TITLE: "Molten Rock, Singing Fire: Physics of Exploding Volcanoes"

SPEAKER: Professor Jonathan Lees,

TIME: Thursday Apr. 3, 2003 at 4 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Volcanic eruptions and seismicity associated with harmonic tremor on continuously active volcanoes remain controversial and pose significant challenges to volcanologists attempting to provide physical models of these exotic phenomena. Two competing models have been invoked to explain harmonic tremor on exploding volcanoes around the world: one involves organ pipe modes and linear superposition of standing waves to achieve periodic signals commonly observed at low level (Strombolian) explosions at numerous sites world wide. An alternative model invokes non-linear choked flow through narrowing conduits as gas escapes to the atmosphere, recently dubbed the pressure cooker model. We examine the fundamentals of these two models and explore the implications and observations associated with each approach.