Yellowstone experiences thousands of small earthquakes every year , virtually all of which are undetectable to people . There have been six earthquakes with at least magnitude 6 or greater in historical times , including the 7.2‑magnitude Hebgen Lake earthquake which occurred just outside the northwest boundary of the park in 1959 . This quake triggered a huge landslide , which caused a partial dam collapse on Hebgen Lake ; immediately downstream , the sediment from the landslide dammed the river and created a new lake , known as Earthquake Lake . Twenty-eight people were killed , and property damage was extensive in the immediate region . The earthquake caused some geysers in the northwestern section of the park to erupt , large cracks in the ground formed and emitted steam , and some hot springs that normally have clear water turned muddy . A 6.1‑magnitude earthquake struck inside the park on June 30 , 1975 , but damage was minimal
Hebgen Lake earthquake
1959 Hebgen Lake earthquake
Yellowstone National Park