Emplacement mechanisms of the South Kona slide complex, Hawaii Island: sampling and observations by remotely operated vehicle Kaiko

Abstract

Emplacement of a giant submarine slide complex, offshore of South Kona, Hawaii Island, was investigated in 2001 by visual observation and in-situ sampling on the bench scarp and a megablock, during two dives utilizing the Remotely Operated Vehicle (ROV) Kaiko and its mother ship R/V Kairei. Topography of the bench scarp and megablocks were defined in 3-D perspective, using high-resolution digital bathymetric data acquired during the cruise. Compositions of 34 rock samples provide constraints on the landslide source regions and emplacement mechanisms. The bench scarp consists mainly of highly fractured, vesiculated, and oxidized a'a lavas that slumped from the subaerial flank of ancestral Mauna Loa. The megablock contains three units: block facies, matrix facies, and draped sediment. The block facies contains hyaloclastite interbedded with massive lava, which slid from the shallow submarine flank of ancestral Mauna Loa, as indicated by glassy groundmass of the hyaloclastite, low oxidation state, and low sulfur content. The matrix facies, which directly overlies the block facies and is similar to a lahar deposit, is thought to have been deposited from the water column immediately after the South Kona slide event. The draped sediment is a thin high-density turbidite layer that may be a distal facies of the Alika-2 debris-avalanche deposit; its composition overlaps with rocks from subaerial Mauna Loa. The deposits generated by the South Kona slide vary from debris avalanche deposit to turbidite. Spatial distribution of the deposits is consistent with deposits related to large landslides adjacent to other Hawaiian volcanoes and the Canary Islands.

Submarine slide blocks and associated soft-sediment deformation in deep-water basins: A review

“…1 and Table 1). Blocks are also documented around volcanic island groups in the Indian and Pacific Oceans (Rees et al, 1993;Wolfe et al, 1994;Moore and Chadwick Jr., 1995;Labazuy, 1996;Leslie et al, 2002;Yokose and Lipman, 2004; Saint-Ange et al, 2013) ( Fig. 1 and Table 1).…”

Submarine landslide deposits of the historical lateral collapse of Ritter Island, Papua New Guinea

“…No lateral boundaries between distinct lobes of similar facies deposits are seen in the Ritter Island deposits. If multiple collapse events had occurred, deposits from the earlier collapse events would be expected to show a partial cover from deposits associated with the later events (Yokose and Lipman, 2004). We see no evidence to indicate that the collapse scar was produced by multiple failure events.…”

Mauna Loa's submarine western flank: Landsliding, deep volcanic spreading, and hydrothermal alteration

“…The JAMSTEC and MBARI submersible surveys in the area (Figure 1) complement several earlier surveys [e.g., Garcia and Davis , 2001; Davis et al , 2003; Moore et al , 1995; Fornari et al , 1980]. The JAMSTEC dives were conducted on several distal landslide blocks, the outer scarps of the north and south benches, and on the upper slopes immediately behind the north bench [ Lipman et al , 2003; Yokose and Lipman , 2004]. The MBARI dives, the main focus of this study, define a traverse along an old landslide scar, extending from the outer scarp of the north bench onto the upper flanks conducted along an old landslide scar (Figure 1).…”

“…Recent submersible dives carried out along the upper flank, outer bench scarp, and distal landslide blocks, by MBARI and JAMSTEC in 2001 and 2002, now indicate that the western flank lithologies are heterogeneous. Volcaniclastic debris appears to be the dominant constituent within the bench, and pillow lavas drape much of the upper flank [ Morgan and Clague , 2003; Lipman et al , 2003; Yokose and Lipman , 2004]. The boundaries between the two domains appear to coincide with the benches, which are also physiographic boundaries.…”

“…Comparisons among the four dives allow us to correlate flank stratigraphy, from which we designate six distinct stratigraphic units, ordered from the base of the section. Dive results are also compared to other dredges and dives in the area [e.g., Moore et al 1995; Lipman et al , 2003; Yokose and Lipman , 2004] (Figure 1).…”