Comparison of 3D Stereo SEM Shape Data With 2D Projections and BET Surface Area Data for Volcanic Ash: When 3D Might Be Advantageous
In this study we present a technique for measuring the shape and surface area of individual grains of volcanic ash using SEM stereo-pairs. The shape and surface area of fine particles is traditionally measured using 2D sections and with BET equipment. However, 2D sections are incomplete shape descriptions and BET analysis is precluded when the amount of sample is limited, for example, in aerial ash cloud sampling. The application we discuss is the stereoscopic surface area analysis of 10 - 300 micrometer ash from the August 1992 Crater Peak/Spurr-eruption. Validation data is presented from measurements of glass micro- spheres in the size range. The stereo results are recast into a single surface area value using the particle size distribution of the ash and area compared to a BET analysis of the ash sample. Differences in surface area values between our technique, 2D shape data and BET are presented and discussed.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 8494 Instruments and techniques