From 1998 to 2002, four cruises by Japan Marine Science and Technology Center (JAMSTEC) research vessels explored the submarine flanks of the Hawaiian Islands. This collaborative Japan-USA research program resulted in new multibeam mapping of the seafloor around Hawai‘i, and seafloor observation and sample collection during 53 manned submersible and 25 remotely-operated vehicle (ROV) dives. In this report, we present major element, S, and Cl compositions of volcanic glasses collected from the submarine flanks of Kilauea Volcano during the JAMSTEC research program. The compositions were determined by electron probe microanalysis (EPMA) at the USGS in Menlo Park, California.

The submarine portion of Kilauea, Hawai‘i’s most active volcano, was a main target during the JAMSTEC program, with 15 manned submersible dives and seven ROV dives. Dive observations revealed that much of the volcano’s south flank, manifested as the midslope bench, consists of volcaniclastic debris, shed from the volcano as turbidites and debris flows. Debris exposed in the outer scarp of the midslope bench spans a large compositional range and records the pre-shield, alkalic phase for this volcano. Coarser debris (breccia clasts) is almost certainly from Kilauea, as are most alkalic sands. For low-S, tholeiitic sand grains, the source volcanoes are probably Mauna Loa and perhaps Mauna Kea.