seismic motion

例句：

1. 1. The seismic activity in the region is causing concern among scientists.
   该地区的地震活动引起了科学家的关注。
2. 2.The seismic waves are traveling through the earth's crust at a speed of about 7.8 kilometers per second.
   地震波以大约每秒7.8公里的速度穿过地球的地壳。
3. 3. The seismometer was used to measure the seismic motion of the earthquake.
   地震仪被用来测量地震的运动。