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Published June 28, 2019 | Published + Supplemental Material
Journal Article Open

Rate-and-state Model Casts New Insight into Episodic Tremor and Slow‐slip Variability in Cascadia


Advances in geodetic and seismic observations have led to the discovery of Episodic Tremor and Slow‐slip (ETS). ETS in Cascadia subduction zone occurs semiregularly and shows intriguing spatio‐temporal variability reportedly associated with frictional properties and stress conditions. Yet the origin of complex ETS behaviors remains largely unknown. Here we develop a laboratory‐based rate‐and‐state asperity‐in‐matrix subduction fault model, supported by geological observations of exhumed fault with heterogeneous frictional properties and pore pressure variation, to reproduce all ETS variability in good agreement with observations. Our results show that differential pore pressure plays a crucial role in affecting fault behaviors. Regions of asperities with decreased pore pressure tend to have increased tremor. Our study suggests that ETS variability can be used to probe otherwise enigmatic fault zone properties.

Additional Information

© 2019 American Geophysical Union. Received 4 MAR 2019; Accepted 20 MAY 2019; Accepted article online 28 MAY 2019; Published online 17 JUN 2019. This work was carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The authors declare that they have no competing interests. The tremor catalog used in this study and more detailed information is publicly available on PNSN website (https://pnsn.org). The rate‐and‐state earthquake simulator we used is available at the GitHub (https://github.com/ydluo/qdyn). Other materials in this study are available upon request.

Attached Files

Published - Luo_et_al-2019-Geophysical_Research_Letters.pdf

Supplemental Material - grl59090-sup-0001-2019gl082694-s01.docx

Supplemental Material - grl59090-sup-0002-2019gl082694-s02.docx


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August 19, 2023
October 20, 2023