Research Article| June 01, 1986 Geologic evidence for a large prehistoric earthquake in eastern Connecticut Robert M. Thorson; Robert M. Thorson 1Department of Geology and Geophysics, University of Connecticut (U-45), 345 Mansfield Road, Storrs, Connecticut 06268 Search for other works by this author on: GSW Google Scholar Wilson S. Clayton; Wilson S. Clayton 1Department of Geology and Geophysics, University of Connecticut (U-45), 345 Mansfield Road, Storrs, Connecticut 06268 Search for other works by this author on: GSW Google Scholar Leonardo Seeber Leonardo Seeber 2Lamont-Doherty Geological Observatory, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Author and Article Information Robert M. Thorson 1Department of Geology and Geophysics, University of Connecticut (U-45), 345 Mansfield Road, Storrs, Connecticut 06268 Wilson S. Clayton 1Department of Geology and Geophysics, University of Connecticut (U-45), 345 Mansfield Road, Storrs, Connecticut 06268 Leonardo Seeber 2Lamont-Doherty Geological Observatory, Palisades, New York 10964 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1986) 14 (6): 463–467. https://doi.org/10.1130/0091-7613(1986)14<463:GEFALP>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Robert M. Thorson, Wilson S. Clayton, Leonardo Seeber; Geologic evidence for a large prehistoric earthquake in eastern Connecticut. Geology 1986;; 14 (6): 463–467. doi: https://doi.org/10.1130/0091-7613(1986)14<463:GEFALP>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Postglacial wedges cutting stratified late Quaternary glacial deposits have been widely reported throughout the northeastern United States. Previous interpretations of these features as periglacial ice-wedge casts have proved untenable for at least several of the reported localities. This conclusion is also reached in our detailed study of 29 such wedges at a gravel quarry in eastern Connecticut. The wedges there are found to be planar vertical zones that widen upward from a few centimetres to as much as 150 cm, and that contain material injected from below as well as collapsed from the sides. These zones are interpreted as extension and collapse fissures that served as conduits for water and liquefied sediment during one or more prehistoric liquefaction events. Seismic excitation seems the most likely cause for the episode(s) of liquefaction and violent dewatering. Similar phenomena were reported to accompany large eighteenth-century earthquakes in New England. If the relation between large earthquakes and wedges is substantiated at our study locality and other localities, these possibly contemporaneous features may provide an opportunity to determine the felt-area magnitude of prehistoric earthquakes in the northeastern United States. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.