Trapped modes of oscillation and localized buckling of a tectonic plate as a possible reason of an earthquake

Author(s):  
S. N. Gavrilov ◽  
Yu. A. Mochalova ◽  
E. V. Shishkina
2016 ◽  
Vol 57 ◽  
pp. 189
Author(s):  
Sunanda Saha ◽  
Swaroop Nandan BORA

Author(s):  
Vladimir Zeitlin

Notions of linear and nonlinear hydrodynamic (in)stability are explained and criteria of instability of plane-parallel flows are presented. Instabilities of jets are investigated by direct pseudospectral collocation method in various flow configurations, starting from the classical barotropic and baroclinic instabilities. Characteristic features of instabilities are displayed, as well as typical patterns of their nonlinear saturation. It is shown that in the Phillips model of Chapter 5, new ageostrophic Rossby–Kelvin and shear instabilities appear at finite Rossby numbers. These instabilities are interpreted in terms of resonances among waves counter-propagating in the flow. It is demonstrated that the classical inertial instability is a specific case of ageostrophic baroclinic instability. At the equator it appears also in the barotropic configuration, and is related to resonances of Yanai waves. The nature of the inertial instability in terms of trapped modes is established. A variety of instabilities of density fronts is displayed.


1975 ◽  
Vol 29 (1-4) ◽  
pp. 1-7 ◽  
Author(s):  
P.L. Bender ◽  
E.C. Silverberg
Keyword(s):  

Author(s):  
Vladimir R. Tuz ◽  
Vyacheslav V. Khardikov ◽  
Natalia V. Sydorchuk ◽  
Denis V. Novitsky ◽  
Sergey L. Prosvirnin
Keyword(s):  

2020 ◽  
Author(s):  
Adrian Lenardic ◽  
Johnny Seales ◽  
William B. Moore ◽  
Matthew B. Weller
Keyword(s):  

1968 ◽  
Vol 34 (1) ◽  
pp. 49-80 ◽  
Author(s):  
M. S. Longuet-Higgins

The possibility of long waves in a rotating ocean being trapped along a straight discontinuity in depth was demonstrated in a recent paper (Longuet-Higgins 1968). The analysis is now extended to the situation where the depth varies continuously, in a zone separating two regions of different depths. The trapping of waves in the transition zone is investigated, taking full account of the horizontal divergence of the motion.If the profile of the depth is assumed to be monotonic, then it is shown that the trapped waves always travel along the transition zone with the shallower water to their right in the northern hemisphere and to their left in the southern hemisphere. The wave period must always exceed a pendulum-day. The period is also bounded below by a quantity depending inversely on the maximum bottom gradient.By allowing the width W of the transition zone to vary, asymptotic forms for the trapped modes are obtained, both as W → 0 and as W → ∞. In the limit as W → 0 the depth becomes discontinuous, and it is shown that the lowest mode then becomes a double Kelvin wave (Longuet-Higgins 1968) propagated along the discontinuity. The periods of the higher modes, on the other hand, all tend to infinity; these modes become steady currents.Numerical calculations of the trapped modes are presented for two different laws of depth in the transition zone. It is found that as W → 0 the lowest mode is insensitive to the form of the depth profile. Higher modes depend on the details of the profile. Hence the lowest mode is the most likely to be observed in the real ocean.The dispersion relation is also investigated. It is shown that the group-velocity of all modes must change sign at some point in the range of wave-numbers, if the divergence is taken into account. When the divergence was neglected the lowest mode appeared to be exceptional, in that the group-velocity was always in the same direction. This anomaly is now removed.


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