1965 La Ligua earthquake

Earthquake and mining disaster in Chile 1965 La Ligua earthquake -32.522 -71.233 region:US inline, title South America 1965-03-28 16:33:16 858940 iscgem858940 1965 3 28 12:33 pm CLST (UTC-03:00) 70.0 km 7.4–7.6 w yes7.5 s Normal (Intraplate) Chile US$125 million (1965 rate) 9 None Yes w yes 6.2–6.4 Yes 400–500 dead The 1965 La Ligua earthquake (also known as the Aconcagua earthquake) struck near La Ligua in Aconcagua Province, Chile, about 140 km mi off us from the capital Santiago on Sunday, March 28 at 12:33 local time. The moment magnitude (w) 7.4–7.6 earthquake killed 400–500 people and inflicted US$1 billion (adjusted for inflation) in damage.Significant Earthquake CHILE: CENTRAL https://www.ngdc.noaa.gov/nndc/struts/results?eq_0=4345&t=101650&s=13&d=22,26,13,12&nd=display https://web.archive.org/web/20170422130841/https://www.ngdc.noaa.gov/nndc/struts/results?eq_0=4345&t=101650&s=13&d=22,26,13,12&nd=display dead April 22, 2017 6 Dec 2020 NGCD28 Feb 2010 Factbox: Chile Has History of Big Earthquakes Reuters https://www.reuters.com/article/us-quake-chile-history-idUSTRE61Q13I20100227 6 Dec 2020 Many deaths were from El Cobre, a mining location that was wiped out after a series of dam failures caused by the earthquake spilled mineral waste onto the area, burying hundreds of residents. The shock was felt throughout the country and along the Atlantic coast of Argentina.29 March 1965 Earthquake Toll Heavy in Chile; Village Buried 38 The Desert Sun 202 https://cdnc.ucr.edu/?a=d&d=DS19650329.2.3&e=-------en--20--1--txt-txIN--------1 5 Dec 2020 Tectonic setting Earthquakes are frequent in Chile, which lies in the so-called Ring of Fire, where many of the world's active volcanoes and seismic activities are concentrated. Off the coast of Chile, the Nazca plate subducts beneath the South American plate along the Peru–Chile Megathrust; a convergent plate boundary. Active subduction produce large earthquakes including the 1960 Valdivia earthquake which had a magnitude of 9.5–9.6 on the moment magnitude scale.Ruiz, Madariaga Sergio, Raúl February 2018 Historical and Recent Large Megathrust Earthquakes in Chile https://www.sciencedirect.com/science/article/pii/S0040195118300271 Tectonophysics 733 37–56 2018Tectp.733...37R 10.1016/j.tecto.2018.01.015 subscription These earthquakes are associated with thrust faulting on the interface of the plate boundary megathrust. Thrusting during large earthquakes cause significant uplift of the seafloor, causing tsunamis. In some occasions, earthquakes occur within the downgoing tectonic plate instead. Earthquake On 22 March 1965, a magnitude 6.2–6.4 earthquake rocked the coastal town of Los Vilos at a depth of 48.8 km mi off us, slightly north of the epicenter of the mainshock.M 6.2 – Offshore Coquimbo, Chile https://earthquake.usgs.gov/earthquakes/eventpage/iscgem858793/executive 6 Dec 2020 United States Geological Survey It has been interpreted as a foreshock of the March 28 quake, although both events were on separate fault planes. The foreshock had a thrust mechanism, different from the mechanism of the mainshock. It occurred much shallower and based on the focal mechanism analyzed, was interpreted as an interplate earthquake on the plate boundary. Whether the 22 March quake was a true foreshock or the seven day time separation was sheer coincidence may never be determined.Malgrange M. Deschamps A. Madariaga R. 1981 Thrust and Extensional Faulting Under the Chilean Coast: 1965, 1971 Aconcagua Earthquakes http://www.geologie.ens.fr/~madariag/Papers/Malgrange-1981.pdf Geophysical Journal International 66 2 313–331 1981GeoJ...66..313M 10.1111/j.1365-246X.1981.tb05958.x free The s 7.5 or w 7.4 mainshock nucleated about 72 km mi off us beneath the community of La Ligua. The focal mechanism of this earthquake suggests normal faulting within the slab of the Nazca plate rather than on the subduction zone interface of the megathrust.Felipe Leytona Javier Ruizb Jaime Camposa Edgar Kausel June 2009 Intraplate and Interplate Earthquakes in Chilean Subduction Zone: A Theoretical and Observational Comparison http://earthjay.com/earthquakes/20190801_chile/Leyton_etal_2009_intraplate_interplate_earthquakes_chilean_subduction.pdf Physics of the Earth and Planetary Interiors 175 1–2 37–46 2009PEPI..175...37L 10.1016/j.pepi.2008.03.017 Elsevier Science Direct The earthquake rupture within the slab occurred on a near-vertical normal fault. Records of aftershocks are sparse due to the poor instrumentation at the time. Few moderately-sized events were recorded. Local seismic stations managed to record approximately five aftershocks each day. Intraslab earthquakes are common in the region as the subducting plate flexes and deform. The largest intermediate-depth intraslab earthquake in the region was a w 8.0 beneath Antofagasta. Impact The maximum intensity of the earthquake was assigned IX (Violent) on the Modified Mercalli intensity scale. The earthquake inflicted serious damage to adobe and unreinforced masonry buildings. Over 21,000 houses collapsed and 70,000 had to be repaired. Houses made of hollow concrete units were especially severely affected, cracks appeared due to the lack of bonding between bricks and the concrete fillings, shear failure, and damage to beams.M. Astroza, F. Andrade, M.O. Moroni 2017 Confined Masonry Buildings: The Chilean Experience http://www.confinedmasonry.org/wp-content/uploads/2017/08/Chile_3462.pdf 16th World Conference on Earthquake At the time it had struck, many Chileans had just finished preparing their lunch means or returned from church