Friction marks on blocks from pyroclastic flows at the Soufriere Hills volcano, Montserrat: Implications for flow mechanisms

Abstract

Research Article| September 01, 2000 Friction marks on blocks from pyroclastic flows at the Soufriere Hills volcano, Montserrat: Implications for flow mechanisms U. Grunewald; U. Grunewald 1Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar R.S.J. Sparks; R.S.J. Sparks 1Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar S. Kearns; S. Kearns 1Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK Search for other works by this author on: GSW Google Scholar J.C. Komorowski J.C. Komorowski 2Observatoire de Guadeloupe, Institut de Physique du Globe, Guadeloupe, French Antilles Search for other works by this author on: GSW Google Scholar Geology (2000) 28 (9): 827–830. https://doi.org/10.1130/0091-7613(2000)28<827:FMOBFP>2.0.CO;2 Article history received: 22 Feb 2000 rev-recd: 02 Jun 2000 accepted: 20 Jun 2000 first online: 02 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 U. Grunewald, R.S.J. Sparks, S. Kearns, J.C. Komorowski; Friction marks on blocks from pyroclastic flows at the Soufriere Hills volcano, Montserrat: Implications for flow mechanisms. Geology 2000;; 28 (9): 827–830. doi: https://doi.org/10.1130/0091-7613(2000)28<827:FMOBFP>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 Friction marks on surfaces of blocks (1 to 10 m) in pyroclastic flow deposits generated by lava dome collapse in the 1995–1999 eruption of the Soufriere Hills volcano, Montserrat, consist of a thin (5 to 10 mm) layer of cataclasite with a polished slickensided surface. In some examples, thin surface layers and veins of pseudotachylyte are found. The friction marks occur in several orientations on all block surfaces. They are typically 0.5 to 10 cm wide and up to ∼1 m long. The marks are similar to tectonic structures on faults. They indicate that the blocks were tumbling and sliding within the flows. Large transient stresses result when the mass of a large sliding block is applied to a small contact area on a neighboring block or the ground. Compositional data indicate that the pseudotachylytes involved melting of the flow matrix. These observations support models of pyroclastic flows as rapid granular avalanches. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.