Determining Volcanic Characteristics of Hawai'ian Style Volcanoes with Vesicle Analyses of spatter clasts from Unrecorded Eruptions
Abstract
Gases escaping from a volcanic fissure can be varied in their volume and rate of assent leading to different fountaining heights, volume of erupted lava, as well as vesicle percentages, densities, and vesicles shape and size in erupted spatter. Smaller, more circular vesicles are the result of higher ejection speed through the vent, while larger, more elongated are the result of lower ejection speed. We compare vesicle data from the 2018 Hawai'i eruption with several sites in the northwest of the U.S.A with similar volcanism to Hawai'ian style eruptions to investigate the similarities and differences in eruption dynamics between hotspot and monogenetic volcanism. Volcanic systems that ascend through thicker crustal material are more likely to have higher fountains because they have greater ability to incorporate volatiles into their melt, and thus they should have a larger percentage of circular vesicles compared to those from the Hawai'ian fountains. We collected 15 spatter samples from Hawai'i and 9 from the mainland, made each rock into thin sections, and imaged them at 4 scales using a petrographic microscope and a Scanning Electron Microscope (SEM). The 2-D vesicle percentage of each image was calculated with the software program ImageJand the vesicles' relative elongation or sphericity as well as relative size were calculated with the modelling program, F.O.A.M.S. ©. The fountain height of the 2018 Hawai'i eruption will be taken from recorded observations conducted by USGS HVO geologist throughout the duration of the eruption. Analysis on the Hawai'i spatter samples show higher vesicle percentages in less dense clast taken from the more productive fissures, such as Child of 8, #9, and #24. The purpose for this data is to show relationships between the vesicles and the relative height of the fountains of the 5 mainland unrecorded eruptions and for better modeling of these sites for potential future eruptions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMV016.0011C
- Keywords:
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- 8499 General or miscellaneous;
- VOLCANOLOGY