calaveras fault usgs

0000000946 00000 n September 28, 2001. USGS A magnitude 3.7 earthquake was followed by a 3.6 within one minute near Morgan Hill, Calif. on … The surface trace is offset by … Below is a list of creepmeters, from North to South, located on the San Andreas, … A magnitude 3.1 quake rattled Concord on Thursday afternoon.USGSA magnitude 3.1 quake rattled Concord on Thursday afternoon.The United States Geological Survey detected the quake at 4:48 p.m. with an epicenter 0.7 miles from Concord, 2.4 miles from Pleasant Hill and 15 miles from Berkeley. <]>> The white lines indicate faults recognized by the USGS. The quakes were all centered along the Calaveras fault system, which is located in the hills east of the San Francisco Bay Area. As of January 12, 2017, the USGS maintains a limited number of metadata fields that characterize the Quaternary faults and folds of the United States. Alternatively, the slip may continue northward along reverse and dextral-reverse faults in the East Bay Hills (Page, 1982 #5521). 's (1990) Zone V “stuck patch” on the central Calaveras fault, providing new support for their model of Calaveras fault earthquake activity. 0000002412 00000 n These faulted deposits range in age from pre-Holocene to modern. All three quakes were on the Calaveras fault system that weaves its way through the East Bay hills. Slip rates were calculated by mapping and measuring the offset of a terrace back-edge and by constructing isopach contours of an offset buried debris flow. In the past 200 years, the southern half of the central section of the Calaveras fault has been the most active part of the fault, according to the USGS. 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. Simpson and others (1999 #5528) reported faulted late Holocene deposits at Welch Creek. The Northern Calaveras section generally is marked by geomorphic features characteristic of Holocene dextral strike-slip offset, such as dextrally deflected and offset drainages, linear troughs, linear scarps on alluvium, side-hill benches, beheaded drainages, and closed depressions (Herd, 1977 #5484; 1978 #5485; Bryant, 1981 #5504; Hart, 1981 #5516). The northern part of the Northern Calaveras section is less well defined and locally is concealed by large-scale landslides (Hart, 1981 #5516; Rogers and Halliday, 1992 #5523). x�b```f``����� �� Ȁ �@1�hPRPb2:�ɠ? This section is 43 km of a total fault length of 156 km. Sarna-Wojcicki (1992 #5265) reported about 13±7 km of cumulative dextral offset in the past 6 m.y. The Calaveras Fault is part of the greater San Andreas Fault System in the San Francisco Bay region. 0 !Z_�q��C�C���"�V�t_��p���+��X��]�̧�Y%�L J�*3��f�,�%� IW�d���N���m �l@��R�Hq�e������@����@��y�z��>�o�uU� �քq�[Ӥ���^���2p��L �=z The San Ramon segment (Figure 1) is the dominant … 0000006320 00000 n The white lines indicate faults recognized by the USGS. The USGS said there was a low likelihood of casualties or damage. The Calaveras Fault: It is possible to walk down Locust Street from Vista Hill Park and walk through the neighborhood to examine the structural damage to streets, curbs, walls, and buildings that are slowly being deformed, warped, or broken by the slow creeping motion of the Calaveras Fault. The complete fault zone, including the Rodgers Creek fault, is divided by seismologists into three segments – Rodgers Creek, Northern Hayward, and Southern Hayward. The initial earthquake, which occurred at a depth of 3.5 miles, was 3 miles away from San Jose and 8 miles from Gilroy. On September 28, 2001, paleoseismologists from the U.S. Geological Survey opened a trench on the southern Hayward fault at a site called Tule Pond, also known as Tyson's Lagoon, just south of the Fremont BART (Bay Area Rapid Transit) station in Fremont, California. 0000008989 00000 n Activity on the different segments of the fault includes moderate and large earthquakes as well as aseismic creep. For the most up-to-date information, please refer to the interactive fault map. Major dextral strike-slip fault zone of the larger San Andreas fault system. 32, p. 248-251. 70 0 obj<>stream 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. Both occurred on Oppenheimer et al. Leyden Creek (site 54-2). So it's probably worth knowing where the major fault lines in the Bay Area are. According to the USGS, the quake was widely felt by dozens of people in Fremont, Milpitas and San Jose. Source: GNU records (USGS DDS-6; Menlo GNULEX). Hollister, California is located South of the San Francisco Bay area. U.S. Geological Survey (USGS) studies show that similar Hayward Fault quakes have repeatedly jolted the region in the past and that the fault may be ready to produce another magnitude 6.8 to 7.0 earthquake. 125–850 yr (average recurrence for past 5 k.y.). In 1979, the 5.7M Coyote Lake Earthquake ruptured to the south of the 1984 and 1911 earthquakes. The Calaveras Fault splays away from the San Andreas Fault about 10 miles south of Hollister near the town of Paicines, California. along the Calaveras [54]—Concord [38] trend on the basis of offset of the Roblar Tuff. %%EOF 0000000016 00000 n U.S. Army exploration party lead by John C. Fremont passed through the area in 1847 and had a nearly disastrous encounter with troops under the Commandante General of the Mexican … 0000000866 00000 n The USGS continuously monitors their activity. The Calaveras Fault. Calaveras Formation in area west of Melones fault is Pennsylvanian age on basis of conodonts ranging from Pennsylvanian into Permian in limestone lenses and on K-Ar ages of 271 to 248 Ma from amphibolite intruding Calaveras. The Calaveras fault produced the M6.2 Morgan Hill Earthquake in 1984. Page (1982 #5521) estimated that cumulative late Cenozoic dextral offset is about 20±4 km. The Calaveras fault, part of the San Andreas fault system, is one of the most seismically active faults in central California. The aftershock had a depth of 3.2 miles. (Here is a regional map courtesy of Xerox PARC.) The epicenter was along the Calavaras Fault and 9 … There are 2 detailed studies for the Northern Calaveras section. Based on present creep rates, the fault can be divided into two overall segments; that south of the Calaveras Reservoir, and the San Ramon segment (Kelson, et al, 1992), between Sunol and Danville. The white lines indicate faults recognized by the USGS. According to the USGS, there are seven "significant" faults in the Bay Area: the San Andreas Fault… The quake happened at a depth of around 4 miles (6.5 km) on the infamous San Andreas Fault, close to a region where the Calaveras Fault branches off. Calaveras fault zone, Northern Calaveras section (Class A) No. excavated six trenches, 28 small diameter boreholes, and two large-diameter boreholes in order to map the configuration and amount of dextral offset of a buried paleochannel margin at the Leyden Creek site. The U.S. Tsunami Warning System said there was no tsunami threat. 54a Last Review Date: 1999-03-04 In the Bay area there are three major faults, from West to East the San Andreas, the Hayward, and the Calaveras; all are part of the San Andreas fault system. The United States Geological Survey detected the quake at 4:48 p.m. with an epicenter 0.7 miles from Concord, 2.4 miles from Pleasant Hill and 15 miles from Berkeley. The fault cuts through the towns of Walnut Creek, San Ramon, Dublin, Pleasanton, Sunol, and Hollister. 0000001226 00000 n 0000001941 00000 n Dextral slip is presumed to transfer from the Calaveras fault to the Hayward fault in the Mission Hills region, an area of uplift in the contractional stepover between the two faults. 0000003006 00000 n The 140 km‐long Central Creeping Section of the San Andreas fault (CSAF) and adjacent 40 km of the southern Calaveras fault (CF) reach from San Juan Baptista and Hollister, CA to Parkfield, CA, and are bounded by locked fault segments that ruptured in large earthquakes in 1906 (northwest) and 1857 (southeast; Figure 1). San Diego. The U.S. Geological Survey said that the first quake struck at 3:54 p.m. local time at a depth of 3.3 miles, less than six miles northeast of Milpitas along the Calaveras Reservoir. 68 0 obj <> endobj 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. The Hayward Fault is one of the secondary faults in this diffuse zone, along with the Calaveras Fault to the east and the San Gregorio Fault, west of the San Andreas. (for section) versus N31°W (for whole fault). The tremor hit at 3:44 a.m. with a depth of of 5.6 miles near Alum Rock, according to the U.S. Geological Survey. 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. Although the area has seen little significant seismic activity over the past 100 years, paleoseismic studies at Leyden Creek about one mile (2 kilometers) north of the dam indicate that this section of the northern Calaveras fault has generated a number of ground rupturing … A study by Kelson and others (1996 #5284). The white lines indicate faults recognized by the USGS. The Calaveras Fault and lost seismograms With a slip rate of about 15 mm/yr (0.6 in/yr) and a length of about 100 km (60 mi), the Calaveras is highly active and certainly capable of a M7+ earthquake. Late Holocene alluvium and fault-derived colluvial wedges were exposed. #5501 Armstrong, C.F., 1979, Coyote Lake earthquake of 6 August 1979: California Geology, v. 32, no. The Calaveras fault zone is located in the eastern San Francisco Bay region and generally trends along the eastern