Subslab heterogeneity and giant megathrust earthquakes

Jianke Fan, Dapeng Zhao

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

The nucleation and rupture processes of giant megathrust earthquakes (M ≥ 9.0) in subduction zones are still controversial. Most previous studies have focused on the subducting plate interface, and the structure beneath the subducting slab and its influence on earthquake generation remain unclear. Here, we present high-resolution seismic velocity tomography beneath six regions where giant earthquakes have occurred. Subslab low-velocity (slow) anomalies are revealed, which may reflect hot mantle upwelling. The giant earthquake hypocentres are generally located above the edges of the slow anomalies or above the gaps between them. Large coseismic slips of the giant earthquakes mainly occurred above gaps between the slow anomalies. We suggest that differential buoyancy force between the slow anomalies and their gaps may be an important factor for earthquake nucleation, and the rupture extent of a giant earthquake may be constrained by the slow anomalies. Hence, it is necessary to conduct seismic tomography to investigate the detailed subslab structure, which may help to pinpoint the potential location and damage zone of a future giant earthquake.

Original languageEnglish
Pages (from-to)349-353
Number of pages5
JournalNature Geoscience
Volume14
Issue number5
DOIs
Publication statusPublished - 2021 May

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