HR: 11:45h
AN: V11G-06    [PDF]
TI: Rapid Mass Wasting Following Nearshore Underwater Volcanism on Kilauea Volcano
AU: * Sansone, F J
EM: sansone@soest.hawaii.edu
AF: Dept. of Oceanography, Univ. of Hawaii at Manoa, 1000 Pope Rd., Honolulu, HI 96822 United States
AU: Smith, J R
EM: jrsmith@soest.hawaii.edu
AF: Hawaii Undersea Research Lab., Univ. of Hawaii at Manoa, 1000 Pope Rd., Honolulu, HI 96822 United States
AU: Culp, J B
EM: jculp@soest.hawaii.edu
AF: Hawaii Undersea Research Lab., Univ. of Hawaii at Manoa, 1000 Pope Rd., Honolulu, HI 96822 United States
AB: The rapid mass wasting of shallow submarine basalts was documented during SCUBA dives (with extensive underwater video and photography) along the flanks of Kilauea volcano, Hawaii during the Ki'i lava entry of the current eruption (19$\deg$20.4'N, 155$\deg$00.0'W). Lava entered the ocean at this site from mid-February to late March 1990, with several pauses. Dives on 19-20 March 1990 confirmed the widespread formation of lava pillows, as well as channelized lava flows, at this site over a water depth range of 20-40 m. Visual observations suggested that the resulting volcanic deposits were generally stable, despite the steep incline of the seafloor ($\sim$40 degrees). (The pre-eruptive seafloor slope was $\sim$14 degrees.) However, dives on 2 April 1990 revealed that nearly all of these relatively large submarine volcanic features had been subject to mass wasting, as the offshore area had been transformed into a debris field composed of material ranging in size from fine sand to boulder fragments. This generally featureless seascape extended uniformly to beyond the visual range of divers ($\sim$60 m water depth). High resolution side-scan bathymetry and imaging indicate that steeply sloped talus fields extend down the flanks of Kilauea in this area to abyssal depths, implying a possible linkage between coastal submarine volcanism and deep-water deposits. This work, combined with other observations at Kilauea, also suggests that coastal submarine volcanism may not generally result in the accumulation of stable rock formations.
DE: 3022 Marine sediments--processes and transport
DE: 3045 Seafloor morphology and bottom photography
DE: 8020 Mechanics
DE: 8414 Eruption mechanisms
DE: 8429 Lava rheology and morphology
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting