The Kern Canyon Fault is a geological fault which runs the length of Kern Canyon in the southern Sierra Nevada mountains in California. The fault was once considered inactive, but recent studies show the contrary. The fault is a break in the southern section of the Sierra Nevada-Great Valley Block, manifesting differences in the stresses in this region over a period of over 100 million years. The fault was formerly right lateral-moving (horizontal sliding), but has changed to a normal (vertical lifting) mode of motion over the past several thousands of years.