Seismological constraints on the mechanisms of intermediate-depth earthquakes in Japan
Abstract/Contents
- Abstract
- Intermediate-depth earthquakes (around 70-300 km deep within plates) appear to occur at temperatures and pressures which would prohibit the frictional failure mechanisms proposed for shallow earthquakes. Understanding the mechanisms by which they occur would contribute greatly to understanding the hazards they pose, which are non-trivial given the existence of historically large and damaging events at these depths. Traditionally, the mechanisms favored to explain intermediate-depth earthquakes have fallen into two camps: dehydration embrittlement, a brittle mechanism, and thermal shear runaway, a ductile mechanism. However, wide variability in the source properties of intermediate-depth earthquakes worldwide suggest that the mechanisms causing these events may be complex and furthermore, may vary depending on geographic setting. In this thesis, I examine intermediate-depth earthquakes from Japan, where intermediate-depth earthquakes occur within two subducting slabs, one of which is warmer and younger than the other. This setting offers a way to directly compare the source properties of intermediate-depth earthquakes in differential slab settings. I approach the data through source parameter scaling arguments, seismicity pattern analysis, and finally I use a simple model to examine the dynamics of a single large event occurring within the colder slab. My findings suggest a spectrum of mechanisms may be at work in generating intermediate-depth earthquakes, and that brittle and viscous processes may both be present in varying degrees, in some ways dependent on the properties such as age and temperature of the slab, in generating intermediate-depth earthquakes. This thesis is thus unique in directly comparing properties of two populations of intermediate-depth earthquakes, and in approaching previously little-examined aspects of intermediate-depth earthquakes, such as their aftershock productivity and dynamic rupture properties.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Chu, Shanna |
|---|---|
| Degree supervisor | Beroza, Gregory C. (Gregory Christian) |
| Thesis advisor | Beroza, Gregory C. (Gregory Christian) |
| Thesis advisor | Dunham, Eric |
| Thesis advisor | Ellsworth, William L |
| Degree committee member | Dunham, Eric |
| Degree committee member | Ellsworth, William L |
| Associated with | Stanford University, Department of Geophysics |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Shanna Chu. |
|---|---|
| Note | Submitted to the Department of Geophysics. |
| Thesis | Thesis Ph.D. Stanford University 2020. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Shanna Chu
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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