HR: 1330h
AN: V22C-0605    [PDF]
TI: Revised Calculated Volumes Of Individual Shield Volcanoes At The Young End Of The Hawaiian Ridge
AU: * Robinson, J E
EM: jrobins@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Road MS 910, Menlo Park, CA 94025 United States
AU: Eakins, B W
EM: beakins@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Road MS 910, Menlo Park, CA 94025 United States
AB: Recent, high-resolution multibeam bathymetry and a digital elevation model of the Hawaiian Islands allow us to recalculate Bargar and Jackson's [1974] volumes of coalesced volcanic edifices (Hawaii, Maui-Nui, Oahu, Kauai, and Niihau) and individual shield volcanoes at the young end of the Hawaiian Ridge, taking into account subsidence of the Pacific plate under the load of the volcanoes as modeled by Watts and ten Brink [1989]. Our volume for the Island of Hawaii (2.48 x10$^{5}$ km$^{3}$) is twice the previous estimate (1.13 x10$^{5}$ km$^{3}$), due primarily to crustal subsidence, which had not been accounted for in the earlier work. The volcanoes that make up the Hawaii edifice (Mahukona, Kohala, Mauna Kea, Hualalai, Mauna Loa, Kilauea, and Loihi) are generally considered to have formed within the past million years and our revised volume for Hawaii indicates that either magma-supply rates are greater than previously estimated (0.25 km$^{3}$/yr as opposed to 0.1 km$^{3}$/yr) or that Hawaii's volcanoes have erupted over a longer period of time ($>$1 million years). Our results also indicate that magma supply rates have increased dramatically to build the Hawaiian edifices: the average rate of the past 5 million years (0.096 km$^{3}$/yr) is substantially greater than the overall average of the Hawaiian Ridge (0.018km$^{3}$/yr) or Emperor Seamounts (0.012 km$^{3}$/yr) as calculated by Bargar and Jackson, and that rates within the past million years are greater still (0.25 km$^{3}$/yr). References: Bargar, K. E., and Jackson, E. D., 1974, Calculated volumes of individual shield volcanoes along the Hawaiian-Emperor Chain, Jour. Research U.S. Geol. Survey, Vol. 2, No. 5, p. 545-550. Watts, A. B., and ten Brink, U. S., 1989, Crustal structure, flexure, and subsidence history of the Hawaiian Islands, Jour. Geophys. Res., Vol. 94, No. B8, p. 10,473-10,500.
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting