Fig. 3: Background seismicity and back-projection images.
From: Two-stage rupture during the Mw 8.3 Okhotsk 2013 deep-focus earthquake constrains slab geometry
a Seismicity in Okhotsk. Red line AA’ and BB’ represent the position of the cross-section in (c) and (d). The colored contours are projections of the back-projected normalized energy at a threshold of 0.25. The grey and white dots (50 km away from line AA’ or line BB’) are from Kamchatka catalog33. The light blue contours are slab model 2.012. The thick blue line is the plate boundary70. b Zoom of (a). Blue arrows indicate the direction of rupture propagation, and ☉ denotes vertical downward propagation. c, d Cross-section view of Okhotsk along line AA’ and line BB’ in (a). The white dots are earthquakes 50 km from line AA’ or line BB’. The colored contours are projections of the back-projected normalized energy stage 1 and stage 2 on the cross-section AA’ and BB’, respectively. The basemap is the tomography model32. The dark red line is the contour of dVp/Vp = 1%. The brown dotted lines are the modified slab model boundary (The white hollow part below indicates that the boundary is not very certain). The grey shaded areas are the MOW inferred based on seismicity.
