The fractal nature of the inhomogeneities in the lithosphere evidenced from seismic wave scattering     

Ru-Shan Wu  Keiiti Aki 《Pure and Applied Geophysics》1985,123(6):805-818

In this paper we show evidences of the fractal nature of the 3-D inhomogeneities in the lithosphere from the study of seismic wave scattering and discuss the relation between the fractal dimension of the 3-D inhomogeneities and that of the fault surfaces. Two methods are introduced to measure the inhomogeneity spectrum of a random medium: 1. the coda excitation spectrum method, and 2. the method of measuring the frequency dependence of scattering attenuation. The fractal dimension can be obtained from the inhomogeneity spectrum of the medium. The coda excitation method is applied to the Hindu-Kush data. Based on the observed coda excitation spectra (for frequencies 1–25 Hz) and the past observations on the frequency dependence of scattering attenuation, we infer that the lithospheric inhomogeneities are multiple scaled and can be modeled as a bandlimited fractal random medium (BLFRM) with an outer scale of about 1 km. The fractal dimension of the 3-D inhomogeneities isD ₃=31/2–32/3, which corresponds to a scaling exponent (Hurst number)H=1/2–1/3. The corresponding 1-D inhomogeneity spectra obey the power law with a powerp=2H+1=2–5/3. The intersection between the earth surface and the isostrength surface of the 3-D inhomogeneities will have fractal dimensionD ₁=1.5–1.67. If we consider the earthquake fault surface as developed from the isosurface of the 3-D inhomogeneities and smoothed by the rupture dynamics, the fractal dimension of the fault trace on the surface must be smaller thanD ₁, in agreement with recent measurements of fractal dimension along the San Andreas fault.  相似文献   

Determination of seismic moment tensor using surface waves   总被引：1，自引：0，他引：1  

Keiiti Aki  Howard Patton 《Tectonophysics》1978,49(3-4)

  相似文献   

Amplitude and phase data inversions for phase velocity anomalies in the Pacific Ocean basin   总被引：1，自引：0，他引：1  

Kiyoshi Yomogida  Keiiti Aki 《Geophysical Journal International》1987,88(1):161-204

  相似文献   

Bias in the estimate of seismic moment tensor by the linear inversion method   总被引：2，自引：0，他引：2  

Howard Patton  Keiiti Aki 《Geophysical Journal International》1979,59(3):479-495

Summary. We investigate the effects of various sources of error on the estimation of the seismic moment tensor using a linear least squares inversion on surface wave complex spectra. A series of numerical experiments involving synthetic data subjected to controlled error contamination are used to demonstrate the effects. Random errors are seen to enter additively or multiplicitively into the complex spectra. We show that random additive errors due to background recording noise do not pose difficulties for recovering reliable estimates of the moment tensor. On the other hand, multiplicative errors from a variety of sources, such as focusing, multipathing, or epicentre mislocation, may lead to significant overestimation or underestimation of the tensor elements and in general cause the estimates to be less reliable.  相似文献   

A numerical study of two-dimensional spontaneous rupture propagation   总被引：4，自引：0，他引：4  

Shamita Das  Keiiti Aki 《Geophysical Journal International》1977,50(3):643-668

  相似文献   

Pre-eruptive migration of earthquakes at the Piton de la Fournaise volcano (Réunion Island)     

Jean Battaglia  Valérie Ferrazzini  Thomas Staudacher  Keiiti Aki  Jean-Louis Cheminée 《Geophysical Journal International》2005,161(2):549-558

  相似文献   

Progress report on the determination of seismic moment tensor from long-period surface waves     

Keiiti Aki 《Tectonophysics》1982,84(1):1-2

  相似文献   

Acknowledgement     

Keiiti Aki  Renata Dmowska 《Pure and Applied Geophysics》1987,125(6):1119-1120

  相似文献   

Distribution of nitrate over sea-salt and soil derived particles — Implications from a field study   总被引：1，自引：0，他引：1  

Tuomo A. Pakkanen  Veli-Matti Kerminen  Risto E. Hillamo  Minna Màkinen  Timo Màkelà  Aki Virkkula 《Journal of Atmospheric Chemistry》1996,24(2):189-205

A method for determining the distribution of supermicrometer nitrate between size-segregated sea-salt and soil derived particles is presented. The analysis is based on field data from six measurements at a coastal site in southern Finland, and on a theoretical treatment taking into account the transfer of gaseous species onto particle surfaces and their subsequent reaction. Significant amounts of nitrate were found in both the particle types, with the fraction of nitrate associated with soil particles varying from 20–50% in the 1–2 m size to near 90% in particles larger than 10 m. Overall, the nitrate accumulation followed closely the relative abundances of these two particle types. Two overlapping modes in supermicron nitrate mass size distributions could be identified. The lower mode, associated with sea-salt, was located between the surface-area and volume distribution of sodium peaking at about 2–3 m of EAD. The upper mode peaked at 3–5 m and followed more closely the surface-area distribution of calcium in all samples. At our site, the accumulation of nitrate into both particle types was shown to be limited by an effective surface reaction rate rather than by gas-phase diffusion. This rate was estimated to be considerably larger for sea-salt particles. Strong evidence in support of the saturation of nitrate in sea-salt particles were obtained.  相似文献   

Seismic foci in the far east | V.N. Aver'yanova, 1973. (Translated from Russian.) Wiley,Chichester, 207 pp., £ 8.45     

K. Aki 《Earth》1974,10(1):78-79

  相似文献