HR: 1340h
AN: OS23B-1313    [Abstracts]
TI: Evidence for Large-Scale Slope Failures on Northern Gulf of Alaska Seamounts
AU: Keller, R
EM: rkeller@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
AU: * Chaytor, J
EM: jchaytor@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
AU: Giles, D
EM: gilesd@geo.oregonstate.edu
AF: Department of Geosciences, Oregon State University, Corvallis, OR 97331
AU: Teasdale, R
EM: rteasdale@csuchico.edu
AF: Department of Geological and Environmental Sciences, California State University, Chico, CA 95929
AU: Walczak, P
EM: walczakp@onid.orst.edu
AF: College of Oceanic & Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
AB: SeaBeam 2100 multibeam bathymetric data from six seamounts in the Kodiak-Bowie seamount chain in the northern Gulf of Alaska collected during August 2004 ({\it R/V Atlantis} cruise 11-15) illuminate the complex eruptive and post-eruptive morphology of these volcanoes. Prominently expressed on the preliminary maps is evidence for large-scale slope failures on a number of these seamounts. Flank morphology suggests that these slope failures take the form of both large coherent masses and smaller debris flows. Two of the seamounts, Giacomini and Pratt, were found to have prominent head-scarp fractures cutting their summit plateaus. These scarps are over 40 meters high in places, and are in the same areas of the seamounts as the earlier slope failures, suggesting repeated failure processes over at least part of the seamounts' histories. We also see evidence for the seamounts being affected by processes on the surrounding seafloor: migration of the active section of the Mukluk deep-sea channel is undercutting the northern slope of Denson Seamount, and appears to be promoting slope failure there. Deep-sea channels are found in close proximity to a number of the seamounts and may have accelerated other slope failures. The sea channels, in addition to fan-body complexes, may also play a role in masking portions of the chaotic debris expected at the base of the failures. As we are still in the early stages of the analysis of these data, many questions remain, primarily in relation to the causes and ages of the slope failures, and the resulting effects in the near and far-fields.
DE: 9355 Pacific Ocean
DE: 3022 Marine sediments--processes and transport
DE: 3045 Seafloor morphology and bottom photography
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting