calaveras fault activity

Ramon. This segment of the Calaveras fault zone consists of numerous linear, en HAZUS can also model how infrastructure other than buildings will be affected by a quake. As shown in Figure 3, A 2010 report by the Earthquake Engineering Research Institute noted the 2 meters of expected offset in the BART Berkeley Hills Tunnel, versus the 0.6 meters of displacement it was engineered to accommodate, could “put the tunnel out of commission indefinitely.”. The Calaveras Fault from Sunol to San Ramon. Valley and Danville. None are known to exist in this For my model runs, I chose an arbitrary epicenter near the Lake Chabot Reservoir dam (which is one of many reservoirs located near the fault that could inundate neighborhoods if the dams fail). Similar to Perkins (1972) findings, it consisted of This “slip deficit” suggests that creep will not prevent future quakes, according to Kristy Tiampo, now at the University of Colorado at Boulder, and her colleagues, who explored the issue in a 2013 study in Earth and Planetary Science Letters. A portion of Crane and Bartow (1988) regional cross-section Local governments could have helped this situation by restricting development in areas near the fault. There are dozens of places where streets and parking lots are cracked, where sidewalks are dramatically offset by creep along the fault, and where cracks have appeared in buildings, such as the concrete wall of a playground near the Hayward Plunge swimming center. East-west cross-section through Golden Eagle Farms area (Sealy section is reproduced as Figure 8. While some of the fault lies at a depth of 15 kilometers, near the Bay Area Rapid Transit (BART) commuter train station in Fremont, the fault breaches the surface. On average it takes 14 minutes to complete this trail. the toe of Pleasanton Ridge (Number 5, Figure 1), in an attempt to locate the Figure 8. fault by identifying the relative locations of underlying Miocene and Cretaceous-age the early 1970's, but never published (Wagner, 1992). The surface trace is offset by several kilometers from the deep … from Sunol The red line is the newly discovered surface trace connecting the southern end of the Hayward Fault to the Calaveras Fault, once thought to be an independent system. shown as number 3 on Figure 1. As shown in the South of the Bay Area the Hayward and Calaveras merge into the San Andreas. (1990) again identified the eastern strand of the Calaveras fault, but did not More than 400,000 commuters use the BART system on weekdays. Country Club deep water well geologic consultations: Consultant's report by of the San Francisco Bay Region: Proceedings, this conference. Today, Hayward has about 149,000 people, and 2.6 million people live in the immediate vicinity of the fault. Calaveras fault (Wagner, 1978). borderland was within a convergent plate margin. the main trace lies buried, to the east of Miocene age strata exposed west of This manuscript was reviewed by C. the main trace of the fault. Engeo, Inc., 1981, Alquist Priolo (Figure 4). _____ Please help us make this site better. rotary borings to drill through the massive ancient landslide deposits blanketing In 1984, Seeley and Perkins The Calaveras and San Antonio reservoirs store more than 180 million cubic meters of water, perched above the city of Fremont and its 224,000 residents. Figure 9. But creep on the Hayward Fault does allow us to map its trace precisely, and to see where large ruptures might happen when the fault does break again. Best among these The seismic hazard forced replacement of the original dam. as shown in Figure 1. The north Central Leyte fault and the south Central Leyte fault, on the other hand, are characterized by aseismic creep and medium-sized events, usually with clusters of foreshocks, respectively. of fault termination features being present. E-mail Dr. J David Rogers at rogersda@umr.edu. Most people have heard of the San Andreas, which they assume will be the source of the next big quake in the Bay Area, thanks in part to Hollywood disaster movies, such as the dreadful “San Andreas,” which perpetuate geologic absurdities. In considering the surface expression We can only hope that the computer model proves the better predictor. on a massive mega-landslide complex, comprised of Great Valley Sequence rocks north of Castlewood, the Johnson Ranch/Golden Eagle Farms property has been Karen D’Souza is a writer for the Bay Area News Group papers, covering healthy living, Bay Area culture and other lifestyle topics. Additionally, if freeway overpasses collapse or become too damaged for vehicles to travel underneath them safely, then freeways are rendered useless. Thirty people in the region were killed by the quake while nearly every building in Hayward was damaged or destroyed. The Hayward Fault is shorter than the San Andreas, running about 70 kilometers from Fremont to Point Pinole, and is therefore not expected to produce the magnitude-8-plus quakes we know the San Andreas can generate. Creeks portion of the old Bishop Ranch (Number 10, Figure 1). an elevation of 800 feet on Pleasanton Ridge. Any copying, redistribution or retransmission of any of the contents of this service without the expressed written permission of the American Geosciences Institute is expressly prohibited. The HAZUS model estimates the death toll of a 2 p.m. quake would be five times greater than a quake occurring at 2 a.m. (The Kobe quake occurred before 6 a.m., as did the 1994 Northridge quake and the 1906 San Francisco quake. is likely that we will experience the strongest ground shaking of the I-680 The 1995 Kobe quake, a magnitude-6.9 event in southern Japan, has been proposed as the best analogue for a future Hayward earthquake, which is expected to have a similar magnitude and may have a similar rupture length. of Figure 2, Cretaceous age units of the Great Valley sequence were repeatedly Sunol-Castlewood Country Club - Immediately study (Rowland, 1979),a large trench was excavated with scrappers, down to a When it ruptures, the Hayward Fault will do more than damage homes, zoos and football stadiums: It will endanger numerous lives and likely deal a devastating economic blow. Wagner found a pod of serpentine separating the Panoche and Briones strata near No vertical exaggeration. However, the accumulated creep on these faults does not match estimates of stress expected to have accumulated on them, as Sarah Titus, now at Carleton College, and her colleagues demonstrated in a 2005 paper in Geology. He found approximately 107 m of Holocene and late Pleistocene of the fault. HAZUS predicts casualties in these ranges: Clearly, there is a big difference in the number of deaths predicted by the HAZUS model for this potential Hayward earthquake and the experience in Kobe, with HAZUS estimating an order of magnitude fewer. The white lines indicate faults recognized by the USGS. The headquarters of Facebook and Google and Apple’s new “spaceship” campus are less than 20 kilometers away — all close enough for shaking to affect the operations of the companies. Of the many faults in the Bay Area, the Hayward Fault has the greatest likelihood of producing such an event. The U.S. Geological Survey (USGS) describes the Hayward Fault as “the single most urbanized earthquake fault in the United States.”. 161 p. Questions or comments on this page? report by Merril, Seeley, Mullin, Sandefur, Inc., Pleasanton: 55 p., 5 appendices. In Berkeley, the fault runs beneath the University of California at Berkeley’s football stadium, where offset on the south wall can be seen. the structural relationships that exist today. this conference. According to the Bureau of Labor Statistics, the region is home to 87,000 businesses, 1.5 million jobs and quarterly wages nearing $25 billion; the Bay Area’s overall GDP would, if it were a separate country, rank as the 19th largest in the world. on the Moller Ranch (Number 7, Figure 1), the Calaveras makes a westerly bend. 116,000), and is not far from the metropolises of San Francisco (pop. The researchers found that the underground portion of the Hayward Fault meets the Calaveras Fault 10 kilometers farther north than where the creeping surface traces of both faults meet. cross-section indicates the structural relationships that Ground movement also has the potential to destroy water delivery systems at multiple levels: at the household level, with pipes breaking and flooding homes or unsecured water heaters detaching; at the neighborhood level, with breaks in municipal water lines or water mains; and at the city level, with municipal water treatment plants failing or reservoirs and dams rupturing. on Geologic Investigation Moller Property, Foothill Boulevard, Pleasanton, California: San Jose lies between the San Andreas Fault, the source of the 1989 Loma Prieta earthquake, and the Calaveras Fault. Nevertheless, given its structural position, In this area, the Calaveras may simply be a wide zone, although most agree that The San Andreas cuts predominantly through remote areas, whereas the entire length of the Hayward Fault runs through densely populated cities such as Oakland (pop. activity and an apparently low slip rate. (See Figure 1, number 9 for overall location) Over time, the strike-slip faults gradually structures, formed within different stress regimes. many instances, the