共查询到20条相似文献，搜索用时 15 毫秒
1.
Correlations of earthquake focal mechanisms 总被引：1，自引：0，他引：1
Y. Y. Kagan 《Geophysical Journal International》1992,110(2):305-320
2.
Multifractal analysis of earthquake catalogues 总被引：1，自引：0，他引：1
3.
Likelihood analysis of earthquake catalogues 总被引：5，自引：0，他引：5
Y. Y. Kagan 《Geophysical Journal International》1991,106(1):135-148
We apply several classes of stochastic multidimensional models to statistical analysis of earthquake catalogues using likelihood methods. We investigate the importance of including different earthquake parameters in the model: epicentral coordinates, hypocentral depth, time limits for interearthquake interaction, and especially spatial distribution of earthquakes as well as spatial aftershock patterns. Results of this study combined with other investigations, suggest that most distributions controlling earthquake interaction have a fractal or scale-invariant form. Developed models are used for statistical analysis of several earthquake catalogues to evaluate parameters of earthquake occurrence. These parameters are shown to be similar for shallow earthquakes of different magnitude ranges and seismogenic regions, confirming self-similarity of the earthquake process. Whereas intermediate earthquakes seem to emulate the pattern of shallow earthquake occurrence, albeit at a much smaller aftershock rate, deep earthquakes differ significantly in their properties. Predictability of standard shallow earthquake catalogues has been analysed; we present evidence that for the best available catalogues the predictability is close to 10 bits per earthquake. Several synthetic earthquake catalogues have been created and processed through the likelihood inversion scheme. The results from likelihood analysis of these catalogues confirm our approach. 相似文献
4.
Testing alarm-based earthquake predictions 总被引：1，自引：0，他引：1
5.
A successfully stress-forecast earthquake 总被引：21，自引：0，他引：21
Stuart Crampin Theodora Volti & Ragnar Stefánsson 《Geophysical Journal International》1999,138(1):F1-F5
A M = 5 earthquake in Iceland has been successfully 'stress forecast' by using variations in time delays of seismic shear wave splitting to assess the time and magnitude at which stress-modified microcracking reaches fracture criticality within the stressed volume where strain is released. Local investigations suggested the approximate location of the forecast earthquake. We report the criteria on which this stress forecast was based. 相似文献
6.
Temporal correlations of earthquake focal mechanisms 总被引：7，自引：0，他引：7
Yan Y. Kagan 《Geophysical Journal International》2000,143(3):881-897
7.
Shamita Das 《Geophysical Journal International》1993,115(3):778-798
8.
Tom Ouchi 《Geophysical Journal International》1982,70(1):173-189
Summary. The frequency of earthquake occurrence in a given region can be formulated as
where n ( t ) is the number of earthquakes per unit time, and r, k and α are constants. Empirically determined values of α range from 0.67 to 1.0. This is a generalization of the modified Omori formula for aftershocks, the latter being an approximation of the former for n > k. This formula adequately describes the initial increasing and later decreasing activity of earthquakes during the Matsushiro and Wakayama swarms as well as aftershocks of large earthquakes.
When a random external force is added to this system as a driving mechanism, the equation above becomes
where v = l n ( n/k ) and R ( t ) is the random Gaussian noise. Repetitive seismic patterns with bursts, which are commonly observed in real earthquake sequences, are predicted from this formulation under stationary conditions. These formulations appear to be quite promising in helping to understand macroscopic features of the microearthquake activity. 相似文献
where n ( t ) is the number of earthquakes per unit time, and r, k and α are constants. Empirically determined values of α range from 0.67 to 1.0. This is a generalization of the modified Omori formula for aftershocks, the latter being an approximation of the former for n > k. This formula adequately describes the initial increasing and later decreasing activity of earthquakes during the Matsushiro and Wakayama swarms as well as aftershocks of large earthquakes.
When a random external force is added to this system as a driving mechanism, the equation above becomes
where v = l n ( n/k ) and R ( t ) is the random Gaussian noise. Repetitive seismic patterns with bursts, which are commonly observed in real earthquake sequences, are predicted from this formulation under stationary conditions. These formulations appear to be quite promising in helping to understand macroscopic features of the microearthquake activity. 相似文献
9.
Stochastic model of earthquake fault geometry 总被引：1，自引：0，他引：1
Y. Y. Kagan 《Geophysical Journal International》1982,71(3):659-691
10.
11.
Simulated annealing for earthquake location 总被引：1，自引：0，他引：1
Stephen D. Billings 《Geophysical Journal International》1994,118(3):680-692
12.
