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'{{Infobox earthquake |name = 1957 San Francisco earthquake |image = |alt = |caption = |map = |map_alt = |map_caption = |map2 = {{Location map+ | USA California |relief = yes |places = {{Location map~|California|lat=38.45|long=-122.7|label=Santa Rosa|mark=Green pog.svg}} {{Location map~|California|lat=36.97|long=-122.02|label=Santa Cruz|mark=Green pog.svg}} {{Location map~|California|lat=37.56|long=-122.73|mark=Bullseye1.png|marksize=40}} |position = top |width = 250 |float = right |caption = }} |date = {{Start date|1957|3|22|mf=y}} |time = {{tooltip|19:44:22 UTC|11:44:22 local time}} <ref name=ISC-GEM/> |duration = |magnitude = 5.7 [[Moment magnitude scale|M_w]] <ref name=ISC-GEM/> |depth = {{convert|15|km|mi|abbr=on}} <ref name=ISC-GEM/> |location = {{coord|37.56|-122.73|region:US|display=inline, title}} <ref name=ISC-GEM/> |type = [[Fault (geology)#Oblique-slip faults|Oblique-slip]] |affected = [[San Francisco Bay Area]] <br> [[Northern California]] <br> United States |damages = $1 million <ref name=Stover/> |intensity = [[Mercalli intensity scale|VII (''Very strong'')]] <ref name=Stover/> |pga = 0.18''[[Peak ground acceleration|g]]'' <ref name=Cloud/> |tsunami = |landslide = Yes <ref name=Tocher/> |foreshocks = |aftershocks = |casualties = 1 dead, 40 injured <ref name=Stover/> }} The '''1957 San Francisco earthquake''' (also known as the '''Daly City earthquake of 1957''') occurred on March 22 at {{tooltip|11:44:22 local time|19:44:22 UTC}} with a [[Moment magnitude scale|moment magnitude]] of 5.7 and a maximum [[Mercalli intensity scale|Mercalli Intensity]] of VII (''Very strong''). The shock was located in [[Northern California]] in the vicinity of the [[San Andreas Fault]]. There was both a foreshock and aftershock sequence that lasted through the month of June. Damage was considered minimal, but financial losses amounted to around [[United States dollar|US$]]1 million. ==Tectonic setting== The San Andreas Fault is a northwest-[[Strike and dip|striking]] [[transform fault]] that accommodates motion between the Pacific and North American Plates. The [[Mendocino Triple Junction]] is an area of high seismicity, and marks its northern extremity at the [[Gorda Plate]], which is subducting beneath the North American Plate. Three moderate events in the San Francisco Bay Area occurred on or near the San Andreas Fault in the early nineteenth-century.<ref>{{citation|title=Active Faults of the World|last=Yeats|first=R.|date=2012|publisher=[[Cambridge University Press]]|isbn=978-0521190855|pages=81, 83}}</ref> ==Earthquake== Eight foreshocks (with a maximum magnitude of 3.8) preceded the main event. The first motion method was used to determine the focal mechanism of the mainshock. It was found to be dissimilar from the [[1906 San Francisco earthquake|1906 earthquake]], and instead showed oblique movement on a steeply-dipping thrust fault, with the eastern side of the fault rising relative to the western side. The strike-slip component was minimal; only about half as much as the thrust component.<ref name=Tocher>{{citation|title=San Francisco earthquakes of March 1957|chapter=Seismographic Results from the 1957 San Francisco Earthquakes|url=https://archive.org/details/sanfranciscoeart57oake|first=D.|last=Tocher|date=1959|series=Special Report 57|publisher=[[California Geological Survey|California Division of Mines]]|pages=61, 65, 70, 71}}</ref> ===Damage=== Damage was non-structural and was limited to content within buildings and cracked plaster and was estimated at $1 million, not including loss to building content. The most significant effects were seen in the western portion of [[Daly City, California|Daly City]] and in the [[Lake Merced]] area of San Francisco. The minimal losses were attributed to the short duration and lack of high intensity shaking.<ref>{{citation|title=San Francisco earthquakes of March 1957|chapter=Damage to Buildings and Other Structures During the San Francisco Earthquake of March 22, 1957|url=https://archive.org/details/sanfranciscoeart57oake|first=K. V.|last=Steinbrugge|first2=V. R.|last2=Bush|first3=E. G.|last3=Zacher|date=1959|series=Special Report 57|publisher=[[California Geological Survey|California Division of Mines]]|pages=75, 76}}</ref> ===Strong motion=== The event was felt over an area of 12,000 square miles. Its scientific value was reinforced because it was captured on 13 strong motion instruments. A maximum (free field) peak ground acceleration of 0.13''[[Peak ground acceleration|g]]'' was recorded in [[Golden Gate Park]] and .18''g'' was recorded on the fourteenth floor of a building in San Francisco.<ref name=Cloud>{{citation|title=San Francisco earthquakes of March 1957|chapter=Intensity and Ground Motion of the San Francisco Earthquake of March 22, 1957|url=https://archive.org/details/sanfranciscoeart57oake|first=W. K.|last=Cloud|date=1959|series=Special Report 57|publisher=[[California Geological Survey|California Division of Mines]]|pages=51, 52}}</ref>{{clear}} ==References== {{reflist|30em|refs= <ref name=ISC-GEM>{{citation|title=ISC-GEM Global Instrumental Earthquake Catalogue (1900–2009)|url=http://www.isc.ac.uk/iscgem/index.php|author=ISC|year=2015|publisher=[[International Seismological Centre]]|series=Version 2.0}}</ref> <ref name=Stover>{{citation|last1=Stover|first1=C. W.|last2=Coffman|first2=J. L.|title=Seismicity of the United States, 1568–1989 (Revised)|series=U.S. Geological Survey Professional Paper 1527|url=http://books.google.com/books?id=bY0KAQAAIAAJ&printsec=frontcover&dq=seismicity+of+the+united+states&hl=en&sa=X&ei=wOqeUIjiI4XBiwKVvIHYDg&ved=0CDcQ6AEwAQ#v=onepage&q&f=false|year=1993|publisher=[[United States Government Printing Office]]|pages=88, 150}}</ref> }} ==External links== * [http://earthquake.usgs.gov/earthquakes/eventpage/iscgem886234#general_summary M5.7 - offshore Northern California] – [[United States Geological Survey]] * [http://www.sfmuseum.org/hist1/1957eq.html The Daly City Earthquake of 1957: What Does it Tell Us?] – [[San Francisco Museum and Historical Society]] {{Earthquakes in California}} {{Earthquakes in the United States}} [[Category:Earthquakes in California]] [[Category:1957 earthquakes]] [[Category:History of the San Francisco Bay Area]] [[Category:1957 in California]] [[Category:1957 natural disasters in the United States]]'