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The origin of harmonic tremor at Old Faithful geyser


Kedar, Sharon (1996) The origin of harmonic tremor at Old Faithful geyser. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/X1RD-ZV73.


Volcanic tremor, the seismic signal which is often associated with eruptions, is among the least understood phenomena in seismology. Large variations in the physical properties of volcanic rocks and fluids along with the complex geological structure make it difficult to obtain reliable source models. Old Faithful geyser, Yellowstone National Park, was chosen as a laboratory for studying fluid-flow-induced seismicity. The geyser's cyclic behavior on an hourly time scale, and its accessibility, make it suitable for a detailed study of seismic behavior between eruptions simultaneously with underwater pressure measurements inside the geyser.

We observe that sharp pressure pulses inside the water-column attributed to steam bubble collapse are followed by distinct seismic events, with a sharp onset and a harmonic horizontal motion whose frequency varies spatially but not temporally. A superposition of these events creates the appearance of continuous harmonic tremor. Since the pressure in the water column exhibits no sign of resonance, the harmonic motion must be caused by elastic waves reverberating in the solid medium. A near-surface soft layer is demonstrated to be a possible elastic model.

The harmonic tremor observed at Old faithful seems analogous to some examples of shallow volcanic tremor.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:harmonic tremor ; Old Faithful geyser
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Unknown, Unknown
Thesis Committee:
  • Unknown, Unknown
Defense Date:5 June 1996
Record Number:CaltechETD:etd-01262009-133713
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:360
Deposited By: Imported from ETD-db
Deposited On:26 Jan 2009
Last Modified:20 Dec 2019 19:18

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