Robert A. J. Matthews 《Geophysical Journal International》1997,131(3):526-529
I apply Decision Theory to the question of how accurate earthquake predictions must be to serve as a reliable basis for action. Even with optimistic estimates of the parameters involved, the lower bound on the required accuracy is extraordinarily demanding, being over 10 times higher than that of current meteorological forecasts. Given the abruptly self-organizing nature of earthquakes, it is extremely unlikely that precursors can attain such levels of accuracy. I therefore conclude that prediction of major earthquakes is, in any practical sense, impossible. 相似文献
13.
The basis for earthquake prediction 总被引：3，自引：0，他引：3
Stuart Crampin 《Geophysical Journal International》1987,91(2):331-347
Summary. Recent advances in understanding the behaviour of shear waves propagating in the crust make the routine prediction of earthquakes seem practicable. Accumulating evidence suggests that most of the Earth's crust is pervaded by distributions of fluid-filled cracks and microcracks that are aligned by the contemporary stress-field so that the cracked rockmass is effectively anisotropic to seismic waves. This causes shear-waves to split, and shear-wave splitting is observed whenever shear-waves propagating along suitable raypaths in the crust are recorded by three-component instruments. These distributions of cracks are known as extensive-dilatancy anisotropy or EDA. Many characteristics of the crack- and stress-geometry can be monitored by analyzing shear-waves propagating through the cracked rockmass. Observations of temporal variations of the behaviour of shear-wave splitting in seismic gaps confirm these hypotheses, and suggest that stress changes before earthquakes may be monitored by analyzing shear-waves. In particular, monitoring earthquake preparation zones with three-component shear-wave vertical-seismic-profiles could lead to techniques for the routine prediction of earthquakes. 相似文献
14.
A statistical evaluation of a 'stress-forecast' earthquake 总被引：5，自引：0，他引：5
15.
3-D rotation of double-couple earthquake sources 总被引：10，自引：0，他引：10
Y. Y. Kagan 《Geophysical Journal International》1991,106(3):709-716
16.
The balance of energy in earthquake faulting 总被引：1，自引：0，他引：1
F. A. Dahlen 《Geophysical Journal International》1977,48(2):239-261
17.
The NW Scotland earthquake swarm of 1974 总被引：1，自引：0，他引：1
Marcelo Assumçã 《Geophysical Journal International》1981,67(3):577-586
Summary. A swarm of earthquakes occurred in the Kintail area of NW Scotland in 1974 August with magnitudes up to ML = 4.6 and reported intensities up to VI MM. One earthquake of the series was recorded by about 60 temporary stations of the LISPB refraction experiment in addition to the permanent LOWNET network. This allowed the determination of an accurate epicentre for that event which was then used as a control event to locate other earthquakes of the Kintail series. The events of that swarm had a strikeslip focal mechanism and seemed to be associated with the Strathconon Fault. 相似文献
18.
Roberto Sabadini Riccardo E. M. Riva Giorgio Dalla Via 《Geophysical Journal International》2007,171(1):231-243
Polar motion is modelled for the large 2004 Sumatra earthquake via dislocation theory for an incompressible elastic earth model, where inertia perturbations are due to earthquake-triggered topography of density–contrast interfaces, and for a compressible model, where inertia perturbation due to compression-dilatation of Earth's material is included; density and elastic parameters are based on a multilayered reference Earth. Both models are based on analytical Green's functions, propagated from the centre to the Earth's surface. Preliminary and updated seismological solutions are considered in elucidating the effects of improving earthquake parameters on polar motion. The large Sumatra thrust earthquake was particularly efficient in driving polar motion since it was responsible for large material displacements occurring orthogonally to the strike of the earthquake and to the Earth's surface, as imaged by GRACE gravity anomalies over the earthquake area. The effects of earthquake-induced topography are four times larger than the effects of Earth's compressibility, for l = 2 geopotential components. For varying compressional Earth properties and seismic solution, modelled polar motion ranges from 8.6 to 9.4 cm in amplitude and between 117° and 130° east longitude in direction. The close relationship between polar motion direction, earthquake longitude and thrust nature of the event, are established in terms of basic physical concepts. 相似文献
19.
Confidence intervals for earthquake source parameters 总被引：2，自引：0，他引：2
G. A. Prieto D. J. Thomson F. L. Vernon P. M. Shearer R. L. Parker 《Geophysical Journal International》2007,168(3):1227-1234