Depositional processes of alluvial fans along the Hilina Pali fault scarp, Island of Hawaii
Role: PhD student (dissertation chapter)
Team: Bob Craddock (Smithsonian)
Funding: Smithsonian Institution Fellowship Program (Pre-Doctoral Fellowship)
We investigated the formative processes of a series of alluvial fans along the Hilina Pali escarpment on the southern flank of Kīlauea volcano in Hawaii. These fans are characterized by steep slopes, coarse sediments, and lobate shapes, primarily formed from large gravel and boulders. Sediment is sourced from eroded alcoves in the escarpment and is transported during high-magnitude rain events, such as Kona storms. Field measurements and calculations of flow rates indicate that these high-magnitude, short-duration events shape these fans.
We conclude that the fans are mainly constructed by sieve lobe deposition, a process where coarse material is deposited as water infiltrates the fan, allowing finer sediment to wash through. This deposition pattern is rare and significant because it forms large lobes of boulder-sized material. The research has broader implications for understanding similar processes in other regions and for interpreting the sedimentary record in environments where alluvial fans form. It provides a detailed look at how large-scale deposition occurs in steep, coarse-grained settings and contributes to the understanding of landscape evolution in volcanic and arid regions.