault. In the case when the static frictions are heavily non-uniform and depend on the location, the rupture propagation becomes quite irregular with appreciably decreased velocities, indicating remarkable stick-slip phenomena. In some cases, there remain unruptured regions where fault slip does not take place, and high stresses remain concentrated up to the final stage. These regions could be the source of aftershocks at a next stage.
The stick—slip faulting and irregular rupture propagation radiate high-frequency seismic waves, and the near-field spectral amplitudes tend to show an inversely linear frequency dependence over high frequencies for heavily non-uniform frictional faults.  相似文献   

Far-infrared properties of metallic dust grains     

Toshihiko Tanabé  Takashi Onaka  Fumio Kamijo 《Astrophysics and Space Science》1984,98(2):323-342

Far-infrared properties of metallic particle are reinvestigated in detail. In the far-infrared region, absorption due to the eddy current generally dominates over that obtained by using the Rayleigh approximation erroneusly. The wavelength dependence of the eddy current term is examined carefully and shown to be less steep than that predicted by the Rayleigh approximation for dust grains larger than 100 nm in radius. It also depends more sensitively on the grain size. A wider temperature distribution is expected corresponding to a given size distribution and hence the emission spectrum becomes less steep than the preductions by the Rayleigh approximation. Iron and graphite particles are investigated as typical interstellar metallic grains. Effects of coating of dielectric materials are also examined. Comparisons with experimental results and with observations are discussed.  相似文献   

Arsenic accumulation and distribution in tissues of black-footed albatrosses     

Fujihara J  Kunito T  Kubota R  Tanaka H  Tanabe S 《Marine pollution bulletin》2004,48(11-12):1153-1160

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Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast     

Kunito T  Nakamura S  Ikemoto T  Anan Y  Kubota R  Tanabe S  Rosas FC  Fillmann G  Readman JW 《Marine pollution bulletin》2004,49(7-8):574-587

Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n = 20), Franciscana dolphin (Pontoporia blainvillei; n = 23), Atlantic spotted dolphin (Stenella frontalis; n = 2), common dolphin (Delphinus capensis; n = 1) and striped dolphin (Stenella coeruleoalba; n = 1) incidentally caught along the coast of Sao Paulo State and Parana State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 microg/g dry wt.) and Zn (range, 242-369 microg/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 microg/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg+0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag2Se in the liver of Franciscana dolphin.  相似文献   

Spin rates of fast-rotating asteroids and fragments in impact disruption     

Toshihiko Kadono  Masahiko Arakawa  Takashi Ito  Keiji Ohtsuki 《Icarus》2009,200(2):694-697

We present a new experimental result of fragment spin-rate in impact disruption, using a thin glass plate. A cylindrical projectile impacts on a side (edge) of the plate. Dispersed fragments are observed using a high-speed camera and the spin rates of fragments are measured. We find that the measured fragment spin-rate decreases with increasing size. Assuming that the rotational energy of fragments is supplied from the residual stress, the spin rate ω decreases with increasing fragment size r as ω∼r−1, which explains the above experimental results. This size-dependence is similar to that of the observed spin rates of small fast-rotating asteroids. Our results suggest that spin rates of fragments of small asteroids immediately after disruption may have a similar size-dependence, and can provide constraints on the subsequent spin-state evolution of small asteroids due to thermal torques.  相似文献   

Editorial Appreciation     

John Leibacher  Takashi Sakurai  Lidia van Driel-Gesztelyi 《Solar physics》2009,255(1):1-2

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Solar Physics Publication Ethics Policies     

John Leibacher  Takashi Sakurai  Lidia van Driel-Gesztelyi 《Solar physics》2009,260(1):1-3

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The impact of radio feedback from active galactic nuclei in cosmological simulations: formation of disc galaxies     

Takashi Okamoto  Rodrigo S. Nemmen  Richard G. Bower 《Monthly notices of the Royal Astronomical Society》2008,385(1):161-180

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Preface: A Topical Issue on the <Emphasis Type="Italic">Hinode</Emphasis> Mission     

Takashi Sakurai 《Solar physics》2008,249(2):165-165

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Development of partial factor design method on bending strength of piles for Japanese Specifications for Highway Bridges     

Toshiaki Nanazawa  Tetsuya Kouno  Gaku Sakashita  Takashi Nakaura 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(3):176-184

ABSTRACT

This paper describes the development of a partial factor design method on the bending strength of piles for the Japanese Specifications for Highway Bridges. First, uncertainties in mobilised bending moments and yield bending moments were evaluated by Monte Carlo simulations. Second, the reliability of piles designed by the previous specifications were evaluated on the basis of reliability analysis considering uncertainties in the mobilised bending moments, yield bending moments, and other factors. Finally, a partial factor design method utilising a survey subsurface investigation method and ground type was developed to reach target reliability levels determined by the Standards.  相似文献