1909 Benavente earthquake

Earthquake affecting Portugal March 2025 1909 Benavente earthquake 1909-04-23 17:39:36 610326344 iscgem610326344 1909 04 23 yes 17:39 GMT Portugal topographic w y 6.0 9Significant Earthquake Database https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/2864 National Geophysical Data Center / World Data Service (NGDC/WDS) National Geophysical Data Center, NOAA 10.7289/V5TD9V7K 1972 Data Set 10 km 38.9 -8.8 inline,title Lisbon, Portugal 30–60 dead, 75 injured The 1909 Benavente earthquake occurred on 23 April at 17:39 GMT with an epicenter in the Lisbon region of Portugal. The earthquake had an estimated moment magnitude of 6.0 and had maximum Mercalli intensity of IX (Violent). Beneath the Lower Tagus Valley, where the earthquake occurred, is a system of normal faults that were reactivated during the Eocene as reverse faults. The earthquake was caused by movement along one of these buried faults. At least 30 people died and 75 people were injured; the towns of Samora Correia and Muge in Benavente were the hardest-hit, with 90 percent of it destroyed. Another 13,000 people were made homeless. In Lisbon, the earthquake caused minor damage to some homes, started fires, and injured several people. Geology The Lower Tagus Valley is a northeast-trending rift in Portugal. It occupies a 3,200 km2 area and extends to Lisbon at its southern end. During the Eocene, the rift underwent inversion which caused pre-existing normal faults to reactivate as reverse faults. One of these faults is the Vila Franca de Xira Fault, a southeast-dipping reverse fault located along the northwestern edge of the valley. The Azambuja Fault is another major structure that lies roughly parallel to the aforementioned fault on the east side of the valley. Beneath the valley is a highly segmented system of faults that trend north-northwest–south-southeast to northwest–southeast, diagonal to the general direction of the valley. Some faults are also oriented north-northeast–south-southwest. These faults are buried under thick layers of sediment and their slip rates are estimated at 0.1 to 0.05 mm per year. The area is seismically active and has produced several significant earthquakes within historical times. In the last 30 years of the 20th century, at least 39 earthquakes had been felt; three with magnitudes of at least 4.0 while 16 events were between 3.0 and 3.9. The first documented earthquake in the region occurred on 26 January 1531. With an estimated magnitude at w 6.9, it caused serious damage in Lisbon and killed two percent of the population.Teves-Costa P. Batlló J. 2011 The 23 April 1909 Benavente earthquake (Portugal): macroseismic field revision https://link.springer.com/article/10.1007/s10950-010-9207-6 Journal of Seismology 15 1 59–70 10.1007/s10950-010-9207-6 2011JSeis..15...59T 129731577 Earthquake The earthquake struck with an epicenter in the Alcochete municipality of Lisbon on 23 April at 17:39 GMT.ISC-GEM Global Instrumental Earthquake Catalogue Version 11.0 International Seismological Centre 25 June 2024 10.31905/D808B825 Data set freeM 6.0 - 2 km SW of Alcochete, Portugal 1909 iscgem610326344 In a study published in Seismological Research Letters, the earthquake had a moment magnitude of 6.0,D. Stich J. Batlló R. Macià P. Teves-Costa J. Morales Moment tensor inversion with single-component historical seismograms: The 1909 Benavente (Portugal) and Lambesc (France) earthquakes Oxford University Press Geophysical Journal International 1 September 2005 162 3 850–858 10.1111/j.1365-246X.2005.02680.x 2005GeoJI.162..850S 130288266 1365-246X free while past estimates placed it at 6.6. It was the largest recorded crustal earthquake in the Iberian Peninsula during the 20th century. It was felt for 215,000 km2, a relatively large area for its magnitude. In comparison, the 1908 Messina earthquake which measured 7.2 had a felt area less than one third of that. A group of researchers analysed 29 seismograms of the earthquake from 13 seismic stations in Spain, France, Italy, Germany, the Netherlands and Sweden, and published their findings in Geophysical Journal International. Their analysis indicated that the earthquake was likely caused by reverse faulting along a buried northeast–southwest striking fault. No causative fault has been identified, although a possible candidate is a postulated northeast–southwest striking fault connecting the Vila Franca de Xira and Azambuja faults or the southern segment of the latter structure. The existence of the former structure has only been inferred from reflection seismology. Although surface fissures and sand volcanoes were observed in the ground, there were no documented surface ruptures from the earthquake. If surface ruptures were to occur, they were very likely small and may have been destroyed due to periodic flooding of the valley.J. Cabral C. Moniz J. Batlló