parallel, ancillary thrust features are more prominent than Accordingly, to precisely refine the earthquake potential of the Hayward-Calaveras fault zone (HCFZ), characterization of the creep rates along the faults with a high spatial resolution is necessary. shortening. Calaveras fault zone, Northern Calaveras section (Class A) No. Along sections of the Central San Andreas and southern Calaveras faults in California, we map rates and patterns of fault creep over 150 km by comparing two older airborne lidar elevation data sets from 2005 and 2007, with newer data collected in 2018. the Western Outlier of the Great Valley Sequence in the hills between the Hayward overall location of the Calaveras fault was north of Sunol, the Calaveras fault is well defined at the base of Pleasanton The last quake was 148 years ago, so we currently sit within that range. The Hayward Fault extends from San Pablo Bay where it joins up with the Rodgers Creek Fault, to south of San Jose, where it merges with the Calaveras Fault, a length of 140 mi (230 km). Between Sunol and Castlewood Country Club, the best mapping of the fault and a left step-over segment, separated by a pressure ridge (Figure These very active faults, which produce small quakes (mostly under magnitude 2.5) on a daily basis as well as occasional quake swarms — a swarm in October 2015 produced more than 400 small quakes in two weeks — cut through important infrastructure in every city in the region, potentially affecting more than 7 million people. to the Hayward fault on the Mission Hills fault (Oppenheimer and Macgregor, Figure 6. The Hetch Hetchy water system is extraordinarily vulnerable to seismic disruption. Local governments could establish community caches of critical supplies — drinking water, food, medicine and tents, for example — in areas likely to be devastated by the shaking. The San Francisco Bay Area also suffers from the unfortunate confluence of large populations and active faults. Castlewood Country Club was constructed Within this "megatrench", the main trace of the Calaveras Taylor, Charles L., 1992, Historical © 2008-2021. Myers, W. Darwin, 1984, Fault This they were able to do with reasonable success, and their Figure 1. I recently ran a HAZUS model for a Hayward Fault rupture. off San Ramon Valley and Environs-April 30, 1988: Northern California Geological 3, 1861, causing continuous ground rupture, 6-8 miles long, between the Amador Here, Skinner (1990) identified several traces of the fault. Kelson, K.I., Lettis, W.R., 9). The western, inactive trace of the Calaveras fault on Moller and Crane (1988) all show the major offset in the older position (Figure 1). The surface expression can be seen near the Fremont Main Library and the Fremont Police Department, as well as two hospitals. What is important to appreciate is that, in Last summer, a startling article appeared in The New Yorker magazine outlining what could happen to the Pacific Northwest in the event of a large earthquake resulting from a full rupture of the Cascadia Subduction Zone. The Calaveras fault produced the M6.2 Morgan Hill Earthquake in 1984. The eastern portion of Perkins (1972) cross-section through Calaveras. A portion of this preceded the current strike-slip regime. For instance, a lot depends on where people are when the quake hits. But if a quake occurred at 2 p.m. on a weekday, many people would be at work or school in vulnerable structures constructed with brick walls and unreinforced masonry. Note plug of serpentine in the fault zone. containing a multitude of splays, step-overs, and other structural discontinuities. These reservoirs sit 8 and 11 kilometers, respectively, from traces of the Hayward Fault as it passes through Fremont. These findings were subsequently incorporated into the Working Group on California Earthquake Probabilities, third Uniform California Earthquake Rupture Forecast, After hurricanes, U.S. beach homes are rebuilt bigger, Geoethics in the Field: Leading by Example, Inside the inferno: How large firenadoes form, Wind or water? Unfortunately, it is also the prime water source for San Francisco. Much remains to be revealed about the consistency has been identified to date. Seeley, Marc W., and Perkins, It was long believed that there was no connection between the Hayward Fault and the Calaveras, but geological studies (particularly the examination of very small and deep earthquakes) suggest that the two may be connected. Darwin Myers Associates, Pleasant Hill: 24 p., 8 figures, 5 plates, 1 appendix. It is likely that the Applied Soil Mechanics, 1988, His trenches suggested that the m deep water well for the Country Club, which was drilled in the narrow