Undocumented late 18th- to early 19th-century volcanic eruptions in the Southwest Rift Zone of Kīlauea Volcano, Hawai‘i

The historical record of volcanic activity at Kīlauea Volcano on the Island of Hawaiʻi begins with the phreatomagmatic blasts of 1790. Three decades later, in 1823, the first party of non-Hawaiian visitors, organized by the English Reverend William Ellis, reached Kīlauea’s summit. A detailed narrative by Ellis includes an account of an eruption in Kīlauea’s Southwest Rift Zone that occurred shortly before his visit. In the absence of other source materials, the interval between the eruptions of 1790 and 1823 has been overlooked by geologists working at Kīlauea, with the presumption that little if anything took place volcanically outside of the summit caldera during that time. Careful stratigraphic observations combined with radiocarbon dating demonstrate that during these years a set of Southwest Rift Zone eruptions took place, including two that were long-lasting (weeks to months). Inclusion of these events gives a more complete historical (post-1790) record for Kīlauea and a better understanding of its eruptive behavior.