Frictional-faulting model for harmonic tremor before Redoubt Volcano eruptions
Nature Geoscience
By: Ksenia Dmitrieva, Alicia J. Hotovec-Ellis, Stephanie G. Prejean, and Eric M. Dunham
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Abstract
Seismic unrest, indicative of subsurface magma transport and pressure changes within fluid-filled cracks and conduits, often precedes volcanic eruptions. An intriguing form of volcano seismicity is harmonic tremor, that is, sustained vibrations in the range of 0.5–5 Hz. Many source processes can generate harmonic tremor. Harmonic tremor in the 2009 eruption of Redoubt Volcano, Alaska, has been linked to repeating earthquakes of magnitudes around 0.5–1.5 that occur a few kilometres beneath the vent. Before many explosions in that eruption, these small earthquakes occurred in such rapid succession—up to 30 events per second—that distinct seismic wave arrivals blurred into continuous, high-frequency tremor. Tremor abruptly ceased about 30 s before the explosions. Here we introduce a frictional-faulting model to evaluate the credibility and implications of this tremor mechanism. We find that the fault stressing rates rise to values ten orders of magnitude higher than in typical tectonic settings. At that point, inertial effects stabilize fault sliding and the earthquakes cease. Our model of the Redoubt Volcano observations implies that the onset of volcanic explosions is preceded by active deformation and extreme stressing within a localized region of the volcano conduit, at a depth of several kilometres.
Suggested Citation
Dmitrieva, K., Hotovec-Ellis, A.J., Prejean, S.G., Dunham, E.M., 2013, Frictional-faulting model for harmonic tremor before Redoubt Volcano eruptions: Nature Geoscience, v. 6, no. 8, p. 652-656, https://doi.org/10.1038/ngeo1879.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Frictional-faulting model for harmonic tremor before Redoubt Volcano eruptions |
| Series title | Nature Geoscience |
| DOI | 10.1038/ngeo1879 |
| Volume | 6 |
| Issue | 8 |
| Publication Date | July 14, 2013 |
| Year Published | 2013 |
| Language | English |
| Publisher | Nature Publishing Group |
| Contributing office(s) | Alaska Volcano Observatory |
| Description | 5 p. |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Nature Geoscience |
| First page | 652 |
| Last page | 656 |
| Country | United States |
| State | Alaska |
| Other Geospatial | Redoubt Volcano |