Contemporary Compressive Stress and Seismicity in Eastern North America: An Example of Intra-Plate Tectonics

Research Article| June 01, 1973 Contemporary Compressive Stress and Seismicity in Eastern North America: An Example of Intra-Plate Tectonics MARC L. SBAR; MARC L. SBAR 1Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar LYNN R. SYKES LYNN R. SYKES 1Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Author and Article Information MARC L. SBAR 1Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 LYNN R. SYKES 1Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1973) 84 (6): 1861–1882. https://doi.org/10.1130/0016-7606(1973)842.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation MARC L. SBAR, LYNN R. SYKES; Contemporary Compressive Stress and Seismicity in Eastern North America: An Example of Intra-Plate Tectonics. GSA Bulletin 1973;; 84 (6): 1861–1882. doi: https://doi.org/10.1130/0016-7606(1973)842.0.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 SocietyGSA Bulletin Search Advanced Search Abstract A large region of high horizontal compressive stress is delimited in eastern North America from a combination of fault plane solutions of earthquakes, in situ stress measurements, and geologic observations. Each of these methods, including in situ stress determination by both overcoring and hydrofracturing, yields nearly identical directions for the principal stresses. The maximum compressive stress trends east to northeast over an area extending from west of the Appalachian Mountain system to the middle of the continent, and from southern Illinois to southern Ontario. In eastern North America, intra-plate earthquakes appear to occur in areas of high stress along unhealed fault zones of late Paleozoic or younger age. An example of this is the seismic belt trending from Boston to the northwest through Ottawa. This seismic zone appears to be located along a continental extension of the Kelvin seamount chain which is postulated by others to be a transform fault related to the early opening of the North Atlantic. Similarly, the 1929 Grand Banks earthquake and the Charleston, South Carolina, seismic trend appear to be located along extensions of other oceanic fracture zones.The relation between high stress and unhealed fault zones may provide a means to assess the earthquake risk within plates. The observed pattern of stresses appears to be post-Mesozoic in origin. This work supports Voight's hypothesis that the compressive stress observed within the North American plate may be generated by the same mechanism that drives the movements of large lithospheric plates. If this is indeed the case, stress measurements may furnish one of the best clues to the driving mechanism of plate tectonics. 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.