A view of Mount St Helens. It had remained dormant for over 130 years when scientists started recording renewed activity in early 1980. On May 18, 1980, a magnitude 5.1 earthquake triggered the largest landslide in recorded history at that time: travelling at 177 to 249 km per hour, four cubic kilometres of rock and glacial ice spread over 62 square kilometres. Fifty-seven people were killed and 200 houses, 27 bridges, 24 km of railways and 298 km of highway were destroyed.