Fig. 1: Present-day plate kinematic setting and mantle structure of the western Pacific subduction zone.
From: Non-collisional orogeny in northeast Japan driven by nearby same-dip double subduction
a, Map indicating the major tectonic plates in the study area, subduction isodepths57, absolute trench and upper plate kinematics40, the location of northeast Japan and the Japan Sea, and the Ryukyu–Nankai/Izu–Bonin–Marianas SDDS system. Negative and positive trench velocity values corresponds to trench advance and retreat, respectively. b, A composite structural cross-section from the northeast Japan arc29 to the back-arc region up to the eastern Korean margin28 (location shown in a). c Seismic tomography sections59 showing the mantle structure and slab seismicity associated with the northeastern Japan subduction and the Ryukyu/Izu–Bonin–Marianas SDDS system. EUR, Eurasian plate; AP, Amurian plate; PSP, Philippine Sea plate; PAC, Pacific plate; OP, Okhotsk plate; HI, Hokkaido Island; SI, Sakhalin Island; NEJ, northeastern Japan; SW, southwest Japan; JS, Japan Sea; R, Ryukyu trench; N, Nankai trench; IB, Izu–Bonin subduction segment; M, Marianas subduction segment; SVPB, extinct Shikoku–Parece–Vela back-arc basin; δVp (%), percent perturbation (or deviation) of P-wave velocity relative to a reference Earth model.
