全文获取类型
收费全文 | 63篇 |
免费 | 1篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 4篇 |
地球物理 | 31篇 |
地质学 | 7篇 |
海洋学 | 5篇 |
天文学 | 1篇 |
自然地理 | 14篇 |
出版年
2021年 | 2篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2003年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1963年 | 1篇 |
1956年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有64条查询结果,搜索用时 109 毫秒
1.
2.
The full waveform synthetic seismogram of multiple scatteredSH waves by many cylindrical cavities in two-dimensional homogeneous elastic media is computed. We used the so-called single-layer potential integral representation of the scattered field and a discretization scheme with line source distribution for each cavity. The total field is the sum of the incident wave plus the field radiated from all sources, each multiplied by an unknown complex constant representing its strength. These constants are determined by imposing the appropriate boundary conditions in the least-squares sense. Here we solve scattering problems involving one, two, four, twelve and fifty cavities regularly distributed in a half-space. The seismograms computed along the free-surface show regions where the incident wave is strongly attenuated, as well as the arrivals of all multiple scattered phases. The accuray of the method is estimated from the degree of agreement of our solution for one cavity with the corresponding analytical solution, and also from the magnitude of the residual tractions along the boundaries of two cavities separated at various distances. Finally we apply the method to compute the case of fifty cylindrical cavities, each of radiusa, randomly distributed in a region 80a wide by 30a deep in a half-space. The value of scattering loss is obtained from the amplitude decay of the primary wave with distance for wavelengths in the range from 1.7a to 13.3a, using the synthetic seismogram calculated for the same distribution of 50 cavities as above, but in full-space. 相似文献
3.
Keiiti Aki 《Pure and Applied Geophysics》1995,145(3-4):647-676
In order to develop capabilities for predicting earthquake processes on the basis of known fault zone structures and stress conditions, we need to find relations between seismogenic structures and processes. In the present paper we search for the scale dependence in various earthquake phenomena with the hope to find some structures in the earth that may control the earthquake processes. Among these phenomena, we shall focus on (1) geologic structures which play some role in nucleation and stopping of earthquake fault rupture, (2) depth ranges of the brittle seismogenic zone, (3) asperities and barriers distributed over a fault plane, (4) source-controlledf
max effect, (5) nonfractal behavior of creep events, and (6) temporal correlation between codaQ
–1 and seismicity of earthquakes with magnitude characteristic to a given area. Our review of various scale-dependent phenomena leads us to propose a working hypothesis that the temporal change in codaQ
–1 may reflect the activity of creep fractures near the brittle-ductile transition zone. 相似文献
4.
5.
6.
In this study, we present a new and effective method to determine the dynamic source parameters (i.e., stress drop and strength distribution). We first assume that the kinematic source parameters, i.e., the slip and rupture time distributions on the fault plane, are known from the previous source inversion studies. Then, using the seismic source representation theorem we determine the dynamic stress field on a fault plane from known kinematic parameters. Finally, we determine the strength of the fault defined as the peak stress just before the rupture. We have tested the validity of this method by using an illustrative two-dimensional analytical example. To assess the applicability of this method, we have applied it to study the 1979 Imperial Valley earthquake, and obtained consistent results with those ofMiyatake's (1992) andQuin's (1990). Compared with previous methods, this new method is simple, straightforward and accurate, and needs much less calculation. Therefore, it is expected to be useful in exploring the seismic source process. 相似文献
7.
A. Sakuma 《Journal of Geodesy》1963,37(3):249-260
Résumé L'état actuel des études préliminaires d'une mesure absolue de g au B.I.P.M. basée sur le principe de la “méthode des deux
stations” [1] est résumé dans cette note.
Une précision de g plus élevée que celle qui a été obtenue jusqu'à présent, est espérée à cause des avantages des mesures
symétriques dans cette méthode et des observations interférentielles des passages d'un corps lancé (un trièdre formé de trois
miroirs orthogonaux) à des stations fixes.
Nous envisageons qu'une précision de g de l'ordre de 0,1 mgal sera réalisable avec cette méthode.
Summary In this note, the present stage is outlined in the preparations for an absolute determination of gravity at B.I.P.M., based on the principle of “La méthode des deux stations” [1] (or so called “The up and down motion method”). It is expected that a value of g of greater accuracy than previous measurements will be obtained, due to the use of the symmetrical measurements by this principle and the use of the interferometric observations of the passage of the projected body (a corner cube reflector) in free fall across fixed horizontal stations. It seems probable that an accuracy of the order of 0.1 mgal will be obtained by this method.相似文献
8.
9.
10.