Abstract
Plate tectonics only allows small deformations in the lithospheric plates. The laboratory experiments with the rock specimens show that the creep is transient when the creep strain is at most 1%. Hence, if we assume that the creep strain in the lithospheric plates is below this threshold, the creep is transient. The present paper addresses the role of the elastic, brittle (pseudo-plastic), and creep rheology of the lithosphere during the accumulation of elastic shear strains on the locked faults in the Earth’s crust, i.e., during the process of preparation of the earthquakes. The effective viscosity characterizing the transient creep is lower than that under the steady-state creep and it depends on the characteristic time of a given process. The characteristic duration of the stress and strain accumulation process in the vicinity of the locked faults is a few dozen years. On these time intervals, the thin upper crustal layer behaves as brittle; the underlying layer behaves as elastic (it is just this layer which accommodates stress accumulation leading to the earthquake), whereas the transient creep is predominant in the lower crust and mantle lithosphere. Transient creep entails nonlinear time dependence of the strains arising in the vicinity of the locked fault in the elastic crust. The perturbations in the magnetic field induced by these strains can be treated as the magnetic precursor of the earthquake.
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References
Berckhemer, H., Auer, F., and Drisler, J., High-temperature anelasticity and elasticity of mantle peridotite, Phys. Earth Planet. Inter., 1979, vol. 20, pp. 48–59.
Birger, B.I., Rheology of the Earth and thermoconvective mechanism for sedimentary basins formation, Geophys. J. Int., 1998, vol. 134, pp. 1–12.
Birger, B.I., Transient creep and convective instability of the lithosphere, Geophys. J. Int., 2012, vol. 191, pp. 909–922.
Birger, B.I., Temperature-dependent transient creep and dynamics of cratonic lithosphere, Geophys. J. Int., 2013, vol. 195, pp. 695–705.
Doetsch, G., Guide to the Applications of Laplace Transforms, London: Van Nostrand, 1963.
Dobrovol’skii, I.P., Matematicheskaya teoriya podgotovki i prognoza tektonicheskogo zemletryaseniya (Mathematical Theory for the Preparation and Prediction of a Tectonic Earthquake), Moscow: FIZMATLIT, 2009.
Garagash, I.A., The model of tectonomagnetic effect formation in the fracture zone with shear, Ros. Zh. Nauk Zemle, 1998, vol. 1, no. 3, pp. 199–204.
Goetze, C., High temperature rheology of Westerly granite, J. Geophys. Res., 1971, vol. 76, pp. 1223–1230.
Goetze, C. and Brace, W.F., Laboratory observations of high-temperature rheology of rocks, Tectonophysics, 1972, vol. 13, pp. 583–600.
Hanson, D.R. and Spetzler, H.A., Transient creep in natural and synthetic, iron bearing olivine single crystals: mechanical results and dislocation microstructures, Tectonophysics, 1994, vol. 235, 9p. 293–315.
Johnston, M.J.S., Review of electrical and magnetic fields accompanying seismic and volcanic activity, Surv. Geophys., 1997, vol. 18, pp. 441–475.
Karato, K., Deformation of Earth Materials—An Introduction to the Rheology of Solid Earth, Cambridge: Cambridge Univ. Press, 2008.
Landau, L.D. and Lifshits, E.M., Elektrodinamika sploshnykh sred (Electrodynamics of Continuous Media), Moscow: GIFML, 1959.
Murrell, S.A.F. and Chakravarty, S., Some new rheological experiments on igneous rock at temperatures up to 1120°C, Geophys. J. R. Astron. Soc., 1973, vol. 34, pp. 211–250.
Murrell, S.A.F., Rheology of the lithosphere–experimental indications, Tectonophysics, 1976, vol. 36, pp. 5–24.
Pavlenkova, N.I., Low velocity and low electrical resistivity layers in the middle crust, Ann. Geophys., 2004, vol. 47, p. 157.
Rabotnov, Yu.N., Polzuchest’ elementov konstruktsii (Creep of the Construction Elements), Moscow: Nauka, 1966.
Sasai, Y., Tectonomagnetic modeling based on the piezomagnetism: review, Ann. Geofis., 2001, vol. 44, pp. 361–368.
Schwarz, G., Electrical conductivity of the Earth’s crust and upper mantle, Surv. Geophys., 1990, vol. 11, pp. 133–161.
Stacey, F.D. and Johnston, M.J.S., Theory of the piezomagnetic effect in titanomagnetite-bearing rocks, Pure Appl. Geophys., 1972, vol. 97, pp. 146–155.
Turcotte, D. and Schubert, G., Geodynamics—Applications of Continuum Physics to Geological Problems, New York: Wiley, 1982.
Weertman, J., Creep laws for the mantle of the Earth, Philos. Trans. R. Soc. London, 1978, vol. A288, pp. 9–26.
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Original Russian Text © B.I. Birger, 2016, published in Fizika Zemli, 2016, No. 6, pp. 154–162.
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Birger, B.I. Accumulation of elastic strains in the upper crust on the locked transform faults and the tectonomagnetic effect. Izv., Phys. Solid Earth 52, 928–935 (2016). https://doi.org/10.1134/S1069351316050037
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DOI: https://doi.org/10.1134/S1069351316050037