Michigan Tech's AshFall course by William I. Rose.
This series of lectures was put together in 2009 as the lecture part of a graduate level course which students did some evaluations of ashfall models, comparing their results with actual ashfall deposits, including the Grain size distributions of ashfall samples as well as isopach maps. The lectures are designed to give students an understanding of ash in the field and laboratory and including some introductory meteorology.
Follow the links below to access individual presentations.
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|Lecture Number/Topic||Online Lecture||Video||Lecture Notes||Supplemental Material||Suggested Exercises|
|Origin of volcanic ash: Mechanisms for formation||View|
|Mechanisms for the formation of volcanic ash are reviewed and discussed, including explosive vesiculation, phreatomagmatic explosions and milling/comminution.
|Phreatic and phreatomagmatic fragmentation||View|
|Discussion of gas thrust, convective thrust and eruption columns. Column height and eruption rate. Convection in the atmosphere, latent heat. Stages of evolution of eruption plumes to volcanic clouds.
|Size of volcanic ash||View|
|Size of ash particles is discussed--ash, lapilli, fine and very fine ash, phi sizes, lognormal distributions and bimodal ones. Patterns of fallout and grain size distributions.
|Particle fall through the atmosphere||View|
|Particle fall in atmosphere. Particle Reynolds Numbers, turbulent and laminar flow. Shapes of volcanic ash particles. Fine particle fallout. Aggregation.
Rose W I, C M Riley and S Dartevelle,...
|Numerical fallout models: An introduction based on Suzuki (1983)||View|
|Suzuki, T., 1983. A theoretical model for dispersion of tephra, in: D. Shimozuru and I. Yokoyama (eds) Arc Volcanism: Physics and Tectonics, Terra Scientific Publishing, Tokyo, 95-116.
|Ashfall deposit geometry--blanket. Grain size/distance patterns. Total grain size distributions.
Rose, W I, S Self, P J Murrow, G G J Ernst C Bonadonna and A J Durant, 2007, Pyroclastic fall...
|Atmospheric layers, pressure temperature relationships. Origin of winds. Wind shear and pressure maps. Weather satellite data, weather radar systems. Cloud classifications. Radiosondes. Latent...
|More Volcano Meteorology||View|
|Adiabatic processes, humidity in the atmosphere. Hydrometeors, stable and unstable air. Coriolis. Winds on a spherical surface.
|Weather Radar systems for mitigation of volcanic cloud hazards to aircraft||View|
|Thunderstorms and Volcanic clouds- analogies||View|
|Direct sampling of volcanic clouds||View||RoseetalJGRHekla.pdf
|Volcanic clouds have only sporadically been directly sampled. Sampling is advantageous to validate remote sensing. Direct sampling was more common in the 1978-1984 period before the hazards to...
|Distal sedimentation and the connection to cloud microphysics||View|
|Detecting volcanic ash from space||View||RoseSpurrJG.pdf
|How satellites detect, map and measure volcanic ash in volcanic clouds. HYSPLIT and volcanic cloud satellite observations. Volcanic cloud stages. Infrared satellite detectors, split window. ...
|Why measure volcanic emissions from space?||View|
|Satellite remote sensing of volcanic SO2 emissions||View|
|The volcanic cloud of the 1992 eruption of Crater Peak, Alaska||View|
|Models of tephra dispersion||View|
|Chaiten eruption observations, May 2008||View|
|A review of the Chaiten eruptions based mainly on satellite observations. This lecture was compiled in October 2009.
|Hazards of volcanic ash||View|
|Reducing the threat to aviation from airborne volcanic ash||View|