HR: 13:55h
AN: V13E-02    [Abstracts]
TI: Lava Lake Filling, Draining, and Density-Driven Crustal Foundering: Kilauea Iki 1959
AU: * Stovall, W K
EM: wstovall@hawaii.edu
AF: Department of Geology and Geophysics, University of Hawaii at Manoa, 1680 East West Road, Honolulu, HI 96822, United States
AU: Houghton, B F
EM: bhought@soest.hawaii.edu
AF: Department of Geology and Geophysics, University of Hawaii at Manoa, 1680 East West Road, Honolulu, HI 96822, United States
AU: Harris, A
EM: harris@higp.hawaii.edu
AF: Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, 1680 East West Road, Honolulu, HI 96822, United States
AU: Swanson, D A
EM: donswan@usgs.gov
AF: U.S. Geological Survey, Hawaii Volcano Observatory, PO BOX 51, Hawaii National Park, HI 96718, United States
AB: The 1959 eruption of Kilauea formed an approximately 46x10⁶ m³ lava lake during 17 episodes of Hawaiian fountaining. The vent location, on the steep walls of the Kilauea Iki pit crater, resulted in interplay between fountaining, pit filling and drain back from the lake into the vent. Previous studies of the Kilauea Iki lava lake have highlighted the post-eruption cooling and crystallization history, but little has been published regarding the processes of lake growth. The lava lake margins preserve features associated with filling, drainage and density-driven crustal foundering during the final eruptive episodes. Features associated with lake filling include relics of numerous vertically accreted layers preserved at the lake margins. The thickness of these onion-skin-like layers relates to variations in lake depth, the length of time a certain level was maintained, and cooling of the lake lava against the crater wall. Horizontal lava shelves are the relics of crusts formed as a result of surficial cooling during periods when the lake remained stable at a particular height for a period of time. Morphology, thickness, spacing and vertical placement of these shelves relate to the length of time a particular level was maintained, lava accretion style, as well as drainage velocity and cooling rates. Shelves were formed in both static environments (where crust standing in a fixed location thickened with time) and dynamic environments (where crust rolling along the lake edge accreted to the wall in a snow-ball-like fashion). Complete crustal overturn was observed repeatedly during the eruption and is a common process in all lava lakes, yet the initiating occurrence of crustal foundering is rarely preserved in situ. The northern margin of the 1959 lake reveals plates of lava plunging into the lake core and permits a detailed interpretation of the mechanics involved in crustal foundering during lake drainback. Density differences between (1) a lava lake crustal plate and (2) overriding and underlying material are several hundred kg/m³. These differences are substantial and lead to inevitable foundering of lake crust and eventually to complete crustal overturn.
DE: 8425 Effusive volcanism
DE: 8428 Explosive volcanism
DE: 8429 Lava rheology and morphology
DE: 8486 Field relationships (1090, 3690)
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting