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Title: Dynamic Analysis of a Large Freestanding Rock Tower (Castleton Tower, Utah)
Abstract We acquired a unique ambient vibration dataset from Castleton Tower, a 120 m high bedrock monolith located near Moab, Utah, to resolve dynamic and material properties of the landform. We identified the first two resonant modes at 0.8 and 1.0 Hz, which consist of mutually perpendicular, linearly polarized horizontal ground motion at the top of the tower. Damping ratios for these modes were low at ∼1%. We successfully reproduced field data in 3D numerical eigenfrequency simulation implementing a Young’s modulus of 7 GPa, a value ∼30% lower than measured on core samples. Our analysis confirms that modal deformation at the first resonant frequencies closely resembles that of a cantilever beam. The outcome is that with basic estimates of geometry and material properties, the resonant frequencies of other freestanding rock monoliths can be estimated a priori. Such estimates are crucial to evaluate the response of rock towers to external vibration inputs.  more » « less
Award ID(s):
1831283
PAR ID:
10167153
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Bulletin of the Seismological Society of America
Volume:
109
Issue:
5
ISSN:
0037-1106
Page Range / eLocation ID:
2125 to 2131
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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