What causes some eruptions to be more explosive than others? Is it the total driving gas fuel, or how fast the gas escapes? This lecture examines both the volatile content and the speed of magma ascent immediately prior to eruption. Chemical zonation preserved inside glass pockets and crystals provides one of the fastest clocks in geology.

These timescales of chemical diffusion operate over minutes to hours in the run-up to eruption. Initial results show that more explosive eruptions may

result from higher rates of magma ascent.

Terry Plank is the Arthur D. Storke Memorial Professor in the Department of Earth and Environmental Sciences at the Lamont Doherty Earth Observatory of Columbia University. She is a geochemist who studies magmas associated with the plate tectonic cycle. She is known particularly for her studies of subduction zones: the inputs on the ocean floor, the temperatures attained beneath volcanoes, the melting process in the mantle, and the water contents of magmas before they erupt.

Plank was born in Wilmington, Delaware in 1963, where she attended the Tatnall School. She graduated from Dartmouth College with a degree in earth sciences, and received a doctorate from Columbia University in 1993. She was on the faculty of the University of Kansas and Boston University before joining Columbia University in 2008. Plank received the Houtermans Medal from the European Association for Geochemistry, the Donath Medal from the Geological Society of America, is a Fellow of the American Geophysical Union, the Geochemical Society, the Geological Society of America, and the Mineralogical Society of America. In 2012 she was named a MacArthur Foundation Fellow, and in 2013 elected to the US National Academy of Sciences.