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58-807: The Gabilan Range trends in a northwest–southeast direction along the Monterey County and San Benito County line. It is bordered on the northeast by the San Andreas Fault , the San Benito River and State Route 25 which separate it from the Diablo Range to the east; and on the west by the Salinas Valley , the Salinas River and U.S. Route 101 which separate it from the Santa Lucia Range nearer

116-427: A detachment layer is present. Thrust tectonics is associated with the shortening and thickening of the crust, or the lithosphere. This type of tectonics is found at zones of continental collision , at restraining bends in strike-slip faults, and at the oceanward part of passive margin sequences where a detachment layer is present. Strike-slip tectonics is associated with the relative lateral movement of parts of

174-599: A spreading center between the Pacific plate and the Farallon plate (which is now mostly subducted, with remnants including the Juan de Fuca plate , Rivera plate , Cocos plate , and the Nazca plate ) was beginning to reach the subduction zone off the western coast of North America. As the relative motion between the Pacific and North American plates was different from the relative motion between

232-574: A different degree of earthquake risk. The average slip rate along the entire fault ranges from 20 to 35 mm (0.79 to 1.38 in) per year. In the north, the fault terminates offshore near Eureka, California , at the Mendocino triple junction , where three tectonic plates meet. The Cascadia subduction zone intersects the San Andreas fault at the Mendocino triple junction. It has been hypothesized that

290-547: A link between the water level in Lake Cahuilla (now the Salton Sea ) and seismic activity along the southern San Andreas Fault. The study suggests that major earthquakes along this section of the fault coincided with high water levels in the lake. The hydrological load caused by high water levels can more than double the stress on the southern San Andreas Fault, which is likely sufficient for triggering earthquakes. This may explain

348-545: A magnitude 7.8 earthquake along the southern San Andreas Fault could cause about 1,800 deaths and $ 213 billion in damage. This scenario hypothesizes the potential effects of a 7.0 magnitude earthquake on the San Andreas Fault in the San Francisco Bay Area. It aims to estimate the impacts on urban infrastructures along with the rebuilding efforts to both the landscape and economy. This study combines not only

406-525: A major earthquake along the Cascadia subduction zone could trigger a rupture along the San Andreas Fault. In the south, the fault terminates near Bombay Beach, California , in the Salton Sea . Here, the plate motion is being reorganized from right-lateral to divergent . In this region (known as the Salton Trough ), the plate boundary has been rifting and pulling apart, creating a new mid-ocean ridge that

464-687: 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 . As it passes the towns of Gorman , Tejon Pass and Frazier Park , the fault begins to bend northward, forming the "Big Bend". This 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,

522-491: Is a combined effort from experts in the physical sciences, social sciences, and engineering both in the public and private sectors- ranging from urban planners to economists/business professionals. Not only does this study aim to estimate the impacts of the event, but aims to estimate the years of rebuilding and funding needed to recover communities from a potential disaster such as the HayWired Scenario. The first volume of

580-531: Is a continental right-lateral strike-slip transform fault that extends roughly 1,200 kilometers (750 mi) through the U.S. state of California . It forms part of the tectonic boundary between the Pacific plate and the North American plate . Traditionally, for scientific purposes, the fault has been classified into three main segments (northern, central, and southern), each with different characteristics and

638-596: Is an extension of the Gulf of California . Sediment deposited by the Colorado River is preventing the trough from being filled in with sea water from the gulf. The fault was first identified in 1895 by Professor Andrew Lawson of UC Berkeley . In the wake of the 1906 San Francisco earthquake , Lawson was tasked with deciphering the origin of the earthquake. He began by surveying and mapping offsets (such as fences or roads that had been sliced in half) along surface ruptures. When

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696-413: Is associated with the stretching and thinning of the crust or the lithosphere . This type of tectonics is found at divergent plate boundaries, in continental rifts , during and after a period of continental collision caused by the lateral spreading of the thickened crust formed, at releasing bends in strike-slip faults , in back-arc basins , and on the continental end of passive margin sequences where

