The Earthquake Fault is located outside of Mammoth Lakes, California.  It is an impressive fissure in the underlying rock, as narrow as 10 feet and as deep as 60 feet, running north-south across Highway 203 toward Earthquake Dome through some of the oldest trees in the region. Look closely at the edges of the “fault,” and you’ll see that the sides of the rock - now 6 to 10 feet apart - fit together perfectly. The fissure opened around 550 to 650 years ago, during a time of intense volcanic activity that included steam blasts at Inyo Craters and eruptions at Deadman, Obsidian, and Glass Creek domes. Early pioneers collected ice here in summertime to make ice cream. There are picnic tables, parking, restrooms and walking trails.

https://www.mammothtrails.org/destination/74/earthquake-fault/