Global seismic energy release of large megathrust earthquakes since 1900: insights from the revised SubQuake catalog and seismic coupling along subduction zones

Subduction zone interfaces (SZI) release 72% of the seismic energy worldwide. Building on the original SubQuake catalog, we present an updated and revised compilation of SZI earthquakes, with Mw³7.5 from 1900 to 2025. This new version, SubQuake 2 (SQ2), is constructed using a semi-automatic selection procedure combining focal mechanisms, slab geometry, and hypocentral uncertainties, followed by systematic validation against the literature. For most SQ2 events, we associate a preferred rupture model. Using this dataset, we reassess empirical scaling laws relating earthquake magnitude to rupture area, length and width, confirming previously established relationships for subduction environments. We then build a global map of rupture areas which highlights the spatial distribution of seismic energy released along all active margins. We find that two-thirds of the total length of active margins has never been ruptured by Mw³7.5 interface event over the past 126 years, while the North Pacific, Andes and Sumatra SZI dominate global seismic energy release. Using kinematic and geometric parameters of the seismogenic zone from the open-access Submap database, we estimate a first-order seismic coupling coefficient by comparing the observed energy released with that expected under full interplate coupling. We discuss the significance and limitations of seismic coupling estimates derived from SQ2 by comparing them with coupling inferred from geodetic observations and from paleoseismic records spanning thousands of years, using the Nankai and Cascadia subduction zones as illustrative examples. Our results highlight the importance of compiling comprehensive paleoseismic catalogs wherever possible to better assess the risk of major earthquakes.