Abstract 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.

Abstract Intraplate volcanism within the Pacific Plate not generated at spreading plate margins is most obvious in Hawaii and the Hawaiian-Emperor volcanic chain. This chain forms a global relief feature of the first order. This chapter consists of five separate sections that summarize the volcanism and geology of Hawaii and the Hawaiian-Emperor chain. Less obvious but probably greater in overall volume are other seamounts and seamount chains scattered across the northern and eastern Pacific basin. Some of these appear to owe their origin to intraplate volcanism, but many probably formed at mid-ocean ridges. Batiza (this volume, Chapter 13) discusses these other, largely submarine, volcanoes. The Island of Hawaii lies at the southeastern end of the Hawaiian-Emperor volcanic chain—a dogleg ridge, largely submarine, stretching nearly 6,000 km across the north Pacific Ocean basin. From Hawaii the chain extends northwestward along the Hawaiian Ridge to a major bend beyond Kure Atoll. North of the bend the chain continues in a northward direction as the submarine ridge of the Emperor Seamounts. Volcanoes are active at the southeast end of the chain and become progressively older to the northwest, reaching ages of 75 to 80 million years at the north end of the Emperor Seamounts. Most of this volcanic chain, with an estimated area of 1,200,000 km 2 , lies beneath the ocean. Only the Hawaiian Islands and a few atolls of the Hawaiian Ridge, totaling some 16,878 km 2 , rise above the sea (Plate 5).