Understanding explosive eruption processes is required for interpreting ancient eruptions and predicting behavior of future eruptions. Observing many eruptions as they occur, however, is dangerous. Further, the size and intensity of eruption plumes and pyroclastic density currents preclude observation into the interiors of those turbulent, hot, particle-laden flows. I use scaled laboratory experiments to what processes control the transport, deposition, and liftoff of pyroclastic density currents.
Some of the recent experimental volcanology research includes:
3D structure of unconfined density currents (accepted at Bulletin of Volcanology)
Effects of substrate roughness on PDC transport
Links between turbulence and sedimentation in dilute PDCs PDF
Effects of Topography on dilute PDCs PDF
Together with contractor Rob Dennen (now at UT Austin), I built an experimental facility at the SI Museum Support Center in Suitland, MD. The interior dimensions of the tank are 28’ long, 20’ across, and 8.5’ tall, allowing us to run unconfined, 3D density currents that have the same dynamic scaling as natural PDCs.
The MSC tank is instrumented with HD video cameras, a high speed video camera (up to 3000 fps at full resolution), high frequency thermocouples, sediment traps, analytical balance, and custom laser illumination.
Video data are used to measure turbulent velocity fields, entrainment rate, sedimentation patterns, and turbulent characteristics. Early results from this tank show that unconfined flows behave very differently from confined currents (in revision at Bulletin of Volcanology).
3D reconstruction of a plume rising from an experimental current. Using a high speed camera (3000 fps) and swept laser sheet we can image the full 3d structure of currents and plumes at high frequency (up to 30 Hz).
As an NSF postdoctoral fellow, I built a PDC tank at the UC Berkeley Richmond Field Station. The tank has interior dimensions of 20’ long, 2’ wide, and 6’ tall. Using this tank I have studied PDC interactions with topography (link to Geology paper), links between current behavior and sedimentation in PDCs (JVGR paper), and how currents interact with substrate roughness. SHown here are sedimentation data from a current that lifted off at ~70 s.