Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia
Abstract In Cascadia, the concomitance of slow slip events (SSE) and tremors during Episodic Tremor and Slip (ETS) episodes is well documented. Brittle tremor patches embedded in the ductile matrix deforming aseismically is the most common concept for the fault structure, but whether tremors and the...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-04-01
|
| Series: | AGU Advances |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024AV001425 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850279304373469184 |
|---|---|
| author | Yuji Itoh Anne Socquet Mathilde Radiguet |
| author_facet | Yuji Itoh Anne Socquet Mathilde Radiguet |
| author_sort | Yuji Itoh |
| collection | DOAJ |
| description | Abstract In Cascadia, the concomitance of slow slip events (SSE) and tremors during Episodic Tremor and Slip (ETS) episodes is well documented. Brittle tremor patches embedded in the ductile matrix deforming aseismically is the most common concept for the fault structure, but whether tremors and their patches impact the SSE initiation is under debate. This study focuses on 13 initiations of major Cascadia ETS. Limited observational constraints exist on the details of ETS initiation because spatiotemporal SSE inversions usually over‐smooth their temporal evolution. Scrutinizing tremors and SSE at the beginning of major ETS events gives us insights into their mechanical relationship. We directly retrieve the temporal evolution of the SSE moment by stacking sub‐daily Global Positioning System (GPS) time series at multiple sites, without slip inversions. Comparison of the GPS stack with tremor count demonstrates that SSE moment release accelerates drastically ∼1 day after the onset of vigorous tremor activity. On the other hand, once the SSE moment release accelerates, the tremor area expands more rapidly, suggesting that the growth of the ETS occurs through a feedback mechanism between slip and tremor once the SSE is well developed. By combining these and previous observations, we propose a conceptual model of ETS initiation: heterogeneous interface strength limits the growth of SSE with unruptured tremor patches acting as relatively high‐strength pins contributing to this heterogeneity. In other words, major ETS emerges probably only when collective tremor patches are critically stressed. |
| format | Article |
| id | doaj-art-e098d049f5994789a92f3475deb66b0c |
| institution | OA Journals |
| issn | 2576-604X |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Wiley |
| record_format | Article |
| series | AGU Advances |
| spelling | doaj-art-e098d049f5994789a92f3475deb66b0c2025-08-20T01:49:07ZengWileyAGU Advances2576-604X2025-04-0162n/an/a10.1029/2024AV001425Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in CascadiaYuji Itoh0Anne Socquet1Mathilde Radiguet2Earthquake Research Institute The University of Tokyo Tokyo JapanUniversity Grenoble Alpes University Savoie Mont Blanc CNRS IRD University Gustave Eiffel Grenoble FranceUniversity Grenoble Alpes University Savoie Mont Blanc CNRS IRD University Gustave Eiffel Grenoble FranceAbstract In Cascadia, the concomitance of slow slip events (SSE) and tremors during Episodic Tremor and Slip (ETS) episodes is well documented. Brittle tremor patches embedded in the ductile matrix deforming aseismically is the most common concept for the fault structure, but whether tremors and their patches impact the SSE initiation is under debate. This study focuses on 13 initiations of major Cascadia ETS. Limited observational constraints exist on the details of ETS initiation because spatiotemporal SSE inversions usually over‐smooth their temporal evolution. Scrutinizing tremors and SSE at the beginning of major ETS events gives us insights into their mechanical relationship. We directly retrieve the temporal evolution of the SSE moment by stacking sub‐daily Global Positioning System (GPS) time series at multiple sites, without slip inversions. Comparison of the GPS stack with tremor count demonstrates that SSE moment release accelerates drastically ∼1 day after the onset of vigorous tremor activity. On the other hand, once the SSE moment release accelerates, the tremor area expands more rapidly, suggesting that the growth of the ETS occurs through a feedback mechanism between slip and tremor once the SSE is well developed. By combining these and previous observations, we propose a conceptual model of ETS initiation: heterogeneous interface strength limits the growth of SSE with unruptured tremor patches acting as relatively high‐strength pins contributing to this heterogeneity. In other words, major ETS emerges probably only when collective tremor patches are critically stressed.https://doi.org/10.1029/2024AV001425Episodic Tremor and Slipslow slip eventtremorCascadiaGNSS |
| spellingShingle | Yuji Itoh Anne Socquet Mathilde Radiguet Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia AGU Advances Episodic Tremor and Slip slow slip event tremor Cascadia GNSS |
| title | Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia |
| title_full | Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia |
| title_fullStr | Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia |
| title_full_unstemmed | Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia |
| title_short | Slip‐Tremor Interaction at the Very Beginning of Episodic Tremor and Slip in Cascadia |
| title_sort | slip tremor interaction at the very beginning of episodic tremor and slip in cascadia |
| topic | Episodic Tremor and Slip slow slip event tremor Cascadia GNSS |
| url | https://doi.org/10.1029/2024AV001425 |
| work_keys_str_mv | AT yujiitoh sliptremorinteractionattheverybeginningofepisodictremorandslipincascadia AT annesocquet sliptremorinteractionattheverybeginningofepisodictremorandslipincascadia AT mathilderadiguet sliptremorinteractionattheverybeginningofepisodictremorandslipincascadia |