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. 0000001075 00000 n 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. Leyden Creek (site 54-2). The white lines indicate faults recognized by the USGS. A study by Kelson and others (1996 #5284). 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 epicenter was along the Calavaras Fault and 9 … 0 The USGS said there was a low likelihood of casualties or damage. H��W�r�H��+jND�0�e�$��-�#��s��P"�$,`�d������3^�Z�r�̗Y/��Df7,�W���Ul"��.�؄��O�iT�Y}[�f���5�. The quakes were all centered along the Calaveras fault system, which is located in the hills east of the San Francisco Bay Area. %%EOF The fault extends northward through the Diablo Range for about 90 miles to the vicinity of Danville. 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. Activity on the different segments of the fault includes moderate and large earthquakes as well as aseismic creep. 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. 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 Calaveras fault, part of the San Andreas fault system, is one of the most seismically active faults in central California. The white lines indicate faults recognized by the USGS. 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. In 1979, the 5.7M Coyote Lake Earthquake ruptured to the south of the 1984 and 1911 earthquakes. 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 northern extent of the fault zone is somewhat conjectural. These faulted deposits range in age from pre-Holocene to modern. Such an earthquake could unexpectedly change people’s lives and impact the Bay Area’s infrastructure and economy, but updated building codes and … The Bay Area fault system and the spot (red star) where the Hayward Fault branches off from the Calaveras Fault. (Here is a regional map courtesy of Xerox PARC.) 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. USGS A magnitude 3.7 earthquake was followed by a 3.6 within one minute near Morgan Hill, Calif. on … 68 14 Simpson and others (1999 #5528) reported faulted late Holocene deposits at Welch Creek. Here the estimated deep slip rates drop from 15 to 6 mm/yr on the Calaveras fault… Calaveras fault zone, Northern Calaveras section (Class A) No. The Calaveras Fault is part of the greater San Andreas Fault System in the San Francisco Bay region. 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. Sarna-Wojcicki (1992 #5265) reported about 13±7 km of cumulative dextral offset in the past 6 m.y. The Calaveras Fault. 70 0 obj<>stream The complete fault zone, including the Rodgers Creek fault, is divided by seismologists into three segments – Rodgers Creek, Northern Hayward, and Southern Hayward. startxref 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). 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