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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS014 Poster presentation 2326
To the global factors, stimulating tectonic movements
Dr. Farshed Karimov
Seismology Institute of Earthquake Engineering and Seismology IASPEI
Zafar Usmanov
At the present investigation an attempt has been undertaken to learn possible origin of geoblocks
equilibrium loss, raising tectonic stresses at the geoblocks contact juncture, leading to earthquake and
creep shifting. The model chosen presents equilibrium state of the material point on a rotating sphere
surface. For the investigation gravity, dry friction and inertia forces have been taken into consideration.
The method suggested can be applied for analyses of screw oscillations of the globe, Chandler's ones in
part, and to study geoblocks equilibrium exposed breaking and earthquake as a result of Earth speed
variations and thus tectonic stresses accumulation. Coriolis force is neglected due to very initial situation
is under the consideration, when point's velocity is negligibly small. For the stable states the point's
velocity and acceleration are identically equal zero. The following equation has been obtained for critical
equilibrium conditions f2 = m2 · R6 · cos2θ0 · (Ω‘ 2 + Ω4 · sin2θ0) / (μ · M · m +Ω2 · R3 · cos2θ0)2 ,
where f is the friction coefficient, M is the Earth mass, μ is the gravity constant, m is the physical point
mass,R is the globe radius, Ω=Ω(t) is angle velocity dependent on time factor t, θ(t)=θ0 determines
critical latitude for stability positions. If Ω' =0, Ω=Ω0 , then at the latitudes θ1 ≤ θ0 ≤ θ2 and -θ2 ≤ θ0
≤ -θ1 under θ1< θ2 there are belts, where stable equilibrium is losing. And there will be three stable
equilibrium areas, polar caps and equatorial belt, divided by two unstable latitude belt states
symmetrically situated relatively equator ring. The ratio m0 / M = q is equal to ratio of gravity force to
centripetal force, which is connected with β parameter from the well known A.Clairaut's formulas for the
gravity force acceleration on the Earth surface spheroid. At the polar vicinity gravity force and reaction
of rest are playing the major role in geoblocks stability. At the equatorial belt centripetal force is joining
them. Friction forces are sufficient at the middle, transition belts. Critical places determined on the Earth
surface for equilibrium states are responding to geoblocks more stressed by surface forces and
therefore more likely to undergone shifting and generation earthquakes. At that surface forces can
generate both normal pressures and tangential strengths between adjacent geoblocks. The first ones
can lead to uplift or slip like geoblock earthquakes, the second ones to horizontal mutual shifting
geoblock earthquakes..
Keywords: crust, geoblocks, tectonics