Warren, S. N., Watters, R. J., Tucker, D. S., (2006), Future Edifice Collapse as a Result of Active Hydrothermal Alteration and Geologic Structure at Mt. Baker, Washington, Eos Trans. AGU, 87(52), Fall Meet. Suppl., Abstract V53A-1746
Future Edifice Collapse as a Result of Active Hydrothermal Alteration and Geologic Structure at Mt. Baker, Washington
Hydrothermally argillic altered rocks are much weaker than their un-altered counterpart and progressive alteration deep within a volcano can lead to the catastrophic collapse of the edifice. This type of failure represents one of the most destructive and far-reaching natural hazards associated with volcanoes. Mapped Holocene debris flows containing hydrothermally altered rock in drainages around Mt. Baker and continuous hydrothermal activity in the Sherman Crater since 1975 suggest that Mt Baker is capable of producing a catastrophic collapse debris flow in the future. This research uses field data obtained from the Sherman Crater in August 2006 combined with laboratory testing and computer modeling to characterize the stability of Mt. Baker. Completed fieldwork includes the collection of in situ rock and clay samples and measurement of major discontinuities at three sites near the Sherman Crater. Additional laboratory work will include coring of rock samples to determine uniaxial and triaxial strength. Magnetic susceptibility data and previous detailed mapping of the Sherman Crater will supplement the data in order to construct a slope stability model of the upper portion of Mt. Baker. Modeling failures under different geologic uncertainties, groundwater pressure and seismic loading better constrain the possible size, direction, and run-out distances of a failure from the edifice. This information helps estimate the hazard and risk to residents and infrastructure in the vicinity.