The 'Earthquake Fault' name is geologically misleading; it is actually a tension crack created by volcanic cooling and shifting rather than a traditional tectonic fault line.
The exposed walls show high-silica rhyolite, which is the result of rapid cooling from ancient lava flows.
The cracks in the formation act as natural snow catchers, which often results in snowpack remaining in the deeper crevices well into the early summer months.
The site is positioned directly above the subterranean magma chamber of the Mammoth Mountain volcanic system.
Earthquake Fault is a distinct geologic feature located in the Inyo National Forest, characterized by deep, narrow crevices cutting through rhyolite volcanic rock. The fissure system extends to a depth of approximately 60 feet and reaches lengths of roughly 1,500 feet. The fault was formed during the volcanic activity that shaped the Long Valley Caldera, rather than by a single seismic event. Visitors walk along a paved loop trail that traverses the perimeter of the primary chasm. The rock walls reveal layers of volcanic ash and pumice deposits from eruptions dating back hundreds of thousands of years. The area is managed by the U.S. Forest Service as part of the Mammoth Lakes region. The site sits at an elevation of approximately 7,600 feet.
The central observation bridge that provides a direct, top-down perspective into the deepest section of the crack.
Wear sturdy, closed-toe walking shoes to navigate the paved but occasionally uneven terrain.
Bring a light jacket as the deep, shaded cracks often create a natural microclimate significantly cooler than the surrounding forest.
Visit during the shoulder seasons to avoid peak crowds and heavy snowmelt that may obstruct trail access.
Attempting to climb or descend into the fenced-off fissure areas, as the volcanic rock is unstable and prone to crumbling.
The site is typically inaccessible by vehicle during winter months due to heavy snowfall and seasonal road closures on the approach route.
Stay behind the protective guardrails at all times to prevent falls into the deep fissures; do not throw objects into the cracks.
