利用GPS数据研究南北地震带北段近期地壳水平形变特征
Study of the Recent Crustal Horizontal Deformation in the Northern Segment of the North-South Seismic Belt Based on GPS Data

采用中国地震局"陆态网络"GPS基准站和流动站观测数据，利用MIT的开源软件GAMIT/GLOBK解算南北地震带北段（33°~42°N，97°~110°E），特别是六盘山地区、祁连地块、银川地堑1999年以来在欧亚框架下，以鄂尔多斯块体作为参考的GPS速度场。计算南北地震带北段5条断裂两侧50~350 km范围内各站垂直/平行于断裂走向的速度投影，以及14个基准站18条基线2010年以来的长度时间序列，试图进一步估计关心区域的应力积累情况，探索断层闭锁段。结合地震活动性，认为南北地震带北段未来50年有发生M8地震的可能性；该段1900年以来的第4个M6、M7地震活跃期可能已经拉开序幕，未来2年有发生M7以上地震的可能性；祁连断裂带、海原断裂、西秦岭北缘地震带具备发生M6和M7地震的优先条件，尤其是海原断裂。
To study the characteristics of the recent crustal horizontal deformation in the northern segment of the North-South seismic belt, the GPS velocity field in the northern segment of the North-South seismic belt (33°~42°N, 97°~110°E) since 1999 was computed based on the GPS data from stations of the Crustal Movement Observation Network of China using the GAMIT/GLOBK software. These findings, combined with information on the seismic activities in the study area, suggest that M≥8.0 earthquakes will likely occur in the northern segment of the North-South seismic belt in the next 50 years; the fourth active period of earthquakes since 1900 with magnitude 6~7 may have already arrived, and in the next two years, an M>7.0 earthquake may occur; there is potential risk of M6 and M7 earthquakes in the Qilianshan, northern Xiqinling, and especially Haiyuan faults.