The resistance of bathymetric highs to subduction results in large-scale morphological distortions of the outer-rise, trench, and fore-arc regions. Once subducted, bathymetric highs induce frictional segmentation along the plate interface that may result in increase or decrease of the plate coupling. However, the mechanics of the collision is inferred mostly from geophysical and geological surveys since earthquakes rarely illuminate finer details of the subduction of seafloor relief. A year-long and energetic seismic sequence at the Loyalty Ridge-Vanuatu Trench allowed us to characterize how strain is released along the collision zone. Earthquakes revealed complex fracturing in the outer-rise and fore-arc regions and segmentation of the interface with both limited magnitude events and aftershock productivity. The complex earthquake activity associated to the collision and subduction of the Loyalty Ridge appears to support a frictionally segmented interface where Mw≥8 megathrust earthquakes are unlikely to nucleate.
Bibliographical noteKAUST Repository Item: Exported on 2022-09-14
Acknowledged KAUST grant number(s): OSR-2016-CRG6-3027-01
Acknowledgements: The stimulating comments of two anonymous reviewers and the editor Lucy Flesch helped to improve the manuscript. This research was supported by King Abdullah University of Science and Technology (KAUST) under the award OSR-2016-CRG6-3027-01. LP acknowledge funds from the project DEEP-GEOTHERMICA.
ASJC Scopus subject areas
- General Earth and Planetary Sciences