valley and Perkins, 1984). As the triple junction passed, the regional stress regime shifted Find what to do today, this weekend, or in February. Despite the notoriety of the San Andreas Fault, it is not the greatest seismic threat to the Bay Area. At the extreme northeastern portion of the Moller Ranch, Skinner The Masbate fault is the central part with large and medium earthquakes accompanied by unusually large ground rupture. One day, the Hayward Fault could produce the greatest natural disaster ever to hit the United States. a particularly interesting study of the fault in south San Ramon for the Twin Household gas meters could be required to have motion-activated automatic shut-off switches, a technology widely used in Japan to reduce post-quake fire danger. Click here for all copyright requests. It is possible that each of these quakes could have produced higher casualties if they had occurred later in the day.). to the Gelderman Ranch, where Montevideo Drive intersects San Ramon Valley Boulevard This analysis shows that the San Andreas fault creeps at a mean rate of 22 mm/year between Parkfield, California, and San Juan Bautista, California. These losses are just the beginning of the infrastructure problems a Hayward Fault quake will create. East of San Francisco, across the muddy, green waters of San Francisco Bay, sits a smaller fracture in the crust: the Hayward Fault. straightened and coalesced as the interplate slip increased. 1. existed during thrusting in the early Quaternary. The article attracted a great deal of attention, especially among people who had never heard of the possibility that the heavily populated Pacific Northwest could, in a geologic moment, become “toast” — as someone quoted in the article put it. Earthquake risk prompts order to drain California dam. Governments, however, have not done theirs. County, California: University of California, Berkeley: Master's thesis: Department tilted Quaternary-age gravels lying within a narrow zone between two strands Geologic and Seismic Hazards Evaluation, Golden Eagle Farm, Pleasanton, California: the Livermore Basin. The worst flooding could happen to the city of Fremont. The Calaveras Fault is a mostly right-lateral, strike-slip fault. Instead of being a single strand, the Calaveras consists of two active traces Figure 7. Most panels, and re-activated suitably orientated thrusts. Note the location of the serpentine outcrop. Rowland, Richard, 1988, Soil The Xianshuihe Fault is located at the eastern boundary of the Tibetan Plateau and is one of the most active faults in China. Just as the citizens of the Pacific Northwest may one day find themselves affected by the Cascadia Subduction Zone, the Bay Area will be damaged by the Hayward Fault. Investigation on A Portion of the Bishop Ranch south of Bollinger Canyon Road Figure 1). The USGS continuously monitors their activity. active trace of the fault was located some 300 m east of the supposed trace, of the San Ramon segment we must be cognizant of the structural style which report (AP-1437) by Engeo, Inc., Concord: 13 p., 4 figures. All of these are ``right-lateral strike-slip faults'', which means that the motion is predominantly horizontal, with the land on the West side of the fault moving North. Calaveras, it does appear to have spawned a Magnitude 6.9 earthquake on July to (see companion article, this volume), no correlatable surface trace of sufficient https://www.earthmagazine.org/article/most-dangerous-fault-america trace is uncertain because it appears to be buried beneath massive ancient landslides, Seeley and Perkins (1984) utilized deep In 1973, Harding was among the first to study the L. Taylor and S. H. Figuers. Inundation maps based on ruptures from these reservoirs show the entire city of Fremont flooded, from the hills to the bay. of weakness, such as the thrusts. Long stretches of freeways in the Bay Area sit near sea level, built on marshy tidal flats that will almost certainly experience liquefaction during the quake. County Zone 7 Water District) along the western margins of the Amador Valley. upper Monterey formation (Briones sandstone). At 2 a.m., most people would be home asleep in wood-framed, single-family homes that are unlikely to collapse completely. to the current mode of a strike-slip motion. This area has been The most recent of these was a magnitude 6.2 earthquake near Morgan Hill in 1984. on the eastern extent of the Calaveras. Given the Hayward’s proximity to large populations, its rupture presents a huge risk. Surface creep features, Hydrogen (H 2) has been monitored continuously at 1.5‐m depth at nine sites along the San Andreas and Calaveras faults in central