Célia Marreiros, Paulo M. Alves, Susana Custódio, Carlos S. Oliveira, Fernando Carrilho
{"title":"“Did You Feel It 50 Years Ago?” The 1969 Mw 7.8 Cape Saint Vincent Earthquake","authors":"Célia Marreiros, Paulo M. Alves, Susana Custódio, Carlos S. Oliveira, Fernando Carrilho","doi":"10.1785/0220230191","DOIUrl":null,"url":null,"abstract":"Abstract On 28 February 1969, an Mw 7.8 earthquake occurred 180 km southwest of Cape Saint Vincent, Portugal. The earthquake was widely felt in mainland Portugal, Madeira Island, Spain, Morocco, and even as far as Andorra and France, reaching a maximum intensity of VIII in the south of Portugal. In 2019, on the 50th anniversary of the earthquake, there was launched online an international “Did You Feel It 50 Years Ago?” (DYFI-50y) survey, published in several languages, for citizens to report the observed effects of the earthquake. This initiative had two main purposes: first, to collect and preserve community observations of the earthquake; and second, to test the online implementation of the DYFI questionnaire at Instituto Português do Mar e da Atmosfera for a damaging event. The DYFI-50y questionnaire was disseminated widely in the media, and a school project was launched for school-age children to collect reports from grandparents or other close elders. In total, more than 3000 reports were collected, a number that is close to the number of reports received for a recent M 6 earthquake in 2009. The collected community reports provide good coverage of mainland Portugal, particularly in Lisbon and Porto’s densely populated urban centers. In low-population areas, the limited results do not allow for robust statistics, and variability becomes significant. The distribution of intensities obtained shows a generally good agreement with other sources, indicating that the community reports are reliable and complement existing intensity maps for this earthquake, further clarifying some of the observed patterns. It was concluded that an online questionnaire is an efficient tool for gathering data several years after the earthquake.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"52 1","pages":"0"},"PeriodicalIF":2.6000,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Seismological Research Letters","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1785/0220230191","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract On 28 February 1969, an Mw 7.8 earthquake occurred 180 km southwest of Cape Saint Vincent, Portugal. The earthquake was widely felt in mainland Portugal, Madeira Island, Spain, Morocco, and even as far as Andorra and France, reaching a maximum intensity of VIII in the south of Portugal. In 2019, on the 50th anniversary of the earthquake, there was launched online an international “Did You Feel It 50 Years Ago?” (DYFI-50y) survey, published in several languages, for citizens to report the observed effects of the earthquake. This initiative had two main purposes: first, to collect and preserve community observations of the earthquake; and second, to test the online implementation of the DYFI questionnaire at Instituto Português do Mar e da Atmosfera for a damaging event. The DYFI-50y questionnaire was disseminated widely in the media, and a school project was launched for school-age children to collect reports from grandparents or other close elders. In total, more than 3000 reports were collected, a number that is close to the number of reports received for a recent M 6 earthquake in 2009. The collected community reports provide good coverage of mainland Portugal, particularly in Lisbon and Porto’s densely populated urban centers. In low-population areas, the limited results do not allow for robust statistics, and variability becomes significant. The distribution of intensities obtained shows a generally good agreement with other sources, indicating that the community reports are reliable and complement existing intensity maps for this earthquake, further clarifying some of the observed patterns. It was concluded that an online questionnaire is an efficient tool for gathering data several years after the earthquake.
1969年2月28日,葡萄牙圣文森特角西南180公里处发生里氏7.8级地震。葡萄牙本土、马德拉岛、西班牙、摩洛哥等地均有震感,甚至远至安道尔和法国,葡萄牙南部最高震级达8级。2019年,在地震50周年之际,网上发起了一项国际活动“50年前你感受到了吗?”(DYFI-50y)的调查报告,以几种语言出版,供市民报告观察到的地震影响。这一举措有两个主要目的:首先,收集和保存社区对地震的观察;第二,在Instituto Português do Mar e da Atmosfera上测试DYFI调查问卷的在线实施情况,以应对破坏性事件。DYFI-50y调查问卷在媒体上广泛传播,并发起了一项针对学龄儿童的学校项目,收集祖父母或其他亲密长者的报告。总共收集了3000多份报告,这个数字接近2009年最近一次6级地震收到的报告数量。收集的社区报告很好地覆盖了葡萄牙大陆,特别是在里斯本和波尔图人口稠密的城市中心。在人口稀少的地区,有限的结果不允许可靠的统计,变异性变得显著。获得的强度分布与其他来源大体一致,表明社区报告是可靠的,并补充了现有的地震强度图,进一步澄清了一些观察到的模式。结论是,在地震发生几年后,在线问卷是收集数据的有效工具。