F - foreshock 中文 - EN166

foreshock n.(大地震前的)預震。

foreshore
“ 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 “事實是，許多主震并非‘突然’發生主震中的10 - 30 %之前在發震之前的一周有前震；有的主震前有長達一年的震前活動性34 ；有的在震前有數年的加大的瞬間釋放3536373839 ，有的則在震前出現地震活動性的靜止404142 。
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，公社或大隊領導干部直接或間接從六個不同的來源獲得信息：（ 1 ）通過市級與縣級革委會傳達給他們的總的省一級的警告；（ 2 ）在營口的例子中，撤離的命令由縣革委會下達；（ 3 ）附近的地震觀測站，特別如石硼峪地震觀測站的情況；（ 4 ）地方的業余前兆檢測工作組，如海城地震觀測站（ “群測點” ）；（ 5 ）附近的村莊與企業，與（ 6 ）前震以及已經造成的損失。
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 地震前后的應力方向可根據大量前震和余震震源機制統計給出；地震應力降可通過地震波或地殼形變資料的震源破裂反演研究得到。
By the afternoon , it became very clear that the foreshocks had caused substantial damage 到下午已經很清楚，前震已經造成了相當的破壞。