Deposit componentry and tephra grain shape data by dynamic-imaging analysis of the Kulanaokuaiki Tephra Member of the Uwēkahuna Ash, Kīlauea volcano, Island of Hawai‘i

Tephra samples from the Kulanaokuaiki Tephra Member (400 to 1000 C.E.) of the Uwēkahuna Ash (200 B.C.E. to 1000 C.E.) were sampled from Kīlauea volcano, Island of Hawai‘i. Samples were analyzed by dynamic imaging analysis using Microtrac CAMSIZER P4 and X2 instruments for grain shape and Anton nitrogen pycnometer instruments for density in the U.S. Geological Survey - Hawaiian Volcano Observatory tephra lab. Componentry analysis was done by hand through point-counting and identification of >200 individual clasts. Data shown is for number of grains picked in each category. Grain shape parameter means of sphericity, aspect ratio, convexity, transparency, compactness, and Krumbein roundness are reported, as well as for half phi grain size bins starting at 4, 3, 2, 1, 0, -1, -2, -3, and -4 phi. Additional methodology and details are outlined in Schmith (2023), Schmith and Swanson (2023), and Nalesnik (2025). This data release includes site and sample metadata, followed by deposit componentry, density, and grain shape.

Nalesnik, A.R. (2025) A Geochemical and Physical Investigation of the Kulanaokuaiki Tephra from Kīlauea volcano, Hawai‘i, Doctoral dissertation, Available from Dissertations & Theses @ University of Delaware ProQuest. [embargoed until December 31st, 2026]

Schmith, J., (2023) Keanakākoʻi Tephra unit D, Kīlauea Volcano, Hawaii: sample details, grain size, and grain shape data for 100 tephra samples: U.S. Geological Survey data release, https://doi.org/10.5066/P97WS3WS.

Schmith, J., Swanson, D.A. (2023) Complex styles of phreatomagmatic explosions at Kīlauea Volcano, Hawaii, controlled by magma structure. Frontiers in Earth Sciences, 11:1153288. doi: https://doi.org/10.3389/feart.2023.1153288