services. This may have reduced the anticipated death toll because many churches had collapsed from ground motions, and there were very few instances of conflagrations. In Salamanca and Illapel, over 100,000 people were left homeless. The Department of Illapel reported more than 90% of homes had been damaged, and a hospital was completely destroyed, adding that "only facades of the houses remain standing". Valparaíso reported 25 deaths and 40% of its buildings damaged from the earthquake. At Santiago, the shock knocked out electricity and stirred panic in many neighborhoods. Four persons died from the temblor, including a woman who fell to her death after jumping off the second floor of a hospital and another during a stampede to race for the exit at a racetrack after a grandstand collapsed, while ten were injured.admin 29 March 2014 El Día Reported on the Strong Earthquake on March 29, 1965 Leaving Extensive Damage and Fatalities El Día http://www.diarioeldia.cl/pais/70-anos-70-historias-terremoto-sacude-zona-central-danos-se-extienden-salamanc 6 Dec 2020February 2021 InternetArchiveBot yes An estimated 2,000 homes were badly damaged in the capital. Additional casualties were reported at Llay-Llay, where four people had died, two each in La Laguna and Quilpué, and one each in San Felipe, Colina, Melon, Olmué and Ventanas. Three deaths were from Viña del Mar when a wall fell on those victims. Chile mining disaster 1965 03 28 yes Chile 350–400 Earthquake + Liquefaction 1965 Central Chile mining disaster Tailings from the failures travelled downstream and buried the town of El Cobre. Tailings dam failure -32.639 -71.162 Severe liquefaction from the earthquake resulted in the failure of 17 tailing dams, the most severe of which affected the town of El Cobre, killing hundreds of residents and workers. Tailing dams failing because of seismic activities were a known risk to surrounding communities, as seen in previous events. Many of these incidents were a result of liquefaction with flow failure, slope instability and quake-related deformations or overtopping. Similar instances of sand tailing dams failing were also observed during earthquakes in 1981, 1985, 1997, and 2010.Espinace Raúl Valenzuela Pamela Villavicencio Gabriel Palma Juan Fourie Andy April 2014 Failures of Sand Tailings Dams in a Highly Seismic Country https://www.researchgate.net/publication/263247119 Canadian Geotechnical Journal 51 4 449–464 10.1139/cgj-2013-0142 2014CaGJ...51..449V El Cobre dam failure Two dams belonging to the El Soldado mine released 350000 and 1,900,000 m3 cuft off us cubic meters of debris respectively, and traveled 12 km mi off us downstream which destroyed the town of El Cobre, in La Calera, burying it under three feet of muck.20 Nov 2020 Chronology of Major Tailings Dam Failures (From 1960) http://www.wise-uranium.org/mdaf.html 6 Dec 2020 WISE Uranium Project About 60 to 70 farmhouses and cottages were swept away by the cascading debris flow. Many of the casualties were miners and peasants who were mining for copper. The official death toll is at 247, but is thought to be as high as 350–400. Aftermath In the immediate hours of the quake, cabinet ministers met with the President of Chile, Eduardo Frei Montalva. The Ministers of Public Works and Defence were taken to the affected town of Llay-Llay to survey the damage extent and plan the rescue and recovery efforts. The Chilean Army was called in for aid to mobilize the arrival of tents and makeshift kitchens to those who had lost their homes. Government officials and military chiefs were also involved in the distribution of food, water, and medical aid.Kennedy Will C. Organizational Activity and the Military in Disaster Operations in Chile in a 1965 Earthquake: A Historical Case Study https://udspace.udel.edu/bitstream/handle/19716/457/PP80.pdf?sequence=3&isAllowed=y 6 Dec 2020 University of Delaware Legacy This tragedy, along with the 1960 earthquakes, was one of the reasons for the formation of the National Office of Emergency of the Interior Ministry which oversees natural disasters and rescue efforts in Chile. Prior to the disaster, there had not been any formal organization to coordinate any rescue and recovery efforts, mainly because local officials and residents have endured many of the frequent earthquakes in the area. The dam failures marked a series of changes to the civil engineering and mining community, and the design of tailing dams. Upstream tailing dams were opted for other means such as downstream tailings dams, rock-fills, and earth dams, despite the higher costs.Valenzuela Luis 15 December 2015 Design, Construction, Operation and the Effect of Fines Content and Permeability on the Seismic Performance of Tailings Sand Dams in Chile https://scielo.conicyt.cl/pdf/oyp/n19/art01.pdf Obras y proyectos revista de ingeniería civil 19 6–22 See also List of earthquakes in Chile List of earthquakes in 1965 List of tailings dam failures References External links Archived footage from British Pathé: Tragic Chilean Earthquake Aftermath At El Cobre (1965) Archived footage with commentary: Chile Hit By Devastating Earthquake 1965 HD Stock Footage 858940 Category:Earthquakes in Chile Category:1965 earthquakes Category:March 1965 in South America Category:Dam failures in South America Category:Mining in Chile Category:Natural disasters in Chile Category:Mining disasters in Chile Category:20th-century floods in South America Category:1960s floods Category:1965 disasters in Chile Category:Tailings dam failures Category:1965 mining disasters Category:Copper mining in Chile