Seamount subduction and megathrust seismicity: the interplay between geometry and friction.

Abstract

<p>It has been widely recognized that the presence of seamounts can profoundly affect megathrust seismicity. With their outstanding topography, seamounts can tune interplate stress and favor the development of a fracture network in the overriding plate. Subducting seamounts can also control fluid accumulation and sediment porosity. However, their role as barriers or triggers for rupture propagation remains a matter of debate.</p> <p>In this work, we used analog models to study how geometric and frictional heterogeneities associated with a single subducting seamount influence the seismogenic behavior of the megathrust. We used four different model configurations (i.e., a flat interface, a high-friction and low-friction seamount, and a low-friction patch) to investigate both the combined and individual effect of geometry and friction.</p> <p>Our results show that low friction areas, either flat or with a seamount relief, reduce interplate coupling. Also the presence of a geometric feature tends to decrease seismic coupling and segment ruptures promoting earthquakes enucleation on the flat region. The maximum barrier efficiency is achieved with the low-friction patch model, where the accumulated stress is preferentially released by the occurrence of small earthquakes. This behavior is well suited to natural cases where seamounts are supposed to lower interplate friction due to fluid release or by the development of fracture systems development, causing microseismicity and slow slip events.</p>

Seamount Subduction and Megathrust Seismicity: The Interplay Between Geometry and Friction

“…Data produced in this study are available open access in Menichelli et al. (2023) (https://doi.org/10.5880/fidgeo.2022.047). This study has been financially supported by the EPOS Research Infrastructure through the contribution of the Italian Ministry of University and Research (MUR)‐EPOS ITALIA Joint Research Unit.…”

“…PIV Data and codes underlying this study are published open access in Menichelli, Corbi, Brizzi, van Rijsingen, Lallemand and Funiciello (2023), https://doi.org/10.5880/fidgeo.2022.047.…”