HR: 1330h
AN: V12B-0585    [PDF]
TI: Regional and Residual Bathymetry and Flexure Modeling of the Nazca Plate
AU: * Kim, S
EM: sskim@soest.hawaii.edu
AF: School of Ocean and Earth Science and Technology, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822 United States
AU: Wessel, P
EM: pwessel@hawaii.edu
AF: School of Ocean and Earth Science and Technology, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822 United States
AU: Naar, D
EM: naar@marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 Seventh Avenue South, St. Petersburg, FL 33701 United States
AB: We investigate the thermo-mechanical properties of the lithosphere along the Easter Seamount Chain and Nazca Ridge, whose bathymetric features are delineated by a broad chain of seamounts in the southeastern Pacific. These properties can be expressed in terms of flexural rigidity or, equivalently, the thickness of an elastic plate that indicates the strength of the lithosphere at the time the seamounts were formed. We can use elastic thickness as indicator of thermal structure or age of the lithosphere at time of loading to understand the origin of seamounts. As a first step, a 30-sec gridded blend of observed and predicted topography was separated into regional and residual components in order to isolate seamount loads from the seafloor. To get robust and objective residuals, we employed spatial median filters with the optimal filter width, $650\pm50$ km, found for this study area. The estimated regional trend detects successfully long-wavelength swelling effects from the East Pacific, Galapagos, and Roggeveen Rises. The uncertainties in the regional and residual separation will be estimated to provide upper and lower bounds on the seamount load. Next, we examine the effective elastic thickness of the lithosphere supporting the seamounts in our study area, based on the relationship between the residual bathymetry and gravity (both shipboard and satellite derived).
DE: 1219 Local gravity anomalies and crustal structure
DE: 3010 Gravity
DE: 8122 Dynamics, gravity and tectonics
DE: 8199 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting