Investigating Past Earthquakes to Inform the Future. The Calaveras Fault is a major branch of the San Andreas Fault System that is located in northern California in the San Francisco Bay Area.Activity on the different segments of the fault includes moderate and large earthquakes as well as aseismic creep.The last large event was the 1984 Morgan Hill event and the last moderate earthquake was the 2007 Alum Rock event. The red line is traced on a fault that offsets the layers. The earthquake will cause $90.4 billion damage to residential buildings and 96.4 to commercial buildings. Thick red lines show the extent of historic ruptures. However, creep occurs in spots along the Hayward Fault. and 70? Let's start in southern California and work our way north. The SAFZ started moving about 28-30 million years ago and has horizontally slipped (transform motion) a total of about 300-350 km (186-220 mi)since it began moving. 1 A). Near fault shear strain rates are 0.6 ± 0.1 μstrain/yr (engineering) with direction N47°W ± 9. You might think that would be good because then you could leave the area beforehand and then return after the earthquake. Fault-plane reflections reveal that two of these faults, the San Andreas and Hayward, dip toward each other below seismogenic depths at 60° and 70°, respectively, and persist to the base of the crust. HAYWARD FAULT RUNNING THROUGH CENTER OF UC BERKELEY SPORTS STADIUM.. MOVEMENT OF EARTH SHOWING HOW EARTHQUAKES DAMAGE HOUSES. The four areas singled out in the study are: Hayward, Rodgers Creek, northern Calaveras and Green Valley. Three earthquakes occurred within a 70-year period between 1838 and 1906, but there were no earthquakes during the 500 years before that, and there have been no earthquakes in the 110 years since 1906. The San Andreas fault system (SAFS) consists of over a dozen faults that accommodate motion between the North American and Pacific Plates (Fig. This website is intended to help clients of Bay Area Retrofit to understand their retrofit proposals. The Hayward Fault dissects Fremont creating offset features. The transform boundary initiated about 30 million years ago when a spreading ridge separating the Pacific and Farallon Plates intersected with the North American continental crust near what is now Los Angeles, California (Fig. The SAFZ is the main part of the boundary between the Pacific tectonic plate on the west side and the North American plate on the east side. The San Francisco Bay area is crossed by several right-lateral strike-slip faults of the San Andreas fault zone. The city of Ukiah, in Northern California sits right next to the Maacama Fault, which is capable of M=7.5 earthquakes and poses a significant threat to the region. Earth scientists have been gathering data at key paleoseismic sites along sections of the San Andreas Fault to figure out the past timeline of earthquakes at each spot. . The San Andreas Fault is a continental transform fault that extends roughly 1,200 kilometers (750 mi) through California. The Hayward fault dataset includes 1489 earthquakes with magnitudes from … Contractor On October 21, 1868, a magnitude 6.8 earthquake struck the San Francisco Bay area. The Hayward Fault is a "tectonic time bomb, due any time for another magnitude 6.8 to 7.0 earthquake," according to a 2008 USGS report. -written by Lisa Wald, Kate Scharer, and Carol Prentice, U.S. Geological Survey. The most recent earthquake occurred during the time of Spanish exploration, about 300 years ago, but there is no historic record of the event. The fault has been creeping about 4.6 mm/yr (0.2 inches/yr) for the last several decades, but that is only half of the long-term slip rate, so stress is building upon this fault. Workers' Comp RWCC64393236 There are only two large known historic earthquakes on the San Andreas Fault in southern CA, the most recent in 1857, and before that one in 1812. The San Andreas Fault and 6 other significant fault zones are present in the Bay Area: the Calaveras, Concord-Green Valley, Greenville, Hayward, Rodgers Creek, and San Gregorio Faults. This shows that the average time between earthquakes includes some intervals that are short and some intervals that are long. This in turn can cause the Hayward Fault to rupture. This fault regularly generates 9.0 temblors similar to the 2004 Sumatra earthquake and tsunami that killed over 227,000 people in Indonesia and India. This fault, called a “tectonic time bomb,” is about 74 miles long. (See Earthquake Outlook for the San Francisco Bay Region 2014—2043). The ground consistently moves a few millimeters each year, pulling apart sidewalks, pipelines and other structures that sit astride the fault. Bold numbers show the average time between big earthquakes, determined at paleoseismic sites (triangles). Earthquake country just got a little scarier. At the time, it was known as the 'great San Francisco quake' (this was before the infamous 1906 quake, produced by the San Andreas fault), and it produced massive amounts of damage and several people lost their lives. The last major earthquake that the Hayward fault produced was in 1868. The new San Pablo Bay link between the Rodgers Creek Fault (which extends out of the image to the upper left to Santa Rosa) and the Hayward fault (which joins the Calaveras Fault out of the image to the lower right) is orange. Most cities in South Bay are about 5 miles from the San Andreas fault, while the Hayward faults cuts through many East Bay cities (see California Geological Survey - CGS's Information Warehouse.). The scariest scenario for the next major earthquake may […] It is now thought to be the “ticking time bomb” fault line and more dangerous than the San Andres. With about 45 years between the historic earthquakes but about 160 years since the last one, it is clear that the fault does not behave like a clock with a regular beat. Be sure and click the Map View and watch the videos. (Public domain.). Each house is unique. No one can predict earthquakes, so what does the science really say? Like the Loma Prieta earthquake of 1989, the San Andreas Fault was responsible for … Many of the sites paleoseismologists have been studying are along key sections of the SAFZ where there is a large population or major infrastructure that would be affected by a large earthquake in the future. On page 10 of Seismic Behavior of Level and Stepped Cripple Walls by Y. H. Chai, it states, “More than half of the $40 billion dollar property losses in the Northridge Earthquake were due to failures of wood frame construction, primarily as a result of the damage or collapse of residential, single-family homes ……………..”  Damage from the Hayward Fault will greatly exceed this. And what does it mean? San Francisco Bay Area Earthquakes: The Hayward and San Andreas Faults are probably the most studied earthquake faults in the world, so a lot is known about them. The San Andreas has long been the quake fault California fears the most. It runs through densely populated areas, including Richmond, El Cerrito, Berkeley, Oakland, San Leandro, Castro Valley, Hayward, Union City, Fremont, and San Jose. Bay Area Retrofit does not recommend performing a retrofit without the guidance and supervision of experienced and knowledgeable retrofit professionals, and is not responsible for costly errors, injuries, or earthquake damage that result from such attempts. Here is a shorter eye-opening 7-minute TV clip on the Cascadia Fault. Our Influence on Retrofit Building Codes, Shear Transfer Ties No Cripple Wall Retrofits, Brick Foundations and Earthquake Retrofitting, Workers’ Compensation and Liability Insurance. The Hayward Fault Zone is located in northern California in the San Francisco Bay Area. The faults are boundaries between blocks, and each block is constantly moving, which we can see by analyzing GPS (Global Positioning System) data. New Study Finds Hayward Fault More Dangerous Than San Andreas. San Francisco Bay Area Earthquakes: The Hayward and San Andreas Faults are probably the most studied earthquake faults in the world, so a lot is known about them. The USGS also has a webpage that analyzes what will happen if a 7.0 earthquake has its epicenter in Oakland or Fremont. The study concluded that there is 33% likelihood of a surface-rupturing earthquake within the next 30 years. Posted April 19, 2018, under Blog. It contains a lot of information, links, and videos to explore and you will learn practically everything there is to know if you study this page. Bay Area Retrofit assumes no responsibility or liability for use by homeowners, contractors, engineers, or anyone else of the information provided on this site. Instead, radiocarbon dating provides the age of the most recent earthquake and six more that occurred since about 800 A.D. A paleoseismology site in Wrightwood, CA has been studied by several scientists, and recently (in 2010) the detailed data from multiple studies were joined together to create a single timeline. Liability Ins PCA 1045011 The fault has been creeping about 4.6 mm/yr (0.2 inches/yr) for the last several decades, but that is only half of the long-term slip rate, so stress is building upon this fault. Historic information doesn’t provide enough data to establish whether or not there is a pattern in the timing of earthquakes, but paleoseismology has provided an abundance of data. Running for nearly 74 miles through cities including Fremont, Hayward, Oakland, Berkeley, and Richmond, the Hayward Fault has the potential to wreak more havoc than most California faults. Dislocation models of the surface deformation adjacent to the Hayward fault measured with the global positioning system and interferometric synthetic aperture radar favor creep at ∼7 millimeters per year to the bottom of the seismogenic zone along a ∼20-kilometer-long northern fault segment. But the data can’t be used to make predictions: we do not understand earthquakes well enough to know exactly where the next earthquake will occur, what the magnitude will be, or exactly when it will happen. Since we have exceeded the average, many people use the term “overdue,” but it’s more complicated than that. Scientists have a good big picture understanding of the San Andreas Fault Zone (SAFZ). Drop, Cover and Hold On sign. Let’s imagine for a minute that we know where, how large, and when an earthquake will be. We test this method on both the Hayward Fault and San Andreas Fault at Parkfield, California. (Credit: Kate Scharer, USGS. Or is the size of the 1812 earthquake (~M7.1) more common? Near fault shear strain rates are 0.6 ± 0.1 μstrain/yr (engineering) with direction N47°W ± 9. The Hayward Fault splinters from the Calaveras Fault, which itself is an offshoot of the In northern California, the zone includes the Hayward, Calaveras, as well as the Northern San Andreas and other faults, and in southern California, the zone is even wider, encompassing the Southern San Andreas, the San Jacinto, and other faults in the Los Angeles area. Click on a pin on the map to see more information. All rights reserved. San Andreas. The most recent major earthquake on this fault was approximately M6.9 and occurred in 1868. The most striking result is that the deformation is not uniformly distributed across the area. A pair of major earthquakes occurred on the central to southern region, where the 1857 faulting overlapped the 1812 earthquake faulting. The San Andreas Fault is locked in many places; much of its energy is released in the form of earthquakes. To see the full scale of the devastation when that tsunami recedes, you would need to be in the international space station.”  