Crustal velocity field of southwest Japan: Subduction and arc‐arc collision

• DOI: 10.1029/2000jb900312
• Publication Date: 2004-02-03T23:27:57Z
• Authors: Shin'ichi Miyazaki; Kosuke Heki
• Keywords: Eurasian Plate; Trough (economics); Collision zone; Island arc; Slab; Pacific Plate

We investigate crustal deformation in southwest Japan over a 3‐year period revealed by permanent dense Global Positioning System (GPS) array. Southwest is part of the Amurian Plate, microplate moving about 10 mm/yr toward east with respect to Eurasian Plate. It overrides Philippine Sea Plate at Nankai Trough and collides northeast arc central Japan. In this paper we first derive GPS site velocities relative stable order isolate signals caused subduction and/or collision. The velocity field has conspicuous feature indicating interseismic elastic loading slab Trough, characterized northwestward movements points throughout studied area. Their amplitudes are largest Pacific coast decay subtle systematic shift azimuths. A model assuming an half‐space, convergence rate based on refined Euler vector, strength coupling inferred from thermal model, could explain western area large extent. Those eastern systematically deviate them, residual components there show east‐west shortening north‐south extension. This may represent thickening trenchward extrusion blocks collision between suggests that gives rise not only but also block. contrast was found across Median Tectonic Line, inland active fault Japan, current network enough for us discuss its depth.