Journal ArticleDOI
Estimation of the size of earthquake preparation zones
TLDR
In this article, an approximate solution of the problem for a soft elastic inclusion in an elastic half-space is presented. But the authors assume that the moduli of the inclusion differ slightly from those of the surrounding medium (by no more than 30%).Abstract:
During the earthquake preparation a zone of cracked rocks is formed in the region of a future earthquake focal zone under the influence of tectonic stresses. In the study of the surrounding medium this region may be considered as a solid inclusion with altered moduli. The inclusion appearance causes a redistribution of the stresses accompanied by corresponding deformations. This paper deals with the study of deformations at the Earth's surface, resulting from the appearance of a soft inclusion. The Appendix contains an approximate solution of the problem for a soft elastic inclusion in an elastic half-space. It is assumed that the moduli of the inclusion differ slightly from those of the surrounding medium (by no more than 30%). The solution permits us to calculate the deformations at the Earth's surface for the inclusion with an arbitrary heterogeneity and anisotropy. The problem is solved by the small perturbation method. The calculation is made for a special case of a homogeneous isotropic inclusion where only the shear modulus decreases. The shear stresses act at infinity. The equations are deduced for the estimation of deformations and tilts at the Earth's surface as a function of the magnitude of the preparing earthquake and the distance from the epicentre. Comparison has shown a satisfactory agreement between the theoretical and field results. Let us assume that the zone of effective manifestation of the precursor deformations is a circle with the centre in the epicentre of the preparing earthquake. The radius of this circle called ‘strain radius’ may be calculated from the equation
$$\rho = 10^{0.43M} km,$$
where M is the magnitude. It was shown that the precursors of other physical nature fall into this circle.read more
Citations
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Journal ArticleDOI
An observational test of the critical earthquake concept
TL;DR: In this paper, the authors test the concept that seismicity prior to a large earthquake can be understood in terms of the statistical physics of a critical phase transition and find the critical region before all earthquakes along the San Andreas system since 1950 with M ≥ 6.5.
Journal ArticleDOI
Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) Model - An Unified Concept for Earthquake Precursors Validation
TL;DR: In this paper, the authors present a multidisciplinary approach to the problem of clarification the nature of short-term earthquake precursors observed in atmosphere, atmospheric electricity and in ionosphere and magnetosphere.
Journal ArticleDOI
Statistical physics approach to understanding the multiscale dynamics of earthquake fault systems
John B. Rundle,Donald L. Turcotte,Robert Shcherbakov,William Klein,William Klein,Charles G. Sammis +5 more
TL;DR: In this paper, the authors argue that the occurrence of earthquakes is a problem that can be attacked using the fundamentals of statistical physics, and they apply statistical physics associated with phase changes and critical points to a variety of cellular automata models.
Journal ArticleDOI
Migration of carrier and trace gases in the geosphere: an overview
TL;DR: The role of gas diffusion and water advection in the transport of endogenous gas to the Earth surface should be strongly minimized in many contexts as mentioned in this paper, in contrast with early views.
Journal ArticleDOI
Gas geochemistry applied to earthquake prediction: An overview
TL;DR: In this paper, the authors studied the anomalous high concentrations of radon, helium, hydrogen, mercury, carbon dioxide, and several other volatiles along active faults, suggesting that the faults may be paths of least resistance for the terrestrial gases generated or stored in the earth to escape to the atmosphere.
References
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Journal ArticleDOI
The Determination of the Elastic Field of an Ellipsoidal Inclusion, and Related Problems
TL;DR: In this paper, it is shown that to answer several questions of physical or engineering interest, it is necessary to know only the relatively simple elastic field inside the ellipsoid.
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Displacements, strains, and tilts at teleseismic distances
TL;DR: In this paper, the dislocation theory representation of faulting is used to compute the residual displacement, strain, and tilt fields at intermediate and large distances from major earthquakes, and it is shown that the distant fields are large enough to be detected by modern instruments.
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Two Models for Earthquake Forerunners
TL;DR: In this article, two different physical models are used to explain precursory phenomena before earthquakes in the United States, the Soviet Union, Japan, and China: the dilatancy diffusion model and the dry model.
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Earthquake lights: A review of observations and present theories
TL;DR: The best documented observations of earthquake lights are from Japanese earthquakes in the early 19309s and mid-19609s as mentioned in this paper, restricted to mountain summits in a quartz-diorite faulted rock.
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Time‐dependent seismology
TL;DR: In this article, it was shown that cracks of low aspect ratio are required to satisfy the velocity and uplift constraints, and the recovery of velocity prior to fracture can be due to fluid flow or crack closure.