Let’s imagine for a minute that we know where, how large, and when an earthquake will be. This in turn can cause the Hayward Fault to rupture. Upon entering your house, you would stumble over toppled bookcases, broken glass from mirrors no longer on the walls, and the contents of kitchen cabinets in piles on the floor. Cartoon sketch of the Pacific Plate-North American Plate boundary showing the San Andreas Fault. Bold numbers show the average time between big earthquakes, determined at paleoseismic sites (triangles). Observations in the trenches along with radiocarbon dating of charcoal, wood chips, and small plant remains, combined with a reevaluation of three previously-studied nearby paleoseismic sites revealed a variation in seismic activity in the past. A pair of major earthquakes occurred on the central to southern region, where the 1857 faulting overlapped the 1812 earthquake faulting. 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. Scientists say the region appears to be overdue for a significant quake. 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. While the San Andreas fault that triggered the great 1906 San Francisco earthquake has become ingrained in California culture, new … (Public domain.). On October 21, 1868, a magnitude 6.8 earthquake struck the San Francisco Bay area. The Hayward fault in the San Francisco Bay area runs through a densely-populated area, so it has been studied quite a bit.The most recent major earthquake on this fault was approximately M6.9 and occurred in 1868. Bay Area Retrofit assumes no responsibility or liability for use by homeowners, contractors, engineers, or anyone else of the information provided on this site. Maybe you’ve heard that the “Big One is overdue” on the San Andreas Fault. The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The Hayward fault dataset includes 1489 earthquakes with magnitudes from … The stuck section slips, and the edge of each block catches up to the rest of the plate. According to government statistics, ab even larger earthquake on the entire Hayward fault plus the already linked Calaveras Fault would reach magnitude 7.3. All rights reserved. The most recent earthquake occurred during the time of Spanish exploration, about 300 years ago, but there is no historic record of the event. Be sure and click the Map View and watch the videos. The highway paralleling the lakes to the left is Interstate 280, ``the most beautiful urban highway in the United States''. In fact, it was considered the “great earthquake” until the San Andreas Fault tore San Francisco apart 38 years later. Over 155,000 housing unites will suffer enough damage to become  uninhabitable  and 350,000 people will be displaced. Since we have exceeded the average, many people use the term “overdue,” but it’s more complicated than that. 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. (See Earthquake Outlook for the San Francisco Bay Region 2014—2043). The North Coast section of the San Andreas Fault is north of San Francisco. When the ground accelerates the house and foundation go with it. 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.). Since then, research has indicated that the likelihood of a Hayward quake is greater and more threatening to the 7 million Bay Area residents than a San Andreas … 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 continental transform fault that extends roughly 1,200 kilometers (750 mi) through California. This shows that the average time between earthquakes includes some intervals that are short and some intervals that are long. and 70? Here is the graphic history of earthquakes on the Hayward fault. 1 B). Geographic Names Information System (GNIS), Mapping, Remote Sensing, and Geospatial Data, Earthquake Outlook for the San Francisco Bay Region 2014—2043, Map of active faults and historic ruptures in California, New Information About the San Andreas Fault, Catching Glimpses of Centuries-Old Earthquakes, Science of the New Madrid Seismic Zone - Paleoseismology, UCERF3: A New Earthquake Forecast for California’s Complex Fault System. 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. The four areas singled out in the study are: Hayward, Rodgers Creek, northern Calaveras and Green Valley. The San Andreas has long been the quake fault California fears the most. It is now thought to be the “ticking time bomb” fault line and more dangerous than the San Andres. Basically, because it’s a big fault that is close to some big cities. Four urban areas of the San Andreas Fault System in Northern California have accumulated a sufficient amount of energy to produce major earthquakes, a new study finds. Introduction [2] The Hayward Fault is located on the eastern side of San Francisco Bay, California, and forms one branch of the San Andreas Fault system that accommodates the relative motion between the North American and Pacific plates. According to the Association of Bay Area Governments the Hayward Fault will cause $165 billion in damage when it ruptures. The resulting 3000-year record includes 29 surface-rupturing earthquakes. Along the San Francisco peninsula no detectable slip occurs (less than 1.5 mm/yr) at the surface, but appreciable strain is accumulating. Or is the size of the 1812 earthquake (~M7.1) more common? 