The hazard of coseismic gaps: The 2021 Fukushima earthquake

Subduction zones are associated with significant seismic hazards around the world and determining the future locations of large earthquakes within these systems is a perpetual challenge of the Earth sciences. This study presents back-projection results from the 2021 Mw 7.1 Fukushima earthquake which show that the rupture area of this event filled a previously identified coseismic gap within the rupture area of the 2011 Mw 9.1 Tohoku-oki earthquake. These results, combined with observations of a similar coseismic gap from the 2010 Mw 8.8 Maule, Chile earthquake that was subsequently filled by a Mw 7.1 aftershock, demonstrate that future assessments of seismic hazards following giant earthquakes should include the identification of coseismic gaps left within main shock rupture areas.