The West Napa fault was more completely mapped by Fox and others (1973 #5253). This earthquake nucleated ~11km beneath Napa Valley on or near the West Napa fault, which is itself one a series of subparallel right-lateral strike-slip faults that comprise the San Andreas fault system. The West Napa Fault runs between the valleys on the eastern edge of the mountains. In November 2016, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the surface trace of the West Napa Fault zone at Saintsbury Winery in Napa, California. The whole zone is about 70 km (44 mi) wide. The causative fault of the earthquake is unknown, but the USGS said it suspected the Browns Valley section of the West Napa fault. The most common usage in recent literature is West Napa fault. Our seismic survey was designed to image a strand of the West Napa Fault Zone (WNFZ), which ruptured during the 24 August 2014 Mw 6.0 South Napa Earthquake. Most Popular on TIME… Although the northern deep anomaly appears to cross the West Napa fault without apparent offset, the shallow wavelength, medium wavelength, and unfiltered magnetic data indicate that the apparent continuity of the deep magnetic anomaly across the West Napa fault separates two distinct magnetic sources. Many faults zoned in this area were identified by … The 2014 Mw 6.0 South Napa earthquake occurred on the West Napa Fault Zone (WNFZ) and caused damage in and around the City of Napa. Napa lies exactly in the axis - or "along the strike" as seismologists call it - of the West Napa Fault, the assumed origin of Sunday's quake. 36a Last Review Date: 2000-06-07 ... Bryant, W.A., 1982, West Napa fault zone and Soda Creek (East Napa) fault, Napa County: California Division of Mines and Geology Fault Evaluation Report FER-129, microfiche copy in Division of Mines and Geology Open-File Report 90-10, 18 p., scale 1:24,000. New state maps show the locations of the West Napa Fault and associated faults in greater detail than ever before in such places as western city of Napa neighborhoods. The fault zone that ruptured in the South Napa earthquake had been previously recognized as a strand of the West Napa Fault zone . Accordingly, we interpret the estimates of z u as a map of the position of a slip front—either coseismic or postseismic—that propagated on an extant fault plane. There's a couple of faults there: the West Napa and Carneros-Franklin faults. West Napa fault, Browns Valley section (Class A) No. Diablo, Rodgers Creek, San Andreas, San Gregorio, and West Napa faults. Parts of the West Napa Fault Zone ruptured during the Aug. 24, 2014 South Napa earthquake, they said. As noted in Table 4.10-3, there are four faults (West Napa, Hunting Creek, Green Valley and Cordelia) that are of concern to Napa County. Some significant faults in the region are the Calaveras, Concord-Green Valley, Greenville, Hayward, Mt. The West Napa fault extends along the western margin of the basin that underlies much of Napa Valley. In October 2016, we acquired high-resolution P- and S-wave seismic data along a 120-m-long, SW-NE-trending profile in Napa, California. by Dr. Wendy Bohon. It clearly confirms that part of the West Napa Fault system was responsible for the 6.0 earthquake that rocked California’s wine-producing region. Helley and Herd (1977 #509) first named the northwest to north northwest-striking zone of predominantly dextral slip faults the West Napa fault zone. However, the fault had not been identified as being particularly hazardous prior to the quake that hit on 24 August. Napa Valley quake . The relative motion on this fault is not well known but thought to be about 1 mm/yr (0.04 in/yr). We acquired seismic reflection, refraction, and guided-wave data along a 115-m-long profile across the known surface rupture zone of the West Napa Fault zone. The West Napa fault system is a relatively minor strike-slip fault in the Contra Costa shear zone, which transfers slip be-tweentheNorthernCalaveras,WestNapa,andConcordfaults (Unruh and Kelson, 2002a,b; Kelson et al., 2004, 2005; Wes-ling and Hanson, 2008; Brossyet al., 2010). The valley is located at the southernmost end of the Mayacamas Mountains and extends from the north at Calistoga to just south of Napa. The West Napa Fault and its branches were first mapped by Weaver (1949), and subsequent work extended from the 1970's into the 1990's (references in the article cited). The West Napa Fault is part of the huge fault zone extending outward from the San Andreas Fault, which lies about 31 miles (50 km) west of Napa Valley.The San … As Bay Area earthquake fault lines go, the West Napa Fault — tentatively identified as the source of Sunday’s magnitude-6.0 temblor — is a relative stranger. The West Napa Fault has identified to have the potential capacity to generate a 6.8 to 7.1 magnitude earthquake (Napa County, BDR, 2005). Linking Faults in Napa Valley and Beyond. This early work reported that the fault and its branches extend 30-35 km along the western margin of the Valley; the Wesling and Hanson report suggests that the fault is 57 km long, extending from Carquinez Strait … It has been mapped as a Late Pleistocene-Holocene active fault, and is considered to be predominantly a right lateral strike-slip fault. This was a shallow-focus … California ’ s wine-producing region is not well known but thought to predominantly. 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