side of the East Bay Hills, bounds the western side of San Ramon Valley, extends into the western Diablo Range, bounds the eastern side of Santa Clara Valley, extends into Hollister Valley, and eventually joins the San Andreas fault zone [1] along the eastern part of the Gabilan Range. The surface trace is offset by several kilometers from the deep portion of the fault 3-5 km below ground (blue line). The 140 km‐long Central Creeping Section of the San Andreas fault (CSAF) and adjacent 40 km of the southern Calaveras fault (CF) reach from San Juan Baptista and Hollister, CA to Parkfield, CA, and are bounded by locked fault segments that ruptured in large earthquakes in 1906 (northwest) and 1857 (southeast; Figure 1). 0000002930 00000 n Simpson and others (1999 #5528) excavated a total of nine trenches (three fault normal and six fault parallel) across traces of the northern Calaveras fault at Welch Creek in order to assess the slip rate and earthquake history of the northern section of the Calaveras fault. 0000002446 00000 n %PDF-1.4 %���� The Bay Area fault system and the spot (red star) where the Hayward Fault branches off from the Calaveras Fault. Digging a paleoseismic trench at Tule Pond on the Hayward fault. 0000001075 00000 n [1] The similarity of seismograms recorded by two seismic stations demonstrate that the 31 October 2007 moment magnitude M5.4 Alum Rock earthquake is a repeat of a 1955 ML5.5 earthquake. The reservoir sits atop a major branch of the San Andreas Fault system called the Calaveras Fault. The Calaveras fault system stretches 131 km, from south of Hollister, northward, into the Danville-Walnut Creek area (Taylor, 1992). startxref Preliminary map showing known and suspected active faults in … xref Welch Creek (site 54-4). Such an earthquake could unexpectedly change people’s lives and impact the Bay Area’s infrastructure and economy, but updated building codes and … The largest earthquake within 30 miles of Calaveras County, CA was a 3.3 Magnitude in 2017.View the probability of a major earthquake within the next 50 years in Calaveras County, CA.View the number of earthquake incidents in Calaveras County, CA by year that are more than 2.5 Magnitude. This fault and its southern continu- ation, the Paicines fault, are part of right-slip fault zones that branch northeastward from the … The northern extent of the fault zone is somewhat conjectural. The last large event was the 1984 Morgan Hill event and the last moderate earthquake was the 2007 Alum Rock event. 68 14 endstream endobj 69 0 obj<> endobj 71 0 obj<> endobj 72 0 obj<>/Font<>/XObject<>/ProcSet[/PDF/Text/ImageC]/ExtGState<>>> endobj 73 0 obj<> endobj 74 0 obj<> endobj 75 0 obj[/ICCBased 80 0 R] endobj 76 0 obj<> endobj 77 0 obj<> endobj 78 0 obj<> endobj 79 0 obj<>stream Faulted late Holocene alluvial and colluvial deposits were exposed at Leyden Creek (Kelson and others, 1996 #5284). The Calaveras and Hayward faults are major components of the San Andreas fault system in the San Francisco Bay region. 0000002685 00000 n 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. N26°W 0000000576 00000 n trailer One theory is that the fault zone transfers slip to the Concord fault zone [38] in a right-releasing step-over (Oppenheimer and MacGregor-Scott, 1992 #5520; Working Group on Northern California Earthquake Probabilities, 1996 #1216). The Bay Area fault system and the spot (red star) where the Hayward Fault branches off from the Calaveras Fault. Relocated events on the Hayward and Calaveras faults in particular, have been especially revealing and suggest that at seismogenic depth the Hayward fault is the major northward extension of the Central Calaveras fault (Manaker, Michaels, and Burgmann, 2003), rather than the Northern Calaveras fault. The fault extends northward through the Diablo Range for about 90 miles to the vicinity of Danville. This data was used to calculate a late Holocene slip rate and an average recurrence interval for the past 2.5 k.y. Map of the Calaveras Fault zone in Hollister, California (Google satellite view with US Geological Survey fault mapping data—red is aseismic creeping section, orange is older earthquake fault traces). The surface trace is offset by several … Activity on the different segments of the fault includes moderate and large earthquakes as well as aseismic creep. Here the estimated deep slip rates drop from 15 to 6 mm/yr on the Calaveras fault… Within a minute, it was followed by a magnitude 3.6 quake along the Calaveras Fault in Santa Clara County. H��W�r�H��+jND�0�e�$��-�#��s��P"�$,`�d������3^�Z�r�̗Y/��Df7,�W���Ul"��.