云南红河断裂带中小地震重定位及其与地质构造的关系

运用双差精确定位方法对1999—2003年间发生在云南红河断裂带上的中小地震进行了重新定位，并分析了精确定位结果与地质构造的关系，结果显示，红河断裂带上重定位前与重定位后的震中分布变化不大，只是重定位后震中分布略向两端集中，北段地震多于南段。说明当前红河断裂带北段比南段、中段地震活动性强，可能受洱源断裂带～程海断裂带的影响。但重定位前、后震源深的分布差异较大，在以洱源为中心的区域上存在一个10km深的条带，这可能与红河断裂在北段形成的拉张区有关。

Relocation Results of Moderate-small Earthquakes in the Red River Fault Zone of Yunnan and Its Relation with Geologic Structure

We used double difference location method to relocate the moderate-small earthquakes on the Red River fault zone of Yunnan from 1999 to 2003, and analyzed the relationship of relocation result and geologic structure. The result shows that the epicenter distribution changes little before and after the relocation, only slightly centralizes to the double ends of the fault zone after the relocation, and the earthquakes on the north section are more than those on the south section. It indicates that probably effected by the Eryuan and Chenghai fault zones, the seismic activity in the north of the Red River fault zone is stronger than that in the south and middle currently. However, the focal depth varies largely before and after the relocation, and there exists a 10-km-deep band centered on the Eryuan area, which may be concerned with pullapart distinct formed in the north section of the Red River fault zone.