Editing San Andreas Fault (section)

== Fault zones ==

=== Northern ===
{{see also|Calaveras Fault||Hayward Fault Zone}}
[[File:Eq-prob.jpg|left|thumb|upright=1.3|A map displaying each of the seven major faults in the [[San Francisco Bay Area]], and the probability of an [[Magnitude (earthquake)|M6.7]] earthquake or higher occurring on each fault between 2003 and 2032|alt=A map tracing all the faults in the Bay Area, and listing probabilities of earthquakes occurring on them.]]
[[File:Summit Tunnel (Tunnel 2) with damage from the 1906 San Francisco earthquake near north portal.png|left|thumb|The slip on the San Andreas Fault which caused the [[1906 San Francisco earthquake]] was visible in [[Wrights Tunnel]] along the [[South Pacific Coast Railroad]] after the earthquake]]

The northern segment of the fault runs from [[Hollister, California|Hollister]], through the [[Santa Cruz Mountains]], epicenter of the [[1989 Loma Prieta earthquake]], then up the [[San Francisco Peninsula]], where it was first identified by [[Andrew Lawson|Professor Lawson]] in 1895, then offshore at [[Daly City, California|Daly City]] near [[Mussel Rock]]. This is the approximate location of the epicenter of the [[1906 San Francisco earthquake]]. The fault returns onshore at [[Bolinas Lagoon]] just north of [[Stinson Beach, California|Stinson Beach]] in [[Marin County]]. It returns underwater through the linear trough of [[Tomales Bay]] which separates the [[Point Reyes Peninsula]] from the mainland, runs just east of Bodega Head through Bodega Bay and back underwater, returning onshore at [[Fort Ross]]. (In this region around the [[San Francisco Bay Area]] several significant "sister faults" run more-or-less parallel, and each of these can create significantly destructive earthquakes.) From Fort Ross, the northern segment continues overland, forming in part a linear valley through which the [[Gualala River]] flows. It goes back offshore at [[Point Arena]]. After that, it runs underwater along the coast until it nears [[Cape Mendocino]], where it begins to bend to the west, terminating at the [[Mendocino triple junction]].

=== Central ===
The central segment of the San Andreas Fault runs in a northwestern direction from Parkfield to [[Hollister, California|Hollister]]. While the southern section of the fault and the parts through Parkfield experience earthquakes, the rest of the central section of the fault exhibits a phenomenon called [[aseismic creep]], where the fault slips continuously without causing earthquakes. It was formed by a transform boundary.<ref>{{Cite news |last=School |first=Columbia Climate |date=February 28, 2022 |title=A slow-motion section of the San Andreas fault may not be so harmless after all |language=en-US |work=phys.org |publisher=Columbia Climate School |url=https://phys.org/news/2022-02-slow-motion-section-san-andreas-fault.html |access-date=2022-03-01}}</ref>

=== Southern ===

{{Location map many
| Salton Trough
| width       = 400
| float       = 
| border      = 
| caption     = Southern San Andreas Fault. The red lines are simplified faults. Right-lateral direction of motion of the [[transform fault]] is shown (pink arrows). The red rhombs are [[pull-apart basin]]s; the northern one is the site of the [[Niland geothermal field]], the southern the [[Cerro Prieto]] geothermal field.
| alt         = 
| relief      = 
| AlternativeMap = 
| overlay_image = <!--transparent-background image of the faults goes here, something like "San Andreas Fault Map.gif"-->Salton_trough_fault_overlay.svg
<!--first label/marker-->
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<!--second label/marker-->
| label2      ='''[[Los Angeles]]'''
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| coordinates2= <!-- {{coord| }} -->{{Coord|34|3|N|118|15|W}}
<!--Third-->
| label3      ='''[[San Diego]]'''
| label3_size = 
| label3_width=
| position3   =  <!-- or: pos2 -->
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| link3       = 
| coordinates3= <!-- {{coord| }} -->{{coord|32|42|54|N|117|09|45|W}}
<!--Fourth-->
| label4      =  <!-- or: label -->'''[[Mexicali]]'''
| coordinates4= {{coord|32|39|48|N|115|28|04|W|region:MX}}
<!--Fifth-->
| label5      =  <!-- or: label -->'''[[Salton Sea]]'''
| position5   =  left
| coordinates5=  <!-- {{coord|...}}--><!-- or: coordinates-->{{Coord|33.3|-115.8|region:US-CA_type:waterbody}}
<!--Tijuana-->
| label6      =  '''[[Tijuana]]'''
| coordinates6=  {{coord|32|31|30|N|117|02|0|W|region:MX}}
<!--Alamo river-->
| label7      =  '''[[Alamo River|Alamo River mouth]]'''
| coordinates7=  {{coord|33.206517|-115.61433|region:US-CA_type:river}}
<!--Colorado river-->
| label8      =  '''[[Colorado River|Colorado River mouth]]'''
| coordinates8=  {{coord|31|54|00|N|114|57|03|W}}
<!--Laguna Salada-->
| label9  =  '''[[Laguna Salada (Mexico)|Laguna Salada]]'''
| position9   = left
| coordinates9= {{coord|32.36|-115.65|region:MX_type:waterbody}}
<!--Yuma-->
| label10  =  '''[[Yuma, Arizona|Yuma]]'''
| position10   =  right
| coordinates10= {{coord|32|41|32|N|114|36|55|W|region:US-AZ}}
<!--Gulf-->
| label11  =  '''[[Gulf of California]]'''
| position11  =  right
| coordinates11 = {{coord|31|25|00|N|114|45|00|W}}
<!--Yuma-->
| label12  =  '''[[Colorado River|Colorado River Valley]]'''
| position12   =  left
| coordinates12= {{coord|33|59|32|N|114|28|55|W|region:US-AZ}}
<!--Cerro Prieto-->
| label13  =  '''[[Cerro Prieto|Cerro Prieto volcano]]'''
| position13   =  right
| coordinates13= {{Coord|32.418|N|115.308|W}}
}}

{{see also|Elsinore Fault Zone|Imperial Fault|Laguna Salada Fault|San Jacinto Fault Zone}}
[[File:Kluft-photo-Carrizo-Plain-Nov-2007-Img 0327.jpg|thumb|Aerial photo of the San Andreas Fault in the [[Carrizo Plain]]]]
[[File:SUNSET ROCKS San Andreas Fault.jpg|thumb|The [[Vasquez Rocks]] in Agua Dulce, California are evidence of the San Andreas Fault and part of the 2,650-mile [[Pacific Crest Trail]].]]
The southern segment (also known as the [[Mojave Desert|Mojave]] segment) begins near [[Bombay Beach, California#Geography|Bombay Beach, California]].  Box Canyon, near the [[Salton Sea]], contains upturned strata associated with that section of the fault.<ref>{{Cite web|url=http://www.americansouthwest.net/california/box_canyon/|title=Box Canyon, near Palm Springs, California|website=americansouthwest.net}}</ref> The fault then runs along the southern base of the [[San Bernardino Mountains]], crosses through [[Cajon Pass]] and continues northwest along the northern base of the [[San Gabriel Mountains]]. These mountains are a result of movement along the San Andreas Fault and are commonly called the Transverse Range. In [[Palmdale, California|Palmdale]], a portion of the fault is easily examined at a roadcut for the [[Antelope Valley Freeway]]. The fault continues northwest alongside the Elizabeth Lake Road to the town of [[Elizabeth Lake, California|Elizabeth Lake]]. As it passes the towns of [[Gorman, California|Gorman]], [[Tejon Pass]] and [[Frazier Park, California|Frazier Park]], the fault begins to bend northward, forming the "Big Bend". This [[Transpression#Restraining bend|restraining bend]] is thought to be where the fault locks up in [[Southern California]], with an earthquake-recurrence interval of roughly 140–160 years. Northwest of Frazier Park, the fault runs through the [[Carrizo Plain]], a long, treeless plain where much of the fault is plainly visible. The Elkhorn Scarp defines the fault trace along much of its length within the plain.

The southern segment, which stretches from [[Parkfield, California|Parkfield]] in [[Monterey County, California|Monterey County]] all the way to the [[Salton Sea]], is capable of an 8.1-magnitude earthquake. At its closest, this fault passes about {{convert|35|mi|km}} to the northeast of Los Angeles. Such a large earthquake on this southern segment would kill thousands of people in Los Angeles, San Bernardino, Riverside, and surrounding areas, and cause hundreds of billions of dollars in damage.<ref>{{cite news |date=October 8, 2010 |author=Rong-Gong Lin II |url=http://latimesblogs.latimes.com/lanow/2010/10/san-andreas-capable-of-80-earthquake-over-340-mile-swath-of-california-researchers-say.html |newspaper=Los Angeles Times|title=San Andreas fault capable of magnitude 8.1 earthquake over 340-mile swath of California, researchers say |access-date=2012-02-17}}</ref>