Dynamics of magma supply to Kīlauea volcano, Hawai‘i: integrating seismic, geodetic and eruption data
Thomas L. Wright, F. W. Klein, 2008. "Dynamics of magma supply to Kīlauea volcano, Hawai‘i: integrating seismic, geodetic and eruption data", Dynamics of Crustal Magma Transfer, Storage and Differentiation, Catherine Annen, Georg F. Zellmer
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We focus on movement of magma beneath Kīlauea from the long summit eruption in 1967–1968 through the first historical sustained eruption on the east rift zone (Mauna Ulu 1969–1974), ending with the occurrence of a magnitude 7.2 earthquake beneath Kīlauea's eastern south flank. Magma from the Hawai‘iian hot spot continuously moves upward to summit storage and drives seaward spreading of Kīlauea's south flank on a 10–12 km deep décollement. Spreading creates dilation in Kīlauea's rift zones and provides room to store magma at depths extending to the décollement surface. During the period of study three types of eruptions – normal (short-lived), episodic and sustained – and three types of intrusions – traditional (summit to rift), inflationary and slow – are classified. Rates of sustained eruption are governed by the geometry of the magmatic plumbing. Swarms of earthquakes beneath the south flank signal increased pressure from magma entering Kīlauea's adjacent rift zone. Magma supply rates are obtained by combining the volume of magma transferred to sites of eruption or intrusion with the volume opened by seaward spreading over the same increment of time. In our interpretation the varying character of eruptions and intrusions requires a gradual increase in magma supply rate throughout the period augmented by incremental increases in spreading rate. The three types of eruptions result from different combinations of magma supply and spreading rate.
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Magmas are subject to a series of processes that lead to their differentiation during transfer through, and storage within, the Earth’s crust. The depths and mechanisms of differentiation, the crustal contribution to magma generation through wall-rock assimilation, the rates and timescales of magma generation, transfer and storage, and how these link to the thermal state of the crust are subject to vivid debate and controversy. This volume presents a collection of research articles that provide a balanced overview of the diverse approaches available to elucidate these topics, and includes both theoretical models and case studies. By integrating petrological, geochemical and geophysical approaches, it offers new insights to the subject of magmatic processes operating within the Earth’s crust, and reveals important links between subsurface processes and volcanism.