DISPERSAL OF VOLCANIC ASH ON MARS: ASH PARTICLE SHAPE ANALYSIS

The objective of the project is to create a representative database of ash dimensions and shapes of volcanic ash particles in size divisions from 2mm to 16 μm, using a novel high-resolution automated microscopy procedure pioneered at UH [Ogliore and Jilly, 2013]. Compiling a database of ash particle dimensions and their shapes, will allow them to be used statistically in estimating the effective cross-sectional areas and their variability as a function of particle size for use in a model of ash deposition on Mars. The shape database created by this project would be the first that analyzed ash particles morphology in three dimensions, allowing us to comment on shape trends that were missed in previous investigations. This shape dimension database will allow more accurate modeling of volcanic ash fallout, specifically that on Mars to help quantify the impact of explosive volcanisms probability in creating vast fine grained deposits. This optical system looks at particles in three dimensions by capturing a series of images as the microscope stage moves upwards, and employs focus-stacking to display elements that have structure extending above or below the depth of field of a single image. The image mosaics are processed through the program ImageJ for particle dimensions, that can provide the necessary range of dimensionless shape factors to calculate effective cross-sections “seeing” the atmospheric gas during fall in Dr. Sarah Fagents ash settling model.