754-421: Is formed in the process of sea-floor spreading ; transform , where plates slide past each other, and convergent , where plates converge and lithosphere is "consumed" by the process of subduction . Convergent and transform boundaries are responsible for most of the world's major ( M w > 7) earthquakes . Convergent and divergent boundaries are also the site of most of the world's volcanoes , such as around

812-562: Is now a California State Park. One of the last relatively undeveloped corridors for wildlife passage between the southern Santa Cruz Mountains and the northern Gabilan Range runs from lands between Mount Pajaro and Rancho Juristac , in southern Santa Cruz and Santa Clara counties respectively, south across California State Route 129 and U.S. Highway 101 to lands between Pinecate Peak and San Juan Bautista in San Benito County. The Land Trust of Santa Cruz County has protected

870-411: Is that Lawson named the fault after this lake. However, according to some of his reports from 1895 and 1908, he actually named it after the surrounding San Andreas Valley. Following the 1906 San Francisco earthquake, Lawson also concluded that the fault extended all the way into Southern California . In 1953, geologist Thomas Dibblee concluded that hundreds of miles of lateral movement could occur along

928-444: Is the range's highest point. There are several other peaks also over 3,000 feet (910 m) in the range. In Spanish, gavilán (gabilan is an older alternate rendering) means "sparrow hawk". Hawks , especially the red-tailed hawk , are common in the range. The Gabilan Mountains and other nearby places are mentioned in several novels by John Steinbeck , such as Of Mice and Men and East of Eden . In The Red Pony notably,

986-448: Is the study of the motions and deformations of the Earth's crust ( geological and geomorphological processes) that are current or recent in geological time . The term may also refer to the motions and deformations themselves. The corresponding time frame is referred to as the neotectonic period . Accordingly, the preceding time is referred to as palaeotectonic period . Tectonophysics is

1044-420: The 1994 Northridge earthquake ) occurs about once every 6.7 years statewide. The same report also estimated there is a 7% probability that an earthquake of magnitude 8.0 or greater will occur in the next 30 years somewhere along the San Andreas Fault. A different USGS study in 2008 tried to assess the physical, social and economic consequences of a major earthquake in southern California. That study predicted that

1102-592: The Salton Sea , contains upturned strata associated with that section of the fault. 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 ,

1160-620: The Santa Cruz Mountains , epicenter of the 1989 Loma Prieta earthquake , then up the San Francisco Peninsula , where it was first identified by Professor Lawson in 1895, then offshore at 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 in Marin County . It returns underwater through

1218-521: The U.S. Geological Survey (USGS) have made variable predictions as to the risk of future seismic events. The ability to predict major earthquakes with sufficient precision to warrant increased precautions has remained elusive. The U.S. Geological Survey's most recent forecast, known as UCERF3 (Uniform California Earthquake Rupture Forecast 3), released in November 2013, estimated that an earthquake of magnitude 6.7 M or greater (i.e. equal to or greater than

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1276-539: The eastern California shear zone . This complicated evolution, especially along the southern segment, is mostly caused by either the "Big Bend" and/or a difference in the motion vector between the plates and the trend of the fault and its surrounding branches. The fault was first identified in Northern California by UC Berkeley geology professor Andrew Lawson in 1895 and named by him after the surrounding San Andreas valley. Eleven years later, Lawson discovered that

1334-582: The foreland to a collisional belt. In plate tectonics, the outermost part of the Earth known as the lithosphere (the crust and uppermost mantle ) act as a single mechanical layer. The lithosphere is divided into separate "plates" that move relative to each other on the underlying, relatively weak asthenosphere in a process ultimately driven by the continuous loss of heat from the Earth's interior. There are three main types of plate boundaries: divergent , where plates move apart from each other and new lithosphere

1392-640: The California economy within the first 6 months post-recovery from the event through estimates of "utility outages, property damages, and supply chain disruptions resulting in an estimated $ 44 billion of gross state product (GSP) losses, or translated at 4% of the California economy"(Wein et al.). This study also projects the recovery of jobs lost in highly impacted areas, such as Alameda County, could take up to 10 years to fully recover job losses and possible economic recession. Trajectories for economic recovery are improved by reconstruction but also delayed with impacts to

1450-519: The Earth's outer shell interact with each other. Principles of tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population. Tectonic studies are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources. An understanding of tectonic principles can help geomorphologists to explain erosion patterns and other Earth-surface features. Extensional tectonics

1508-663: The Farallon and North American plates, the spreading ridge began to be "subducted", creating a new relative motion and a new style of deformation along the plate boundaries. These geological features are what are chiefly seen along San Andreas Fault. It also includes a possible driver for the deformation of the Basin and Range , separation of the Baja California peninsula , and rotation of the Transverse Range . The main southern section of

1566-661: The HayWired Scenario study was released in 2017, with consistent continuations and contributions by engineers. This continuation was published in the second volume, Engineering Implications, in 2018. As of the 2021 Fact sheet update, there are several estimates on damages ranging from the approximate people affected at home, work, effects of lifeline infrastructures such as telecommunications, and more. This group of scientists have worked together to create estimates of how hazards such as liquefaction, landslides, and fire ignition will impact access to utilities, transportation, and general emergency services. This study goes into detail about

1624-659: The North American plate has forced the San Andreas to jog westward. This has led to the formation of the Transverse Ranges in Southern California, and to a lesser but still significant extent, the Santa Cruz Mountains (the location of the Loma Prieta earthquake in 1989). Studies of the relative motions of the Pacific and North American plates have shown that only about 75 percent of the motion can be accounted for in

1682-460: The Pacific Ring of Fire . Most of the deformation in the lithosphere is related to the interaction between plates at or near plate boundaries. The latest studies, based on the integration of available geological data, and satellite imagery and Gravimetric and magnetic anomaly datasets have shown that the crust of the Earth is dissected by thousands of different types of tectonic elements which define

1740-656: The Pacific Coast. The northern limit of the Gabilan Range lies just south of Pinecate Peak and San Juan Bautista, California . According to the USGS GNIS, GPS coordinates for the southern border of the Gabilan Range follow Chalone Creek which enters the Salinas River east of Greenfield, California . Chalone Creek is the principal drainage of Pinnacles National Park . Fremont Peak , at 3,455 feet (1,053 m) in elevation,

1798-461: The San Andreas Fault near Parkfield in central California consistently produces a magnitude 6.0 earthquake approximately once every 22 years. Following recorded seismic events in 1857, 1881, 1901, 1922, 1934, and 1966, scientists predicted that another earthquake should occur in Parkfield in 1993. It eventually occurred in 2004 . Due to the frequency of predictable activity, Parkfield has become one of

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1856-467: The San Andreas Fault proper has only existed for about 5 million years. The first known incarnation of the southern part of the fault was Clemens Well-Fenner- San Francisquito fault zone around 22–13 Ma. This system added the San Gabriel Fault as a primary focus of movement between 10–5 Ma. Currently, it is believed that the modern San Andreas will eventually transfer its motion toward a fault within

1914-422: The San Andreas Fault stretched southward into southern California after reviewing the effects of the 1906 San Francisco earthquake . Large-scale (hundreds of miles) lateral movement along the fault was first proposed in a 1953 paper by geologists Mason Hill and Thomas Dibblee . This idea, which was considered radical at the time, has since been vindicated by modern plate tectonics . Seismologists discovered that

1972-463: The San Andreas fault has reached a sufficient stress level for an earthquake of magnitude greater than 7.0 on the moment magnitude scale to occur. This study also found that the risk of a large earthquake may be increasing more rapidly than scientists had previously believed. Moreover, the risk is currently concentrated on the southern section of the fault, i.e. the region around Los Angeles, because strong earthquakes have occurred relatively recently on

2030-510: The San Andreas towards Walker Lane. Assuming the plate boundary does not change as hypothesized, projected motion indicates that the landmass west of the San Andreas Fault, including Los Angeles, will eventually slide past San Francisco, then continue northwestward toward the Aleutian Trench , over a period of perhaps twenty million years. The San Andreas began to form in the mid- Cenozoic about 30 Mya (million years ago). At this time,

2088-574: The abnormally long period of time since the last major earthquake in the region since the lake has dried up. The San Andreas Fault System has been the subject of a flood of studies. In particular, scientific research performed during the last 23 years has given rise to about 3,400 publications. A study published in 2006 in the journal Nature by Yuri Fialko, an associate professor at the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps Institution of Oceanography , found that

2146-1177: The central ( 1857 ) and northern ( 1906 ) segments of the fault, while the southern section has not seen any similar rupture for at least 300 years. According to this study, a major earthquake on that southern section of the San Andreas fault would result in major damage to the Palm Springs – Indio metropolitan area and other cities in San Bernardino , Riverside and Imperial counties in California, and Mexicali Municipality in Baja California . It would be strongly felt (and potentially cause significant damage) throughout much of Southern California , including densely populated areas of Los Angeles County , Ventura County , Orange County , San Diego County , Ensenada Municipality and Tijuana Municipality , Baja California, San Luis Rio Colorado in Sonora and Yuma, Arizona . Older buildings would be especially prone to damage or collapse, as would buildings built on unconsolidated gravel or in coastal areas where water tables are high (and thus subject to soil liquefaction ). Of

2204-462: The construction industry. A 2008 paper, studying past earthquakes along the Pacific coastal zone, found a correlation in time between seismic events on the northern San Andreas Fault and the southern part of the Cascadia subduction zone (which stretches from Vancouver Island to Northern California). Scientists believe quakes on the Cascadia subduction zone may have triggered most of the major quakes on

2262-419: The crust or the lithosphere. This type of tectonics is found along oceanic and continental transform faults which connect offset segments of mid-ocean ridges . Strike-slip tectonics also occurs at lateral offsets in extensional and thrust fault systems. In areas involved with plate collisions strike-slip deformation occurs in the over-riding plate in zones of oblique collision and accommodates deformation in

2320-526: 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 in Monterey County all the way to the Salton Sea , is capable of an 8.1-magnitude earthquake. At its closest, this fault passes about 35 miles (56 km) to

2378-482: The fault. A National Science Foundation funded project called the San Andreas Fault Observatory at Depth (SAFOD) near Parkfield, California , involved drilling through the fault from 2004 to 2007. The aim was to collect core samples and make direct geophysical and geochemical observations to better understand fault behavior at depth. The northern segment of the fault runs from Hollister , through

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2436-639: The first block of land intended to protect the Santa Cruz Mountains-Gabilan Range Wildlife Corridor, the 2,640 acres (4.13 sq mi) Rocks Ranch in Aromas at the border of San Benito and Monterey counties. This Monterey County, California -related article is a stub . You can help Misplaced Pages by expanding it . This San Benito County, California -related article is a stub . You can help Misplaced Pages by expanding it . San Andreas Fault The San Andreas Fault

2494-433: The geological impacts/effects of the event, but also the societal impacts such as property damage, economic rebuilding, and aims at estimating damages if cities increased risk-reduction. It was developed for preparedness geared towards Bay Area residents and as a warning with an attempt to encourage local policy makers to create infrastructure and protections that would further risk reduction and resilience-building. This study

2552-517: The influence of plate tectonics . The rate of slippage averages about 33 to 37 millimeters (1.3 to 1.5 in) a year across California. The southwestward motion of the North American plate towards the Pacific is creating compressional forces along the eastern side of the fault. The effect is expressed as the Coast Ranges. The northwest movement of the Pacific plate is also creating significant compressional forces which are especially pronounced where

2610-528: 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,

2668-422: The location of these offsets were plotted on a map, he noted that they made a near perfect line on top of the fault he previously discovered. He concluded that the fault must have been the origin of the earthquake. This line ran through San Andreas Lake , a sag pond . The lake was created from an extensional step over in the fault, which created a natural depression where water could settle. A common misconception

2726-461: The main character (Jody Tiflin) names his pony "Gabilan" after the mountain range. The mountains also appear in the 1875 memoirs of Major General William Tecumseh Sherman . Fremont Peak was named for John C. Frémont , an American explorer and a Captain in the U.S. Army Corps of Topographical Engineers who assessed the military value of the peak in 1846, posing a threat to the Mexican authorities. It

2784-407: The most important areas in the world for large earthquake research. In 2004, work began just north of Parkfield on the San Andreas Fault Observatory at Depth (SAFOD). The goal of SAFOD is to drill a hole nearly 3 kilometres (1.9 mi) into the Earth's crust and into the San Andreas Fault. An array of sensors will be installed to record earthquakes that happen near this area. A 2023 study found

2842-609: The movements of the San Andreas and its various branch faults. The rest of the motion has been found in an area east of the Sierra Nevada mountains called the Walker Lane or Eastern California Shear Zone. The reason for this is not clear. Several hypotheses have been offered and research is ongoing. One hypothesis – which gained interest following the Landers earthquake in 1992 – suggests the plate boundary may be shifting eastward away from

2900-475: 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. The Pacific plate , to the west of the fault, is moving in a northwest direction while the North American plate to the east is moving toward the southwest, but relatively southeast under

2958-642: The northern San Andreas within the past 3,000 years. The evidence also shows the rupture direction going from north to south in each of these time-correlated events. However the 1906 San Francisco earthquake seems to have been the exception to this correlation because the plate movement was mostly from south to north and it was not preceded by a major quake in the Cascadia zone. The San Andreas Fault has had some notable earthquakes in historic times: Tectonics Tectonics (from Latin tectonicus ; from Ancient Greek τεκτονικός ( tektonikós )  'pertaining to building ') are

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3016-490: 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 . The central segment of the San Andreas Fault runs in a northwestern direction from Parkfield to Hollister . While

3074-404: The processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of planetary tectonics extends the concept to other planets and moons. These processes include those of mountain-building , the growth and behavior of the strong, old cores of continents known as cratons , and the ways in which the relatively rigid plates that constitute

3132-451: 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. The southern segment (also known as the Mojave segment) begins near Bombay Beach, California . Box Canyon, near

3190-526: The specific populations to be hardest impacted by a potential earthquake of a 7.0 magnitude, specifically in the San Francisco Bay Area. This includes intensified hardships for those with low-income, racially and culturally-diverse populations, and people with literacy hardships that would significantly "increase their risk of displacement and add to recovery challenges" (Wein et al.). In addition to societal and landscape impacts, this study looks at potential business interruptions. This portion estimates impacts to

3248-576: The study of the physical processes associated with deformation of the crust and mantle from the scale of individual mineral grains up to that of tectonic plates. Seismotectonics is the study of the relationship between earthquakes, active tectonics, and individual faults in a region. It seeks to understand which faults are responsible for seismic activity in an area by analysing a combination of regional tectonics, recent instrumentally recorded events, accounts of historical earthquakes, and geomorphological evidence. This information can then be used to quantify

3306-412: The study, Fialko stated: All these data suggest that the fault is ready for the next big earthquake but exactly when the triggering will happen and when the earthquake will occur we cannot tell. It could be tomorrow or it could be 10 years or more from now. Nevertheless, in the 18 years since that publication there has not been a substantial quake in the Los Angeles area, and two major reports issued by

3364-403: The subdivision into numerous smaller microplates which have amalgamated into the larger Plates. Salt tectonics is concerned with the structural geometries and deformation processes associated with the presence of significant thicknesses of rock salt within a sequence of rocks. This is due both to the low density of salt, which does not increase with burial, and its low strength. Neotectonics

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