We first obtained their learned event facet phrases and event expressions, most of which refer to general events.
then we followed their paper and identified two types of news articles that are likely to describe a civil unrest event by matching the obtained phrases to the English Gigaword fifth edition (Parker et al., 2011) we first consider news articles that contain a civil unrest keyword such as "strike" and "protest" 1 , then we identify an article as relevant if it contains a sentence where either two types of facet phrases or one facet phrase together with an event expression are found.