The Elsinore Fault Zone is a large right-lateral strike-slip

geological 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 ...

structure in

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

. The fault is part of the trilateral split 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 ...

system and is one of the largest, though quietest faults in Southern California.

Fault characteristics

The Elsinore fault zone, not including Whittier, Chino, and Laguna Salada faults, is long with a slip-rate of 4.0 millimeters/year (0.15 in/yr). It is estimated that this zone is capable of producing a quake of 6.5–7.5 M_W. The projected interval between major rupture events is 250 years. The last major rupture event on the main Elsinore fault was in 1910 with a 6 M_W earthquake centered just northwest of the city of Lake Elsinore.

Fault segments and geography

The fault runs from the mountainous

Peninsular Ranges The Peninsular Ranges (also called the Lower California province) are a group of mountain ranges that stretch from Southern California to the southern tip of the Baja California peninsula; they are part of the North American Coast Ranges, which ...

region between

El Centro El Centro (Spanish for "The Center") is a city and county seat of Imperial County, California, United States. El Centro is the largest city in the Imperial Valley, the east anchor of the Southern California Border Region, and the core urban are ...

and

San Diego San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...

, northwest to the Chino Hills range and Chino Hills. On the southern end of the fault zone is the southeastern extension of the Elsinore fault zone, the

Laguna Salada Fault The Laguna Salada Fault is a geological fault between the United States and Mexico. About long, it straddles the Imperial County-California–Baja California border. Earthquakes 1892 According to some seismologists the 1892 Laguna Salada ...

. At its northern end, the Elsinore fault zone splits into two segments, the

Chino Fault The Chino Fault extends along the eastern Chino Hills range region, from Corona in Riverside County to the Los Serranos, Chino Hills area of San Bernardino County in Southern California. Geology The Chino Fault and Whittier Fault are the two upp ...

and the

Whittier Fault The Whittier Fault is a geologic fault located in eastern Los Angeles County in Southern California, that is one of the two upper branches of the Elsinore Fault Zone, with the Chino Fault the second. Geology The Whittier Fault is a right-l ...

. In the

Elsinore Trough The Elsinore Trough is a graben rift valley in Riverside County, southern California. It is created by the Elsinore Fault Zone. It is located between the Santa Ana Mountains to the west, and the Temescal Mountains of the Perris Block and the T ...

, the Elsinore fault zone creates four

graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

rift valley A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear dep ...

s between the Santa Ana Mountain Block and the

Perris Block The Perris Block is the central block of three major fault-bounded blocks of the northern part of the Peninsular Ranges. The Perris Block lies between the Santa Ana Block to the west and the San Jacinto Block to the east. The Perris Block, was ...

: the Temescal Valley, the

Elsinore Valley Elsinore Valley is a graben rift valley in western Riverside County, California, a part of the Elsinore Trough. The Elsinore Valley is a graben between the Santa Ana Block to the southwest and the Perris Block on the northeast. It is a complex grab ...

with its large

sag pond A sag pond is a body of fresh water collected in the lowest parts of a depression (geology), depression formed between two sides of an active geologic fault, strike-slip, transtensional or normal fault zone. Formation A sag pond is formed along ...

Lake Elsinore Lake Elsinore is a natural freshwater lake in Riverside County, California, located east of the Santa Ana Mountains and fed by the San Jacinto River. Originally named ''Laguna Grande'' by Spanish explorers, it was renamed for the town of Elsino ...

and the

Temecula Valley The Temecula Valley is a graben rift valley in western Riverside County, California. The Temecula Valley is one of the graben valleys making up the Elsinore Trough, created by the Elsinore Fault Zone. It lies between the Wildomar Fault on the ea ...

and

Wolf Valley Wolf Valley is a graben rift valley in the Elsinore Trough, in western Riverside County, California. Overview Wolf Valley is the southernmost of the graben valleys making up the Elsinore Trough, created by the Elsinore Fault Zone. It lies betw ...

. In the Elsinore Trough the fault zone is split into pairs of parallel strands with the

Glen Ivy North Fault A glen is a valley, typically one that is long and bounded by gently sloped concave sides, unlike a ravine, which is deep and bounded by steep slopes. Whittow defines it as a "Scottish term for a deep valley in the Highlands" that is "narrower ...

and

Lee Lake Fault Lee may refer to: Name Given name * Lee (given name), a given name in English Surname * Chinese surnames romanized as Li or Lee: ** Li (surname 李) or Lee (Hanzi ), a common Chinese surname ** Li (surname 利) or Lee (Hanzi ), a Chinese s ...

forming the first valley, the

Glen Ivy South Fault A glen is a valley, typically one that is long and bounded by gently sloped concave sides, unlike a ravine, which is deep and bounded by steep slopes. Whittow defines it as a "Scottish term for a deep valley in the Highlands" that is "narrower ...

and

Willard Fault Willard may refer to: People * Willard (name) Geography Places in the United States * Willard, Colorado * Willard, Georgia * Willard, Kansas * Willard, Kentucky * Willard, Michigan, a small unincorporated community in Beaver Township, Bay ...

s the second and the Willard and

Wildomar Fault Wildomar is a city in southwest Riverside County, California, United States. The city was incorporated on July 1, 2008. As of the 2020 census, the population was 36,875. The community has grown very quickly during the early twenty-first century; t ...

s the last two valleys to the southeast. A multi-year study published in 2018 suggests a connection between the Elsinore Fault and other fault lines farther south, in Mexico: "...observations of the Yuha Desert and Salton Trough suggest that the 2010 M7.2 El Mayor ‐ Cucapah earthquake rupture, the Laguna Salada fault in Baja California, Mexico, and the Elsinore fault in California are part of the same fault system."

References

External links

M6.5 Earthquake on the Elsinore Fault (Santa Ana)
–

Southern California Earthquake Center The Southern California Earthquake Center (SCEC) is a collaboration of more than 1,000 scientists across 100 research institutions with a mission to: conduct research on earthquakes in Southern California and elsewhere by gathering data, conductin ...

Fault characteristics

Fault segments and geography

References

Further reading

External links