Fault Network Geometry's Control on Earthquake Rupture Behavior
Description:
While fault slip behavior has been predominantly attributed to local fault plane properties such as frictional parameters and roughness, the role of larger scale fault geometry has remained relatively unexplored. Emerging observations highlight the importance of fault system geometry in the mechanics governing earthquake rupture processes. Drawing from compiled observations, we study how the geometrical complexities of fault networks impact various aspects of fault slip behavior, including how these complexities affect fault creep and earthquake source spectra. We quantify fault network complexity by measuring the degree of surface fault trace misalignment and the local variability of earthquake focal mechanisms. We investigate the relationships between metrics of fault complexity and surface creep rates, earthquake corner frequencies, and earthquake moment rate function complexity, demonstrating that complex fault networks suppress fault creep, lead to higher earthquake corner frequencies, and introduce complexities in the moment rate functions. We interpret these observations as a consequence of geometric locking, which inhibits fault creep, and the elastic loading and unloading of discrete fault structures, which leads to enhanced high-frequency seismic radiation. Our study is based on a dataset of diverse geophysical parameters gathered from California, supplemented by measurements from Japan, central Italy, and worldwide. The observations from independent sources, spanning different scales and geological regions, consistently support our hypothesis that complex fault systems contribute significantly to complex earthquake ruptures. Our findings demonstrate the potential for a new framework in which earthquake rupture behavior is governed primarily by fault network geometry.
Session: Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales [Poster Session]
Type: Poster
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Jaeseok
Student Presenter: Yes
Invited Presentation:
Authors
Jaeseok Lee Presenting Author jaeseok_lee@brown.edu Brown University |
Victor Tsai Corresponding Author victor_tsai@brown.edu Brown University |
Greg Hirth greg_hirth@brown.edu Brown University |
Daniel Trugman dtrugman@unr.edu University of Nevada, Reno |
Avigyan Chatterjee achatterjee@unr.edu University of Nevada, Reno |
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Fault Network Geometry's Control on Earthquake Rupture Behavior
Category
Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales