By the afternoon , it became very clear that the foreshocks had caused substantial damage 到下午已经很清楚，前震已经造成了相当的破坏。
2.
The pre - seismic and post - seismic stress direction can be statistically determined by a large collection of foreshock and aftershock focal mechanism data while the stress drop can be determined through the source fracture inversion from seismic wave data or crust deformation data 地震前后的应力方向可根据大量前震和余震震源机制统计给出；地震应力降可通过地震波或地壳形变资料的震源破裂反演研究得到。
3.
On 4 february 1975 , the commune or brigade leading cadres would have obtained information directly or indirectly from six different sources : ( 1 ) the general provincial warning relayed to them through city and county committees , ( 2 ) in the case of yingkou county , an evacuation order from the county committee , ( 3 ) nearby earthquake observatories , particularly the shipengyu observatory , ( 4 ) local amateur precursory monitoring groups such as the team of the haicheng observatory , ( 5 ) neighboring villages and industrial units , and ( 6 ) the foreshocks and the damage they were already causing 1975年2月4日，公社或大队领导干部直接或间接从六个不同的来源获得信息： （ 1 ）通过市级与县级革委会传达给他们的总的省一级的警告； （ 2 ）在营口的例子中，撤离的命令由县革委会下达； （ 3 ）附近的地震观测站，特别如石硼峪地震观测站的情况； （ 4 ）地方的业余前兆检测工作组，如海城地震观测站（ “群测点” ） ； （ 5 ）附近的村庄与企业，与（ 6 ）前震以及已经造成的损失。
4.
“ the fact is that many main shocks do not occur " suddenly " : 10 - 30 % of them are preceded by foreshocks during the week before their occurrence ; some are preceded by year - long pre - activity9 ; some are preceded by increased moment release during the years before them10 - 14 , and some are preceded by seismic quiescence15 - 17 “事实是，许多主震并非‘突然’发生主震中的10 - 30 %之前在发震之前的一周有前震；有的主震前有长达一年的震前活动性34 ；有的在震前有数年的加大的瞬间释放3536373839 ，有的则在震前出现地震活动性的静止404142 。
