1965 Puget Sound earthquake

Earthquake in Washington May 2025 October 2024 1965 Puget Sound earthquake 1965-04-29 15:28:45 858143 iscgem858143 1965 04 29 08:28:45 PDT 1965 Puget Sound earthquake.jpg Washington 6.7 w y 59 km on 47.4 -122.3 inline,title Dip-slip Puget Sound region Washington United States None $12.5–28 million VIII 0.204 g at Olympia 7 dead USGS ShakeMap The 1965 Puget Sound earthquake occurred at 08:28 AM PDT (15:28 UTC) on April 29 within the Puget Sound region of Washington state. It had a magnitude of 6.7 on the moment magnitude scale and a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale. It caused the deaths of seven people and about $12.5–28 million in damage.https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/4351 Significant Earthquake Information National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information. 1972 NOAA National Centers for Environmental Information 10.7289/V5TD9V7K March 22, 2024https://earthquake.usgs.gov/earthquakes/states/events/1965_04_29.php Puget Sound area, Washington 1965 04 29 15:28:43.7 UTC Magnitude 6.5 Intensity VIII United States Geological Survey October 21, 2009 Historic Earthquakes January 8, 2012 There were no recorded aftershocks.Oakeshott G.B. July 1965 The Seattle Earthquake Mineral Information Service 18 7 140–141 ftp://ftp.consrv.ca.gov/pub/dmg/pubs/cg/1965/18_07.pdf https://web.archive.org/web/20200312171703/ftp://ftp.consrv.ca.gov/pub/dmg/pubs/cg/1965/18_07.pdf 2020-03-12 dead January 8, 2012 Tectonic setting Puget Sound faults The western part of Washington State lies above the Cascadia subduction zone, where the Juan de Fuca plate is being subducted beneath the North American plate. The seismicity of this region consists of rare great megathrust earthquakes, like the 1700 Cascadia earthquake, and more common earthquakes originating from within the subducting slab. These events relate to normal faulting, associated with the bending of the slab, possibly related to a phase change below about 40 km from basalt/gabbro to eclogite.Wong I.G. 2005 Low Potential for Large Intraslab Earthquakes in the Central Cascadia Subduction Zone Bulletin of the Seismological Society of America 95 5 1880–1902 10.1785/0120040132 http://classes.engr.oregonstate.edu/cce/winter2011/ce570-001/References/01a%20SOURCE-%20Earthquake%20Faults/Cascadia%20Subduction%20Zone/2005%20Wong%20-%20Low%20Potential%20for%20Intraslab%20Earthquakes.pdf January 8, 2012 2005BuSSA..95.1880W https://web.archive.org/web/20120302224537/http://classes.engr.oregonstate.edu/cce/winter2011/ce570-001/References/01a%20SOURCE-%20Earthquake%20Faults/Cascadia%20Subduction%20Zone/2005%20Wong%20-%20Low%20Potential%20for%20Intraslab%20Earthquakes.pdf March 2, 2012 dead Earthquake The earthquake had an estimated magnitude of 6.6 s y, 6.5 b y and 6.7 w y. At 10–20 seconds the duration of strong ground motion was relatively short.Mullineaux D.R. Bonilla M.G. Schlocker J. Geological Survey Research 1967 https://books.google.com/books?id=Z1rwAAAAMAAJ&pg=SL4-PA183 January 8, 2012 United States Geological Survey Professional paper 575-D 1967 United States Government Printing Office 183–191 Relation of building damage to geology in Seattle, Washington during the April 1965 earthquake The earthquake's focal mechanism indicates that it resulted from normal faulting within the Juan de Fuca slab. There were no recorded aftershocks, similar to observations from the 1949 Olympia and 2001 Nisqually earthquakes and a characteristic of such intraslab events. thumb|Damage to the Union Pacific Railway occurred when fill slid away from beneath part of a branch line just outside Olympia Intensity The pattern of shaking intensity was somewhat variable, with a large region with an intensity of VII (Very strong) containing localized areas of intensity VIII (Severe). These variations generally relate closely to the underlying geology, with higher intensities recorded where there was either artificial fill or alluvium, although there were some exceptions. The observed pattern of intensities was very similar to those from the 1949 Olympia and 2001 Nisqually earthquakes. Damage Three people were killed by falling debris in the Duwamish valley floor area of Seattle, and four others died from heart attacks.http://www.crew.org/sites/default/files/CascDeepEQweb.pdf Cascadia Deep Earthquakes Cascadia Region Earthquake Workshop 2008 Open File Report 2008-1 Washington Division of Geology and Earth Resources 8 January 8, 2012 https://web.archive.org/web/20120302224541/http://www.crew.org/sites/default/files/CascDeepEQweb.pdf March 2, 2012 dead There was minor damage recorded over a large area, including fallen chimneys and cracked mortar. The two Boeing plants at Renton and Seattle, both built on artificial fill and mudflats, suffered major damage. The State Capitol building in Olympia suffered cracking to the dome and supporting buttresses, leaving it in a condition where a major aftershock could have caused complete collapse.Is Capitol dome at risk? Huge stone columns knocked out of line David Postman March 4, 2001 The Seattle Times http://archives.seattletimes.nwsource.com/cgi-bin/texis.cgi/web/vortex/display?slug=quakedome04m&date=20010304 January 8, 2012 December 9, 2012 https://archive.today/20121209073716/http://archives.seattletimes.nwsource.com/cgi-bin/texis.cgi/web/vortex/display?slug=quakedome04m&date=20010304 dead Single-story unreinforced brick buildings performed the worst in the earthquake with wood-framed structures generally performing very well. Major highways had relatively little damage, with some sections of U.S. Route 101 sinking 1 to 2 ft m. The Tacoma Narrows Bridge was closed for 30 minutes as a precaution but reopened with only damage to light fixtures and weather seals on cables.May 1965 All The Fear A Word Can Make—Earthquake! 14 Washington Highway News 12 4 Washington State Department of Highways https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/4814/rec/5 WSDOT Library Digital Collections August 17, 2022 Ground acceleration A peak ground acceleration of 0.204g was measured at Olympia. Aftermath The damage and deaths in the 1965 earthquake helped bring about the installation of the Pacific Northwest Seismic Network in 1969.https://earthquake.usgs.gov/monitoring/anss/regions/nw/ ANSS – Advanced National Seismic System Pacific Northwest Region United States Geological Survey July 27, 2011 January 8, 2012 See also List of earthquakes in 1965 List of earthquakes in Washington References Dewey J.W. Hopper M.G. Wald D.J. Quitoriano V. & Adams E.R. Intensity Distribution and Isoseismal Maps for the Nisqually, Washington, Earthquake of 28 February 2001 http://www.wou.edu/las/physci/taylor/g473/seismic_hazards/dewey_etal_2002_nisqually_EQ_intensity.pdf Open-File Report 02-346 2002 United States Geological Survey 15 External links 858143 Category:Earthquakes in Washington (state) Category:1965 earthquakes Category:1965 in Washington (state) Category:1965 natural disasters in the United States Category:Puget Sound region Puget Sound earthquake