The Search for Time-dependent Coupling Changes in Southern Cascadia
Description:
Estimates of earthquake hazards in subduction zones are heavily dependent on models of interseismic coupling on the megathrust. Recent studies have challenged the long-held assumption that fault coupling on the megathrust remains constant during the interseismic period. In particular, Materna et al. (2019) proposed that dynamically triggered increases and decreases in plate coupling could occur due to regional earthquakes. This study aims to investigate and detect these time-dependent changes in plate interface coupling in southern Cascadia by employing a semi-automated method to reproduce previous findings and explore additional earthquake events. Our analysis focuses on the dynamic stressing from medium to large regional earthquakes in Cascadia and their potential to induce coupling changes on the subduction plate interface, especially updip from the Episodic Tremor and Slip (ETS) zone. We observe localized coupling changes coinciding with the -30km depth contour around 40.3°N and prominently offshore along the -10km contour along the Cascadia margin. These observations suggest potential connections between earthquake-induced stress changes and the geometry of the plate interface. The roles of plate interface geometry and fluid transport from the ETS zones in triggering substantial temporal variations in interseismic coupling are also examined.
A better understanding of when and where dynamically triggered coupling changes occur could improve the accuracy of time-dependent earthquake hazard forecasts in the future. Additionally, we are extending our investigation to Chile to identify if similar phenomena occur in that region as indicated in the past literature. This work will provide valuable insights for future research on the temporal variability of fault coupling and its implications for seismic hazard assessment in subduction zone settings.
Session: Predictability of Seismic and Aseismic Slip: From Basic Science to Operational Forecasts - I
Type: Oral
Date: 4/16/2025
Presentation Time: 05:00 PM (local time)
Presenting Author: Angikar
Student Presenter: Yes
Invited Presentation:
Poster Number:
Authors
Angikar Roy Presenting Author Corresponding Author a.roy@ku.edu University of Kansas |
Noel Jackson nmjackson@ku.edu University of Kansas |
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The Search for Time-dependent Coupling Changes in Southern Cascadia
Session
Predictability of Seismic and Aseismic Slip: From Basic Science to Operational Forecasts