Abstract: Following the idea of "Safety Island" the crustal stability zonation map of China (1:5000000)is first compiled on a grid basis in different steps using fuzzy synthetic judgement, image recognition and an expert appraisal system.
A strong earthquake and another moderately strong shock have recently been reported to occur in Menglian county of Yunnan province and Yongdeng county of Gansu province indicated as unstable and fairly unstable regions on the map. It is therefore emphasized that a tentative quantification of the evaluation of regional crustal stability proves significant in practical applications.