n.前震
An increase in foreshock activity triggered the evacuation warning. 前震活動的增加引發(fā)了疏散警報。
In the Pacific Northwest, there is no evidence of foreshock activity for most historic earthquakes. 在太平洋西北地區(qū)，歷史上的大多數(shù)地震都沒有前震活動的證據(jù)。
