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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. B9, 2415, doi:10.1029/2003JB002411, 2003

Slope failure and volcanic spreading along the submarine south flank of Kilauea volcano, Hawaii

Julia K. Morgan

Department of Earth Science, Rice University, Houston, Texas, USA


Gregory F. Moore

Department of Geology and Geophysics, School of Ocean and Earth Science and Technology (SOEST), University of Hawaii, Honolulu, Hawaii, USA


David A. Clague

Monterey Bay Aquarium Research Institute, Moss Landing, California, USA


Abstract

New multichannel reflection data and high-resolution bathymetry over the submarine slopes of Kilauea volcano provide evidence for current and prior landsliding, suggesting a dynamic interplay among slope failure, regrowth, and volcanic spreading. Disrupted strata along the upper reaches of Kilauea's flank denote a coherent slump, correlated with the active Hilina slump. The slump comprises mostly slope sediments, underlain by a detachment 3–5 km deep. Extension and subsidence along the upper flank is compensated by uplift and folding of the slump toe, which surfaces about midway down the submarine flank. Uplift of strata forming Papa`u seamount and offset of surface features along the western boundary of Kilauea indicate that the slump has been displaced ∼3 km in a south-southeast direction. This trajectory matches coseismic and continuous ground displacements for the Hilina slump block on land, and contrasts with the southeast vergence of the rest of the creeping south flank. To the northeast, slope sediments are thinned and disrupted within a recessed region of the central flank, demonstrating catastrophic slope failure in the recent past. Debris from the collapsed flank was shed into the moat in front of Kilauea, building an extensive apron. Seaward sliding of Kilauea's flank offscraped these deposits to build an extensive frontal bench. A broad basin formed behind the bench and above the embayed flank. Uplift and back tilting of young basin fill indicate recent, and possibly ongoing, bench growth. The Hilina slump now impinges upon the frontal bench; this buttress may tend to reduce the likelihood of future catastrophic detachment.

Received 19 January 2003; accepted 7 May 2003; published 5 September 2003.

Index Terms: 0930 Exploration Geophysics: Oceanic structures; 1824 Hydrology: Geomorphology (1625); 3022 Marine Geology and Geophysics: Marine sediments—processes and transport; 3025 Marine Geology and Geophysics: Marine seismics (0935); 8010 Structural Geology: Fractures and faults.

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Citation: Morgan, J. K., G. F. Moore, and D. A. Clague (2003), Slope failure and volcanic spreading along the submarine south flank of Kilauea volcano, Hawaii, J. Geophys. Res., 108(B9), 2415, doi:10.1029/2003JB002411.