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. Where does the information come from? According to a new study, the Hayward fault line that runs under Oakland, California is believed to be more dangerous than the infamous San Andreas fault line that spans Southern California.. The ground consistently moves a few millimeters each year, pulling apart sidewalks, pipelines and other structures that sit astride the fault. This page was last edited on 23 August 2020, at 21:45. unconsolidated surficial deposits. However, the edges of the blocks, the faults themselves, are stuck and only move where there is a large earthquake (some faults creep a little bit, but most are locked). 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. HAYWARD FAULT RUNNING THROUGH CENTER OF UC BERKELEY SPORTS STADIUM.. MOVEMENT OF EARTH SHOWING HOW EARTHQUAKES DAMAGE HOUSES. The last major earthquake that the Hayward fault produced was in 1868. The San Francisco Bay area is crossed by several right-lateral strike-slip faults of the San Andreas fault zone. (Credit: Kate Scharer, USGS. Earthquake country just got a little scarier. The relative motion between these two tectonic plates is 50 mm/yr (about 2 inches/yr), but that rate is distributed across all the faults that are part of the SAFZ. 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. Public domain.). The most recent major earthquake on this fault was approximately M6.9 and occurred in 1868. In detail, the fault is a complex zone of crushed and broken rock from a few hundred feet to a mile wide. 1 A). For a 12-minute video concerning the Hayward Fault, see the KQED documentary Predictable Peril. Many earthquakes have occurred along it, including famous ones in 1857, 1906 and 1989. Investigating past earthquakes to inform the future. 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. This fault, called a “tectonic time bomb,” is about 74 miles long. San Andreas. Near fault shear strain rates are 0.6 ± 0.1 μstrain/yr (engineering) with direction N47°W ± 9. 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. 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. 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. What does the science say? It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizontal). Map of faults in southern California. And what does it mean? New studies farther to the northwest along the Peninsula section of the San Andreas Fault also show a long interval between the 1906 earthquake and the previous earthquake, which occurred around 1300. The author Kathryn Schultz writes “When the next very big earthquake hits, the northwest edge of the continent, from California to Canada and the continental shelf to the Cascades, will drop by as much as six feet and rebound thirty to a hundred feet to the west . Many smaller faults branch from and join the San Andreas fault zone. Let's start in southern California and work our way north. The 150th anniversary of the 1868 earthquake, and all historical earthquake anniversaries, are opportunities to remind people that we live in earthquake country and 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. ...and thank-you to the Facebook poster who gave us the idea for the title! The Hayward Fault dissects Fremont creating offset features. Contractors Lic #558462 Scientists say the region appears to be overdue for a significant quake. The San Andreas Fault is the most famous fault in the world. Click the … It has an average repeat cycle of 140 years. Thick red lines show the extent of historic ruptures. The San Francisco Bay area is crossed by several right-lateral strike-slip faults of the San Andreas fault zone. The Hayward Fault is an offset of the San Andreas Fault system that dominates the landforms of eastern San Francisco Bay. 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. The San Andreas Fault is locked in many places; much of its energy is released in the form of earthquakes. A paleoseismic study in 2007 at Tyson’s Lagoon (now a BART station) found evidence for 12 paleoearthquakes (including the historical 1868 earthquake) with an average time between earthquakes of about 160 years. Its notoriety comes partly from the disastrous 1906 San Francisco earthquake, but rather more importantly because it passes through California, a highly-populated state that is frequently in the news.And with many research institutions dedicated to studying such an accessible fault, the SAF has become a household name. The results of this study indicate that this section of the San Andreas Fault is likely to have a large earthquake in the not-too-distant future. The faults shown here are represented by simple lines which do not convey how complicated they can be. Prior to 1300, the intervals are shorter, about 200 years. The In 1836 there was a large earthquake but the larges was felt on October 21, 1868. The San Andreas Fault and the San Francisco Bay Area This image shows San Andreas Lake and Crystal Springs reservoir from the air, looking SouthEast from HERE. The Hayward fault slips in large earthquakes and by aseismic creep observed along its surface trace. Retrofit design is based on many factors. Studies of this section of the fault suggest an average recurrence interval of 200-300 years. The red line is traced on a fault that offsets the layers. Since then, research has indicated that the likelihood of a Hayward quake is greater and more threatening to the 7 million Bay Area residents than a San Andreas … Exposure of the San Andreas Fault in a trench. From 1812 to 1906 it generated four major earthquakes of M 7 or larger in two pairs on two major portions of the fault. Fault-plane reflections reveal that two of these faults, the San Andreas and Hayward, dip toward each other below seismogenic depths at 60?? Since then, nearly three million people have moved next to the Hayward fault with little regard for its earthquake potential. 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. Here is a shorter eye-opening 7-minute TV clip on the Cascadia Fault. The Hayward Fault. The fault marks the boundary between the North American and Pacific lithospheric plates. 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. 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 paleoseismic data on different parts of the San Andreas Fault Zone are all telling us that some sections appear to be past the average, or "overdue" for a significant earthquake. However, creep occurs in spots along the Hayward Fault. Four urban areas of the San Andreas Fault System in Northern California have accumulated a sufficient amount of energy to produce major earthquakes, a new study finds. Along the San Francisco peninsula no detectable slip occurs (less than 1.5 mm/yr) at the surface, but appreciable strain is accumulating. New Study Finds Hayward Fault More Dangerous Than San Andreas. CHART SHOWING THE MAGNITUDE AND DATES OF LARGE EARTHQUAKES IN CALIFORNIA. When it stops, your body moves as it is pushed forward. Scientists are now saying that the “Big One” in California may not be caused by the San Andreas fault line, but by the Hayward Bay fault line. The Hayward fault is a 90 kilometer long crack in the Earth's crust that travels through the San Francisco Bay area. Scientists are keeping a nervous eye on the Hayward fault, which runs along the most urbanized edge of San Francisco’s East Bay.The Hayward fault activity is capable of generating destructive earthquakes. Note that because the magnitude scale is a log scale, there is about a 25-fold difference in the energy released by these different earthquakes. 408-664-6355 CBS News did a short but excellent documentary on the huge impact a rupture of the Cascadia Fault will have on our country. (Credit: Kate Scharer, USGS. The San Andreas Fault is locked in many places; much of its energy is released in the form of earthquakes. This includes Cripple Wall Retrofits, No Cripple Wall Retrofits, Retrofits of Homes with Living Area above a Garage, and Hillside Home Retrofits, THE SAN ANDREAS FAULT IS QUITE DANGEROUS AND CAN CREATE AN EARTHQUAKE 8.0 OR MORE ON THE RICHTER SCALE. As of 2020 it has been 151 years since the last big earthquake in 1868. The Hayward Fault. The plate is moving slowly all the time, but the edges move in fits and starts. Where does the information come from? 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. First, let's zoom out and look at the big picture. The San Andreas fault caused the biggest earthquakes in California with an approximate magnitude 7.9 in 1857 (Southern California) and 1906 (San Francisco). In fact, when the "big one" happens, it is more likely to happen on the Hayward Fault than it is to happen on the San Andreas Fault. This web page tries to compile the most up-to-date information in one place. Like the Loma Prieta earthquake of 1989, the San Andreas Fault was responsible for … The slip rate near the San Andreas fault is … 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. No data point selected. Drop, Cover and Hold On sign. The study concluded that there is 33% likelihood of a surface-rupturing earthquake within the next 30 years. 510-548-1111. 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. 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. IN TERMS OF DAMAGE THE HAYWARD AND SAN ANDREAS FAULT EARTHQUAKES WILL BE THE LARGEST EARTHQUAKES IN HISTORY. The Hazel Dell site near Corralitos, CA was trenched in 2013 to characterize the Santa Cruz Mountains section of the San Andreas Fault. 1. 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