Semiannual patterns of erosion and deposition in upper Monterey Canyon from serial multibeam bathymetry

Research Article| September 01, 2005 Semiannual patterns of erosion and deposition in upper Monterey Canyon from serial multibeam bathymetry Douglas P. Smith; Douglas P. Smith 1Division of Science and Environmental Policy, California State University Monterey Bay, 100 Campus Center, Seaside, California 93933, USA Search for other works by this author on: GSW Google Scholar Genoveva Ruiz; Genoveva Ruiz 1Division of Science and Environmental Policy, California State University Monterey Bay, 100 Campus Center, Seaside, California 93933, USA Search for other works by this author on: GSW Google Scholar Rikk Kvitek; Rikk Kvitek 1Division of Science and Environmental Policy, California State University Monterey Bay, 100 Campus Center, Seaside, California 93933, USA Search for other works by this author on: GSW Google Scholar Pat J. Iampietro Pat J. Iampietro 1Division of Science and Environmental Policy, California State University Monterey Bay, 100 Campus Center, Seaside, California 93933, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2005) 117 (9-10): 1123–1133. https://doi.org/10.1130/B25510.1 Article history received: 20 Oct 2003 rev-recd: 02 Dec 2004 accepted: 04 Jan 2005 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 Douglas P. Smith, Genoveva Ruiz, Rikk Kvitek, Pat J. Iampietro; Semiannual patterns of erosion and deposition in upper Monterey Canyon from serial multibeam bathymetry. GSA Bulletin 2005;; 117 (9-10): 1123–1133. doi: https://doi.org/10.1130/B25510.1 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 Recently acquired 3-m-resolution 244 kHz multibeam seafloor bathymetry (0.5 m depth precision) reveals geomorphology at sufficient detail to interpret small-scale features and short-term processes in the upper 4 km of Monterey Canyon, California. The study area includes the continental shelf and canyon features from 10 m to 250 m depth. The canyon floor contains an axial channel laterally bounded by elevated complex terrace surfaces. Sand waves with 2 m height and 35 m average wavelength dominate the active part of the canyon floor. The sand waves are strongly asymmetrical, indicating net down-canyon sediment transport in this reach. Terraces, including a broad 25-m-tall terrace complex near the head of the canyon, bear evidence of recent degradation of the canyon floor. Slump scars and gullies having a variety of sizes and relative ages shape the canyon walls. Serial georeferenced digital elevation models were analyzed to detect net changes in bathymetry or morphology occurring during both a six month period (September 2002 to March 2003) and a 24-h period (24 March to 25 March). Significant changes over the six month period include: (1) complete reorganization of the sand waves on the channel floor, (2) local channel degradation creating new 2-m-tall erosional terraces on the channel margins, (3) local channel widening that laterally eroded older channel margin terraces, and (4) 60 m extension of one minor gully head on a steep canyon wall. There were no discernable changes in morphology during the 24-h study period. Raster subtraction of serial bathymetric grids provides estimates of sediment erosion and deposition that occurred between the canyon head and a point 2 km down canyon during the six month study. Erosion of 320,000 m3 (±80,000 m3) of sediment occurred mainly in the tributaries, along the margins of the axial channel, and in the lowest 700 m of the analyzed reach. This eroded volume was approximately balanced by 260,000 m3 (±70,000 m3) of sediment deposition that was concentrated in the nearshore region along the rim of the canyon head. There was no measurable sediment gain or loss during the 24-h study period. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.