The Maacama Fault is a right lateral-moving (dextral)

geologic fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

located in the

Coast Ranges The Pacific Coast Ranges (officially gazetted as the Pacific Mountain System in the United States) are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. Although th ...

of northwestern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. It is considered to be the northernmost segment of the

Hayward Fault The Hayward Fault Zone is a right-lateral strike-slip geologic fault zone capable of generating destructive earthquakes. This fault is about long, situated mainly along the western base of the hills on the east side of San Francisco Bay. It runs ...

subsystem of the

San Andreas Fault The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonics, tectonic boundary between the Pacific Plate and the North American Plate, and its motion is Fault (geology)#Strike-slip fau ...

zone. Creep along the Maacama is about 8 mm per year, consistent with the steady movement along the rest of the Hayward Fault system. It is also capable of producing large earthquakes. The Maacama Fault runs just east of Ukiah and just west of Willits.

References

USGS Database: Maacama Faultstorage.water.ca.gov: geo_plate_faulting
Seismic faults of California Geology of Sonoma County, California Geology of Mendocino County, California California Coast Ranges {{MendocinoCountyCA-geo-stub