Comparison of Pre- and Post-Eruption Surveys of the 2005-2006 East Pacific Rise Volcanic Event: Implications for Fast-Spreading Mid-Ocean Ridge Eruption Processes.

HR: 0800h
AN: V21A-0383 [Abstracts]
TI: Comparison of Pre- and Post-Eruption Surveys of the 2005-2006 East Pacific Rise Volcanic Event: Implications for Fast-Spreading Mid-Ocean Ridge Eruption Processes.
AU: Soule, S A
EM: ssoule@whoi.edu
AF: Woods Hole Oceanographic Institution, Geology and Geophysics Dept., Woods Hole, MA 02543, United States
AU: * White, S M
EM: swhite@geol.sc.edu
AF: University of South Carolina, Dept. of Geological Sciences, Columbia, SC 29208, United States
AU: Fornari, D J
EM: dfornari@whoi.edu
AF: Woods Hole Oceanographic Institution, Geology and Geophysics Dept., Woods Hole, MA 02543, United States
AU: Ferrini, V L
EM: ferrini@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, United States
AU: Tivey, M A
EM: mtivey@whoi.edu
AF: Woods Hole Oceanographic Institution, Geology and Geophysics Dept., Woods Hole, MA 02543, United States
AB: We present two high-resolution DSL-120A sidescan data sets collected before (2001) and after (2007) a recent eruption along the East Pacific Rise (EPR) that image the ridge crest between 9° 45`N and 9° 57`N at 2-m resolution. These data provide a unique perspective on the volcanic processes and seafloor features that developed during the 2005-06 eruptions. Co-registration of the two data sets is facilitated by bottom-moored transponder navigation and an exceptional correspondence in the morphology of the bounding walls of the axial summit trough (AST), which has uniquely shaped, small-scale offsets that, in many places, remain unchanged since 2001. By cataloging changes in the acoustic characteristics of the seafloor between the datasets, we are able to refine our estimates of the 2005-2006 eruption extent. The 2007 sidescan data, along with correlative bottom imaging using the WHOI TowCam system and ROV Jason2, allow us to interpret the heterogeneity and distribution of surface morphologies that develop within a single eruptive unit, and illustrate the mechanisms that distribute lava across the ridge crest. The most easily identified change resulting from the 2005-2006 eruption is the development of an extensive network of lava channels, primarily between 9° 49`-52`N, which distributed new lava more than 2 km from the AST. The sidescan data are complemented by phase bathymetry and SM2000 multibeam bathymetry collected with the DSL-120A at 2-m resolution, as well as near-bottom, sub-meter resolution SM2000 bathymetry data collected with ROV Jason 2. Comparison of these data with pre-eruption bathymetric data reveal localized changes over portions of the eruption area, which help constrain the overall emplacement of lava. Comparison of pre- and post-eruption magnetic field intensity profiles over the ridge crest provide additional insight into patterns of lava deposition during the eruption.
DE: 3005 Marine magnetics and paleomagnetics (1550)
DE: 3045 Seafloor morphology, geology, and geophysics
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8416 Mid-oceanic ridge processes (1032, 3614)
DE: 8429 Lava rheology and morphology
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting