In this paper,the space-time distribution features of shallow geotemperature field in the boundary regions between Qinghai and Gansu Provinces during 1980-1990 before the Menyuan earthquake Ms=6.4 of 1986 and Gonghe earthquake Ms=7.0 of 1990 are studied.The main conclusions are as follows:
In 1985,before the Menyuan earthquake,there appeared the shallow geotemperature rising, region,centered in Qinghai Lake,forming a elliptic area from Huangyuan to Mengyuan, and in 1986 the geotemperature value of the rising region decreased.From 1987,before, the Gonghe earthquake,there appeared, the rising region of shallow geotemperature with large and long time, concentrated in Huangyuan-Gonghe-Xinghai of Qinghai.In the region far from seismic centre,the geotemperature value went up early,and was small amplitude;nearby the epicenter,the geotemperature increasing was late but its amplitude was large.Immediately before the earthquakes,the shallow geotemperature showed undulating feature of sudden rising-sudden dropping.