On the thermal anomaly due to the fluid convection in faulted and fractured-porous regions of the crust

The conditions of heat flow generation on the Earth's surface are examined in terms of a thermal convection mechanism. An analytical model of a two-layer medium is used to obtain qualitative results. The lower layer consists of a porous saturated medium in which the thermal convection takes place. The upper layer is an impermeable heat-conducting half-space. Simple analytical solutions of single-cell thermal convection in the porous medium and thermal conductivity in the upper layer are studied. The continuity conditions of these solutions are satisfied at the boundary; the subsequent averaging of the solutions makes it possible to derive some integrated characteristics, as well as the Rayleigh and Nusselt numbers. It is the values of these numbers that are of practical interest.