Abstract

The rate of magma supply from the mantle to Kīlauea Volcano, Hawaiʻi, was steady throughout the second half of the 20th century, resulting in persistent, long-lived eruptive activity. In 2003, however, inflation of the surface, increased lava effusion from the 1983-present flank eruptive vent, and a sudden jump in CO2 emissions signaled a more than doubling in magma supply to the volcano. By 2007, the surge had ended, and effusion rate, deformation, and CO2 emissions returned to nominal levels. Over the next several years, eruptive activity appeared to wane, although the rate of lava effusion could not be accurately quantified. Measurements of lava discharge from satellite-derived topographic difference maps, available since 2011, confirm that the eruption rate of lava is now about half the long-term average, which, coupled with a lack of volcano-wide inflation, argues for a near halving in the magma supply rate. Evidence over the last two decades thus indicates the magma supply to Kīlauea can fluctuate on timescales of only a few years—behavior that exerts a powerful control on the dynamics of hotspot volcanism in Hawaiʻi.