original: With little warning, a second earthquake of magnitude 5.1 May 18 triggered a massive collapse of the north face of the mountain.
simplifications: A second earthquake of magnitude 5.1 May 18 triggered a collapse of the north face of the mountain. a large earthquake suddenly hit on the 18th of May and damaged the north of the mountain. A second earthquake caused a massive break off from the north face of the mountain. A second earthquake of 5.1 magnitude caused a massive collapse of the north face of the mountain on May 18th. It occurred without warning. With little warning, a second earthquake of magnitude 5.1 on May 18 caused a huge collapse of the north face of the mountain. With little warning, a second earthquake of magnitude 5.1 collapsed the north face of the mountain. It was May 18. A second earthquake on May 18 caused the north face of the mountain to collapse. A second earthquake of magnitude 5.1 triggered a massive collapse of the north face of the mountain on May 18th. On May 18,  with little warning, a second earthquake of magnitude caused a massive collapse of the north face of the mountain. A 2nd earthquake size of  5.1 on May 18 set off  with little warning, a huge fall down  of the mountain's north face.