我国西北地区为何多地震从７０年代中期到８０年代中期，我国大陆各地较少发生７级以上的强烈地震，地震活动出现了一个相对平衡的阶段。然而，这种平稳阶段在１９８５年被新疆乌恰大地震所打破。全国地震活动形势分析表明，我国大陆的地震活动从８０年代中期到９０年代末... How Many Earthquake Occurred in Northwest China From the mid-1970s to the mid-1980s, there were fewer strong earthquakes of magnitude 7 or above in all parts of China, and there was a relatively balanced stage in seismic activity. However, this stationary phase was broken in 1985 by the Wuqia earthquake in Xinjiang. The analysis of the situation of the national earthquake shows that the seismic activity in mainland China has changed from the mid-80s to the late 90s.