Comparison between (left) Q
-1and (right) P -wave velocity. Vertical cross-sections along the lines (a) A, (b) B, (c) C, (d) D, and (e) E in the inset map are shown. Solid lines indicate the upper surfaces of the Philippine Sea and Pacific slabs, and dashed lines denote the Moho for the continental plate and Philippine Sea and Pacific slabs. Black bars and red triangles on the top of each panel denote the land area and volcanoes, respectively. White stars and gray dots represent small repeating earthquakes and other earthquakes, respectively, that occurred within 5 km from each line. Earthquakes (M ≥ 2) that occurred from 2001 to 2012 are represented by gray dots. The P-wave velocity model is reproduced from Nakajima and Hasegawa (2010).