Sentence:When the first model sank in August 1991, the [e1]crash[/e1] caused a [e2]seismic event[/e2] registering 3.0 on the Richter scale, and left nothing but a pile of debris at 220m of depth.
 e1: crash. 
 e2 : seismic event.
Answer: Cause-Effect(e1,e2)