Detecting low frequency earthquakes within deep tectonic tremor
Abstract/Contents
- Abstract
- Prior to analyzing any earthquake, the event must be detected. Although fundamental, earthquake detection remains a challenging task- particularly for small-magnitude events where the amplitudes of the signal of interest approach the noise level of the recording instrument. In particular, high precision event detection is important with regard to analyzing tectonic tremor, formerly referred to as non-volcanic tremor. Tectonic tremor is a non-impulsive, low-amplitude, semi-continuous seismic signal whose time series is similar to volcanic tremor. Despite the time series similarity to volcanic tremor, tectonic tremor is often recorded at plate boundaries- mostly convergent boundaries at subduction zones- away from volcanic centers. Unlike large earthquakes where seismic signals are impulsive with high amplitudes and a finite duration, tectonic tremor is emergent, semi-continuous and low amplitude causing tremor locations to have large errors. In southwest Japan tectonic tremor has been shown to consist of several repeating low frequency earthquakes indicating shear failure on the subduction plate interface that occur during several days, however these events are difficult to detect due to their low amplitude approaching the noise level. In this thesis I demonstrate two methods to identify periods of waveform similarity during the tremor and show that these similar events are low frequency earthquake swarms located on the deep extent of four plate boundaries: southwest Japan, Cascadia, Costa Rica, and the Alaska-Aleutian subduction zones. Although each subduction zone has a different incoming plate rate, age and thermal profile, these factors do not exhibit a strong influence on tremor occurrence indicating tremor may occur in almost- if not all subduction zones.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Brown, Justin Ross |
|---|---|
| Associated with | Stanford University, Department of Geophysics |
| Primary advisor | Beroza, Gregory C. (Gregory Christian) |
| Thesis advisor | Beroza, Gregory C. (Gregory Christian) |
| Thesis advisor | Lawrence, Jesse |
| Thesis advisor | Segall, Paul, 1954- |
| Thesis advisor | Sleep, Norman H |
| Advisor | Lawrence, Jesse |
| Advisor | Segall, Paul, 1954- |
| Advisor | Sleep, Norman H |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Justin R. Brown. |
|---|---|
| Note | Submitted to the Department of Geophysics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Justin Ross Brown
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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