FEMA conservatively anticipates a death toll of 13,000. Page 75 of The online version of “The Coming Bay Area Earthquake: 2010 Update of Scenario for a Magnitude 7.0 Earthquake on the Hayward Fault published by the Earthquake Engineering Research Institute describes the situation vividly. The San Andreas Fault is a crack in the Earth's crust in California, some 680 miles long. 510-548-1111. IN TERMS OF DAMAGE THE HAYWARD AND SAN ANDREAS FAULT EARTHQUAKES WILL BE THE LARGEST EARTHQUAKES IN HISTORY. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizontal). CBS News did a short but excellent documentary on the huge impact a rupture of the Cascadia Fault will have on our country. From 1812 to 1906 it generated four major earthquakes of M 7 or larger in two pairs on two major portions of the fault. The Maacama fault is the northward continuation of the Hayward-Rodgers Creek fault system in northern California. The Hayward fault runs through the East Bay hills from Richmond to San Jose. Here is the graphic history of earthquakes on the Hayward fault. New Study Finds Hayward Fault More Dangerous Than San Andreas. The Hayward Fault is 40 miles long and about 8 miles deep and trends along the east side of San Francisco Bay. Fault-plane reflections reveal that two of these faults, the San Andreas and Hayward, dip toward each other below seismogenic depths at 60?? An earthquake occurs when the stress from the force of the moving plate overcomes the friction causing the plate boundary edges, the fault, to stick. The San Andreas Fault is locked in many places; much of its energy is released in the form of earthquakes. Basically, because it’s a big fault that is close to some big cities. The recurrence intervals (times between earthquakes) at Wrightwood are more regular than clustered (determined by a mathematical analysis), and only four times in the past has the interval between two major earthquakes been longer than the current interval (since 1857). Investigating past earthquakes to inform the future. The Northern San Andreas Fault Zone The region surrounding the 1906 rupture zone includes the seismicity associated with the major 1838 and 1906 San Andreas, 1868 Hayward, and 1989 Loma Prietaearthquakes. However, creep occurs in spots along the Hayward Fault. San Jose, Sunnyvale, Fremont, Oakland, Berkeley and Surrounding Areas The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The threat to San Francisco from the Hayward fault was recognized by A. C. Lawson in 1908 in Report of the State Earthquake Commission, The California earthquake of April 18, 1906, p. 447: "The foot of Market Street, San Francisco, is about midway between the San Andreas rift and the fault scarp upon which movement occurred in 1868. But focusing only on avoiding an earthquake doesn’t address most of the effects from the shaking. The Hayward Fault is a "tectonic time bomb, due any time for another magnitude 6.8 to 7.0 earthquake," according to a 2008 USGS report. History shows that five large earthquakes on the Hayward fault have occurred on average every 150 years—last being in 1868. Using the forecasts, we can properly engineer structures, plan for earthquake response, and be prepared at home to make a big difference in the impact of a significant earthquake. ...and thank-you to the Facebook poster who gave us the idea for the title! This means that earthquakes as large as M=7.4 are possible on both sides of San Francisco Bay, rather than just on the San Andreas, as we had thought before. Hayward Bay Fault Could Be More Dangerous Than San Andreas: It’s a “Ticking Time Bomb” The following video is brought to you courtesy of the DAHBOO77 YouTube Channel. The new San Pablo Bay link between the Rodgers Creek Fault (which extends out of the image to the upper left to Santa Rosa) and the Hayward fault (which joins the Calaveras Fault out of the image to the lower right) is orange. Since then, nearly three million people have moved next to the Hayward fault with little regard for its earthquake potential. (Public domain.). San Andreas. The Hayward Fault. At that location, the record is about 1000 years long, and in that time period, there are about 9 large earthquakes recorded in the sediments, including the 1857 rupture. This means that earthquakes as large as M=7.4 are possible on both sides of San Francisco Bay, rather than just on the San Andreas, as we had thought before. When the ground stops suddenly the house wants to keep on going and slides off the foundation. San Francisco Bay and Parkfield that have preinstrumental and modern earthquake epicenters and have towns that can provide felt intensities. For a 12-minute video concerning the Hayward Fault, see the KQED documentary Predictable Peril. The Hayward Fault. Careful analysis of the age of the earthquakes, including the uncertainties in radiocarbon dating (see Determining the Age of a Paleoearthquake in Introduction to Paleoseismology), showed that the average time between earthquakes is about 100 years. The Hayward Fault is an offset of the San Andreas Fault system that dominates the landforms of eastern San Francisco Bay. 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