Abstract

Ice Springs Volcanic Field, located in the Black Rock Desert west of Fillmore, Utah, is composed of three large craters, Crescent, Miter, and Terrace, and several smaller craters. Concern over the hazards of the volcanic field, ±660 years old, reactivating prompted the creation of a hazards model. This study focuses on Miter Crater in order to conduct a ballistic analysis of the blocks and bombs observed along the crater rim. Data analysis of Miter Crater ejecta was then used to create a hazards model for ballistic volcanic ejecta. Thirty-four blocks and bombs were recorded along the rim of Miter Crater. Teardrop, quot (cowpie), spheroidal, and ribbon bombs were recorded and sampled around the crater rim. All blocks sampled were massive basalts and were found in situ in the northeastern quadrant (the only undisturbed section of Miter Crater from quarrying). Data collected was then used to model possible trajectories and muzzle velocities for each block and bomb according to their respective recorded parameters in the program Eject!. The application of drag to large, dense blocks did little to change flight paths. With smaller blocks and bombs, the effect of drag on flight paths became increasingly dramatic at higher ejection angles. The eruptions involving these blocks and bombs likely experienced a relatively large zone of reduced drag and/or multiple collisions that aided in the transport of smaller ejecta. A hazards map was created that shows four zones of differing risk levels. Intuitively, the level of risk due to ejecta impact decreases as one heads away from the eruptive center. The extent of the largest zone reaches approximately 1300 m in diameter. A model was devised that used a polar plot to prove the risk trend shown in the hazards map. The model was also used to create ballistic curves for conditions of zero drag, constant drag, and zones of reduced drag.

Advisor

Judge, Shelley

Department

Geology

Disciplines

Cosmochemistry

Keywords

ballistic, volcanology, blocks, bombs, ice springs volcanic field, miter crater, black rock desert

Publication Date

2013

Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis Exemplar

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© Copyright 2013 William Cary