Mathematical simulation of geotemperature field and thermal stress field in Sanjiang region of Yunnan

By the mathematical simulation of geotemperature field, deep quasi-stable thermal state and shallow thermal characteristics are reproduced in Sanjiang region of Yunnan. Faults are treated in two ways, 1) as constant heat source in terms ofq=μτ, that is, the quantity of frictional generated heat is constant, in order to simulate frictional heat generated by fault moving; 2) as heat conduits with high thermal conductivities to simulate such a phenomenon that there exist thermal fluids (for example, magma) in fault zones during tectonic movement. And then, through the simulation of thermal stress, the quantity (several bars to hundred bars) and the pattern of thermal stress vectors are obtained, which provides a new clue to the explanation and prediction of earthquakes. And larger tensional and shear stresses occur where the variation of geotemperature and the thickness of thermal lithosphere gradient belt. The stresses are concentrated in the temperature gradient belt. The shear belts of studied area are temperature gradient belts where the variation of the lithosphere thickness is larger and deep heat flow is high and thermal stresses concentrated. All of these may explain the facts that most of the earthquakes, hot springs occur along the fault zones. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 313–321, 1993. The study was financially supported by Chinese Natural Sciences Funds Item Ancient Tethys Tectonic Evolution in Western Yunnan and by centre for Remote sensing, Ministry of Metallurgy.