关键词: 红河断裂带, SiO₂地热温标, 热储温度, 循环深度, 地震活动性, 弱化程度

Abstract: Heat reservoir temperature of water samples collected from 14 hot springs on the northern segment of the Honghe fault zone is calculated by using SiO₂-geothermometer, and in connection with local geothermal gradients, circulation depth of the hot spring waters is also calculated. Meanwhile, frequency and focal depth of earthquakes occurring from 886 to 1987 are counted up and analysed. From the point of view of weakening effect of water on fault and its wall rocks, the author discusses the effect of deep circulation of the hot spring water on strength and frictional force of fault and seismic activity. The result indicates that difference in the seismic activity on each sub-segment is related to the degree of weakening effect of water on the various sub-segments. It is suggested that the Eryuan sub-segment on which the circulation depth of the hot spring waters is greatest corresponds to a slip zone, while the Jianchuan and Midu sub-segments on which the circulation depth of the hot spring waters is smaller, and Dali sub-segment with very few hot spring correspond to the locked zones, and that a strong earthquake would be prepared at both ends of the zone in which circulation depth of hot spring waters is greater.

Key words: The Honghe fault zone, SiO₂-geothermometer, Heat reservoir temperature, Circulation depth, Seismic activity, Weakening degree