The Mount Diablo Thrust Fault, also known as the Mount Diablo Blind Thrust, is a

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If ...

in the vicinity of

Mount Diablo Mount Diablo is a mountain of the Diablo Range, in Contra Costa County, California, Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton, California, Clayton and northeast of Danville, Califo ...

Contra Costa County, California ) of the San Francisco Bay , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_name1 = California , subdivision_type2 ...

. The fault lies between the Calaveras Fault, the

Greenville Fault The Clayton-Marsh Creek-Greenville Fault is a fault located in the eastern San Francisco Bay Area of California, in Alameda County and Contra Costa County. It is part of the somewhat parallel system of faults that are secondary to the San Andreas ...

, and the Concord Fault, all right-lateral

strike-slip 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 ...

s, and appears to transfer movement from the Calaveras and Greenville Faults to the Concord Fault, while continuing to uplift Mount Diablo.

Tectonic forces

The

Pacific Plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and Iza ...

is a major section of the Earth's crust, gradually expanding by the eruption of magma along the

East Pacific Rise The East Pacific Rise is a mid-ocean rise (termed an oceanic rise and not a mid-ocean ridge due to its higher rate of spreading that results in less elevation increase and more regular terrain), a divergent tectonic plate boundary located along ...

to the southeast. It is also being subducted far to the northwest into the Aleutian Trench under the

North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...

well north of San Francisco. In California, the plate borders the North American Plate along a transform boundary, the San Andreas Fault. The westward component of the North American Plate's motion and the irregularity of the San Andreas Fault results in some compressive force along the San Andreas and its associated faults, thus helping lift the Coast Ranges. The Mount Diablo Thrust Fault and the Great Valley Blind Thrust faults are consequences of this compression. Movement along the Mount Diablo Thrust Fault includes crustal shortening of about 2.6 mm and uplift of about 1 mm per year.

Seismic parameters

The Mount Diablo Thrust Fault is approximately 25 km long, and dips at an angle of 38 degrees to the northeast. The Mount Diablo Thrust Fault is capable of generating an earthquake of magnitude M_W=6.7. The predicted rupture surface begins 8 km below the surface, and there is thus no surface expression of the fault, and a low likelihood of surface rupture in the event of a large earthquake on the fault. No large historic earthquakes are known to have occurred on the Mount Diablo Thrust Fault. The recurrence interval for large earthquakes along the fault is predicted to be about 400 years.

Related faults

Compressive stresses are produced by offset and converging slip-strike motions between the Calaveras Fault and the

Clayton-Marsh Creek-Greenville Fault The Clayton-Marsh Creek-Greenville Fault is a fault located in the eastern San Francisco Bay Area of California, in Alameda County and Contra Costa County. It is part of the somewhat parallel system of faults that are secondary to the San Andreas ...

which manifest in the Mount Diablo Thrust Fault.

Nearby cities

The Mount Diablo Thrust Fault underlays several cities and unincorporated communities in Contra Costa County:

Alamo The Battle of the Alamo (February 23 – March 6, 1836) was a pivotal event in the Texas Revolution. Following a 13-day siege, Mexican troops under President General Antonio López de Santa Anna reclaimed the Alamo Mission near San Ant ...

Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...

, Blackhawk, Brentwood, Clayton,

Concord Concord may refer to: Meaning "agreement" * Pact or treaty, frequently between nations (indicating a condition of harmony) * Harmony, in music * Agreement (linguistics), a change in the form of a word depending on grammatical features of other ...

, Danville, Diablo, San Ramon, and Walnut Creek.

References

{{California Faults Seismic faults of California Geology of Contra Costa County, California Mount Diablo Geography of the San Francisco Bay Area Buried rupture earthquakes