How active is a passive margin? Paleoseismicity in northeastern Brazil

Research Article| July 01, 2000 How active is a passive margin? Paleoseismicity in northeastern Brazil Francisco H.R. Bezerra; Francisco H.R. Bezerra 1Departamento de Geologia, CCET, Universidade Federal do Rio Grande do Norte, Natal-RN, 59072-970, Brazil Search for other works by this author on: GSW Google Scholar C. Vita-Finzi C. Vita-Finzi 2Department of Geological Sciences, University College, London WC1E 6BT, UK Search for other works by this author on: GSW Google Scholar Geology (2000) 28 (7): 591–594. https://doi.org/10.1130/0091-7613(2000)282.0.CO;2 Article history received: 01 Dec 1999 rev-recd: 24 Mar 2000 accepted: 03 Apr 2000 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Francisco H.R. Bezerra, C. Vita-Finzi; How active is a passive margin? Paleoseismicity in northeastern Brazil. Geology 2000;; 28 (7): 591–594. doi: https://doi.org/10.1130/0091-7613(2000)282.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyGeology Search Advanced Search Abstract The seismicity of intraplate areas reflects both far-field plate-boundary stresses and local effects, including dormant structures. In northeastern Brazil, within the passive margin of the South American plate, a short instrumental seismic record yields a pattern consistent with east-west plate push via events that do not exceed mb = 5.2. Paleoseismic evidence from remote sensing, well records, earthquake-induced liquefaction, and radiocarbon dating of beachrock, coastal peats, and fault-filling sediment indicates the occurrence of larger prehistoric Holocene earthquakes, including some of Ms ≥ 6.8. The finding is of obvious significance for seismic hazard assessment, but because the azimuth of the maximum horizontal stress (SHmax) may be a poor guide to the present stress field, intraplate events on reactivated structures are of limited value for testing deformation models. You do not currently have access to this article.