A detailed field and petrologic study of the ca. 1800 A.D. flows at Huala??lai Volcano documents at least two eruptive episodes, the Hu'ehu'e flow field ending in 1801, and the Ka'maupu??lehu flow several decades earlier. The morphology and stratigraphy of the Ka'upu??lehu flow require an emplacement duration of several days to weeks. Based on a comparison with recent eruptive activity at Mauna Loa volcano, the eruption cannot have occurred at the anomalously high rate (104-105 m3/s) proposed by previous workers. The hummocky flow surface of the later phase of the Hu'ehu'e eruption suggests a duration of months, based on a comparison with recent eruptive activity at Ki??lauea Volcano. Although none of the ca. 1800 flows show evidence for extraordinarily fast emplacement or unusual fluid rheologies, both flows show unusual features. The abundant xenoliths for which the Ka'u??pu??lehu flow is famous were transported in numerous episodes of deposition and remobilization, during which they eroded the channel systems through which they traveled. Lava transport in proximal and medial regions of both flow fields was probably through lava tubes, as evidenced by preserved tubes and by the prevalence of pa??hoehoe-lined channels that require thermally efficient transport of lava over great distances. Both flows also show abundant evidence for re-occupation of older cones and lava tubes, a characteristic that may typify infrequent eruptions of older volcanic systems. Although lava flows from Huala??lai Volcano do not show anomalous eruptive behavior, they pose a substantial hazard for coastal communities of Kona.
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Emplacement of the most recent lava flows on Huala??lai Volcano, Hawai'i