P. Figueiredo J. Carvalho L. Matias P. Teves-Costa R. Dias N. Simão The 1909 Benavente (Portugal) earthquake: search for the source Natural Hazards 2013 69 2 1211–1227 10.1007/s11069-011-0062-8 2013NatHa..69.1211C 10400.9/2321 129232872 free Impact thumb|right|Painting of King Manuel II in Benavente after the earthquake The earthquake was assigned a maximum Mercalli-Cancani intensity of X (Extreme) near the epicenter, over 450 km2. Liquefaction occurred in the Tagus and Sorraia river plains. At Lisbon, 30 km away, the shaking was felt VI (Strong).Sismo sentido em Lisboa na mesma zona dos grandes abalos de 1531 e 1909 Earthquake felt in Lisbon in the same area as the great earthquakes of 1531 and 1909 https://www.dn.pt/sociedade/sismo-sentido-em-lisboa-ocorreu-na-mesma-zona-dos-grandes-abalos-de-1531-e-1909--13472236.html Diário de Notícias 29 October 2021 pt 18 March 2021 Intensity VI was also felt in the cities of Setúbal and Évora, causing some damage, while intensity V shaking was felt in Spain.110 Anos Do Sismo De Benavente 110 Years Of The Benavente Earthquake https://www.ipma.pt/pt/media/noticias/news.detail.jsp?f=/pt/media/noticias/arquivo/2019/110_anos_sismo_benavente.html Instituto Português do Mar e da Atmosfera 29 October 2021 24 April 2019 A reassessment of the maximum intensity on the Modified Mercalli intensity scale in 1956 revised the maximum intensity to IX (Violent). According to Público, at least 60 people were reported killed including 46 deaths in Benavente, and 75 people were severely injured. Many people were outdoors working in the fields at the time, which may have prevented further deaths.Talixa Jorge Centenário do sismo de 1909 que arrasou Benavente e Samora Correia será assinalado com novo simulacro Centenary of the 1909 earthquake that devastated Benavente and Samora Correia will be marked with a new simulacrum https://www.publico.pt/2009/04/12/jornal/centenario-do-sismo-de-1909-que-arrasou-benavente--e-samora-correia-sera-assinalado-com-novo-simulacro-302542 28 October 2021 Público 12 April 2009 Portuguese A report by the Ottawa Citizen citing Portuguese officials said 13,000 people were homeless.Many homeless: Much suffering as a result of earthquake https://books.google.com/books?id=o1kuAAAAIBAJ&dq=lisbon+earthquake&pg=PA37&article_id=5592,5232347 Ottawa Citizen 28 April 1909 The National Geophysical Data Center listed the number of deaths at 30. In Benavente, the towns of Samora Correia and Muge sustained the heaviest damage; nearly 90 percent of these towns were destroyed.Nuno Miguel Ropio Magnitude de terramoto corrigida 100 anos depois Earthquake magnitude corrected 100 years later https://www.jn.pt/local/noticias/lisboa/lisboa/magnitude-de-terramoto-corrigida-100-anos-depois-1208232.html 29 October 2021 Jornal de Notícias 22 April 2009 Portuguese Forty percent of buildings in Benavente were razed or had to be torn down, and another 40 percent required repairs. In Santo Estevao, only 46 of the 207 buildings remained intact.J. F. B. D. Fonseca S. P. Vilanova The 23 April 23 1909 Benavente (Portugal) M 6.3 Earthquake Seismological Research Letters 2010 81 3 534–536 10.1785/gssrl.81.3.534 2010SeiRL..81..534F https://www.researchgate.net/publication/250075618 Several churches were also damaged; most had cracks in their walls but the greatest damage was inflicted on the Misericórdia Church when its ceiling collapsed onto the altar. At the nearby seminary, plasters fell along the corridor.T. L. Moreira pt Memórias da Cidade: Quando a Terra tremeu em 1909 e 1969 Memories of the City: When the Earth shook in 1909 and 1969 https://correiodoribatejo.pt/memorias-da-cidade-quando-a-terra-tremeu-em-1909-e-1969/ 29 October 2021 Correio do Ribatejo 19 March 2019 In Lisbon, several people were injured, the walls of some homes cracked and fires occurred in the southern part of the city.Earthquake In Lisbon Takes Fire. Fifty-Five People Killed https://books.google.com/books?id=9aYUAAAAIBAJ&dq=lisbon+earthquake&pg=PA4&article_id=7440,1593235 The Sydney Morning Herald 26 April 1909Earthquake in Lisbon and Spanish cities https://books.google.com/books?id=MwZYAAAAIBAJ&dq=lisbon+earthquake&pg=PA6&article_id=3325,6126438 17 February 2025 Easton Free Press 24 April 1909 See also List of earthquakes in 1909 List of earthquakes in Portugal 1909 Provence earthquake References Further reading de Pro-Díaz Y. Vilanova S. Canora C. Ranking Earthquake Sources Using Spatial Residuals of Seismic Scenarios: Methodology Application to the 1909 Benavente Earthquake Bulletin of the Seismological Society of America 2022 113 2 710–731 0037-1106 10.1785/0120220067 254778078 Category:Earthquakes in Portugal Category:1909 earthquakes Category:1909 in Portugal Category:Centro Region, Portugal Category:Santarém District Category:April 1909 in Europe Category:1900s in Lisbon Category:Buried rupture earthquakes Category:Tagus