California since December 1980.Site characteristic small noninstrumental diurnal variations were recorded during quiescent periods at most sites. Calaveras near the Castlewood Country Club area of Pleasanton, as it likely 224,000) and Berkeley (pop. When such events occur, it An earthquake swarm of four small temblors rattled areas around a reservoir in Northern California on Tuesday, the second time in three days that multiples quakes struck the … Hurricane Harvey's most destructive force. the scene of numerous explorations in the 1980's. was an important finding because it documents that serpentine can be found adjacent Perkins mapped the fault as two distinct strands, the Calaveras Fault. Repairs for many of these problems, which involve digging up streets and rebuilding major parts of the water infrastructure, would take months to years. State's mapping work by Hart (1981),although Wagner (1978), Dibblee (1980), earth/debris flow deposits and colluvium. We use the … In 2015, the Working Group on California Earthquake Probabilities released the third Uniform California Earthquake Rupture Forecast, which increased the probability of a major quake (magnitude 6.7 or above) in the San Francisco Bay region to 72 percent within the next 30 years. (Figure 1) is the dominant structural feature of the Amador and San Ramon Valleys, How will hundreds of thousands of newly homeless people in the region survive absent running water, absent sewage systems, and absent electricity? BART has made efforts to retrofit its infrastructure, but a 2002 study estimated that major damage from an earthquake to the underwater trans-bay tunnel, through which the rail line travels, could shut down the BART system for two to three years, with disastrous effects on the local economy. (The latter gave its name to the fault when it was first recognized in 1895.) California, Berkeley: Ph.D. dissertation, Department of Geology and Geophysics, to inactive strands of the fault. Another way to assess the Hayward Fault’s potential damage is through FEMA’s hazard modeling program, HAZUS, which allows users to select variables such as the location of an earthquake’s epicenter, the length of a rupture, the magnitude and depth of a quake, and the time of day when it occurs. is shown in Figure 6. we can expect strong energy propagation and release along the segment when the lower half of Figure 2, what remains today is a composite mix of old and new Berlogar Geotechnical Consultants, 32 figures, 3 appendices. Society, San Ramon. about portions of the San Ramon segment of the Calaveras by briefly describing The Sierra Vista Trail opened in 2011, connecting the Ridge Trail at the lower elevations with the Upper and Lower Calaveras Fault Trails, and creating a long 8.9-mile Ridge Trail segment. zone is the active trace. for a series of small developments (Engeo, 1981, Figure 1). forming their western boundaries and creating the structural barrier which comprises Myers shows the two segments joining up with one another a short distance and quiescent, containing a plug of serpentine, some 6 m wide (Figure 7). The San Ramon segment for Presley of Northern California: consultant's report (AP-2523): 37 p., 119 It’s just a matter of time before a large earthquake on the Hayward Fault happens, but how we choose to prepare — or not to prepare — will make a tremendous difference to those caught in the aftermath of this inevitable disaster. The entrance to the Oakland Zoo is marked by the fault; the zoo even notes the location of the fault on its grounds with a sign. Figure 4. San Ramon In much of the segment, its surface of the San Francisco Bay Region: Proceedings, this conference. In San Leandro, the Hayward Fault runs near the Fairmont Hospital and the earthen dam holding back the Lake Chabot Reservoir. In a 2012 paper in the Bulletin of the Seismological Society of America, Lienkaemper and colleagues determined that the fault’s recurrence interval over the last two millennia is about 161 years, plus or minus 65 years. Active splays of the Calaveras Fault (Myers, 1984) near San I set up the model runs under three scenarios with varying event magnitudes: low (magnitude 6.7), moderate (7), and major (7.2). area. Figure 5. This section shows the thrust splays emanating The idea of a Kobe-type quake occurring on the Hayward is unsettling: Out of a population of 1.5 million in Kobe, nearly 5,000 people were killed. One way to assess this question is to compare a potential large Hayward quake to events of similar size in areas of similar population. Perspective on the Location of the Calaveras Fault: this proceedings.

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