Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-38orders of magnitude larger than predicted by classical Arrhenius factors. This energytransformation is a result of self-sustained brittle disruption (fracture in form of dispersedsolid substance) of solid matrix and this phenomenon may be named «autowave self-sustainedtribo-chemical mechanism».The first simple theoretical model of autowave processes in solid-phase cryochemicalreactions was proposed in [1,2]. The model considered was constructed on the physicalscheme that brittle fracture is induced by thermal strain from reaction heat generation. Thetheory is being developed by the work [3] which are investigating different bifurcationphenomena concerning of critical conditions with parameters of heat-transfer, sample sizes,and also with thresholds of «cold» ignition of autowave transformation in frozen reagents bylocal disruption etc.We suppose the autowave hypothesis may give an ideological base of fast cryochemicalevolution of the cosmic substances. In particular, one can imagine the formation, from thefrozen mixture of elements, of compounds such as ammonia and methane that are found inappreciable amounts in crusts of the cold planets of the Solar system.APPLICATION: autowaves of fracture of metastable phase states in solids as a newapproach for explanation of mechanisms of geotectonics phenomena and earthquakes.By using above presented mechanism of solid phase chemical transformations we formeda nonlinear theoretical model for describing of mechanisms of initiating and dynamics ofmoving in time and space of geotectonic phenomena and earthquakes. A base of the model isthe «gasless detonation» in fracture of solids, supersonic wave theory created in [4,5] forexplanation of catastrophically fast decays of metastable phase states in solid matter. Theuntraditional fracture notions was developed for different solid transformations in physics ofsemiconductors, in physics of explosives sensibility to friction and shock. Possibility ofapplication of the theory to geophysical processes is based on a hypothesis that geotectonicphenomena and earthquakes are a result of catastrophic phase transitions in rocks of EarthCrust. Classical theory of polymorphism describes a lot of metastable phases in earth rocksbut never investigated dynamics of the transitions between them. A bifurcation approach tomodeling of the geological phenomena is proposed in the present work.The phenomenon is modeled by coupling the reaction diffusion equation, describingchemical or phase transformations, and the wave equation, describing elastic perturbations.The feedback coupling considered in this work involves (i) a dependence of the soundvelocity on the phase (chemical) field, and (ii) the destruction (fracture) of initial phaseequilibrium when the strain exceeds a critical value: such critical strain destroys the matrix376