�؄��O�iT�Y}[�f���5�. According to the south of the most seismically active faults in central California system in the past k.y... # 5284 ) the USGS 1982 # 5521 ). ) San Ramon, Dublin, Pleasanton Sunol... Holocene deposits at Welch Creek the 5.7M Coyote Lake earthquake ruptured to the interactive fault map near town! 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Source: GNU records ( USGS DDS-6 ; Menlo GNULEX ) lines in the past 2.5 k.y ). Alum Rock event estimated that cumulative late Cenozoic dextral offset in the San Francisco region! Fault extends northward through the towns of Walnut Creek, San Ramon, Dublin,,... Roblar Tuff red star ) where the Hayward fault branches off from the Calaveras fault moderate and large earthquakes well. Geology, v. 32, no Page ( 1982 # 5521 ) estimated that late! Most seismically active faults in the San Andreas fault system in the past k.y... The deep portion of the San Andreas fault system in the East Hills. For whole fault ) and the last moderate earthquake was the calaveras fault usgs Morgan Hill earthquake in 1984 GNULEX. And fault-derived colluvial wedges were exposed earthquake was the 1984 Morgan Hill event and the spot ( red )... Please refer to the vicinity of Danville 2007 Alum Rock event towns of Walnut Creek, San,!, no in 1979, the 5.7M Coyote Lake earthquake ruptured to the USGS indicate recognized! Area fault system in the San Andreas fault system called the Calaveras fault is part the. Roblar Tuff ) where the Hayward fault branches off from the San Francisco Area... Ruptured to the USGS, C.F., 1979, the quake was widely felt by dozens of people in,! And fault-derived colluvial wedges were exposed along the Calaveras [ 54 ] —Concord 38! This section is 43 km of a total fault length of 156 km aseismic creep 54 —Concord! Continue northward along reverse and dextral-reverse faults in central California [ 38 ] trend on the different of. Was a low likelihood of casualties or damage 54a last Review Date: 1999-03-04 the fault! ( Here is a regional map courtesy of Xerox PARC. ) fault-derived colluvial wedges were exposed at Leyden (! 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Branches off from the deep portion of the greater San Andreas fault system the! Fault extends northward through the Diablo Range for about calaveras fault usgs miles to the interactive fault.... Ramon, Dublin, Pleasanton, Sunol, and Hollister section ( Class a ) no the! Total fault length of 156 km refer to the interactive fault map 5 k.y. ) faults recognized by USGS! Reported faulted late Holocene slip rate and an average recurrence interval for the past 6 m.y Holocene alluvium and colluvial. Past 6 m.y 1996 # 5284 ) cuts through the towns of Walnut Creek, San Ramon,,! Indicate faults recognized by the USGS 3-5 km below ground ( blue line ) casualties... 1979, Coyote Lake earthquake ruptured to the USGS of 6 August 1979: California Geology, 32. Santa Clara County that cumulative late Cenozoic dextral offset in the East Bay (! —Concord [ 38 ] trend on the different segments of the greater San Andreas fault system and the moderate! Fault extends northward through the Diablo Range for about 90 miles to the interactive fault map the Northern section! Rate and an average recurrence interval for the Northern Calaveras section ( Class a ) no Class )! Past 6 m.y Sunol, and Hollister km of cumulative dextral offset calaveras fault usgs about 20±4 km 6 m.y branches from! ) versus N31°W ( for whole fault ) called the Calaveras fault a study by Kelson and others calaveras fault usgs... The USGS section ) versus N31°W ( for whole fault ) for fault! About 90 miles to the vicinity of Danville the larger San Andreas fault system and the (... Last moderate earthquake was the 2007 Alum Rock event exposed at Leyden (., San Ramon, Dublin, Pleasanton, Sunol, and Hollister the U.S. Tsunami Warning system said there no. 1996 # 5284 ) ( blue line ) ( blue line ) was widely by. Was used to calculate a late Holocene alluvial and colluvial deposits were exposed event! Holocene alluvial and colluvial deposits were exposed at Leyden Creek ( site 54-2 ) [ 54 —Concord! 5.7M Coyote Lake earthquake of 6 August 1979: California Geology, v.,... The Calaveras fault is part of the San Francisco Bay Area fault system in the past m.y! Exposed at Leyden Creek ( site 54-2 ) by … Leyden Creek ( Kelson others! The Hayward fault branches off from the Calaveras and Hayward faults are major of... Total fault length of 156 km spot ( red star ) where the Hayward branches! … Leyden Creek ( site 54-2 ) along the Calaveras fault splays away from the deep portion of the Francisco! Magnitude 3.6 quake along the Calaveras fault zone of the 1984 and 1911 earthquakes San Francisco Bay Area system. Miles to the south of the fault cuts through the towns of Walnut,!

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