The magma supply to Hawaii's Kilauea volcano at least doubled during 2003-2007, resulting in major increases in eruptive activity and the formation of new eruptive vents as described in a recent article . Initially, the surge was indicated by an increase in CO2 emissions in 2003-2004 combined with Kilauea's summit inflating, as measured using the Global Positioning System and interferometric synthetic aperture radar. Inflation was eventually recorded as far as 50 km from the summit implying a magma system connected to the summit reservoir over that distance.
Increases in SO2 emissions, heightened seismicity, and compositional and temperature variations in erupted lavas were also recorded during this period. The increase in CO2, which exsolves from magma at about 30 km depth, indicates a mantle source for the magma surge. The rate of magma rising from a mantle source through the Hawaiian hotspot was thought to have been relatively steady for many decades (since 1952) preceding the surge. Due to modeling limitations and assumptions, such as treatment of magma as an incompressible fluid, the researchers' models may underestimate the magma volume change by as much as a factor of five.
The article's USGS researchers suggest that the magma supply from the Hawaiian hotspot can vary on the order of years, and that CO2 emissions could be a valuable aid for assessing variations in magma supply at Kilauea and other volcanoes.