Fig. 2

a Fault model and relocated 24 h aftershock distribution (orange circles) for the 2021 Fukushima-oki earthquake. b–e Their cross-sections along lines AA′, BB′, and CC′ for subregions 21a, 21b, 21c, and 21d in Panel a. f Fault model and relocated 24 h aftershock distribution (red circles) for the 2022 Fukushima-oki earthquake. g–j Their cross-sections along the lines DD′, EE′, and FF′ for subregions 22a, 22b, 22c, and 22d in Panel f. The orange and red stars indicate the relocated epicenters of the 2021 and 2022 the mainshocks, respectively. The blue meshes and lines show the fault models. For each cross-section, the viewing direction is displayed at the lower right corner. Gray-white and red-white focal mechanisms represent the first motion solution by JMA and moment tensor solutions from the F-net catalog, respectively. The gray broken lines in Panel a denote the plate boundary depths as in Fig. 1. The shapes of the plate boundary along the lines in Panels a and f are shown in the cross-sections. The gray dotted lines represent the surface at a depth of 8.4 km from the plate boundary, which corresponds to the typical thickness of the oceanic crust of the Pacific plate in the JIVSM model. The pink lines show the same depth limit as in Fig. 1