Stability and Collapse, Old Man of the Mountains, Franconia Notch, New Hampshire

Abstract

Research Article| January 01, 2005 Stability and Collapse, Old Man of the Mountains, Franconia Notch, New Hampshire BRIAN K. FOWLER BRIAN K. FOWLER 1North American Reserve, 67 Water Street, Suite 207, Laconia, NH 03246-3300 Search for other works by this author on: GSW Google Scholar Author and Article Information BRIAN K. FOWLER 1North American Reserve, 67 Water Street, Suite 207, Laconia, NH 03246-3300 Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 Copyright © 2005 Geological Society of America Environmental & Engineering Geoscience (2005) 11 (1): 17–27. https://doi.org/10.2113/11.1.17 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation BRIAN K. FOWLER; Stability and Collapse, Old Man of the Mountains, Franconia Notch, New Hampshire. Environmental & Engineering Geoscience 2005;; 11 (1): 17–27. doi: https://doi.org/10.2113/11.1.17 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 SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract On May 3, 2003, the Old Man of the Mountains natural rock profile collapsed, resulting in the unfortunate loss of the official emblem of the state of New Hampshire. A systematic reconnaissance of its stability had been performed in 1976 by the New Hampshire Highway Department as part of the environmental impact statement for Interstate 93. This reconnaissance estimated the Profile's in-place stability and its capacity to withstand blasting vibration from below. The work showed that 1) the dead weight of the Profile's blocks cantilevered at their combined point of bearing created a delicate stability; 2) the Profile from the nose up was relatively more stable than from the upper lip and chin down; 3) the Profile was subject to toppling collapse if natural processes or dynamic stress disturbed it; and 4) blasting could take place beneath it if no vibration in excess of those in the ambient natural environment was allowed to reach the rock mass. Careful blast monitoring during construction of Interstate 93 between 1985 and 1986 showed this vibration objective was achieved. Most recently, estimates of the mechanism and cause of the Profile's collapse suggest it was a progressive toppling failure initiated by a sudden loss of intact compressive strength in the granite immediately beneath the point of bearing of the cantilevered chin. The granite's intact strength had been naturally compromised over time by kaolinization decomposition and freeze–thaw degradation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.