THERMAL STRUCTURE OF THELITHOSPHERE IN NORTH CHINA

The thermal structure of the lithosphere in North China (105°E_124°E, 30°N_ 41°N) was calculated using two kinds of average heat flow models and four heat production models which were obtained from observed heat production or from the inversion of Curie depth distribution. Analyses of the results and comparison of the depths of thermal lithosphere and the temperature of the Moho-discontinuity obtained by different models show that the 3rd heat production model is the best one. The temperature at Moho-discontinuity is about from 450℃ to 750℃ and is consistent with ones from other models in 80 percent of the whole area within the error of 15%. The depth of the thermal lithosphere bottom obtained by this model is about from 60 km to 180 km and is consistent with ones from other models in 70 percent of the whole area within the error of 15%. It is found that big fault systems are related to thinner parts of the lithosphere and the earthquakes of M S6.5 occurred near the thinner parts of the lithosphere and the area in which the temperature of the Moho-discontinuity is higher.