Fig. 1: Location and structure of the JFAST core.

a Map of the Japan Trench with the JFAST and Site 436 sites identified by red dots. White dotted contours indicate regions of equal slip during the Tohoku-Oki earthquake as inferred by geophysical data12,13,14,15. b Schematic structure of the accretionary prism perpendicular to the trench recovered at JFAST traced over a seismic section16, and c close-up of the schematic JFAST stratigraphy with interpreted structure17, 18 and pictures of typical structures from regions of the core where damage has been observed.