GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.3 GNGTS 2023 Fig. 1. Map of the earthquakes in the northwestern Pacific subduction zone. Only events with M ≥ 3.0 are displayed, The labeled red lines depict depth contours of the upper boundary of the subducting slab. The seismic events in the light blue shaded box, as seen from N285° (arrow on the map), are reported in the vertical cross-section at the bottom. The black lines indicate the trace of the Kurile and Izu–Bonin vertical sections shown in Fig. 2. Fig. 2. Vertical sections for the Kurile and Izu–Bonin subduction zones, along the trench-parallel profiles reported in Figure 1. The lines indicate equal age from the start of subduction at the trench (Liu et al., 2017). Fig. 3. Conceptual sketch of the features observed in Kurile and Izu-Bonin subduction zones. The seismicity bands are drawn as gray stripes. The stress distribution with depth is schematically drawn along two cross sections for each subduction zone, where blue (red) tones shading depict the tensional (compressional) stress, with darker colors indicating larger absolute values. The Metastable Olivine Wedge (MOW) is marked by the black wedge-shaped line at about 410 km depth. The Izu–Bonin slab tear is also indicated (pink oval).