1993 Klamath Falls earthquakes

Earthquakes in Oregon, US May 2025 October 2024 1993 Klamath Falls earthquakes Oregon 250 none 1 Oregon 42.21 -122.07 Bullseye1.png 40 top Oregon Klamath Falls 42.22 -121.78 9 Normal doublet 1993-09-21 03:28:55 1993-09-21 05:45:35 uw10313838 uw10313718 209100 209133 September 20, 1993 8:28 p.m. 10:45 p.m. Doublet earthquake 6.0 w y 5.9 w 9 km flip VII 42.21 -122.07 inline,title Southern Oregon Northern California 2 dead $10 million The 1993 Klamath Falls earthquakes took place in Klamath Falls, Oregon, beginning on Monday, September 20 at 8:28 p.m. The doublet earthquake registered respective magnitudes of 6.0 and 5.9 on the moment magnitude scale. The earthquakes were located at a depth of 9 km flip and tremors continued to be felt more than three months after the initial shocks. Tectonics and previous activity The tectonic structure of south-central Oregon is riddled with fault lines. The West Klamath Lake fault zone is capable of earthquakes up to Richter magnitude 7.3. The magnitude 5.4 Coos Bay earthquake which preceded a later 2002 Klamath Falls earthquake occurred along the northern segment of the Blanco fracture zone, which is separate from the inland Klamath Basin and Range geological province.http://www.livinglocal360.com/index.php/about-the-klamath-falls-earthquake-6412/ About the Klamath Falls earthquake Totten, Michael July 24, 2009 Living Local 360 March 22, 2014 https://web.archive.org/web/20140221054134/http://www.livinglocal360.com/index.php/about-the-klamath-falls-earthquake-6412/ February 21, 2014 dead These fault networks have caused several previous earthquakes in the Klamath Falls area. Records from 1945 indicate approximately fifteen seismic events, prior to the 1993 events, circulating within a 10 mi km on radius of Klamath Falls.Scientists not surprised by quake magnitude or location September 22, 1993 A1 The Oregonian Portland, Oregon However, of those observed during the preceding fifty years, only six were considered significant. Previously most tremors measured less than 4 Mw with the strongest being 4.3 Mw in 1948. Earthquake The September 1993 earthquakes began striking at approximately 8:16 p.m. local time. The first major quake registered 5.9 on the moment magnitude scale with a foreshock registering 4.2 Mw about twelve minutes before.The 1993 Klamath Falls, Oregon, earthquake sequence: Source mechanisms from regional data Jochen Braunmiller John Nabelek Beate Leitner Geophysical Research Letters 22 2 105–108 January 15, 1995 http://scholarsarchive.library.oregonstate.edu/xmlui/bitstream/handle/1957/19939/Braunmiller_et_al_Geophys_Res_Lett_1995.pdf?sequence=1 1995GeoRL..22..105B 10.1029/94GL02844 128472543 January 26, 2014 https://web.archive.org/web/20140202194047/http://scholarsarchive.library.oregonstate.edu/xmlui/bitstream/handle/1957/19939/Braunmiller_et_al_Geophys_Res_Lett_1995.pdf?sequence=1 February 2, 2014 dead The second major shock was at 10:45 p.m. Over the next five months at least 300 more tremors were recorded. The strongest aftershock occurred on December 4, 1993, and measured 5.4Mw.https://earthquake.usgs.gov/earthquakes/states/events/1993_09_21.php Historic earthquakes United States Geological Survey January 26, 2014 https://web.archive.org/web/20100209050859/http://earthquake.usgs.gov/earthquakes/states/events/1993_09_21.php February 9, 2010 dead The tremors during the September 1993 Klamath Falls earthquakes were some of the strongest felt in Oregon's history over the past 50 years.Klamath Falls, Oregon, Earthquakes on September 20, 1993 Steven R. Brantley Earthquakes & Volcanoes 24 3 104 The first shock was only 4.2 Mw. The two major quakes, which measured 5.9 and 6.0, were, up to that point in Oregon's history, the strongest recorded earthquakes and resulted in the most damage.http://www.heraldandnews.com/news/local_news/article_83afbfed-f2c4-5f00-b3d9-ef330a56ef67.html Herald and News Klamath Falls, Oregon Schools will not withstand earthquake May 24, 2007 Lee Beachhttp://www.oregongeology.org/pubs/GMS/gms100.pdf Earthquake hazard maps for Oregon 1996 Ian P. Madin Matthew M. Mabey Oregon Department of Geology and Mineral Industries Donald A. Hull January 26, 2014 https://web.archive.org/web/20140201210827/http://www.oregongeology.org/pubs/GMS/gms100.pdf February 1, 2014 dead The epicenter of both earthquakes was located northwest of Klamath Falls in the Mountain Lakes Wilderness.Quakes rattle southern Oregon September 21, 1993 Ashbel S. Green James Long The Oregonian Portland, Oregon A10, E1 The epicenter of the second major shock was slightly more to the north than the previous tremors.Sherrod D.R. Historic and prehistoric earthquakes near Klamath Falls Oregon, Earthquakes and Volcanoes 24 106–120 1993 The major shocks were felt as far north as Eugene, Oregon, and as far south as Redding, California. All of the shocks, from the first foreshock to the last aftershock some two months later, were clustered around latitude 42o20'N and longitude 122o05'W, west northwest of Klamath Falls.https://www.wou.edu/las/physci/taylor/g473/seismic_hazards/wiley_etal_1993.pdf Klamath Falls earthquakes, September 20, 1993 – Including the strongest quake ever measured in Oregon Thomas J. Wiley Oregon Geology 55 6 November 1993 127 etal Damage and casualties The destructive force of the 1993 Klamath Falls earthquakes was measured at VII on the Mercalli intensity scale. There were only two recorded casualties, one of which involved a motorist who was crushed in a rock slide on U.S. Route 97. The second death was a result of a heart attack. The tremors precipitated landslides and also caused structural damage to buildings, including the county courthouse, in addition to private residences, businesses and historic buildings in Klamath Falls. Damage was estimated at $10 million. Aftermath In the wake of the earthquakes, several damaged buildings in Klamath Falls and elsewhere in Klamath County had to be repaired. The city of Klamath Falls obtained a Community Development Block Grant which was used to partially fund upgrades to local public buildings, including the courthouse annex.http://www.sierrainstitute.us/neai/OR_case_studies/Klamath_Falls_OR.pdf Klamath Falls, Klamath County, Oregon Northwest Economic Adjustment Initiative Assessment Forest Community Research Grace M. Zilverberg January 26, 2014 https://web.archive.org/web/20120306031726/http://www.sierrainstitute.us/neai/OR_case_studies/Klamath_Falls_OR.pdf March 6, 2012 dead Within three weeks after the first major shocks four seismographs were installed in the area by the U.S. Geological Survey. These were helpful in recording subsequent seismic activity. See also List of earthquakes in 1993 List of earthquakes in the United States References External links 209100 Category:1993 earthquakes Category:1993 in Oregon Category:Earthquakes in the United States Category:Natural disasters in Oregon Category:Klamath Falls, Oregon Category:September 1993 in the United States Category:1993 natural disasters in the United States