Thompson Postdoctoral Fellow in Geophysics Darcy Ogden, of Stanford University, delivered today’s DTM Seminar. Her talk, entitled, “Rockets Made of Rocks? The Dynamics and Hazards of Volcanic Jets,” discussed volcanic plumes that result from explosive volcanic eruptions that are analogous to gas decompression through rocket nozzles, including acceleration to supersonic velocities and the formation of shock waves. Using numerical simulations, Ogden demonstrated some of the effects of these flow features on eruption column behavior and hazards. In explosive volcanic eruptions, these expanding particulate-laden gases decompress through erodible and brittle vents formed from layers of rock. The shape of the vent can change in response to the stresses applied by the fast-moving expanding gas, which is controlled by the vent shape. Preliminary results from numerical simulations exploring this coupled phenomenon were also presented.