1992 Murindó earthquake

Earthquake in Colombia 10.0 km 10 dead, 115 injured 6.7 mw yes 1010XI (ESI 2007) Colombia Strike-slip 7.2 wb y usp0005fey usp0005fha 03:32 10:11 268025 1992-10-18 15:11:59 Colombia 7.075 -76.862 region:EC_type:event inline,title 268313 The 1992 Murindó earthquake (also known as the Atrato earthquake) occurred on October 18 at 15:11 UTC (10:11 a.m. local time) with an epicenter in the Department of Chocó, northern Colombia. The shallow magnitude 7.2 earthquake struck northwest of the town of Murindó, killing ten and injured more than a hundred.Significant Earthquake Information COLOMBIA: MURINDO, APARTADO, MEDELLIN https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/5342 15 Dec 2020 NGDC Thirty-three municipalities were severely damaged. The preferred focal mechanism of this earthquake is highly debated with either thrust, reverse, or left-lateral strike-slip. Tectonic setting Subduction of the Nazca plate beneath the North Andes plate (part of the South American plate) occasionally produces moderately large to great earthquakes along the coast of Colombia. The megathrust fault forms the northern part of the Peru–Chile Trench, which has been the source of very large earthquakes including the 1906 Ecuador–Colombia earthquake; the magnitude 8.8 is the biggest in the region and the 6th largest earthquake to be instrumentally recorded. Earthquake From the earthquake's depth and proximity to the trench, this was not a subduction-related earthquake. On October 17, a magnitude 6.7 foreshock struck between Murindó and Opogodó 31 hours before the mainshock. Its focal mechanism was of reverse origin.M 6.7 – northern Colombia https://earthquake.usgs.gov/earthquakes/eventpage/usp0005fey/ 15 Dec 2020 USGS-ANSS It ruptured along a thrust or reverse fault for 50 km. Because of its size and rupture length, this quake could be considered an independent mainshock. The earthquake of October 18 was slightly more complex, consisting of two events separated by a time gap of 12 seconds. Two focal mechanisms were discovered during the mainshock thrust and strike-slip, which meant that there was a transition of faulting.Charles J. Ammon Thorne Lay Aaron A. Velasco John E. Vidale Thorne Lay John Vidale August 1994 Routine Estimation of Earthquake Source Complexity: the 18 October 1992 Colombian Earthquake https://earthweb.ess.washington.edu/vidale/Reprints/BSSA/1994_Ammon_Lay_etal.pdf Bulletin of the Seismological Society of America 84 1266–1271 This quake ruptured a 90 km section of the fault.Yingping Li June 1993 Study of the source process of the 1992 Colombia M s =7.3 earthquake with the empirical Green's Function Method https://www.researchgate.net/publication/259026117 Geophysical Research Letters 20 11 1087–1090 10.1029/93GL01219 1993GeoRL..20.1087L A third event 100 seconds later could be part of the mainshock sequence.Event 268315 Northern Colombia http://www.isc.ac.uk/cgi-bin/web-db-v4?event_id=268315&out_format=IMS1.0&request=COMPREHENSIVE 15 Dec 2020 International Seismological Centre ISC: On-Line BulletinM 5.2 – northern Colombia https://earthquake.usgs.gov/earthquakes/eventpage/usp0005fhd/executive 15 Dec 2020 USGS-ANSS It is believed that this earthquake was a result of slippage along the Murindó Fault, a left-lateral strike-slip fault, and other smaller structures. No surface rupture was ever mentioned in reports. Effects Foreshock A maximum intensity of VIII (Severe) was assigned to the magnitude 6.7 earthquake, and was felt in Murindó. It caused no deaths but 20 people were injured, and nearly all the buildings in the town were destroyed.Significant Earthquake Information COLOMBIA: MURINDO, CALI https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/5341 15 Dec 2020 NGDC It caused cracks to appear near rivers and liquefaction in the affected area. Mainshock The mainshock was much more severe, reaching X on the Modified Mercalli and MSK intensity scale. It was reassessed in the early 21st century based on its environmental effects and was assigned XI on the Environmental Seismic Intensity scale.S. Mosquera-Machado C. Lalinde-Pulido E. Salcedo-Hurtado A. M. Michetti June 2009 Ground effects of the 18 October 1992, Murindo earthquake (NW Colombia), using the Environmental Seismic Intensity Scale (ESI 2007) for the assessment of intensity https://www.researchgate.net/publication/249552400 Geological Society, London, Special Publications 316 1 123–144 10.1144/SP316.7 2009GSLSP.316..123M 11383/2626 131499647 free The original intensity was mis-assigned likely due to the lack of buildings and underdevelopment in the affected region. In Murindó and the Atrato Valley, shaking intensity was IX (Violent), accounting for most of the damage to human settlements. Most of the affected areas were on low-relief terrain, with small hills that form the eastern part of the North Andes. These low hills were stripped of vegetation from landslides, covering an area of 480 km2. Between 30 and 40% of the vegetation in the area was gone. Slope failures were also seen along riverbanks of the Atrato and Murindo rivers. Small slides were also seen in the city of Medellin. Many of the liquefaction cases were sand ejection from lateral-spreading. These phenomenons caused subsidence in some areas measured at 1.5 meters. Villages near riverbanks were affected because blocks of land were sliding into the rivers, turning them muddy. A mud volcano in San Pedro de Uraba ejected 50,000 m3 of material, and exploded in a fiery ignition of gases, killing seven and injuring 20 while another at San Juan de Uraba emerged from the sea, creating Damaquiel Island near the coast. The death toll was relatively low because most of the residents had fled the town damaged by the foreshock. One child was killed after a school wall collapsed in Vigia del Fuerte. Further away in Bogota, five buildings were evacuated for fear that they would collapse. Rescue and recovery efforts were hampered as the only road leading to the affected region was buried under a landslide. Floods swept the affected towns after water overflowed from an earthquake lake on the Atrato River.Colombia – Earthquake and Volcanic Activity Oct 1992 UN DHA Information Reports 1-5 https://reliefweb.int/report/colombia/colombia-earthquake-and-volcanic-activity-oct-1992-un-dha-information-reports-1-5 15 Dec 2020 ReliefWeb The total damage from the foreshock and mainshock amounted to more than US$100 million.Ronald Arvidsson, Jaime Toral Boutet & Ota Kulhanek 13 March 2001 Foreshocks and aftershocks of the MW = 7.1, 1992, earthquake in the Atrato region, Colombia Journal of Seismology 6 1–11 See also List of earthquakes in Colombia References Category:1992 in Colombia Category:1992 earthquakes Category:October 1992 in South America Category:Earthquakes in Colombia Category:History of Antioquia Department